Becket, In your scenario with one message from producer A and one message from producer B, those are two different messages, and they should be tracked as two different messages. So I would argue for using record CRC -- CRC that is actually used by the system + it will not require computing a different CRC again which will add performance overhead.
If the broker ever changes the CRC, the scenarios when that happens should be very well defined. As far as I know, the scenarios when CRC is overwritten by the broker (including KIP-31/32 changes): -- topic config is LogAppendTime for timestamp type -- upgrade/downgrade -- compression codec change (which could be inferred from config). Monitoring/audit just needs to know when CRCs are safe to use, which is most often is known from config. In the future, this can be further addressed by broker interceptors. Thanks, Anna On Fri, Jan 29, 2016 at 11:30 AM, Becket Qin <becket....@gmail.com> wrote: > Neha, > > CRC is definitely an important type of metadata of a record. I am not > arguing about that. But I think we should distinguish between two types of > checksum here, 1) the checksum of user data. and 2) the checksum including > system appended bytes. > > I completely agree that (1) is good to add. But I am not sure if we should > expose (2) to user, because this means any underlying protocol change will > give a different CRC for exact same message. For example, let's say > producer A is sending message with timestamp. Producer B is sending message > without timestamp. Even they are given the exact same message, the CRC > returned would be different. > > Also, Kafka broker will modify the system appended bytes in different > scenarios, such as compression codec change, message format > conversion(After KIP-31 and KIP-32). > > So my concern is that we are exposing CRC which including system appended > bytes to user. > > Other than this I think everything looks good. Nice work, Anna. > > Thanks, > > Jiangjie (Becket) Qin > > On Fri, Jan 29, 2016 at 8:11 AM, Joel Koshy <jjkosh...@gmail.com> wrote: > > > Responding to some of the earlier comments in the thread: > > > > @Jay/@Neha, > > > > I think any one of onCommit/onAppend/onArrival would work for the > concrete > > use-case that I had outlined. I think onArrival is additionally useful > for > > custom validation - i.e., reject the message and do not append if it > > violates some cluster-specific rule (for e.g., if some header timestamp > is > > older than xyz). However, the thing with user-supplied validation is we > > would have to do with a (new) generic error code in the producer > response. > > While there is a risk of a broker interceptor having high latency I think > > that is acceptable since it is the user's responsibility to ensure low > > latency - the producer call-back and onAcknowledgment interceptor are > > similar in this regard although those are less risky. Even so, I think > > there are clear use-cases for broker interceptors so I feel the risk part > > is something that just needs to be documented. @Jay that is a good point > > about moving from Message/MessageSet to Records although that may be less > > difficult to absorb since it is a broker-side interceptor and so people > > don't need to get a ton of applications in their company to switch to use > > it. > > > > Re: onEnqueued: monitoring serialization latency can be done via metrics > > but this is more useful for recording whether serialization succeeded or > > not. onAcknowledgment subsumes this but it also subsumes other possible > > errors (such as produce errors). It is more fine-grained than most people > > need though (i.e., I don't think we will use it even if it is present.) > > > > Re: checksums: I think it is a good addition to metadata; and for > > low-volume or super-critical topics can be used for very strict auditing. > > > > There are a couple of typos/edits for the wiki itself: > > > > - Under Kafka Producer changes: > > - you have references to KafkaConsumer constructor and > > ConsumerConfig.originals. > > - sendRecord -> sentRecord (may be clearer) > > - Under ProducerInterceptor interface: there is a mention of > onEnqueued > > which was rejected > > - Comment for ConsumerRecord.record should probably be: // NEW: record > > size in bytes (*after decompression*) > > > > > > BTW - Anna, nice work on the KIP! > > > > Joel > > > > On Fri, Jan 29, 2016 at 6:57 AM, Neha Narkhede <n...@confluent.io> > wrote: > > > > > Becket, > > > > > > Is your concern the presence of CRC in the RecordMetadata or do you > want > > to > > > brainstorm how CRC can be used for auditing? I think we shouldn't try > to > > > think about the various ways that people can do monitoring using > > > interceptors and the metadata we provide. The entire point of having > > > pluggable interceptors is so that people can employ their own creative > > > mechanisms to make use of interceptors. > > > > > > I do think that it is worth discussing whether or not CRC makes sense > as > > > record metadata to the user. My take is that the CRC is the best > > size-bound > > > summary of serialized record content available to us which is expensive > > to > > > recompute if the user were to redo it. I'd argue this summary of a > record > > > qualifies as its metadata. After all, we use the record CRC for a very > > > important test of the system durability as it travels through the > system. > > > > > > 1. Isn't the TopicPartition + Offset already uniquely identified a > > message? > > > > It seems better than CRC no matter from summary point of view or > > auditing > > > > point of view. > > > > > > > > > The offset is a system-assigned value of uniqueness to the message. If > > you > > > trusted the system that much, you are not looking to monitor it > > out-of-band > > > :-) > > > > > > > > > > 2. Currently CRC only has 4 bytes. So it will have collision when > there > > > are > > > > more than ~4 billion messages. Take LinkedIn as an example, we have > 1.3 > > > > trillion messages per day. So there will be at least a couple of > > hundreds > > > > collision for each CRC code every day, whereas TopicPartition+Offset > > will > > > > not have any collision. > > > > > > > > > The CRC isn't sent over the wire and doesn't add any extra overhead in > > > processing, so what is your concern? If you aren't convinced about its > > > usefulness, you can always use the default do-nothing interceptor at > > > LinkedIn and ignore the CRC. > > > > > > Without having > > > > the entire message bytes, they may not be able to verify its > > correctness, > > > > and the CRC could even be invalid if the broker ever overwritten any > > > field > > > > or did format conversion. > > > > > > > > > > This doesn't make sense to me. The CRC is used for the most important > > > durability check by Kafka - to verify that the message was not garbled > > over > > > the wire. The system can't change it; it has to match on the consumer > > side > > > or we will not return it to the user. > > > > > > On Fri, Jan 29, 2016 at 3:23 AM, Becket Qin <becket....@gmail.com> > > wrote: > > > > > > > Anna, > > > > > > > > It is still not clear to me why we should expose CRC to end user. > > > > Followings are my confusions. > > > > > > > > 1. Isn't the TopicPartition + Offset already uniquely identified a > > > message? > > > > It seems better than CRC no matter from summary point of view or > > auditing > > > > point of view. > > > > > > > > 2. Currently CRC only has 4 bytes. So it will have collision when > there > > > are > > > > more than ~4 billion messages. Take LinkedIn as an example, we have > 1.3 > > > > trillion messages per day. So there will be at least a couple of > > hundreds > > > > collision for each CRC code every day, whereas TopicPartition+Offset > > will > > > > not have any collision. > > > > > > > > 3. CRC is calculated after all the fields have been filled in by > > > producer, > > > > including timestamp, attributes, etc. It might also get recomputed on > > > > broker side. So if users only get CRC from record metadata. Without > > > having > > > > the entire message bytes, they may not be able to verify its > > correctness, > > > > and the CRC could even be invalid if the broker ever overwritten any > > > field > > > > or did format conversion. > > > > > > > > Thanks, > > > > > > > > Jiangjie (Becket) Qin > > > > > > > > > > > > > > > > > > > > On Thu, Jan 28, 2016 at 5:58 PM, Anna Povzner <a...@confluent.io> > > wrote: > > > > > > > > > On a second thought, yes, I think we should expose record size that > > > > > represents application bytes. This is Becket's option #1. > > > > > > > > > > I updated the KIP wiki with new fields in RecordMetadata and > > > > > ConsumerRecord. > > > > > > > > > > I would like to start a voting thread tomorrow if there are no > > > objections > > > > > or more things to discuss. > > > > > > > > > > Thanks, > > > > > Anna > > > > > > > > > > > > > > > > > > > > On Thu, Jan 28, 2016 at 2:25 PM, Anna Povzner <a...@confluent.io> > > > wrote: > > > > > > > > > > > Regarding record size as bytes sent over the wire, my concern is > > that > > > > it > > > > > > is almost impossible to calculate per-record. We could do as: 1) > > > > > compressed > > > > > > bytes / number of records in a compressed message, as Todd > > mentioned; > > > > or > > > > > 2) > > > > > > or same as #1 but take it proportional to uncompressed record > size > > > vs. > > > > > > total uncompressed size of records. All of these calculations > give > > us > > > > an > > > > > > estimate. So maybe record size as bytes sent over the wire is > not a > > > > > > per-record metadata, but rather per topic/partition measure that > is > > > > > better > > > > > > to be exposed through metrics? > > > > > > > > > > > > > > > > > > On Thu, Jan 28, 2016 at 2:09 PM, Todd Palino <tpal...@gmail.com> > > > > wrote: > > > > > > > > > > > >> It may be difficult (or nearly impossible) to get actual > > compressed > > > > > bytes > > > > > >> for a message from a compressed batch, but I do think it’s > useful > > > > > >> information to have available for the very reason noted, > bandwidth > > > > > >> consumed. Does it make sense to have an interceptor at the batch > > > level > > > > > >> that > > > > > >> can provide this? The other option is to estimate it (such as > > making > > > > an > > > > > >> assumption that the messages in a batch are equal in size, which > > is > > > > not > > > > > >> necessarily true), which is probably not the right answer. > > > > > >> > > > > > >> -Todd > > > > > >> > > > > > >> > > > > > >> On Thu, Jan 28, 2016 at 1:48 PM, Anna Povzner < > a...@confluent.io> > > > > > wrote: > > > > > >> > > > > > >> > Hi Becket, > > > > > >> > > > > > > >> > It will be up to the interceptor to implement their audit or > > > > > monitoring > > > > > >> > strategy. I would also imagine there is more than one good way > > to > > > do > > > > > >> audit. > > > > > >> > So, I agree that some of the interceptors may not use CRC, and > > we > > > > will > > > > > >> not > > > > > >> > require it. The question is now whether intercepting CRCs is > > > > needed. I > > > > > >> > think they are very useful for monitoring and audit, because > CRC > > > > > >> provides > > > > > >> > an a easy way to get a summary of a message, rather than using > > > > message > > > > > >> > bytes or key/value objects. > > > > > >> > > > > > > >> > Regarding record size, I agree that bandwidth example was not > a > > > good > > > > > >> one. I > > > > > >> > think it would be hard to get actual bytes sent over the wire > > > (your > > > > > #2), > > > > > >> > since multiple records get compressed together and we would > need > > > to > > > > > >> decide > > > > > >> > which bytes to account to which record. So I am inclined to > only > > > do > > > > > your > > > > > >> > #1. However, it still makes more sense to me just to return > > record > > > > > size > > > > > >> > including the header, since this is the actual record size. > > > > > >> > > > > > > >> > Thanks, > > > > > >> > Anna > > > > > >> > > > > > > >> > On Thu, Jan 28, 2016 at 11:46 AM, Becket Qin < > > > becket....@gmail.com> > > > > > >> wrote: > > > > > >> > > > > > > >> > > Anna, > > > > > >> > > > > > > > >> > > Using CRC to do end2end auditing might be very costly > because > > > you > > > > > will > > > > > >> > need > > > > > >> > > to collect all the CRC from both producer and consumer. And > it > > > is > > > > > >> based > > > > > >> > on > > > > > >> > > the assumption that broker does not modify the record. > > > > > >> > > Can you shed some idea on how end to end auditing will be > > using > > > > the > > > > > >> CRC > > > > > >> > > before we decide to expose such low level detail to the end > > > user? > > > > It > > > > > >> > would > > > > > >> > > also be helpful if you can compare it with something like > > > sequence > > > > > >> number > > > > > >> > > based auditing. > > > > > >> > > > > > > > >> > > About the record size, one thing worth notice is that the > size > > > of > > > > > >> Record > > > > > >> > is > > > > > >> > > not the actual bytes sent over the wire if we use > compression. > > > So > > > > > that > > > > > >> > does > > > > > >> > > not really tell user how much bandwidth they are using. > > > > Personally I > > > > > >> > think > > > > > >> > > two kinds of size may be useful. > > > > > >> > > 1. The record size after serialization, i.e. application > > bytes. > > > > (The > > > > > >> > > uncompressed record size can be easily derived as well) > > > > > >> > > 2. The actual bytes sent over the wire. > > > > > >> > > We can get (1) easily, but (2) is difficult to get at Record > > > level > > > > > >> when > > > > > >> > we > > > > > >> > > use compression. > > > > > >> > > > > > > > >> > > Thanks, > > > > > >> > > > > > > > >> > > Jiangjie (Becket) Qin > > > > > >> > > > > > > > >> > > On Thu, Jan 28, 2016 at 10:55 AM, Anna Povzner < > > > a...@confluent.io > > > > > > > > > > >> > wrote: > > > > > >> > > > > > > > >> > > > Hi Becket, > > > > > >> > > > > > > > > >> > > > The use-case for CRC is end-to-end audit, rather than > > checking > > > > > >> whether > > > > > >> > a > > > > > >> > > > single message is corrupt or not. > > > > > >> > > > > > > > > >> > > > Regarding record size, I was thinking to extract record > size > > > > from > > > > > >> > Record. > > > > > >> > > > That will include header overhead as well. I think total > > > record > > > > > size > > > > > >> > will > > > > > >> > > > tell users how much bandwidth their messages take. Since > > > header > > > > is > > > > > >> > > > relatively small and constant, users also will get an idea > > of > > > > > their > > > > > >> > > > key/value sizes. > > > > > >> > > > > > > > > >> > > > Thanks, > > > > > >> > > > Anna > > > > > >> > > > > > > > > >> > > > On Thu, Jan 28, 2016 at 9:29 AM, Becket Qin < > > > > becket....@gmail.com > > > > > > > > > > > >> > > wrote: > > > > > >> > > > > > > > > >> > > > > I am +1 on #1.2 and #3. > > > > > >> > > > > > > > > > >> > > > > #2: Regarding CRC, I am not sure if users care about > CRC. > > is > > > > > there > > > > > >> > any > > > > > >> > > > > specific use case? Currently we validate messages by > > calling > > > > > >> > > > ensureValid() > > > > > >> > > > > to verify the checksum and throw exception if it does > not > > > > match. > > > > > >> > > > > > > > > > >> > > > > Message size would be useful. We can add that to > > > > ConsumerRecord. > > > > > >> Can > > > > > >> > > you > > > > > >> > > > > clarify the message size you are referring to? Does it > > > include > > > > > the > > > > > >> > > > message > > > > > >> > > > > header overhead or not? From user's point of view, they > > > > probably > > > > > >> > don't > > > > > >> > > > care > > > > > >> > > > > about header size. > > > > > >> > > > > > > > > > >> > > > > Thanks, > > > > > >> > > > > > > > > > >> > > > > Jiangjie (Becket) Qin > > > > > >> > > > > > > > > > >> > > > > > > > > > >> > > > > On Wed, Jan 27, 2016 at 8:26 PM, Neha Narkhede < > > > > > n...@confluent.io > > > > > >> > > > > > > >> > > > wrote: > > > > > >> > > > > > > > > > >> > > > > > Anna, > > > > > >> > > > > > > > > > > >> > > > > > Thanks for being diligent. > > > > > >> > > > > > > > > > > >> > > > > > +1 on #1.2 and sounds good on #3. I recommend adding > > > > checksum > > > > > >> and > > > > > >> > > size > > > > > >> > > > > > fields to RecordMetadata and ConsumerRecord instead of > > > > > exposing > > > > > >> > > > metadata > > > > > >> > > > > > piecemeal in the interceptor APIs. > > > > > >> > > > > > > > > > > >> > > > > > Thanks, > > > > > >> > > > > > Neha > > > > > >> > > > > > > > > > > >> > > > > > On Wed, Jan 27, 2016 at 4:10 PM, Anna Povzner < > > > > > >> a...@confluent.io> > > > > > >> > > > wrote: > > > > > >> > > > > > > > > > > >> > > > > > > Hi All, > > > > > >> > > > > > > > > > > > >> > > > > > > The KIP wiki page is now up-to-date with the scope > we > > > have > > > > > >> agreed > > > > > >> > > on: > > > > > >> > > > > > > Producer and Consumer Interceptors with a minimal > set > > of > > > > > >> mutable > > > > > >> > > API > > > > > >> > > > > that > > > > > >> > > > > > > are not dependent on producer and consumer internal > > > > > >> > implementation. > > > > > >> > > > > > > > > > > > >> > > > > > > I have few more API details that I would like to > bring > > > > > >> attention > > > > > >> > to > > > > > >> > > > > > or/and > > > > > >> > > > > > > discuss: > > > > > >> > > > > > > > > > > > >> > > > > > > 1. Handling exceptions > > > > > >> > > > > > > > > > > > >> > > > > > > Exceptions can provide an additional level of > control. > > > For > > > > > >> > example, > > > > > >> > > > we > > > > > >> > > > > > can > > > > > >> > > > > > > filter messages on consumer side or stop messages on > > > > > producer > > > > > >> if > > > > > >> > > they > > > > > >> > > > > > don’t > > > > > >> > > > > > > have the right field. > > > > > >> > > > > > > > > > > > >> > > > > > > I see two options: > > > > > >> > > > > > > 1.1. For callbacks that can mutate records (onSend > and > > > > > >> > onConsume), > > > > > >> > > > > > > propagate exceptions through the original calls > > > > > >> > > (KafkaProducer.send() > > > > > >> > > > > and > > > > > >> > > > > > > KafkaConsumer.poll() respectively). For other > > callbacks, > > > > > catch > > > > > >> > > > > exception, > > > > > >> > > > > > > log, and ignore. > > > > > >> > > > > > > 1.2. Catch exceptions from all the interceptor > > callbacks > > > > and > > > > > >> > > ignore. > > > > > >> > > > > > > > > > > > >> > > > > > > The issue with 1.1. is that it effectively changes > > > > > >> > > > KafkaProducer.send() > > > > > >> > > > > > and > > > > > >> > > > > > > KafkaConsumer.poll() API, since now they may throw > > > > > exceptions > > > > > >> > that > > > > > >> > > > are > > > > > >> > > > > > not > > > > > >> > > > > > > documented in KafkaProducer/Consumer API. Another > > option > > > > is > > > > > to > > > > > >> > > allow > > > > > >> > > > to > > > > > >> > > > > > > propagate some exceptions, and ignore others. > > > > > >> > > > > > > > > > > > >> > > > > > > I think our use-cases do not require propagating > > > > exceptions. > > > > > >> So, > > > > > >> > I > > > > > >> > > > > > propose > > > > > >> > > > > > > option 1.2. Unless someone has suggestion/use-cases > > for > > > > > >> > propagating > > > > > >> > > > > > > exceptions. Please let me know. > > > > > >> > > > > > > > > > > > >> > > > > > > 2. Intercepting record CRC and record size > > > > > >> > > > > > > > > > > > >> > > > > > > Since we decided not to add any intermediate > callbacks > > > > (such > > > > > >> as > > > > > >> > > > > onEnqueue > > > > > >> > > > > > > or onReceive) to interceptors, I think it is still > > > > valuable > > > > > to > > > > > >> > > > > intercept > > > > > >> > > > > > > record CRC and record size in bytes for monitoring > and > > > > audit > > > > > >> > > > use-cases. > > > > > >> > > > > > > > > > > > >> > > > > > > I propose to add checksum and size fields to > > > > RecordMetadata > > > > > >> and > > > > > >> > > > > > > ConsumerRecord. Another option would be to add them > as > > > > > >> parameters > > > > > >> > > in > > > > > >> > > > > > > onAcknowledgement() and onConsume() callbacks. > > > > > >> > > > > > > > > > > > >> > > > > > > 3. Callbacks that allow to modify records look as > > > follows: > > > > > >> > > > > > > ProducerRecord<K, V> onSend(ProducerRecord<K, V> > > > record); > > > > > >> > > > > > > ConsumerRecords<K, V> onConsume(ConsumerRecords<K, > V> > > > > > >> records); > > > > > >> > > > > > > > > > > > >> > > > > > > This means that interceptors can potentially modify > > > > > >> > topic/partition > > > > > >> > > > in > > > > > >> > > > > > > ProducerRecord and topic/partition/offset in > > > > > ConsumerRecord. I > > > > > >> > > > propose > > > > > >> > > > > > that > > > > > >> > > > > > > it is up to the interceptor implementation to ensure > > > that > > > > > >> > > > > > topic/partition, > > > > > >> > > > > > > etc is correct. KafkaProducer.send() will use topic, > > > > > >> partition, > > > > > >> > > key, > > > > > >> > > > > and > > > > > >> > > > > > > value from ProducerRecord returned from the > onSend(). > > > > > >> Similarly, > > > > > >> > > > > > > ConsumerRecords returned from KafkaConsumer.poll() > > would > > > > be > > > > > >> the > > > > > >> > > ones > > > > > >> > > > > > > returned from the interceptor. > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > Please let me know if you have any suggestions or > > > > objections > > > > > >> to > > > > > >> > the > > > > > >> > > > > > above. > > > > > >> > > > > > > > > > > > >> > > > > > > Thanks, > > > > > >> > > > > > > Anna > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > On Wed, Jan 27, 2016 at 2:56 PM, Anna Povzner < > > > > > >> a...@confluent.io > > > > > >> > > > > > > > >> > > > > wrote: > > > > > >> > > > > > > > > > > > >> > > > > > > > Hi Mayuresh, > > > > > >> > > > > > > > > > > > > >> > > > > > > > I see why you would want to check for messages > left > > in > > > > the > > > > > >> > > > > > > > RecordAccumulator. However, I don't think this > will > > > > > >> completely > > > > > >> > > > solve > > > > > >> > > > > > the > > > > > >> > > > > > > > problem. Messages could be in-flight somewhere > else, > > > > like > > > > > in > > > > > >> > the > > > > > >> > > > > > socket, > > > > > >> > > > > > > or > > > > > >> > > > > > > > there maybe in-flight messages on the consumer > side > > of > > > > the > > > > > >> > > > > MirrorMaker. > > > > > >> > > > > > > So, > > > > > >> > > > > > > > if we go the route of checking whether there are > any > > > > > >> in-flight > > > > > >> > > > > messages > > > > > >> > > > > > > for > > > > > >> > > > > > > > topic deletion use-case, maybe it is better count > > them > > > > > with > > > > > >> > > > onSend() > > > > > >> > > > > > and > > > > > >> > > > > > > > onAcknowledge() -- whether all messages sent were > > > > > >> > acknowledged. I > > > > > >> > > > > also > > > > > >> > > > > > > > think that it would be better to solve this > without > > > > > >> > interceptors, > > > > > >> > > > > such > > > > > >> > > > > > as > > > > > >> > > > > > > > fix error handling in this scenario. However, I do > > not > > > > > have > > > > > >> any > > > > > >> > > > good > > > > > >> > > > > > > > proposal right now, so these are just general > > > thoughts. > > > > > >> > > > > > > > > > > > > >> > > > > > > > Thanks, > > > > > >> > > > > > > > Anna > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > On Wed, Jan 27, 2016 at 11:18 AM, Mayuresh Gharat > < > > > > > >> > > > > > > > gharatmayures...@gmail.com> wrote: > > > > > >> > > > > > > > > > > > > >> > > > > > > >> Calling producer.flush(), flushes all the data. > So > > > this > > > > > is > > > > > >> OK. > > > > > >> > > But > > > > > >> > > > > > when > > > > > >> > > > > > > >> you > > > > > >> > > > > > > >> are running Mirror maker, I am not sure there is > a > > > way > > > > to > > > > > >> > > flush() > > > > > >> > > > > from > > > > > >> > > > > > > >> outside. > > > > > >> > > > > > > >> > > > > > >> > > > > > > >> > > > > > >> > > > > > > >> Thanks, > > > > > >> > > > > > > >> > > > > > >> > > > > > > >> Mayuresh > > > > > >> > > > > > > >> > > > > > >> > > > > > > >> On Wed, Jan 27, 2016 at 11:08 AM, Becket Qin < > > > > > >> > > > becket....@gmail.com> > > > > > >> > > > > > > >> wrote: > > > > > >> > > > > > > >> > > > > > >> > > > > > > >> > Mayuresh, > > > > > >> > > > > > > >> > > > > > > >> > > > > > > >> > Regarding your use case about mirror maker. Is > it > > > > good > > > > > >> > enough > > > > > >> > > as > > > > > >> > > > > > long > > > > > >> > > > > > > >> as we > > > > > >> > > > > > > >> > know there is no message for the topic in the > > > > producer > > > > > >> > > anymore? > > > > > >> > > > If > > > > > >> > > > > > > that > > > > > >> > > > > > > >> is > > > > > >> > > > > > > >> > the case, call producer.flush() is sufficient. > > > > > >> > > > > > > >> > > > > > > >> > > > > > > >> > Thanks, > > > > > >> > > > > > > >> > > > > > > >> > > > > > > >> > Jiangjie (Becket) Qin > > > > > >> > > > > > > >> > > > > > > >> > > > > > > >> > On Tue, Jan 26, 2016 at 6:18 PM, Mayuresh > Gharat > > < > > > > > >> > > > > > > >> > gharatmayures...@gmail.com > > > > > >> > > > > > > >> > > wrote: > > > > > >> > > > > > > >> > > > > > > >> > > > > > > >> > > Hi Anna, > > > > > >> > > > > > > >> > > > > > > > >> > > > > > > >> > > Thanks a lot for summarizing the discussion > on > > > this > > > > > >> kip. > > > > > >> > > > > > > >> > > > > > > > >> > > > > > > >> > > It LGTM. > > > > > >> > > > > > > >> > > This is really nice : > > > > > >> > > > > > > >> > > We decided not to add any callbacks to > producer > > > and > > > > > >> > consumer > > > > > >> > > > > > > >> > > interceptors that will depend on internal > > > > > >> implementation > > > > > >> > as > > > > > >> > > > part > > > > > >> > > > > > of > > > > > >> > > > > > > >> this > > > > > >> > > > > > > >> > > KIP. > > > > > >> > > > > > > >> > > *However, it is possible to add them later as > > > part > > > > of > > > > > >> > > another > > > > > >> > > > > KIP > > > > > >> > > > > > if > > > > > >> > > > > > > >> > there > > > > > >> > > > > > > >> > > are good use-cases.* > > > > > >> > > > > > > >> > > > > > > > >> > > > > > > >> > > Do you agree with the use case I explained > > > earlier > > > > > for > > > > > >> > > knowing > > > > > >> > > > > the > > > > > >> > > > > > > >> number > > > > > >> > > > > > > >> > > of records left in the RecordAccumulator for > a > > > > > >> particular > > > > > >> > > > topic. > > > > > >> > > > > > It > > > > > >> > > > > > > >> might > > > > > >> > > > > > > >> > > be orthogonal to this KIP, but will be > helpful. > > > > What > > > > > do > > > > > >> > you > > > > > >> > > > > think? > > > > > >> > > > > > > >> > > > > > > > >> > > > > > > >> > > Thanks, > > > > > >> > > > > > > >> > > > > > > > >> > > > > > > >> > > Mayuresh > > > > > >> > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > > > >> > > > > > > >> > > On Tue, Jan 26, 2016 at 2:46 PM, Todd Palino > < > > > > > >> > > > tpal...@gmail.com > > > > > >> > > > > > > > > > > >> > > > > > > >> wrote: > > > > > >> > > > > > > >> > > > > > > > >> > > > > > > >> > > > This looks good. As noted, having one > mutable > > > > > >> > interceptor > > > > > >> > > on > > > > > >> > > > > > each > > > > > >> > > > > > > >> side > > > > > >> > > > > > > >> > > > allows for the use cases we can envision > > right > > > > now, > > > > > >> and > > > > > >> > I > > > > > >> > > > > think > > > > > >> > > > > > > >> that’s > > > > > >> > > > > > > >> > > > going to provide a great deal of > opportunity > > > for > > > > > >> > > > implementing > > > > > >> > > > > > > things > > > > > >> > > > > > > >> > like > > > > > >> > > > > > > >> > > > audit, especially within a multi-tenant > > > > > environment. > > > > > >> > > Looking > > > > > >> > > > > > > >> forward to > > > > > >> > > > > > > >> > > > getting this available in the clients. > > > > > >> > > > > > > >> > > > > > > > > >> > > > > > > >> > > > Thanks! > > > > > >> > > > > > > >> > > > > > > > > >> > > > > > > >> > > > -Todd > > > > > >> > > > > > > >> > > > > > > > > >> > > > > > > >> > > > > > > > > >> > > > > > > >> > > > On Tue, Jan 26, 2016 at 2:36 PM, Anna > > Povzner < > > > > > >> > > > > > a...@confluent.io> > > > > > >> > > > > > > >> > wrote: > > > > > >> > > > > > > >> > > > > > > > > >> > > > > > > >> > > > > Hi All, > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > Here is meeting notes from today’s KIP > > > meeting: > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > 1. We agreed to keep the scope of this > KIP > > to > > > > be > > > > > >> > > producer > > > > > >> > > > > and > > > > > >> > > > > > > >> > consumer > > > > > >> > > > > > > >> > > > > interceptors only. Broker-side > interceptor > > > will > > > > > be > > > > > >> > added > > > > > >> > > > > later > > > > > >> > > > > > > as > > > > > >> > > > > > > >> a > > > > > >> > > > > > > >> > > > > separate KIP. The reasons were already > > > > mentioned > > > > > in > > > > > >> > this > > > > > >> > > > > > thread, > > > > > >> > > > > > > >> but > > > > > >> > > > > > > >> > > the > > > > > >> > > > > > > >> > > > > summary is: > > > > > >> > > > > > > >> > > > > * Broker interceptor is riskier and > > requires > > > > > >> careful > > > > > >> > > > > > > >> consideration > > > > > >> > > > > > > >> > > about > > > > > >> > > > > > > >> > > > > overheads, whether to intercept leaders > vs. > > > > > >> > > > > leaders/replicas, > > > > > >> > > > > > > >> what to > > > > > >> > > > > > > >> > > do > > > > > >> > > > > > > >> > > > on > > > > > >> > > > > > > >> > > > > leader failover and so on. > > > > > >> > > > > > > >> > > > > * Broker interceptors increase > monitoring > > > > > >> resolution, > > > > > >> > > but > > > > > >> > > > > not > > > > > >> > > > > > > >> > > including > > > > > >> > > > > > > >> > > > it > > > > > >> > > > > > > >> > > > > in this KIP does not reduce usefulness of > > > > > producer > > > > > >> and > > > > > >> > > > > > consumer > > > > > >> > > > > > > >> > > > > interceptors that enable end-to-end > > > monitoring > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > 2. We agreed to scope ProducerInterceptor > > and > > > > > >> > > > > > > ConsumerInterceptor > > > > > >> > > > > > > >> > > > callbacks > > > > > >> > > > > > > >> > > > > to minimal set of mutable API that are > not > > > > > >> dependent > > > > > >> > on > > > > > >> > > > > > producer > > > > > >> > > > > > > >> and > > > > > >> > > > > > > >> > > > > consumer internal implementation. > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > ProducerInterceptor: > > > > > >> > > > > > > >> > > > > *ProducerRecord<K, V> > > > onSend(ProducerRecord<K, > > > > V> > > > > > >> > > > record);* > > > > > >> > > > > > > >> > > > > *void onAcknowledgement(RecordMetadata > > > > metadata, > > > > > >> > > Exception > > > > > >> > > > > > > >> > exception);* > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > ConsumerInterceptor: > > > > > >> > > > > > > >> > > > > *ConsumerRecords<K, V> > > > > > >> onConsume(ConsumerRecords<K, V> > > > > > >> > > > > > > records);* > > > > > >> > > > > > > >> > > > > *void onCommit(Map<TopicPartition, > > > > > >> OffsetAndMetadata> > > > > > >> > > > > > offsets);* > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > We will allow interceptors to modify > > > > > >> ProducerRecord on > > > > > >> > > > > > producer > > > > > >> > > > > > > >> side, > > > > > >> > > > > > > >> > > and > > > > > >> > > > > > > >> > > > > modify ConsumerRecords on consumer side. > > This > > > > > will > > > > > >> > > support > > > > > >> > > > > > > >> end-to-end > > > > > >> > > > > > > >> > > > > monitoring and auditing and support the > > > ability > > > > > to > > > > > >> add > > > > > >> > > > > > metadata > > > > > >> > > > > > > >> for a > > > > > >> > > > > > > >> > > > > message. This will support Todd’s > Auditing > > > and > > > > > >> Routing > > > > > >> > > > > > > use-cases. > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > We did not find any use-case for > modifying > > > > > records > > > > > >> in > > > > > >> > > > > > > onConsume() > > > > > >> > > > > > > >> > > > callback, > > > > > >> > > > > > > >> > > > > but decided to enable modification of > > > consumer > > > > > >> records > > > > > >> > > for > > > > > >> > > > > > > >> symmetry > > > > > >> > > > > > > >> > > with > > > > > >> > > > > > > >> > > > > onSend(). > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > 3. We agreed to ensure compatibility > > when/if > > > we > > > > > add > > > > > >> > new > > > > > >> > > > > > methods > > > > > >> > > > > > > to > > > > > >> > > > > > > >> > > > > ProducerInterceptor and > ConsumerInterceptor > > > by > > > > > >> using > > > > > >> > > > default > > > > > >> > > > > > > >> methods > > > > > >> > > > > > > >> > > with > > > > > >> > > > > > > >> > > > > an empty implementation. Ok to assume > Java > > 8. > > > > > >> (This is > > > > > >> > > > > > Ismael’s > > > > > >> > > > > > > >> > method > > > > > >> > > > > > > >> > > > #2). > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > 4. We decided not to add any callbacks to > > > > > producer > > > > > >> and > > > > > >> > > > > > consumer > > > > > >> > > > > > > >> > > > > interceptors that will depend on internal > > > > > >> > implementation > > > > > >> > > > as > > > > > >> > > > > > part > > > > > >> > > > > > > >> of > > > > > >> > > > > > > >> > > this > > > > > >> > > > > > > >> > > > > KIP. However, it is possible to add them > > > later > > > > as > > > > > >> part > > > > > >> > > of > > > > > >> > > > > > > another > > > > > >> > > > > > > >> KIP > > > > > >> > > > > > > >> > > if > > > > > >> > > > > > > >> > > > > there are good use-cases. > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > *Reasoning.* We did not have concrete > > > use-cases > > > > > >> that > > > > > >> > > > > justified > > > > > >> > > > > > > >> more > > > > > >> > > > > > > >> > > > methods > > > > > >> > > > > > > >> > > > > at this point. Some of the use-cases were > > for > > > > > more > > > > > >> > > > > fine-grain > > > > > >> > > > > > > >> latency > > > > > >> > > > > > > >> > > > > collection, which could be done with > Kafka > > > > > Metrics. > > > > > >> > > > Another > > > > > >> > > > > > > >> use-case > > > > > >> > > > > > > >> > > was > > > > > >> > > > > > > >> > > > > encryption. However, there are several > > design > > > > > >> options > > > > > >> > > for > > > > > >> > > > > > > >> encryption. > > > > > >> > > > > > > >> > > One > > > > > >> > > > > > > >> > > > > is to do per-record encryption which > would > > > > > require > > > > > >> > > adding > > > > > >> > > > > > > >> > > > > ProducerInterceptor.onEnqueued() and > > > > > >> > > > > > > >> ConsumerInterceptor.onReceive(). > > > > > >> > > > > > > >> > > One > > > > > >> > > > > > > >> > > > > could argue that in that case encryption > > > could > > > > be > > > > > >> done > > > > > >> > > by > > > > > >> > > > > > > adding a > > > > > >> > > > > > > >> > > custom > > > > > >> > > > > > > >> > > > > serializer/deserializer. Another option > is > > to > > > > do > > > > > >> > > > encryption > > > > > >> > > > > > > after > > > > > >> > > > > > > >> > > message > > > > > >> > > > > > > >> > > > > gets compressed, but there are issues > that > > > > arise > > > > > >> > > regarding > > > > > >> > > > > > > broker > > > > > >> > > > > > > >> > doing > > > > > >> > > > > > > >> > > > > re-compression. We decided that it is > > better > > > to > > > > > >> have > > > > > >> > > that > > > > > >> > > > > > > >> discussion > > > > > >> > > > > > > >> > > in a > > > > > >> > > > > > > >> > > > > separate KIP and decide that this is > > > something > > > > we > > > > > >> want > > > > > >> > > to > > > > > >> > > > do > > > > > >> > > > > > > with > > > > > >> > > > > > > >> > > > > interceptors or by other means. > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > Todd, Mayuresh and others who missed the > > KIP > > > > > >> meeting, > > > > > >> > > > please > > > > > >> > > > > > let > > > > > >> > > > > > > >> me > > > > > >> > > > > > > >> > > know > > > > > >> > > > > > > >> > > > > your thoughts on the scope we agreed on > > > during > > > > > the > > > > > >> > > > meeting. > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > I will update the KIP proposal with the > > > current > > > > > >> > decision > > > > > >> > > > by > > > > > >> > > > > > end > > > > > >> > > > > > > of > > > > > >> > > > > > > >> > > today. > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > Thanks, > > > > > >> > > > > > > >> > > > > Anna > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > On Tue, Jan 26, 2016 at 11:41 AM, > Mayuresh > > > > > Gharat < > > > > > >> > > > > > > >> > > > > gharatmayures...@gmail.com> wrote: > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > > Hi, > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > I won't be able to make it to KIP > hangout > > > due > > > > > to > > > > > >> > > > conflict. > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > Anna, here is the use case where > knowing > > if > > > > > there > > > > > >> > are > > > > > >> > > > > > messages > > > > > >> > > > > > > >> in > > > > > >> > > > > > > >> > the > > > > > >> > > > > > > >> > > > > > RecordAccumulator left to be sent to > the > > > > kafka > > > > > >> > cluster > > > > > >> > > > > for a > > > > > >> > > > > > > >> topic > > > > > >> > > > > > > >> > is > > > > > >> > > > > > > >> > > > > > useful. > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > 1) Consider a pipeline : > > > > > >> > > > > > > >> > > > > > A ---> Mirror-maker -----> B > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > 2) We have a topic T in cluster A > > mirrored > > > to > > > > > >> > cluster > > > > > >> > > B. > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > 3) Now if we delete topic T in A and > > > > > immediately > > > > > >> > > proceed > > > > > >> > > > > to > > > > > >> > > > > > > >> delete > > > > > >> > > > > > > >> > > the > > > > > >> > > > > > > >> > > > > > topic in cluster B, some of the the > > > > > Mirror-maker > > > > > >> > > > machines > > > > > >> > > > > > die > > > > > >> > > > > > > >> > because > > > > > >> > > > > > > >> > > > > > atleast one of the batches in > > > > RecordAccumulator > > > > > >> for > > > > > >> > > > topic > > > > > >> > > > > T > > > > > >> > > > > > > >> fail to > > > > > >> > > > > > > >> > > be > > > > > >> > > > > > > >> > > > > > produced to cluster B. We have seen > this > > > > > >> happening > > > > > >> > in > > > > > >> > > > our > > > > > >> > > > > > > >> clusters. > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > If we know that there are no more > > messages > > > > left > > > > > >> in > > > > > >> > the > > > > > >> > > > > > > >> > > > RecordAccumulator > > > > > >> > > > > > > >> > > > > to > > > > > >> > > > > > > >> > > > > > be produced to cluster B, we can safely > > > > delete > > > > > >> the > > > > > >> > > topic > > > > > >> > > > > in > > > > > >> > > > > > > >> > cluster B > > > > > >> > > > > > > >> > > > > > without disturbing the pipeline. > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > Thanks, > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > Mayuresh > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > On Tue, Jan 26, 2016 at 10:31 AM, Anna > > > > Povzner > > > > > < > > > > > >> > > > > > > >> a...@confluent.io> > > > > > >> > > > > > > >> > > > > wrote: > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > > Thanks Ismael and Todd for your > > feedback! > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > I agree about coming up with lean, > but > > > > useful > > > > > >> > > > interfaces > > > > > >> > > > > > > that > > > > > >> > > > > > > >> > will > > > > > >> > > > > > > >> > > be > > > > > >> > > > > > > >> > > > > > easy > > > > > >> > > > > > > >> > > > > > > to extend later. > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > When we discuss the minimal set of > > > producer > > > > > and > > > > > >> > > > consumer > > > > > >> > > > > > > >> > > interceptor > > > > > >> > > > > > > >> > > > > API > > > > > >> > > > > > > >> > > > > > in > > > > > >> > > > > > > >> > > > > > > today’s KIP meeting (discussion item > #2 > > > in > > > > my > > > > > >> > > previous > > > > > >> > > > > > > email), > > > > > >> > > > > > > >> > lets > > > > > >> > > > > > > >> > > > > > compare > > > > > >> > > > > > > >> > > > > > > two options: > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > *1. Minimal set of immutable API for > > > > producer > > > > > >> and > > > > > >> > > > > consumer > > > > > >> > > > > > > >> > > > > interceptors* > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > ProducerInterceptor: > > > > > >> > > > > > > >> > > > > > > public void onSend(ProducerRecord<K, > V> > > > > > >> record); > > > > > >> > > > > > > >> > > > > > > public void > > > > onAcknowledgement(RecordMetadata > > > > > >> > > metadata, > > > > > >> > > > > > > >> Exception > > > > > >> > > > > > > >> > > > > > > exception); > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > ConsumerInterceptor: > > > > > >> > > > > > > >> > > > > > > public void > > onConsume(ConsumerRecords<K, > > > V> > > > > > >> > > records); > > > > > >> > > > > > > >> > > > > > > public void > > onCommit(Map<TopicPartition, > > > > > >> > > > > > OffsetAndMetadata> > > > > > >> > > > > > > >> > > offsets); > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > Use-cases: > > > > > >> > > > > > > >> > > > > > > — end-to-end monitoring; custom > tracing > > > and > > > > > >> > logging > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > *2. Minimal set of mutable API for > > > producer > > > > > and > > > > > >> > > > consumer > > > > > >> > > > > > > >> > > > interceptors* > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > ProducerInterceptor: > > > > > >> > > > > > > >> > > > > > > ProducerRecord<K, V> > > > > onSend(ProducerRecord<K, > > > > > >> V> > > > > > >> > > > > record); > > > > > >> > > > > > > >> > > > > > > void onAcknowledgement(RecordMetadata > > > > > metadata, > > > > > >> > > > > Exception > > > > > >> > > > > > > >> > > exception); > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > ConsumerInterceptor: > > > > > >> > > > > > > >> > > > > > > void onConsume(ConsumerRecords<K, V> > > > > > records); > > > > > >> > > > > > > >> > > > > > > void onCommit(Map<TopicPartition, > > > > > >> > OffsetAndMetadata> > > > > > >> > > > > > > offsets); > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > Additional use-cases to #1: > > > > > >> > > > > > > >> > > > > > > — Ability to add metadata to a > message > > or > > > > > fill > > > > > >> in > > > > > >> > > > > standard > > > > > >> > > > > > > >> fields > > > > > >> > > > > > > >> > > for > > > > > >> > > > > > > >> > > > > > audit > > > > > >> > > > > > > >> > > > > > > and routing. > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > Implications > > > > > >> > > > > > > >> > > > > > > — Partition assignment will be done > > based > > > > on > > > > > >> > > modified > > > > > >> > > > > > > >> key/value > > > > > >> > > > > > > >> > > > instead > > > > > >> > > > > > > >> > > > > > of > > > > > >> > > > > > > >> > > > > > > original key/value. If key/value > > > > > >> transformation is > > > > > >> > > not > > > > > >> > > > > > > >> consistent > > > > > >> > > > > > > >> > > > (same > > > > > >> > > > > > > >> > > > > > key > > > > > >> > > > > > > >> > > > > > > and value does not mutate to the > same, > > > but > > > > > >> > modified, > > > > > >> > > > > > > >> key/value), > > > > > >> > > > > > > >> > > then > > > > > >> > > > > > > >> > > > > log > > > > > >> > > > > > > >> > > > > > > compaction would not work. However, > > audit > > > > and > > > > > >> > > routing > > > > > >> > > > > > > >> use-cases > > > > > >> > > > > > > >> > > from > > > > > >> > > > > > > >> > > > > Todd > > > > > >> > > > > > > >> > > > > > > will likely do consistent > > transformation. > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > *Additional callbacks (discussion > item > > #3 > > > > in > > > > > my > > > > > >> > > > previous > > > > > >> > > > > > > >> email):* > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > If we want to support encryption, we > > > would > > > > > >> want to > > > > > >> > > be > > > > > >> > > > > able > > > > > >> > > > > > > to > > > > > >> > > > > > > >> > > modify > > > > > >> > > > > > > >> > > > > > > serialized key/value, rather than key > > and > > > > > value > > > > > >> > > > objects. > > > > > >> > > > > > > This > > > > > >> > > > > > > >> > will > > > > > >> > > > > > > >> > > > add > > > > > >> > > > > > > >> > > > > > the > > > > > >> > > > > > > >> > > > > > > following API to producer and > consumer > > > > > >> > interceptors: > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > ProducerInterceptor: > > > > > >> > > > > > > >> > > > > > > SerializedKeyValue > > > > onEnqueued(TopicPartition > > > > > >> tp, > > > > > >> > > > > > > >> > ProducerRecord<K, > > > > > >> > > > > > > >> > > V> > > > > > >> > > > > > > >> > > > > > > record, SerializedKeyValue > > > > > serializedKeyValue); > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > ConsumerInterceptor: > > > > > >> > > > > > > >> > > > > > > SerializedKeyValue > > > onReceive(TopicPartition > > > > > tp, > > > > > >> > > > > > > >> > SerializedKeyValue > > > > > >> > > > > > > >> > > > > > > serializedKeyValue); > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > I am leaning towards implementing the > > > > minimal > > > > > >> set > > > > > >> > of > > > > > >> > > > > > > >> immutable or > > > > > >> > > > > > > >> > > > > mutable > > > > > >> > > > > > > >> > > > > > > interfaces, making sure that we have > a > > > > > >> > compatibility > > > > > >> > > > > plan > > > > > >> > > > > > > that > > > > > >> > > > > > > >> > > allows > > > > > >> > > > > > > >> > > > > us > > > > > >> > > > > > > >> > > > > > to > > > > > >> > > > > > > >> > > > > > > add more callbacks in the future (per > > > > Ismael > > > > > >> > > comment), > > > > > >> > > > > and > > > > > >> > > > > > > add > > > > > >> > > > > > > >> > more > > > > > >> > > > > > > >> > > > > APIs > > > > > >> > > > > > > >> > > > > > > later. E.g., for encryption use-case, > > > there > > > > > >> could > > > > > >> > be > > > > > >> > > > an > > > > > >> > > > > > > >> argument > > > > > >> > > > > > > >> > in > > > > > >> > > > > > > >> > > > > doing > > > > > >> > > > > > > >> > > > > > > encryption after message compression > > vs. > > > > > >> > per-record > > > > > >> > > > > > > encryption > > > > > >> > > > > > > >> > that > > > > > >> > > > > > > >> > > > > could > > > > > >> > > > > > > >> > > > > > > be done using the above additional > API. > > > > There > > > > > >> is > > > > > >> > > also > > > > > >> > > > > more > > > > > >> > > > > > > >> > > > implications > > > > > >> > > > > > > >> > > > > > for > > > > > >> > > > > > > >> > > > > > > every API that modifies records: > > > modifying > > > > > >> > > serialized > > > > > >> > > > > > > >> key/value > > > > > >> > > > > > > >> > > will > > > > > >> > > > > > > >> > > > > > again > > > > > >> > > > > > > >> > > > > > > impact partition assignment (we will > > > likely > > > > > do > > > > > >> > that > > > > > >> > > > > after > > > > > >> > > > > > > >> > partition > > > > > >> > > > > > > >> > > > > > > assignment), which may impact log > > > > compaction > > > > > >> and > > > > > >> > > > mirror > > > > > >> > > > > > > maker > > > > > >> > > > > > > >> > > > > > partitioning. > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > Thanks, > > > > > >> > > > > > > >> > > > > > > Anna > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > On Tue, Jan 26, 2016 at 7:26 AM, Todd > > > > Palino > > > > > < > > > > > >> > > > > > > >> tpal...@gmail.com> > > > > > >> > > > > > > >> > > > > wrote: > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > > Finally got a chance to take a look > > at > > > > > this. > > > > > >> I > > > > > >> > > won’t > > > > > >> > > > > be > > > > > >> > > > > > > >> able to > > > > > >> > > > > > > >> > > > make > > > > > >> > > > > > > >> > > > > > the > > > > > >> > > > > > > >> > > > > > > > KIP meeting due to a conflict. > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > I’m somewhat disappointed in this > > > > > proposal. I > > > > > >> > > think > > > > > >> > > > > that > > > > > >> > > > > > > the > > > > > >> > > > > > > >> > > > explicit > > > > > >> > > > > > > >> > > > > > > > exclusion of modification of the > > > messages > > > > > is > > > > > >> > > > > > > short-sighted, > > > > > >> > > > > > > >> and > > > > > >> > > > > > > >> > > not > > > > > >> > > > > > > >> > > > > > > > accounting for it now is going to > > bite > > > us > > > > > >> later. > > > > > >> > > > Jay, > > > > > >> > > > > > > aren’t > > > > > >> > > > > > > >> > you > > > > > >> > > > > > > >> > > > the > > > > > >> > > > > > > >> > > > > > one > > > > > >> > > > > > > >> > > > > > > > railing against public interfaces > and > > > how > > > > > >> > > difficult > > > > > >> > > > > they > > > > > >> > > > > > > >> are to > > > > > >> > > > > > > >> > > > work > > > > > >> > > > > > > >> > > > > > with > > > > > >> > > > > > > >> > > > > > > > when you don’t get them right? The > > > > “simple” > > > > > >> > change > > > > > >> > > > to > > > > > >> > > > > > one > > > > > >> > > > > > > of > > > > > >> > > > > > > >> > > these > > > > > >> > > > > > > >> > > > > > > > interfaces to make it able to > return > > a > > > > > >> record is > > > > > >> > > > going > > > > > >> > > > > > to > > > > > >> > > > > > > >> be a > > > > > >> > > > > > > >> > > > > > > significant > > > > > >> > > > > > > >> > > > > > > > change and is going to require all > > > > clients > > > > > to > > > > > >> > > > rewrite > > > > > >> > > > > > > their > > > > > >> > > > > > > >> > > > > > interceptors. > > > > > >> > > > > > > >> > > > > > > > If we’re not willing to put the > time > > to > > > > > think > > > > > >> > > > through > > > > > >> > > > > > > >> > > manipulation > > > > > >> > > > > > > >> > > > > now, > > > > > >> > > > > > > >> > > > > > > > then this KIP should be shelved > until > > > we > > > > > are. > > > > > >> > > > > > Implementing > > > > > >> > > > > > > >> > > > something > > > > > >> > > > > > > >> > > > > > > > halfway is going to be worse than > > > taking > > > > a > > > > > >> > little > > > > > >> > > > > > longer. > > > > > >> > > > > > > In > > > > > >> > > > > > > >> > > > > addition, > > > > > >> > > > > > > >> > > > > > I > > > > > >> > > > > > > >> > > > > > > > don’t believe that manipulation > > > requires > > > > > >> > anything > > > > > >> > > > more > > > > > >> > > > > > > than > > > > > >> > > > > > > >> > > > > > interceptors > > > > > >> > > > > > > >> > > > > > > to > > > > > >> > > > > > > >> > > > > > > > receive the full record, and then > to > > > > return > > > > > >> it. > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > There are 3 use case I can think of > > > right > > > > > now > > > > > >> > > > without > > > > > >> > > > > > any > > > > > >> > > > > > > >> deep > > > > > >> > > > > > > >> > > > > > discussion > > > > > >> > > > > > > >> > > > > > > > that can make use of interceptors > > with > > > > > >> > > modification: > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > 1. Auditing. The ability to add > > > metadata > > > > > to a > > > > > >> > > > message > > > > > >> > > > > > for > > > > > >> > > > > > > >> > > auditing > > > > > >> > > > > > > >> > > > is > > > > > >> > > > > > > >> > > > > > > > critical. Hostname, service name, > > > > > timestamps, > > > > > >> > etc. > > > > > >> > > > are > > > > > >> > > > > > all > > > > > >> > > > > > > >> > pieces > > > > > >> > > > > > > >> > > > of > > > > > >> > > > > > > >> > > > > > data > > > > > >> > > > > > > >> > > > > > > > that can be used on the other side > of > > > the > > > > > >> > pipeline > > > > > >> > > > to > > > > > >> > > > > > > >> > categorize > > > > > >> > > > > > > >> > > > > > > messages, > > > > > >> > > > > > > >> > > > > > > > determine loss and transport time, > > and > > > > pin > > > > > >> down > > > > > >> > > > > issues. > > > > > >> > > > > > > You > > > > > >> > > > > > > >> may > > > > > >> > > > > > > >> > > say > > > > > >> > > > > > > >> > > > > > that > > > > > >> > > > > > > >> > > > > > > > these things can just be part of > the > > > > > message > > > > > >> > > schema, > > > > > >> > > > > but > > > > > >> > > > > > > >> anyone > > > > > >> > > > > > > >> > > who > > > > > >> > > > > > > >> > > > > has > > > > > >> > > > > > > >> > > > > > > > worked with a multi-user data > system > > > > > >> (especially > > > > > >> > > > those > > > > > >> > > > > > who > > > > > >> > > > > > > >> have > > > > > >> > > > > > > >> > > > been > > > > > >> > > > > > > >> > > > > > > > involved with LinkedIn) know how > > > > difficult > > > > > >> it is > > > > > >> > > to > > > > > >> > > > > > > maintain > > > > > >> > > > > > > >> > > > > consistent > > > > > >> > > > > > > >> > > > > > > > message schemas and to get other > > people > > > > to > > > > > >> put > > > > > >> > in > > > > > >> > > > > fields > > > > > >> > > > > > > for > > > > > >> > > > > > > >> > your > > > > > >> > > > > > > >> > > > > use. > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > 2. Encryption. This is probably the > > > most > > > > > >> obvious > > > > > >> > > > case > > > > > >> > > > > > for > > > > > >> > > > > > > >> > record > > > > > >> > > > > > > >> > > > > > > > manipulation on both sides. The > > ability > > > > to > > > > > >> tie > > > > > >> > in > > > > > >> > > > end > > > > > >> > > > > to > > > > > >> > > > > > > end > > > > > >> > > > > > > >> > > > > encryption > > > > > >> > > > > > > >> > > > > > > is > > > > > >> > > > > > > >> > > > > > > > important for data that requires > > > external > > > > > >> > > compliance > > > > > >> > > > > > (PCI, > > > > > >> > > > > > > >> > HIPAA, > > > > > >> > > > > > > >> > > > > > etc.). > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > 3. Routing. By being able to add a > > bit > > > of > > > > > >> > > > information > > > > > >> > > > > > > about > > > > > >> > > > > > > >> the > > > > > >> > > > > > > >> > > > > source > > > > > >> > > > > > > >> > > > > > or > > > > > >> > > > > > > >> > > > > > > > destination of a message to the > > > metadata, > > > > > you > > > > > >> > can > > > > > >> > > > > easily > > > > > >> > > > > > > >> > > construct > > > > > >> > > > > > > >> > > > an > > > > > >> > > > > > > >> > > > > > > > intelligent mirror maker that can > > > prevent > > > > > >> loops. > > > > > >> > > > This > > > > > >> > > > > > has > > > > > >> > > > > > > >> the > > > > > >> > > > > > > >> > > > > > opportunity > > > > > >> > > > > > > >> > > > > > > > to result in significant > operational > > > > > >> savings, as > > > > > >> > > you > > > > > >> > > > > can > > > > > >> > > > > > > get > > > > > >> > > > > > > >> > rid > > > > > >> > > > > > > >> > > of > > > > > >> > > > > > > >> > > > > the > > > > > >> > > > > > > >> > > > > > > > need for tiered clusters in order > to > > > > > prevent > > > > > >> > loops > > > > > >> > > > in > > > > > >> > > > > > > >> mirroring > > > > > >> > > > > > > >> > > > > > messages. > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > All three of these share the > feature > > > that > > > > > >> they > > > > > >> > add > > > > > >> > > > > > > metadata > > > > > >> > > > > > > >> to > > > > > >> > > > > > > >> > > > > > messages. > > > > > >> > > > > > > >> > > > > > > > With the pushback on having > arbitrary > > > > > >> metadata > > > > > >> > as > > > > > >> > > an > > > > > >> > > > > > > >> “envelope” > > > > > >> > > > > > > >> > > to > > > > > >> > > > > > > >> > > > > the > > > > > >> > > > > > > >> > > > > > > > message, this is a way to provide > it > > > and > > > > > >> make it > > > > > >> > > the > > > > > >> > > > > > > >> > > responsibility > > > > > >> > > > > > > >> > > > > of > > > > > >> > > > > > > >> > > > > > > the > > > > > >> > > > > > > >> > > > > > > > client, and not the Kafka broker > and > > > > system > > > > > >> > > itself. > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > -Todd > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > On Tue, Jan 26, 2016 at 2:30 AM, > > Ismael > > > > > Juma > > > > > >> < > > > > > >> > > > > > > >> > ism...@juma.me.uk> > > > > > >> > > > > > > >> > > > > > wrote: > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > Hi Anna and Neha, > > > > > >> > > > > > > >> > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > I think it makes a lot of sense > to > > > try > > > > > and > > > > > >> > keep > > > > > >> > > > the > > > > > >> > > > > > > >> interface > > > > > >> > > > > > > >> > > > lean > > > > > >> > > > > > > >> > > > > > and > > > > > >> > > > > > > >> > > > > > > to > > > > > >> > > > > > > >> > > > > > > > > add more methods later when/if > > there > > > > is a > > > > > >> > need. > > > > > >> > > > What > > > > > >> > > > > > is > > > > > >> > > > > > > >> the > > > > > >> > > > > > > >> > > > current > > > > > >> > > > > > > >> > > > > > > > > thinking with regards to > > > compatibility > > > > > >> when/if > > > > > >> > > we > > > > > >> > > > > add > > > > > >> > > > > > > new > > > > > >> > > > > > > >> > > > methods? > > > > > >> > > > > > > >> > > > > A > > > > > >> > > > > > > >> > > > > > > few > > > > > >> > > > > > > >> > > > > > > > > options come to mind: > > > > > >> > > > > > > >> > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > 1. Change the interface to an > > > abstract > > > > > >> class > > > > > >> > > with > > > > > >> > > > > > empty > > > > > >> > > > > > > >> > > > > > implementations > > > > > >> > > > > > > >> > > > > > > > for > > > > > >> > > > > > > >> > > > > > > > > all the methods. This means that > > the > > > > path > > > > > >> to > > > > > >> > > > adding > > > > > >> > > > > > new > > > > > >> > > > > > > >> > methods > > > > > >> > > > > > > >> > > > is > > > > > >> > > > > > > >> > > > > > > clear. > > > > > >> > > > > > > >> > > > > > > > > 2. Hope we have moved to Java 8 > by > > > the > > > > > >> time we > > > > > >> > > > need > > > > > >> > > > > to > > > > > >> > > > > > > add > > > > > >> > > > > > > >> > new > > > > > >> > > > > > > >> > > > > > methods > > > > > >> > > > > > > >> > > > > > > > and > > > > > >> > > > > > > >> > > > > > > > > use default methods with an empty > > > > > >> > implementation > > > > > >> > > > for > > > > > >> > > > > > any > > > > > >> > > > > > > >> new > > > > > >> > > > > > > >> > > > method > > > > > >> > > > > > > >> > > > > > > (and > > > > > >> > > > > > > >> > > > > > > > > potentially make existing methods > > > > default > > > > > >> > > methods > > > > > >> > > > > too > > > > > >> > > > > > at > > > > > >> > > > > > > >> that > > > > > >> > > > > > > >> > > > point > > > > > >> > > > > > > >> > > > > > for > > > > > >> > > > > > > >> > > > > > > > > consistency) > > > > > >> > > > > > > >> > > > > > > > > 3. Introduce a new interface that > > > > > inherits > > > > > >> > from > > > > > >> > > > the > > > > > >> > > > > > > >> existing > > > > > >> > > > > > > >> > > > > > > Interceptor > > > > > >> > > > > > > >> > > > > > > > > interface when we need to add new > > > > > methods. > > > > > >> > > > > > > >> > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > Option 1 is the easiest and it > also > > > > means > > > > > >> that > > > > > >> > > > > > > interceptor > > > > > >> > > > > > > >> > > users > > > > > >> > > > > > > >> > > > > only > > > > > >> > > > > > > >> > > > > > > > need > > > > > >> > > > > > > >> > > > > > > > > to override the methods that they > > are > > > > > >> > interested > > > > > >> > > > > (more > > > > > >> > > > > > > >> useful > > > > > >> > > > > > > >> > > if > > > > > >> > > > > > > >> > > > > the > > > > > >> > > > > > > >> > > > > > > > number > > > > > >> > > > > > > >> > > > > > > > > of methods grows). The downside > is > > > that > > > > > >> > > > interceptor > > > > > >> > > > > > > >> > > > implementations > > > > > >> > > > > > > >> > > > > > > > cannot > > > > > >> > > > > > > >> > > > > > > > > inherit from another class (a > > > > > >> straightforward > > > > > >> > > > > > workaround > > > > > >> > > > > > > >> is > > > > > >> > > > > > > >> > to > > > > > >> > > > > > > >> > > > make > > > > > >> > > > > > > >> > > > > > the > > > > > >> > > > > > > >> > > > > > > > > interceptor a forwarder that > calls > > > > > another > > > > > >> > > class). > > > > > >> > > > > > Also, > > > > > >> > > > > > > >> our > > > > > >> > > > > > > >> > > > > existing > > > > > >> > > > > > > >> > > > > > > > > callbacks are interfaces, so > seems > > a > > > > bit > > > > > >> > > > > inconsistent. > > > > > >> > > > > > > >> > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > Option 2 may be the most > appealing > > > one > > > > as > > > > > >> both > > > > > >> > > > users > > > > > >> > > > > > and > > > > > >> > > > > > > >> > > > ourselves > > > > > >> > > > > > > >> > > > > > > retain > > > > > >> > > > > > > >> > > > > > > > > flexibility. The main downside is > > > that > > > > it > > > > > >> > relies > > > > > >> > > > on > > > > > >> > > > > us > > > > > >> > > > > > > >> moving > > > > > >> > > > > > > >> > > to > > > > > >> > > > > > > >> > > > > Java > > > > > >> > > > > > > >> > > > > > > 8, > > > > > >> > > > > > > >> > > > > > > > > which may be more than a year > away > > > > > >> potentially > > > > > >> > > (if > > > > > >> > > > > we > > > > > >> > > > > > > >> support > > > > > >> > > > > > > >> > > the > > > > > >> > > > > > > >> > > > > > last > > > > > >> > > > > > > >> > > > > > > 2 > > > > > >> > > > > > > >> > > > > > > > > Java releases). > > > > > >> > > > > > > >> > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > Thoughts? > > > > > >> > > > > > > >> > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > Ismael > > > > > >> > > > > > > >> > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > On Tue, Jan 26, 2016 at 4:59 AM, > > Neha > > > > > >> > Narkhede < > > > > > >> > > > > > > >> > > > n...@confluent.io> > > > > > >> > > > > > > >> > > > > > > > wrote: > > > > > >> > > > > > > >> > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > Anna, > > > > > >> > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > I'm also in favor of including > > just > > > > the > > > > > >> APIs > > > > > >> > > for > > > > > >> > > > > > which > > > > > >> > > > > > > >> we > > > > > >> > > > > > > >> > > have > > > > > >> > > > > > > >> > > > a > > > > > >> > > > > > > >> > > > > > > clear > > > > > >> > > > > > > >> > > > > > > > > use > > > > > >> > > > > > > >> > > > > > > > > > case. If more use cases for > finer > > > > > >> monitoring > > > > > >> > > > show > > > > > >> > > > > up > > > > > >> > > > > > > in > > > > > >> > > > > > > >> the > > > > > >> > > > > > > >> > > > > future, > > > > > >> > > > > > > >> > > > > > > we > > > > > >> > > > > > > >> > > > > > > > > can > > > > > >> > > > > > > >> > > > > > > > > > always update the interface. > > Would > > > > you > > > > > >> > please > > > > > >> > > > > > > highlight > > > > > >> > > > > > > >> in > > > > > >> > > > > > > >> > > the > > > > > >> > > > > > > >> > > > > KIP > > > > > >> > > > > > > >> > > > > > > the > > > > > >> > > > > > > >> > > > > > > > > APIs > > > > > >> > > > > > > >> > > > > > > > > > that you think we have an > > immediate > > > > use > > > > > >> for? > > > > > >> > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > Joel, > > > > > >> > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > Broker-side monitoring makes a > > lot > > > of > > > > > >> sense > > > > > >> > in > > > > > >> > > > the > > > > > >> > > > > > > long > > > > > >> > > > > > > >> > term > > > > > >> > > > > > > >> > > > > > though I > > > > > >> > > > > > > >> > > > > > > > > don't > > > > > >> > > > > > > >> > > > > > > > > > think it is a requirement for > > > > > end-to-end > > > > > >> > > > > monitoring. > > > > > >> > > > > > > >> With > > > > > >> > > > > > > >> > the > > > > > >> > > > > > > >> > > > > > > producer > > > > > >> > > > > > > >> > > > > > > > > and > > > > > >> > > > > > > >> > > > > > > > > > consumer interceptors, you have > > the > > > > > >> ability > > > > > >> > to > > > > > >> > > > get > > > > > >> > > > > > > full > > > > > >> > > > > > > >> > > > > > > > > > publish-to-subscribe end-to-end > > > > > >> monitoring. > > > > > >> > > The > > > > > >> > > > > > broker > > > > > >> > > > > > > >> > > > > interceptor > > > > > >> > > > > > > >> > > > > > > > > > certainly improves the > resolution > > > of > > > > > >> > > monitoring > > > > > >> > > > > but > > > > > >> > > > > > it > > > > > >> > > > > > > >> is > > > > > >> > > > > > > >> > > also > > > > > >> > > > > > > >> > > > a > > > > > >> > > > > > > >> > > > > > > > riskier > > > > > >> > > > > > > >> > > > > > > > > > change. I prefer an incremental > > > > > approach > > > > > >> > over > > > > > >> > > a > > > > > >> > > > > > > big-bang > > > > > >> > > > > > > >> > and > > > > > >> > > > > > > >> > > > > > > recommend > > > > > >> > > > > > > >> > > > > > > > > > taking baby-steps. Let's first > > make > > > > > sure > > > > > >> the > > > > > >> > > > > > > >> > > producer/consumer > > > > > >> > > > > > > >> > > > > > > > > interceptors > > > > > >> > > > > > > >> > > > > > > > > > are successful. And then come > > back > > > > and > > > > > >> add > > > > > >> > the > > > > > >> > > > > > broker > > > > > >> > > > > > > >> > > > interceptor > > > > > >> > > > > > > >> > > > > > > > > > carefully. > > > > > >> > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > Having said that, it would be > > great > > > > to > > > > > >> > > > understand > > > > > >> > > > > > your > > > > > >> > > > > > > >> > > proposal > > > > > >> > > > > > > >> > > > > for > > > > > >> > > > > > > >> > > > > > > the > > > > > >> > > > > > > >> > > > > > > > > > broker interceptor > independently. > > > We > > > > > can > > > > > >> > > either > > > > > >> > > > > add > > > > > >> > > > > > an > > > > > >> > > > > > > >> > > > > interceptor > > > > > >> > > > > > > >> > > > > > > > > > on-append or on-commit. If > people > > > > want > > > > > to > > > > > >> > use > > > > > >> > > > this > > > > > >> > > > > > for > > > > > >> > > > > > > >> > > > > monitoring, > > > > > >> > > > > > > >> > > > > > > then > > > > > >> > > > > > > >> > > > > > > > > > possibly on-commit might be > more > > > > > useful? > > > > > >> > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > Thanks, > > > > > >> > > > > > > >> > > > > > > > > > Neha > > > > > >> > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > On Mon, Jan 25, 2016 at 6:47 > PM, > > > Jay > > > > > >> Kreps < > > > > > >> > > > > > > >> > j...@confluent.io > > > > > >> > > > > > > >> > > > > > > > > >> > > > > > > >> > > > > > wrote: > > > > > >> > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > Hey Joel, > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > What is the interface you are > > > > > thinking > > > > > >> of? > > > > > >> > > > > > Something > > > > > >> > > > > > > >> like > > > > > >> > > > > > > >> > > > this: > > > > > >> > > > > > > >> > > > > > > > > > > onAppend(String topic, > int > > > > > >> partition, > > > > > >> > > > > Records > > > > > >> > > > > > > >> > records, > > > > > >> > > > > > > >> > > > long > > > > > >> > > > > > > >> > > > > > > time) > > > > > >> > > > > > > >> > > > > > > > > > > ? > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > One challenge right now is > that > > > we > > > > > are > > > > > >> > still > > > > > >> > > > > using > > > > > >> > > > > > > the > > > > > >> > > > > > > >> > old > > > > > >> > > > > > > >> > > > > > > > > > > Message/MessageSet classes on > > the > > > > > >> broker > > > > > >> > > which > > > > > >> > > > > I'm > > > > > >> > > > > > > not > > > > > >> > > > > > > >> > sure > > > > > >> > > > > > > >> > > > if > > > > > >> > > > > > > >> > > > > > we'd > > > > > >> > > > > > > >> > > > > > > > > want > > > > > >> > > > > > > >> > > > > > > > > > to > > > > > >> > > > > > > >> > > > > > > > > > > support over the long haul > but > > it > > > > > >> might be > > > > > >> > > > okay > > > > > >> > > > > > just > > > > > >> > > > > > > >> to > > > > > >> > > > > > > >> > > > create > > > > > >> > > > > > > >> > > > > > the > > > > > >> > > > > > > >> > > > > > > > > > records > > > > > >> > > > > > > >> > > > > > > > > > > instance for this interface. > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > -Jay > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > On Mon, Jan 25, 2016 at 12:37 > > PM, > > > > > Joel > > > > > >> > > Koshy < > > > > > >> > > > > > > >> > > > > > jjkosh...@gmail.com> > > > > > >> > > > > > > >> > > > > > > > > > wrote: > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > I'm definitely in favor of > > > having > > > > > >> such > > > > > >> > > hooks > > > > > >> > > > > in > > > > > >> > > > > > > the > > > > > >> > > > > > > >> > > > > > > produce/consume > > > > > >> > > > > > > >> > > > > > > > > > > > life-cycle. Not sure if > > people > > > > > >> remember > > > > > >> > > this > > > > > >> > > > > but > > > > > >> > > > > > > in > > > > > >> > > > > > > >> > Kafka > > > > > >> > > > > > > >> > > > 0.7 > > > > > >> > > > > > > >> > > > > > > this > > > > > >> > > > > > > >> > > > > > > > > was > > > > > >> > > > > > > >> > > > > > > > > > > > pretty much how it was: > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > > > > > >> > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > > >> > > > > > > >> > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > https://github.com/apache/kafka/blob/0.7/core/src/main/scala/kafka/producer/async/CallbackHandler.scala > > > > > >> > > > > > > >> > > > > > > > > > > > i.e., we had something > > similar > > > to > > > > > the > > > > > >> > > > > > interceptor > > > > > >> > > > > > > >> > > proposal > > > > > >> > > > > > > >> > > > > for > > > > > >> > > > > > > >> > > > > > > > > various > > > > > >> > > > > > > >> > > > > > > > > > > > stages of the producer > > request. > > > > The > > > > > >> > > producer > > > > > >> > > > > > > >> provided > > > > > >> > > > > > > >> > > > > > call-backs > > > > > >> > > > > > > >> > > > > > > > for > > > > > >> > > > > > > >> > > > > > > > > > > > beforeEnqueue, > afterEnqueue, > > > > > >> > > afterDequeuing, > > > > > >> > > > > > > >> > > beforeSending, > > > > > >> > > > > > > >> > > > > > etc. > > > > > >> > > > > > > >> > > > > > > So > > > > > >> > > > > > > >> > > > > > > > > at > > > > > >> > > > > > > >> > > > > > > > > > > > LinkedIn we in fact did > > > auditing > > > > > >> within > > > > > >> > > > these > > > > > >> > > > > > > >> > call-backs > > > > > >> > > > > > > >> > > > (and > > > > > >> > > > > > > >> > > > > > not > > > > > >> > > > > > > >> > > > > > > > > > > > explicitly in the wrapper). > > > Over > > > > > time > > > > > >> > and > > > > > >> > > > with > > > > > >> > > > > > 0.8 > > > > > >> > > > > > > >> we > > > > > >> > > > > > > >> > > moved > > > > > >> > > > > > > >> > > > > > that > > > > > >> > > > > > > >> > > > > > > > out > > > > > >> > > > > > > >> > > > > > > > > to > > > > > >> > > > > > > >> > > > > > > > > > > the > > > > > >> > > > > > > >> > > > > > > > > > > > wrapper libraries. > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > On a side-note while audit > > and > > > > > other > > > > > >> > > > > monitoring > > > > > >> > > > > > > can > > > > > >> > > > > > > >> be > > > > > >> > > > > > > >> > > done > > > > > >> > > > > > > >> > > > > > > > > internally > > > > > >> > > > > > > >> > > > > > > > > > > in a > > > > > >> > > > > > > >> > > > > > > > > > > > convenient way I think it > > > should > > > > be > > > > > >> > > > clarified > > > > > >> > > > > > that > > > > > >> > > > > > > >> > > having a > > > > > >> > > > > > > >> > > > > > > wrapper > > > > > >> > > > > > > >> > > > > > > > > is > > > > > >> > > > > > > >> > > > > > > > > > in > > > > > >> > > > > > > >> > > > > > > > > > > > general not a bad idea and > I > > > > would > > > > > >> even > > > > > >> > > > > consider > > > > > >> > > > > > > it > > > > > >> > > > > > > >> to > > > > > >> > > > > > > >> > > be a > > > > > >> > > > > > > >> > > > > > > > > > > best-practice. > > > > > >> > > > > > > >> > > > > > > > > > > > Even with 0.7 we still had > a > > > > > wrapper > > > > > >> > > library > > > > > >> > > > > and > > > > > >> > > > > > > >> that > > > > > >> > > > > > > >> > API > > > > > >> > > > > > > >> > > > has > > > > > >> > > > > > > >> > > > > > > > largely > > > > > >> > > > > > > >> > > > > > > > > > > > stayed the same and has > > helped > > > > > >> protect > > > > > >> > > > against > > > > > >> > > > > > > >> > (sometimes > > > > > >> > > > > > > >> > > > > > > backwards > > > > > >> > > > > > > >> > > > > > > > > > > > incompatible) changes in > open > > > > > source. > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > While we are on this topic > I > > > have > > > > > one > > > > > >> > > > comment > > > > > >> > > > > > and > > > > > >> > > > > > > >> Anna, > > > > > >> > > > > > > >> > > you > > > > > >> > > > > > > >> > > > > may > > > > > >> > > > > > > >> > > > > > > > have > > > > > >> > > > > > > >> > > > > > > > > > > > already considered this > but I > > > > don't > > > > > >> see > > > > > >> > > > > mention > > > > > >> > > > > > of > > > > > >> > > > > > > >> it > > > > > >> > > > > > > >> > in > > > > > >> > > > > > > >> > > > the > > > > > >> > > > > > > >> > > > > > KIP: > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > Add a custom message > > > > > >> > interceptor/validator > > > > > >> > > > on > > > > > >> > > > > > the > > > > > >> > > > > > > >> > broker > > > > > >> > > > > > > >> > > on > > > > > >> > > > > > > >> > > > > > > message > > > > > >> > > > > > > >> > > > > > > > > > > > arrival. > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > We decompress and do basic > > > > > >> validation of > > > > > >> > > > > > messages > > > > > >> > > > > > > on > > > > > >> > > > > > > >> > > > > arrival. I > > > > > >> > > > > > > >> > > > > > > > think > > > > > >> > > > > > > >> > > > > > > > > > > there > > > > > >> > > > > > > >> > > > > > > > > > > > is value in supporting > custom > > > > > >> validation > > > > > >> > > and > > > > > >> > > > > > > expand > > > > > >> > > > > > > >> it > > > > > >> > > > > > > >> > to > > > > > >> > > > > > > >> > > > > > support > > > > > >> > > > > > > >> > > > > > > > > > custom > > > > > >> > > > > > > >> > > > > > > > > > > > on-arrival processing. Here > > is > > > a > > > > > >> > specific > > > > > >> > > > > > > use-case I > > > > > >> > > > > > > >> > have > > > > > >> > > > > > > >> > > > in > > > > > >> > > > > > > >> > > > > > > mind. > > > > > >> > > > > > > >> > > > > > > > > The > > > > > >> > > > > > > >> > > > > > > > > > > blog > > > > > >> > > > > > > >> > > > > > > > > > > > that James referenced > > describes > > > > our > > > > > >> > > auditing > > > > > >> > > > > > > >> > > > infrastructure. > > > > > >> > > > > > > >> > > > > In > > > > > >> > > > > > > >> > > > > > > > order > > > > > >> > > > > > > >> > > > > > > > > > to > > > > > >> > > > > > > >> > > > > > > > > > > > audit the Kafka cluster > > itself > > > we > > > > > >> need > > > > > >> > to > > > > > >> > > > run > > > > > >> > > > > a > > > > > >> > > > > > > >> > "console > > > > > >> > > > > > > >> > > > > > auditor" > > > > > >> > > > > > > >> > > > > > > > > > service > > > > > >> > > > > > > >> > > > > > > > > > > > that consumes everything > and > > > > spits > > > > > >> out > > > > > >> > > audit > > > > > >> > > > > > > events > > > > > >> > > > > > > >> > back > > > > > >> > > > > > > >> > > to > > > > > >> > > > > > > >> > > > > the > > > > > >> > > > > > > >> > > > > > > > > > cluster. > > > > > >> > > > > > > >> > > > > > > > > > > I > > > > > >> > > > > > > >> > > > > > > > > > > > would prefer not having to > > run > > > > this > > > > > >> > > service > > > > > >> > > > > > > because: > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > - Well, it is one more > > > service > > > > > >> that > > > > > >> > we > > > > > >> > > > have > > > > > >> > > > > > to > > > > > >> > > > > > > >> run > > > > > >> > > > > > > >> > and > > > > > >> > > > > > > >> > > > > > monitor > > > > > >> > > > > > > >> > > > > > > > > > > > - Consuming everything > > takes > > > > up > > > > > >> > > bandwidth > > > > > >> > > > > > which > > > > > >> > > > > > > >> can > > > > > >> > > > > > > >> > be > > > > > >> > > > > > > >> > > > > > avoided > > > > > >> > > > > > > >> > > > > > > > > > > > - The console auditor > > > consumer > > > > > >> itself > > > > > >> > > can > > > > > >> > > > > lag > > > > > >> > > > > > > and > > > > > >> > > > > > > >> > > cause > > > > > >> > > > > > > >> > > > > > > > temporary > > > > > >> > > > > > > >> > > > > > > > > > > audit > > > > > >> > > > > > > >> > > > > > > > > > > > discrepancies > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > One way we can mitigate > this > > is > > > > by > > > > > >> > having > > > > > >> > > > > > > >> mirror-makers > > > > > >> > > > > > > >> > > in > > > > > >> > > > > > > >> > > > > > > between > > > > > >> > > > > > > >> > > > > > > > > > > clusters > > > > > >> > > > > > > >> > > > > > > > > > > > emit audit events. The > > problem > > > is > > > > > >> that > > > > > >> > the > > > > > >> > > > > very > > > > > >> > > > > > > last > > > > > >> > > > > > > >> > > > cluster > > > > > >> > > > > > > >> > > > > in > > > > > >> > > > > > > >> > > > > > > the > > > > > >> > > > > > > >> > > > > > > > > > > > pipeline will not have any > > > audit > > > > > >> which > > > > > >> > is > > > > > >> > > > why > > > > > >> > > > > we > > > > > >> > > > > > > >> need > > > > > >> > > > > > > >> > to > > > > > >> > > > > > > >> > > > have > > > > > >> > > > > > > >> > > > > > > > > something > > > > > >> > > > > > > >> > > > > > > > > > > to > > > > > >> > > > > > > >> > > > > > > > > > > > audit the cluster. > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > If we had a custom message > > > > > validator > > > > > >> > then > > > > > >> > > > the > > > > > >> > > > > > > audit > > > > > >> > > > > > > >> can > > > > > >> > > > > > > >> > > be > > > > > >> > > > > > > >> > > > > done > > > > > >> > > > > > > >> > > > > > > > > > > on-arrival > > > > > >> > > > > > > >> > > > > > > > > > > > and we won't need a console > > > > > auditor. > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > One potential issue in this > > > > > approach > > > > > >> and > > > > > >> > > any > > > > > >> > > > > > > >> elaborate > > > > > >> > > > > > > >> > > > > > on-arrival > > > > > >> > > > > > > >> > > > > > > > > > > > processing for that matter > is > > > > that > > > > > >> you > > > > > >> > may > > > > > >> > > > > need > > > > > >> > > > > > to > > > > > >> > > > > > > >> > > > > deserialize > > > > > >> > > > > > > >> > > > > > > the > > > > > >> > > > > > > >> > > > > > > > > > > message > > > > > >> > > > > > > >> > > > > > > > > > > > as well which can drive up > > > > produce > > > > > >> > request > > > > > >> > > > > > > handling > > > > > >> > > > > > > >> > > times. > > > > > >> > > > > > > >> > > > > > > However > > > > > >> > > > > > > >> > > > > > > > > I'm > > > > > >> > > > > > > >> > > > > > > > > > > not > > > > > >> > > > > > > >> > > > > > > > > > > > terribly concerned about > that > > > > > >> especially > > > > > >> > > if > > > > > >> > > > > the > > > > > >> > > > > > > >> audit > > > > > >> > > > > > > >> > > > header > > > > > >> > > > > > > >> > > > > > can > > > > > >> > > > > > > >> > > > > > > be > > > > > >> > > > > > > >> > > > > > > > > > > > separated out easily or > even > > > > > >> > deserialized > > > > > >> > > > > > > partially > > > > > >> > > > > > > >> as > > > > > >> > > > > > > >> > > this > > > > > >> > > > > > > >> > > > > > Avro > > > > > >> > > > > > > >> > > > > > > > > thread > > > > > >> > > > > > > >> > > > > > > > > > > > touches on > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > > > > > >> > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > > >> > > > > > > >> > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > http://search-hadoop.com/m/F2svI1HDLY12W8tnH1&subj=Re+any+optimization+in+reading+a+partial+schema+in+the+decoder+ > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > Thanks, > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > Joel > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > On Mon, Jan 25, 2016 at > 12:02 > > > PM, > > > > > >> > Mayuresh > > > > > >> > > > > > Gharat > > > > > >> > > > > > > < > > > > > >> > > > > > > >> > > > > > > > > > > > gharatmayures...@gmail.com > > > > > > wrote: > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > Nice KIP. Excellent idea. > > > > > >> > > > > > > >> > > > > > > > > > > > > Was just thinking if we > can > > > add > > > > > >> > > onDequed() > > > > > >> > > > > to > > > > > >> > > > > > > the > > > > > >> > > > > > > >> > > > > > > > > ProducerIterceptor > > > > > >> > > > > > > >> > > > > > > > > > > > > interface. Since we have > > the > > > > > >> > > onEnqueued(), > > > > > >> > > > > it > > > > > >> > > > > > > will > > > > > >> > > > > > > >> > help > > > > > >> > > > > > > >> > > > the > > > > > >> > > > > > > >> > > > > > > > client > > > > > >> > > > > > > >> > > > > > > > > or > > > > > >> > > > > > > >> > > > > > > > > > > the > > > > > >> > > > > > > >> > > > > > > > > > > > > tools to know how much > time > > > the > > > > > >> > message > > > > > >> > > > > spent > > > > > >> > > > > > in > > > > > >> > > > > > > >> the > > > > > >> > > > > > > >> > > > > > > > > > RecordAccumulator. > > > > > >> > > > > > > >> > > > > > > > > > > > > Also an API to check if > > there > > > > are > > > > > >> any > > > > > >> > > > > messages > > > > > >> > > > > > > >> left > > > > > >> > > > > > > >> > > for a > > > > > >> > > > > > > >> > > > > > > > > particular > > > > > >> > > > > > > >> > > > > > > > > > > > topic > > > > > >> > > > > > > >> > > > > > > > > > > > > in the RecordAccumulator > > > would > > > > > >> help. > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > Thanks, > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > Mayuresh > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > On Mon, Jan 25, 2016 at > > 11:29 > > > > AM, > > > > > >> Todd > > > > > >> > > > > Palino > > > > > >> > > > > > < > > > > > >> > > > > > > >> > > > > > > tpal...@gmail.com > > > > > >> > > > > > > >> > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > wrote: > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > Great idea. I’ve been > > > talking > > > > > >> about > > > > > >> > > this > > > > > >> > > > > > for 2 > > > > > >> > > > > > > >> > years, > > > > > >> > > > > > > >> > > > and > > > > > >> > > > > > > >> > > > > > I’m > > > > > >> > > > > > > >> > > > > > > > > glad > > > > > >> > > > > > > >> > > > > > > > > > > > > someone > > > > > >> > > > > > > >> > > > > > > > > > > > > > is finally picking it > up. > > > > Will > > > > > >> take > > > > > >> > a > > > > > >> > > > look > > > > > >> > > > > > at > > > > > >> > > > > > > >> the > > > > > >> > > > > > > >> > KIP > > > > > >> > > > > > > >> > > > at > > > > > >> > > > > > > >> > > > > > some > > > > > >> > > > > > > >> > > > > > > > > point > > > > > >> > > > > > > >> > > > > > > > > > > > > > shortly. > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > -Todd > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > On Mon, Jan 25, 2016 at > > > 11:24 > > > > > AM, > > > > > >> > Jay > > > > > >> > > > > Kreps > > > > > >> > > > > > < > > > > > >> > > > > > > >> > > > > > > j...@confluent.io> > > > > > >> > > > > > > >> > > > > > > > > > > wrote: > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > Hey Becket, > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > Yeah this is really > > > similar > > > > > to > > > > > >> the > > > > > >> > > > > > callback. > > > > > >> > > > > > > >> The > > > > > >> > > > > > > >> > > > > > difference > > > > > >> > > > > > > >> > > > > > > > is > > > > > >> > > > > > > >> > > > > > > > > > > really > > > > > >> > > > > > > >> > > > > > > > > > > > > in > > > > > >> > > > > > > >> > > > > > > > > > > > > > > who sets the > behavior. > > > The > > > > > >> idea of > > > > > >> > > the > > > > > >> > > > > > > >> > interceptor > > > > > >> > > > > > > >> > > is > > > > > >> > > > > > > >> > > > > > that > > > > > >> > > > > > > >> > > > > > > it > > > > > >> > > > > > > >> > > > > > > > > > > doesn't > > > > > >> > > > > > > >> > > > > > > > > > > > > > > require any code > change > > > in > > > > > >> apps so > > > > > >> > > you > > > > > >> > > > > can > > > > > >> > > > > > > >> > globally > > > > > >> > > > > > > >> > > > add > > > > > >> > > > > > > >> > > > > > > > > behavior > > > > > >> > > > > > > >> > > > > > > > > > to > > > > > >> > > > > > > >> > > > > > > > > > > > > your > > > > > >> > > > > > > >> > > > > > > > > > > > > > > Kafka usage without > > > > changing > > > > > >> app > > > > > >> > > code. > > > > > >> > > > > > > Whereas > > > > > >> > > > > > > >> > the > > > > > >> > > > > > > >> > > > > > callback > > > > > >> > > > > > > >> > > > > > > > is > > > > > >> > > > > > > >> > > > > > > > > > > added > > > > > >> > > > > > > >> > > > > > > > > > > > by > > > > > >> > > > > > > >> > > > > > > > > > > > > > the > > > > > >> > > > > > > >> > > > > > > > > > > > > > > app. The idea is to > > kind > > > of > > > > > >> > obviate > > > > > >> > > > the > > > > > >> > > > > > need > > > > > >> > > > > > > >> for > > > > > >> > > > > > > >> > > the > > > > > >> > > > > > > >> > > > > > > wrapper > > > > > >> > > > > > > >> > > > > > > > > code > > > > > >> > > > > > > >> > > > > > > > > > > > that > > > > > >> > > > > > > >> > > > > > > > > > > > > > e.g. > > > > > >> > > > > > > >> > > > > > > > > > > > > > > LinkedIn maintains to > > > hold > > > > > this > > > > > >> > kind > > > > > >> > > > of > > > > > >> > > > > > > stuff. > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > -Jay > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > On Sun, Jan 24, 2016 > at > > > > 4:21 > > > > > >> PM, > > > > > >> > > > Becket > > > > > >> > > > > > Qin > > > > > >> > > > > > > < > > > > > >> > > > > > > >> > > > > > > > > > becket....@gmail.com> > > > > > >> > > > > > > >> > > > > > > > > > > > > > wrote: > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > This could be a > > useful > > > > > >> feature. > > > > > >> > > And > > > > > >> > > > I > > > > > >> > > > > > > think > > > > > >> > > > > > > >> > there > > > > > >> > > > > > > >> > > > are > > > > > >> > > > > > > >> > > > > > > some > > > > > >> > > > > > > >> > > > > > > > > use > > > > > >> > > > > > > >> > > > > > > > > > > > cases > > > > > >> > > > > > > >> > > > > > > > > > > > > to > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > mutate the data > like > > > > > rejected > > > > > >> > > > > > alternative > > > > > >> > > > > > > >> one > > > > > >> > > > > > > >> > > > > > mentioned. > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > I am wondering if > > there > > > > is > > > > > >> > > > functional > > > > > >> > > > > > > >> > overlapping > > > > > >> > > > > > > >> > > > > > between > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > ProducerInterceptor.onAcknowledgement() > > > > > >> > > > > > > and > > > > > >> > > > > > > >> the > > > > > >> > > > > > > >> > > > > > producer > > > > > >> > > > > > > >> > > > > > > > > > > callback? > > > > > >> > > > > > > >> > > > > > > > > > > > I > > > > > >> > > > > > > >> > > > > > > > > > > > > > can > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > see that the > Callback > > > > could > > > > > >> be a > > > > > >> > > per > > > > > >> > > > > > > record > > > > > >> > > > > > > >> > > setting > > > > > >> > > > > > > >> > > > > > while > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > onAcknowledgement() > > is > > > a > > > > > >> > producer > > > > > >> > > > > level > > > > > >> > > > > > > >> > setting. > > > > > >> > > > > > > >> > > > > Other > > > > > >> > > > > > > >> > > > > > > than > > > > > >> > > > > > > >> > > > > > > > > > that, > > > > > >> > > > > > > >> > > > > > > > > > > > is > > > > > >> > > > > > > >> > > > > > > > > > > > > > > there > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > any difference > > between > > > > > them? > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > Thanks, > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > Jiangjie (Becket) > Qin > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > On Fri, Jan 22, > 2016 > > at > > > > > 6:21 > > > > > >> PM, > > > > > >> > > > Neha > > > > > >> > > > > > > >> Narkhede > > > > > >> > > > > > > >> > < > > > > > >> > > > > > > >> > > > > > > > > > > n...@confluent.io> > > > > > >> > > > > > > >> > > > > > > > > > > > > > > wrote: > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > James, > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > That is one of > the > > > many > > > > > >> > > monitoring > > > > > >> > > > > use > > > > > >> > > > > > > >> cases > > > > > >> > > > > > > >> > > for > > > > > >> > > > > > > >> > > > > the > > > > > >> > > > > > > >> > > > > > > > > > > interceptor > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > interface. > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > Thanks, > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > Neha > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > On Fri, Jan 22, > > 2016 > > > at > > > > > >> 6:18 > > > > > >> > PM, > > > > > >> > > > > James > > > > > >> > > > > > > >> Cheng > > > > > >> > > > > > > >> > < > > > > > >> > > > > > > >> > > > > > > > > > jch...@tivo.com> > > > > > >> > > > > > > >> > > > > > > > > > > > > > wrote: > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > Anna, > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > I'm trying to > > > > > understand > > > > > >> a > > > > > >> > > > > concrete > > > > > >> > > > > > > use > > > > > >> > > > > > > >> > case. > > > > > >> > > > > > > >> > > > It > > > > > >> > > > > > > >> > > > > > > sounds > > > > > >> > > > > > > >> > > > > > > > > > like > > > > > >> > > > > > > >> > > > > > > > > > > > > > producer > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > interceptors > > could > > > be > > > > > >> used > > > > > >> > to > > > > > >> > > > > > > implement > > > > > >> > > > > > > >> > part > > > > > >> > > > > > > >> > > of > > > > > >> > > > > > > >> > > > > > > > > LinkedIn's > > > > > >> > > > > > > >> > > > > > > > > > > > Kafak > > > > > >> > > > > > > >> > > > > > > > > > > > > > > Audit > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > tool? > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > >> > https://engineering.linkedin.com/kafka/running-kafka-scale > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > Part of that is > > > done > > > > > by a > > > > > >> > > > wrapper > > > > > >> > > > > > > >> library > > > > > >> > > > > > > >> > > > around > > > > > >> > > > > > > >> > > > > > the > > > > > >> > > > > > > >> > > > > > > > > kafka > > > > > >> > > > > > > >> > > > > > > > > > > > > producer > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > that > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > keeps a count > of > > > the > > > > > >> number > > > > > >> > of > > > > > >> > > > > > > messages > > > > > >> > > > > > > >> > > > produced, > > > > > >> > > > > > > >> > > > > > and > > > > > >> > > > > > > >> > > > > > > > > then > > > > > >> > > > > > > >> > > > > > > > > > > > sends > > > > > >> > > > > > > >> > > > > > > > > > > > > > that > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > count > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > to a > side-topic. > > It > > > > > >> sounds > > > > > >> > > like > > > > > >> > > > > the > > > > > >> > > > > > > >> > producer > > > > > >> > > > > > > >> > > > > > > > interceptors > > > > > >> > > > > > > >> > > > > > > > > > > could > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > possibly > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > be > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > used to > implement > > > > that? > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > -James > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > On Jan 22, > > 2016, > > > at > > > > > >> 4:33 > > > > > >> > PM, > > > > > >> > > > > Anna > > > > > >> > > > > > > >> > Povzner < > > > > > >> > > > > > > >> > > > > > > > > > > a...@confluent.io > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > wrote: > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > Hi, > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > I just > created > > a > > > > > KIP-42 > > > > > >> > for > > > > > >> > > > > adding > > > > > >> > > > > > > >> > producer > > > > > >> > > > > > > >> > > > and > > > > > >> > > > > > > >> > > > > > > > > consumer > > > > > >> > > > > > > >> > > > > > > > > > > > > > > interceptors > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > for > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > intercepting > > > > messages > > > > > >> at > > > > > >> > > > > different > > > > > >> > > > > > > >> points > > > > > >> > > > > > > >> > > on > > > > > >> > > > > > > >> > > > > > > producer > > > > > >> > > > > > > >> > > > > > > > > and > > > > > >> > > > > > > >> > > > > > > > > > > > > > consumer. > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > > > > > >> > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > > >> > > > > > > >> > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-42%3A+Add+Producer+and+Consumer+Interceptors > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > Comments and > > > > > >> suggestions > > > > > >> > are > > > > > >> > > > > > > welcome! > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > Thanks, > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > Anna > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > >> > > ________________________________ > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > This email and > > any > > > > > >> > attachments > > > > > >> > > > may > > > > > >> > > > > > > >> contain > > > > > >> > > > > > > >> > > > > > > confidential > > > > > >> > > > > > > >> > > > > > > > > and > > > > > >> > > > > > > >> > > > > > > > > > > > > > > privileged > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > material for > the > > > sole > > > > > >> use of > > > > > >> > > the > > > > > >> > > > > > > >> intended > > > > > >> > > > > > > >> > > > > > recipient. > > > > > >> > > > > > > >> > > > > > > > Any > > > > > >> > > > > > > >> > > > > > > > > > > > review, > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > copying, > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > or distribution > > of > > > > this > > > > > >> > email > > > > > >> > > > (or > > > > > >> > > > > > any > > > > > >> > > > > > > >> > > > > attachments) > > > > > >> > > > > > > >> > > > > > by > > > > > >> > > > > > > >> > > > > > > > > > others > > > > > >> > > > > > > >> > > > > > > > > > > is > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > prohibited. > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > If you are not > > the > > > > > >> intended > > > > > >> > > > > > recipient, > > > > > >> > > > > > > >> > please > > > > > >> > > > > > > >> > > > > > contact > > > > > >> > > > > > > >> > > > > > > > the > > > > > >> > > > > > > >> > > > > > > > > > > > sender > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > immediately and > > > > > >> permanently > > > > > >> > > > delete > > > > > >> > > > > > > this > > > > > >> > > > > > > >> > email > > > > > >> > > > > > > >> > > > and > > > > > >> > > > > > > >> > > > > > any > > > > > >> > > > > > > >> > > > > > > > > > > > > attachments. > > > > > >> > > > > > > >> > > > > > > > > > > > > > No > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > employee or > agent > > > of > > > > > TiVo > > > > > >> > Inc. > > > > > >> > > > is > > > > > >> > > > > > > >> > authorized > > > > > >> > > > > > > >> > > to > > > > > >> > > > > > > >> > > > > > > > conclude > > > > > >> > > > > > > >> > > > > > > > > > any > > > > > >> > > > > > > >> > > > > > > > > > > > > > binding > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > agreement on > > behalf > > > > of > > > > > >> TiVo > > > > > >> > > Inc. > > > > > >> > > > > by > > > > > >> > > > > > > >> email. > > > > > >> > > > > > > >> > > > > Binding > > > > > >> > > > > > > >> > > > > > > > > > agreements > > > > > >> > > > > > > >> > > > > > > > > > > > > with > > > > > >> > > > > > > >> > > > > > > > > > > > > > > TiVo > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > Inc. may only > be > > > made > > > > > by > > > > > >> a > > > > > >> > > > signed > > > > > >> > > > > > > >> written > > > > > >> > > > > > > >> > > > > > agreement. > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > -- > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > Thanks, > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > Neha > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > -- > > > > > >> > > > > > > >> > > > > > > > > > > > > > *—-* > > > > > >> > > > > > > >> > > > > > > > > > > > > > *Todd Palino* > > > > > >> > > > > > > >> > > > > > > > > > > > > > Staff Site Reliability > > > > Engineer > > > > > >> > > > > > > >> > > > > > > > > > > > > > Data Infrastructure > > > Streaming > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > linkedin.com/in/toddpalino > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > -- > > > > > >> > > > > > > >> > > > > > > > > > > > > -Regards, > > > > > >> > > > > > > >> > > > > > > > > > > > > Mayuresh R. Gharat > > > > > >> > > > > > > >> > > > > > > > > > > > > (862) 250-7125 > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > -- > > > > > >> > > > > > > >> > > > > > > > > > Thanks, > > > > > >> > > > > > > >> > > > > > > > > > Neha > > > > > >> > > > > > > >> > > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > -- > > > > > >> > > > > > > >> > > > > > > > *—-* > > > > > >> > > > > > > >> > > > > > > > *Todd Palino* > > > > > >> > > > > > > >> > > > > > > > Staff Site Reliability Engineer > > > > > >> > > > > > > >> > > > > > > > Data Infrastructure Streaming > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > linkedin.com/in/toddpalino > > > > > >> > > > > > > >> > > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > -- > > > > > >> > > > > > > >> > > > > > -Regards, > > > > > >> > > > > > > >> > > > > > Mayuresh R. Gharat > > > > > >> > > > > > > >> > > > > > (862) 250-7125 > > > > > >> > > > > > > >> > > > > > > > > > > >> > > > > > > >> > > > > > > > > > >> > > > > > > >> > > > > > > > > >> > > > > > > >> > > > > > > > > >> > > > > > > >> > > > > > > > > >> > > > > > > >> > > > -- > > > > > >> > > > > > > >> > > > *—-* > > > > > >> > > > > > > >> > > > *Todd Palino* > > > > > >> > > > > > > >> > > > Staff Site Reliability Engineer > > > > > >> > > > > > > >> > > > Data Infrastructure Streaming > > > > > >> > > > > > > >> > > > > > > > > >> > > > > > > >> > > > > > > > > >> > > > > > > >> > > > > > > > > >> > > > > > > >> > > > linkedin.com/in/toddpalino > > > > > >> > > > > > > >> > > > > > > > > >> > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > > > >> > > > > > > >> > > -- > > > > > >> > > > > > > >> > > -Regards, > > > > > >> > > > > > > >> > > Mayuresh R. Gharat > > > > > >> > > > > > > >> > > (862) 250-7125 > > > > > >> > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > > >> > > > > > > >> > > > > > >> > > > > > > >> > > > > > >> > > > > > > >> > > > > > >> > > > > > > >> -- > > > > > >> > > > > > > >> -Regards, > > > > > >> > > > > > > >> Mayuresh R. Gharat > > > > > >> > > > > > > >> (862) 250-7125 > > > > > >> > > > > > > >> > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > > >> > > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > > > > > > >> > > > > > -- > > > > > >> > > > > > Thanks, > > > > > >> > > > > > Neha > > > > > >> > > > > > > > > > > >> > > > > > > > > > >> > > > > > > > > >> > > > > > > > >> > > > > > > >> > > > > > >> > > > > > >> > > > > > >> -- > > > > > >> *—-* > > > > > >> *Todd Palino* > > > > > >> Staff Site Reliability Engineer > > > > > >> Data Infrastructure Streaming > > > > > >> > > > > > >> > > > > > >> > > > > > >> linkedin.com/in/toddpalino > > > > > >> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > -- > > > Thanks, > > > Neha > > > > > >
