On Mon, Sep 26, 2016 at 6:10 PM, Gary Gregory <garydgreg...@gmail.com> wrote:
> On Mon, Sep 26, 2016 at 6:09 PM, Gary Gregory <garydgreg...@gmail.com> > wrote: > >> On Mon, Sep 26, 2016 at 5:21 PM, Ralph Goers <ralph.go...@dslextreme.com> >> wrote: >> >>> I thought you didn’t want to write to a file? >>> >> >> I do not but if the buffer is large enough, log events should stay in >> RAM. But it is not quite right anyway because I'd have to interpret the >> contents of the file to turn back into log events. >> >> I started reading up on the Chronicle appender; thank you Remko for >> pointing it out. >> >> An appender to a cache of objects is really want I want since I also want >> to be able to evict the cache. TBC... >> > > Like a JSR-107 Appender... > Looking at EHCache and https://ignite.apache.org/jcache/1.0.0/javadoc/javax/cache/Cache.html I can see that a cache is always a kind of map, which leads to what the key should be. A sequence number like we have in the pattern layout seems like a natural choice. I could see a Jsr107Appender that tracks a sequence number as the key. The issue is that the JSR107 Cache interface defines the iterator order as undefined which would force a client trying to drain a Jsr107Appender to sort all entries before being able to serialize them. Unless I can find a list-based Cache implementation within EhCache for example. Gary > > Gary > >> >> Gary >> >> >>> The Chronicle stuff Remko is linking to is also worth exploring. >>> >>> Ralph >>> >>> >>> >>> On Sep 26, 2016, at 5:04 PM, Gary Gregory <garydgreg...@gmail.com> >>> wrote: >>> >>> oh... what about our own http://logging.apache.org/ >>> log4j/2.x/manual/appenders.html#MemoryMappedFileAppender >>> >>> ? >>> >>> Gary >>> >>> On Mon, Sep 26, 2016 at 4:59 PM, Remko Popma <remko.po...@gmail.com> >>> wrote: >>> >>>> In addition to the Flume based solution, here is another alternative >>>> idea: use Peter Lawrey's Chronicle[1] library to store log events in a >>>> memory mapped file. >>>> >>>> The appender can just keep adding events without worrying about >>>> overflowing the memory. >>>> >>>> The client that reads from this file can be in a separate thread (even >>>> a separate process by the way) and can read as much as it wants, and send >>>> it to the server. >>>> >>>> Serialization: You can either serialize log events to the target format >>>> before storing them in Chronicle (so you have binary blobs in each >>>> Chronicle excerpt), client reads these blobs and sends them to the server >>>> as is. Or you can use the Chronicle Log4j2 appender[2] to store the events >>>> in Chronicle format. The tests[3] show how to read LogEvent objects from >>>> the memory mapped file, and the client would be responsible for serializing >>>> these log events to the target format before sending data to the server. >>>> >>>> [1]: https://github.com/peter-lawrey/Java-Chronicle >>>> [2]: https://github.com/OpenHFT/Chronicle-Logger >>>> [3]: https://github.com/OpenHFT/Chronicle-Logger/blob/master >>>> /logger-log4j-2/src/test/java/net/openhft/chronicle/logger/l >>>> og4j2/Log4j2IndexedChronicleTest.java >>>> >>>> Remko >>>> >>>> Sent from my iPhone >>>> >>>> On 2016/09/27, at 5:57, Gary Gregory <garydgreg...@gmail.com> wrote: >>>> >>>> Please allow me to restate the use case I have for the >>>> CollectionAppender, which is separate from any Flume-based or Syslog-based >>>> solution, use cases I also have. Well, I have a Syslog use case, and >>>> whether or not Flume is in the picture will really be a larger discussion >>>> in my organization due to the requirement to run a Flume Agent.) >>>> >>>> A program (like a JDBC driver already using Log4j) communicates with >>>> another (like a DBMS, not written in Java). The client and server >>>> communicate over a proprietary socket protocol. The client sends a list of >>>> buffers (in one go) to the server to perform one or more operations. One >>>> kind of buffer this protocol defines is a log buffer (where each log event >>>> is serialized in a non-Java format.) This allows each communication from >>>> the client to the server to say "This is what's happened up to now". What >>>> the server does with the log buffers is not important for this discussion. >>>> >>>> What is important to note is that the log buffer and other buffers go >>>> to the server in one BLOB; which is why I cannot (in this use case) send >>>> log events by themselves anywhere. >>>> >>>> I see that something (a CollectionAppender) must collect log events >>>> until the client is ready to serialize them and send them to the server. >>>> Once the events are drained out of the Appender (in one go by just getting >>>> the collection), events can collect in a new collection. A synchronous >>>> drain operation would create a new collection and return the old one. >>>> >>>> The question becomes: What kind of temporary location can the client >>>> use to buffer log event until drain time? A Log4j Appender is a natural >>>> place to collect log events since the driver uses Log4j. The driver will >>>> make its business to drain the appender and work with the events at the >>>> right time. I am thinking that the Log4j Appender part is generic enough >>>> for inclusion in Log4j. >>>> >>>> Further thoughts? >>>> >>>> Thank you all for reading this far! >>>> Gary >>>> >>>> On Sun, Sep 25, 2016 at 1:20 PM, Ralph Goers < >>>> ralph.go...@dslextreme.com> wrote: >>>> >>>>> I guess I am not understanding your use case quite correctly. I am >>>>> thinking you have a driver that is logging and you want those logs >>>>> delivered to some other location to actually be written. If that is your >>>>> use case then the driver needs a log4j2.xml that configures the >>>>> FlumeAppender with either the memory or file channel (depending on your >>>>> needs) and points to the server(s) that is/are to receive the events. The >>>>> FlumeAppender handles sending them in batches with whatever size you want >>>>> (but will send them in smaller amounts if they are in the channel too >>>>> long). Of course you would need the log4j-flume and flume jars. So on the >>>>> driver side you wouldn’t need to write anything, just configure the >>>>> appender and make sure the jars are there. >>>>> >>>>> For the server that receives them you would also need Flume. Normally >>>>> this would be a standalone component, but it really wouldn’t be hard to >>>>> incorporate it into some other application. The only thing you would have >>>>> to write would be the sink that writes the events to the database or >>>>> whatever. To incorporate it into an application you would have to look at >>>>> the main() method of flume and covert that to be a thread that you kick >>>>> off. >>>>> >>>>> Ralph >>>>> >>>>> >>>>> >>>>> On Sep 25, 2016, at 12:01 PM, Gary Gregory <garydgreg...@gmail.com> >>>>> wrote: >>>>> >>>>> Hi Ralph, >>>>> >>>>> Thanks for your feedback. Flume is great in the scenarios that do not >>>>> involve sending a log buffer from the driver itself. >>>>> >>>>> I can't require a Flume Agent to be running 'on the side' for the use >>>>> case where the driver chains a log buffer at the end of the train of >>>>> database IO buffer. For completeness talking about this Flume scenario, if >>>>> I read you right, I also would need to write a custom Flume sink, which >>>>> would also be in memory, until the driver is ready to drain it. Or, I >>>>> could >>>>> query some other 'safe' and 'reliable' Flume sink that the driver could >>>>> then drain of events when it needs to. >>>>> >>>>> Narrowing down on the use case where the driver chains a log buffer at >>>>> the end of the train of database IO buffer, I'll think I have to see about >>>>> converting the Log4j ListAppender into a more robust and flexible version. >>>>> I think I'll call it a CollectionAppender and allow various Collection >>>>> implementations to be plugged in. >>>>> >>>>> Gary >>>>> >>>>> Gary >>>>> >>>>> On Sat, Sep 24, 2016 at 3:44 PM, Ralph Goers < >>>>> ralph.go...@dslextreme.com> wrote: >>>>> >>>>>> If you are buffering events in memory you run the risk of losing >>>>>> events if something should fail. >>>>>> >>>>>> That said, if I had your requirements I would use the FlumeAppender. >>>>>> It has either an in-memory option to buffer as you are suggesting or it >>>>>> can >>>>>> write to a local file to prevent data loss if that is a requirement. It >>>>>> already has the configuration options you are looking for and has been >>>>>> well >>>>>> tested. The only downside is that you need to have either a Flume >>>>>> instance >>>>>> receiving the messages are something that can receive Flume events over >>>>>> Avro, but it is easier just to use Flume and write a custom sink to do >>>>>> what >>>>>> you want with the data. >>>>>> >>>>>> Ralph >>>>>> >>>>>> On Sep 24, 2016, at 3:13 PM, Gary Gregory <garydgreg...@gmail.com> >>>>>> wrote: >>>>>> >>>>>> Hi All, >>>>>> >>>>>> I can't believe it, but through a convoluted use-case, I actually >>>>>> need an in-memory list appender, very much like our test-only >>>>>> ListAppender. >>>>>> >>>>>> The requirement is as follows. >>>>>> >>>>>> We have a JDBC driver and matching proprietary database that >>>>>> specializes in data virtualization of mainframe resources like DB2, VSAM, >>>>>> IMS, and all sorts of non-SQL data sources ( >>>>>> http://www.rocketsoftware.com/products/rocket-data/rocket-d >>>>>> ata-virtualization) >>>>>> >>>>>> The high level requirement is to merge the driver log into the >>>>>> server's log for full-end to end tractability and debugging. >>>>>> >>>>>> When the driver is running on the z/OS mainframe, it can be >>>>>> configured with a z/OS specific Appender that can talk to the server log >>>>>> module directly. >>>>>> >>>>>> When the driver is running elsewhere, it can talk to the database via >>>>>> a Syslog socket Appender. This requires more set up on the server side >>>>>> and >>>>>> for the server to do special magic to know how the incoming log events >>>>>> match up with server operations. Tricky. >>>>>> >>>>>> The customer should also be able to configure the driver such that >>>>>> anytime the driver communicates to the database, it sends along whatever >>>>>> log events have accumulated since the last client-server roundtrip. This >>>>>> allows the server to match exactly the connection and operations the >>>>>> client >>>>>> performed with the server's own logging. >>>>>> >>>>>> In order to do that I need to buffer all log events in an Appender >>>>>> and when it's time, I need to get the list of events and reset the >>>>>> appender >>>>>> to a new empty list so events can keep accumulating. >>>>>> >>>>>> My proposal is to either turn our ListAppender into such an appender. >>>>>> For sanity, the appender could be configured with various sizing >>>>>> policies: >>>>>> >>>>>> - open: the list grows unbounded >>>>>> - closed: the list grows to a given size and _new_ events are dropped >>>>>> on the floor beyond that >>>>>> - latest: the list grows to a given size and _old_ events are dropped >>>>>> on the floor beyond that >>>>>> >>>>>> Thoughts? >>>>>> >>>>>> Gary >>>>>> >>>>>> -- >>>>>> E-Mail: garydgreg...@gmail.com | ggreg...@apache.org >>>>>> Java Persistence with Hibernate, Second Edition >>>>>> <http://www.manning.com/bauer3/> >>>>>> JUnit in Action, Second Edition <http://www.manning.com/tahchiev/> >>>>>> Spring Batch in Action <http://www.manning.com/templier/> >>>>>> Blog: http://garygregory.wordpress.com >>>>>> Home: http://garygregory.com/ >>>>>> Tweet! http://twitter.com/GaryGregory >>>>>> >>>>>> >>>>>> >>>>> >>>>> >>>>> -- >>>>> E-Mail: garydgreg...@gmail.com | ggreg...@apache.org >>>>> Java Persistence with Hibernate, Second Edition >>>>> <http://www.manning.com/bauer3/> >>>>> JUnit in Action, Second Edition <http://www.manning.com/tahchiev/> >>>>> Spring Batch in Action <http://www.manning.com/templier/> >>>>> Blog: http://garygregory.wordpress.com >>>>> Home: http://garygregory.com/ >>>>> Tweet! http://twitter.com/GaryGregory >>>>> >>>>> >>>>> >>>> >>>> >>>> -- >>>> E-Mail: garydgreg...@gmail.com | ggreg...@apache.org >>>> Java Persistence with Hibernate, Second Edition >>>> <http://www.manning.com/bauer3/> >>>> JUnit in Action, Second Edition <http://www.manning.com/tahchiev/> >>>> Spring Batch in Action <http://www.manning.com/templier/> >>>> Blog: http://garygregory.wordpress.com >>>> Home: http://garygregory.com/ >>>> Tweet! http://twitter.com/GaryGregory >>>> >>>> >>> >>> >>> -- >>> E-Mail: garydgreg...@gmail.com | ggreg...@apache.org >>> Java Persistence with Hibernate, Second Edition >>> <http://www.manning.com/bauer3/> >>> JUnit in Action, Second Edition <http://www.manning.com/tahchiev/> >>> Spring Batch in Action <http://www.manning.com/templier/> >>> Blog: http://garygregory.wordpress.com >>> Home: http://garygregory.com/ >>> Tweet! http://twitter.com/GaryGregory >>> >>> >>> >> >> >> -- >> E-Mail: garydgreg...@gmail.com | ggreg...@apache.org >> Java Persistence with Hibernate, Second Edition >> <http://www.manning.com/bauer3/> >> JUnit in Action, Second Edition <http://www.manning.com/tahchiev/> >> Spring Batch in Action <http://www.manning.com/templier/> >> Blog: http://garygregory.wordpress.com >> Home: http://garygregory.com/ >> Tweet! http://twitter.com/GaryGregory >> > > > > -- > E-Mail: garydgreg...@gmail.com | ggreg...@apache.org > Java Persistence with Hibernate, Second Edition > <http://www.manning.com/bauer3/> > JUnit in Action, Second Edition <http://www.manning.com/tahchiev/> > Spring Batch in Action <http://www.manning.com/templier/> > Blog: http://garygregory.wordpress.com > Home: http://garygregory.com/ > Tweet! http://twitter.com/GaryGregory > -- E-Mail: garydgreg...@gmail.com | ggreg...@apache.org Java Persistence with Hibernate, Second Edition <http://www.manning.com/bauer3/> JUnit in Action, Second Edition <http://www.manning.com/tahchiev/> Spring Batch in Action <http://www.manning.com/templier/> Blog: http://garygregory.wordpress.com Home: http://garygregory.com/ Tweet! http://twitter.com/GaryGregory