Previous spotting of the issue was a red herring. We removed our custom
code and are still facing random "org.codehaus.jackson.JsonParseException:
Illegal Character" during PutDatabaseRecord due to a flowfile containing
malformed JSON post MergeContent. Error never occurs immediately and is
usually once we've processed several million records. We did a NOOP run,
which was ConsumeKafka -> UpdateCounter and everything seemed ok.
Here's the current form of the flow:
1. ConsumeKafka_2_0 - Encoding headers as ISO-8859-1 due to some
containing binary data
1. I have a fork of nifi with changes to allow base64 and hex
encoding of select nifi headers.
2. Next test will be without pulling any headers
2. RouteOnAttribute - Validate attributes
3. Base64EncodeContent - Content is binary, converting to a format we
can store to later process
4. ExtractText - Copy Base64 encoded content to attribute
5. AttributesToJson - Provenance shows output as being fine
6. MergeContent - Provenance shows output of malformed JSON being
written in the combined flowflle.
7. PutDatabaseRecord - Schema specified as Schema Text
Since we've removed all traces of custom code what are peoples thoughts on
possible causes? Could this be an OS issue, or are there any known issues
with specific versions of RHEL?
Logically I think it makes sense to remove JSON from the equation as a
whole.
Thanks,
Jason
On Wed, Jun 24, 2020 at 2:54 PM Jason Iannone <bread...@gmail.com> wrote:
> Exactly my thought, and we've been combing through the code but nothing
> significant has jumped out. Something that does are Nifi JIRA's, NIFI-6923,
> NIFI-6924, and NIFI-6846. Considering we're on 1.10.0 I've requested
> upgrading to 1.11.4.
>
> Thanks,
> Jason
>
> On Tue, Jun 23, 2020 at 9:05 AM Mark Payne <marka...@hotmail.com> wrote:
>
>> It should be okay to create a buffer like that. Assuming the FlowFile is
>> small. Typically we try to avoid buffering the content of a FlowFile into
>> memory. But if it’s a reasonable small FlowFile, that’s probably fine.
>>
>> To be honest, if the issue is intermittent and doesn’t always happen on
>> the same input, it sounds like a threading/concurrency bug. Do you have a
>> buffer or anything like that as a member variable?
>>
>> On Jun 22, 2020, at 10:02 PM, Jason Iannone <bread...@gmail.com> wrote:
>>
>> I'm now thinking its due to how we handled reading the flowfile content
>> into a buffer.
>>
>> Previous:
>> session.read(flowFile, in -> {
>> atomicVessel.set(ByteStreams.toByteArray(in));
>> });
>>
>> Current:
>> final byte[] buffer = new byte[(int) flowFile.getSize()];
>> session.read(flowFile, in -> StreamUtils.fillBuffer(in, buffer, true));
>>
>> Making this change reduced the occurrences of the data corruption, but we
>> still saw it occur. What I'm now wondering is if sizing the byte array
>> based on flowFile.getSize() is ideal? The contents of the file are raw
>> bytes coming from ConsumeKafka_2_0.
>>
>> Thanks,
>> Jason
>>
>> On Mon, Jun 22, 2020 at 4:51 PM Mark Payne <marka...@hotmail.com> wrote:
>>
>>> Jason,
>>>
>>> Glad to hear it. This is where the data provenance becomes absolutely
>>> invaluable. So now you should be able to trace the lineage of that FlowFile
>>> back to the start using data provenance. You can see exactly what it looked
>>> like when it was received. If it looks wrong there, the provenance shows
>>> exactly where it was received from so you know where to look next. If it
>>> looks good on receipt, you can trace the data through the flow and see
>>> exactly what the data looked like before and after each processor. And when
>>> you see which processor resulted in corruption, you can easily download the
>>> data as it looks when it went into the processor to make it easy to
>>> re-ingest and test.
>>>
>>> Thanks
>>> -Mark
>>>
>>>
>>> On Jun 22, 2020, at 4:46 PM, Jason Iannone <bread...@gmail.com> wrote:
>>>
>>> I spoke too soon, and must be the magic of sending an email! We found
>>> what appears to be corrupted content and captured the binary, hoping to
>>> play it through the code and see what's going on.
>>>
>>> Thanks,
>>> Jason
>>>
>>> On Mon, Jun 22, 2020 at 4:35 PM Jason Iannone <bread...@gmail.com>
>>> wrote:
>>>
>>>> Hey Mark,
>>>>
>>>> We hit the issue again, and when digging into the lineage we can see
>>>> the content is fine coming into MergeContent but is corrupt on output of
>>>> Join. Any other suggestions?
>>>>
>>>> Thanks,
>>>> Jason
>>>>
>>>> On Wed, Jun 10, 2020 at 2:26 PM Mark Payne <marka...@hotmail.com>
>>>> wrote:
>>>>
>>>>> Jason,
>>>>>
>>>>> Control characters should not cause any problem with MergeContent.
>>>>> MergeContent just copies bytes from one stream to another. It’s also worth
>>>>> noting that attributes don’t really come into play here. MergeContent is
>>>>> combining the FlowFile content, so even if it has some weird attributes,
>>>>> those won’t cause a problem in the output content. NiFi stores attributes
>>>>> as a mapping of String to String key/value pairs (i.e., Map<String,
>>>>> String>). So the processor is assuming that if you want to convert a
>>>>> message header to an attribute, that header must be a string.
>>>>>
>>>>> Content in the repository is stored using “slabs” or “blocks.” One
>>>>> processor at a time has the opportunity to write to a file in the content
>>>>> repository. When the processor finishes writing and transfers the FlowFile
>>>>> to the next processor, NiFi keeps track of which file its content was
>>>>> written to, the byte offset where its content starts, and the length of
>>>>> the
>>>>> content. The next time that a processor needs to write to the content of a
>>>>> FlowFile, it may end up appending to that same file on disk, but the
>>>>> FlowFile that the content corresponds to will keep track of the byte
>>>>> offset
>>>>> into the file where its content begins and how many bytes in that file
>>>>> belong to that FlowFile.
>>>>>
>>>>> My recommendation to track this down would be to find a FlowFile that
>>>>> is corrupt, and then use the data provenance feature [1] to view its
>>>>> lineage. Look at the FlowFiles that were joined together by MergeContent
>>>>> and see if any of those is corrupt.
>>>>>
>>>>> Thanks
>>>>> -Mark
>>>>>
>>>>> [1]
>>>>> http://nifi.apache.org/docs/nifi-docs/html/user-guide.html#data_provenance
>>>>>
>>>>> On Jun 10, 2020, at 2:07 PM, Jason Iannone <bread...@gmail.com> wrote:
>>>>>
>>>>> Hey Mark,
>>>>>
>>>>> I was thinking over this more and despite no complaints from Jackson
>>>>> Objectmapper is it possible that hidden and/or control characters are
>>>>> present in the JSON values which would then cause MergeContent to behave
>>>>> this way? I looked over the code and nothing jumped out, but there is
>>>>> something we had to do because of how the publisher is setting kafka
>>>>> header
>>>>> attributes. Some attributes are bytes and not strings converted to bytes,
>>>>> and ConsumeKafka seems to assume that these can always be converted to a
>>>>> String. We had to change the encoding to be ISO8859 due to running into
>>>>> issues with the bytes getting corrupted.
>>>>>
>>>>> I'm also trying to better understand how the content is being stored
>>>>> in the content repository, and whether something is going wrong when
>>>>> writing it out.
>>>>>
>>>>> Thanks,
>>>>> Jason
>>>>>
>>>>> On Tue, Jun 9, 2020 at 8:02 PM Mark Payne <marka...@hotmail.com>
>>>>> wrote:
>>>>>
>>>>>> Hey Jason,
>>>>>>
>>>>>> Thanks for reaching out. That is definitely odd and not something
>>>>>> that I’ve seen or heard about before.
>>>>>>
>>>>>> Are you certain that the data is not being corrupted upstream of the
>>>>>> processor? I ask because the code for the processor that handles writing
>>>>>> out the content is pretty straight forward and hasn’t been modified in
>>>>>> over
>>>>>> 3 years, so I would expect to see it happen often if it were a bug in the
>>>>>> MergeContent processor itself. Any chance that you can create a flow
>>>>>> template/sample data that recreates the issue? Anything particularly
>>>>>> unique
>>>>>> about your flow?
>>>>>>
>>>>>> Thanks
>>>>>> -Mark
>>>>>>
>>>>>>
>>>>>> > On Jun 9, 2020, at 6:47 PM, Jason Iannone <bread...@gmail.com>
>>>>>> wrote:
>>>>>> >
>>>>>> > Hi all,
>>>>>> >
>>>>>> > Within Nifi 1.10.0 we're seeing unexpected behavior with
>>>>>> mergecontent. The processor is being fed in many flowfiles with
>>>>>> individual
>>>>>> JSON records. The records have various field types including a
>>>>>> hex-encoded
>>>>>> byte[]. We are not trying to merge JSON records themselves but rather
>>>>>> consolidate many flowfiles into fewer flowfiles.
>>>>>> >
>>>>>> > What we're seeing is that a random flowfile is split causing the
>>>>>> merge file to be invalid JSON. When running multiple bins we saw the
>>>>>> flowfile split across bins.
>>>>>> >
>>>>>> > Example
>>>>>> > Flowfile 1: {"name": "1", "hexbytes": A10F15B11D14", timestamp:
>>>>>> "123456789" }
>>>>>> > Flowfile 2: {"name": "2", "hexbytes": A10F15D14B11", timestamp:
>>>>>> "123456790" }
>>>>>> > Flowfile 3: {"name": "3", "hexbytes": A10F15D14B11", timestamp:
>>>>>> "123456790" }
>>>>>> >
>>>>>> > Merged Result:
>>>>>> > {"name": "1", "hexbyters": A10F15B11D14", timestamp: "123456789" }
>>>>>> > xbytes": A10F15D14B11", timestamp: "123456790" }
>>>>>> > {"name": "3", "hexbytes": A10F15D14B11", timestamp: "123456790" }
>>>>>> > {"name": "3", "h
>>>>>> >
>>>>>> > Mergecontent Configuration:
>>>>>> > Concurrent Tasks: 4
>>>>>> > Merge Strategy: Bin-Packing Algorithm
>>>>>> > Merge Format: Binary Concatenation
>>>>>> > Attribute Strategy: Keep Only Common Attributes
>>>>>> > Min. number of entries 1000
>>>>>> > Max number of entries: 20000
>>>>>> > Minimum group size: 10 KB
>>>>>> > Maximum number of bins: 5
>>>>>> > Header, Footer, and Demaractor are not set.
>>>>>> >
>>>>>> > We then backed off the below to reduce min and max entries, bin to
>>>>>> 1, and thread to 1 and still see the same issue.
>>>>>> >
>>>>>> > Any insights?
>>>>>> >
>>>>>> > Thanks,
>>>>>> > Jason
>>>>>>
>>>>>>
>>>>>
>>>
>>
