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Enhance json parser error logging to better track Istio Proxy error message #15176

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kaisun2000
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Description

Currently the inter Druid communication via rest endpoints is based on json formatted payload. Upon parsing error, there is only a generic exception stating expected json token type and current json token type. There is no detailed error log about the content of the payload causing the violation.

In the micro-service world, the trend is to deploy the Druid servers in k8 with the mesh network. Often the istio proxy or other proxies is used to intercept the network connection between Druid servers. The proxy may give error messages for various reasons. These error messages are not expected by the json parser. The generic error message from Druid can be very misleading as the user may think the message is based on the response from the other Druid server.

For example, this is an example of mysterious error message

QueryInterruptedException{msg=Next token wasn't a START_ARRAY, was[VALUE_STRING] from url[http://xxxxx:8088/druid/v2/], code=Unknown exception, class=org.apache.druid.java.util.common.IAE, host=xxxxx:8088}"

While the context of the message is the following from the proxy when it can't tunnel the network connection.

pstream connect error or disconnect/reset before header

So this very simple PR is just to enhance the logging and get the real underlying message printed out. This would save a lot of head scratching time if Druid is deployed with mesh network.

Release note


Improved: enhanced the json parser unexpected token logging with the context of the expected VALUE_STRING token. This way, it is easier to track to mesh/proxy network error messages, instead misleading user to track the Druid server rest endpoint responses.

This PR has:

  • been self-reviewed.
  • added documentation for new or modified features or behaviors.
  • a release note entry in the PR description.
  • added Javadocs for most classes and all non-trivial methods. Linked related entities via Javadoc links.
  • added or updated version, license, or notice information in licenses.yaml
  • added comments explaining the "why" and the intent of the code wherever would not be obvious for an unfamiliar reader.
  • added unit tests or modified existing tests to cover new code paths, ensuring the threshold for code coverage is met.
  • added integration tests.
  • been tested in a test Druid cluster.

… would

greatly help tracing to the root of error in case istio proxy return unexpected
error messages during meeting connection issues.
@cryptoe cryptoe self-assigned this Oct 17, 2023
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cryptoe commented Oct 19, 2023

Thanks for the PR @kaisun2000 . Please add test cases for this change.
You can look at JsonParserIteratorTest for reference.

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After the changes its a +1 from my side.

public static class IAEExceptionConversionTest
{
@Rule
public ExpectedException expectedException = ExpectedException.none();

Check notice

Code scanning / CodeQL

Deprecated method or constructor invocation Note test

Invoking
ExpectedException.none
should be avoided because it has been deprecated.
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Thanks @kaisun2000 for the contribution.
Change LGTM.

@cryptoe cryptoe merged commit 60c2ad5 into apache:master Oct 27, 2023
81 of 82 checks passed
CaseyPan pushed a commit to CaseyPan/druid that referenced this pull request Nov 17, 2023
…essage (apache#15176)

Currently the inter Druid communication via rest endpoints is based on json formatted payload. Upon parsing error, there is only a generic exception stating expected json token type and current json token type. There is no detailed error log about the content of the payload causing the violation.

In the micro-service world, the trend is to deploy the Druid servers in k8 with the mesh network. Often the istio proxy or other proxies is used to intercept the network connection between Druid servers. The proxy may give error messages for various reasons. These error messages are not expected by the json parser. The generic error message from Druid can be very misleading as the user may think the message is based on the response from the other Druid server.

For example, this is an example of mysterious error message

QueryInterruptedException{msg=Next token wasn't a START_ARRAY, was[VALUE_STRING] from url[http://xxxxx:8088/druid/v2/], code=Unknown exception, class=org.apache.druid.java.util.common.IAE, host=xxxxx:8088}"

While the context of the message is the following from the proxy when it can't tunnel the network connection.

pstream connect error or disconnect/reset before header

So this very simple PR is just to enhance the logging and get the real underlying message printed out. This would save a lot of head scratching time if Druid is deployed with mesh network.

Co-authored-by: Kai Sun <[email protected]>
@LakshSingla LakshSingla added this to the 29.0.0 milestone Jan 29, 2024
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3 participants