Added support for GAUGE_LIST metric type

[kaisecheng]

Release notes

Fixed warning in logs about an unknown type of metric.

What does this PR do?

added support of List type to eliminate the warning.

Why is it important/What is the impact to the user?

Prior to the changes, log emits a warning about an unknown gauge metric type when running pipeline-to-pipeline due to serialization of {send_to:[pipeline_name]}.

A gauge metric of an unknown type (org.jruby.specialized.RubyArrayOneObject) has been created for key: send_to. This may result in invalid serialization.  It is recommended to log an issue to the responsible developer/development team.

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have made corresponding change to the default configuration files (and/or docker env variables)
• I have added tests that prove my fix is effective or that my feature works

Author's Checklist

• test locally

How to test this PR locally

Run Logstash with pipeline-to-pipeline

upstream.conf

input { 
  stdin { }
} 
output { 
    pipeline { 
        send_to => [tube] 
    } 
}

downstream.conf

input { 
    pipeline { 
        address => tube 
    } 
} 
output { 
    stdout { }
}

1. start logstash
   bin/logstash -f /path/to/p2p/dir/
2. warning should not emit
3. check metrics API. No error or missing part.
   curl "localhost:9600/_node/stats"

Related issues

• Closes: Warning in logs => A gauge metric of an unknown type (org.jruby.specialized.RubyArrayOneObject) has been created for key: send_to #13106

Use cases

Screenshots

Logs

[github-actions]

🤖 GitHub comments

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Just comment with:

• run docs-build : Re-trigger the docs validation. (use unformatted text in the comment!)

[mergify]

This pull request does not have a backport label. Could you fix it @kaisecheng? 🙏
To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-8./d is the label to automatically backport to the 8./d branch. /d is the digit.
• If no backport is necessary, please add the backport-skip label

[elastic-sonarqube]

Quality Gate passed

Issues
0 New issues
0 Fixed issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarQube

[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 6e69e83

History

• 💔 Build #3027 failed e758def

[andsel]

LGTM

[github-actions]

@Mergifyio backport 8.17 8.18 8.19 9.0

[mergify]

backport 8.17 8.18 8.19 9.0

✅ Backports have been created

Details

• #17723 [8.17] (backport #17721) Added support for GAUGE_LIST metric type has been created for branch 8.17
• #17724 [8.18] (backport #17721) Added support for GAUGE_LIST metric type has been created for branch 8.18
• #17725 [8.19] (backport #17721) Added support for GAUGE_LIST metric type has been created for branch 8.19
• #17726 [9.0] (backport #17721) Added support for GAUGE_LIST metric type has been created for branch 9.0