Add logic for beats User-Agent

[fearful-symmetry]

Proposed commit message

This adds a bit of logic to change the beats ES connection user agent if the beat is running under agent, dependent upon both the fleet status and the underlying management mode of agent itself.

In order for this to be fully functional, we'll need a PR from elastic-agent to add support for the AgentManagedMode enum. That PR is incoming.

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
• I have added tests that prove my fix is effective or that my feature works
• I have added an entry in CHANGELOG.next.asciidoc or CHANGELOG-developer.next.asciidoc.

Related

Closes elastic/elastic-agent#3065

[elasticmachine]

Pinging @elastic/elastic-agent (Team:Elastic-Agent)

[mergify]

This pull request does not have a backport label.
If this is a bug or security fix, could you label this PR @fearful-symmetry? 🙏.
For such, you'll need to label your PR with:

• The upcoming major version of the Elastic Stack
• The upcoming minor version of the Elastic Stack (if you're not pushing a breaking change)

To fixup this pull request, you need to add the backport labels for the needed
branches, such as:

• backport-v8./d.0 is the label to automatically backport to the 8./d branch. /d is the digit

[belimawr]

LGTM, I agree with Craig's suggestion. Once it's implemented I'll approve the PR.

[elasticmachine]

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• Start Time: 2024-05-03T22:00:05.623+0000

• Duration: 112 min 42 sec

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Test	Results
Failed	0
Passed	29427
Skipped	2061
Total	31488

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🤖 GitHub comments

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[amitkanfer]

Did we also want to add --unprivileged to the User Agent string (if running in that mode)? @pierrehilbert

[strawgate]

Not to pile on... But distinguishing managed from standalone might be nice too...

[elasticmachine]

Pinging @elastic/elastic-agent-data-plane (Team:Elastic-Agent-Data-Plane)

[pierrehilbert]

@amitkanfer As we are already having this information in the local metadata, do you have a specific case you want to cover by adding it to User-Agent? For Telemetry only?

@strawgate We discussed this quickly during our meeting on Thursday and I think this is a great idea to user the User-Agent for that! @fearful-symmetry WDYT?

[fearful-symmetry]

@pierrehilbert I think that's a good idea. I'm not sure if there's any way for beats to know what mode agent is running under? Never heard of anything like that. If we're interested in telemetry, I wonder if we can add that string to some headers sent by agent itself somehow?

[jlind23]

@fearful-symmetry @pierrehilbert can we piggy back on this to also tackle elastic/elastic-agent#3065?

[fearful-symmetry]

@jlind23 that issue seems largely the same as https://github.com/elastic/ingest-dev/issues/3202, with the addition of also reporting the agent version. I'm not sure it's possible for the agent version to differ from the beats version?

[cmacknz]

I'm not sure it's possible for the agent version to differ from the beats version?

For now and with independent releases they'll always be the same major.minor, the patch may differ.

[mergify]

This pull request is now in conflicts. Could you fix it? 🙏
To fixup this pull request, you can check out it locally. See documentation: https://help.github.com/articles/checking-out-pull-requests-locally/

git fetch upstream
git checkout -b beats-user-agent-managed upstream/beats-user-agent-managed
git merge upstream/main
git push upstream beats-user-agent-managed

[fearful-symmetry]

Alright, PR updated with all the feature requests; elastic-agent PR incoming...

[belimawr]

I still believe the test can be simpler and not rely on the current implementation details from mock-es. See #39403 (comment) for more details.

[fearful-symmetry]

I think the CI errors are unrelated?

[pierrehilbert]

Looks like we are all green.
@belimawr could you please do another review?