feat(host_metrics source): add temperature metrics collector

[somaz94]

Summary

Adds a temperature collector to the host_metrics source. When enabled, it reads hardware temperature sensors via sysinfo::Components and emits three gauges, each tagged with the component label of the sensor it was read from:

• temperature_celsius — current temperature
• temperature_max_celsius — highest recorded temperature
• temperature_critical_celsius — critical threshold (only when the sensor reports one)

The collector is opt-in (it is not part of the default collector set). Many environments where Vector runs — containers, virtual machines, most cloud instances — expose no temperature sensors, so enabling it by default would add a per-scrape Components refresh that yields nothing. Users add temperature to collectors to turn it on. Components that do not report a given value are skipped, and hosts without sensors simply produce no metrics.

Closes: #21389

Vector configuration

sources:
  host:
    type: host_metrics
    collectors:
      - temperature

How did you test this PR?

• Added a generates_temperature_metrics unit test that asserts every emitted metric is a gauge named temperature* and carries the component tag. The test tolerates an empty result so it also passes in sensorless CI environments.
• Updated the hand-written metric documentation and regenerated the component config docs (generated/host_metrics.cue) for the new temperature collector enum value.

Change Type

• Bug fix
• New feature
• Dependencies
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

Does this PR include user facing changes?

• Yes. Added a changelog fragment under changelog.d/.
• No. A maintainer will apply the no-changelog label to this PR.

References

• Closes: could you pls add sensors info in host_metrics #21389

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[somaz94]

I have read the CLA Document and I hereby sign the CLA

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 34f8b6fec3

ℹ️ About Codex in GitHub

Codex has been enabled to automatically review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

When you sign up for Codex through ChatGPT, Codex can also answer questions or update the PR, like "@codex address that feedback".

[somaz94]

Thanks for the approval @evazorro! CLA is signed and CI is green. It looks like this still needs a second review to land. Anything I can do to help move it along?

[evazorro]

Hi @somaz94, I checked in with the dev team and they can review it after you've resolved the comments from the AI review tool. More information here: https://github.com/vectordotdev/vector/blob/master/AI_POLICY.md#ai-review-comments

Thanks for contributing!

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 438cb1c41f

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".