backend: Allow configuring log level via environment variable #4458

aadhil2k4 · 2026-01-26T19:36:23Z

Summary

This PR adds the ability to configure the Headlamp backend log level via the HEADLAMP_CONFIG_LOG_LEVEL environment variable.

Related Issue

Fixes #4139

Changes

Added support for configuring the backend log level via the HEADLAMP_CONFIG_LOG_LEVEL environment variable
Initialized the global zerolog log level during application startup
Ensured invalid or missing log level values safely default to info

Steps to Test

Go backend folder:
```
cd backend
```

Run the following command:

npm run backend:start -- --log-level debug

If it doesnt work, build the backend again using npm run backend:build and follow the above steps.

Screenshots (if applicable)

Debug log level

Warn log level

Notes for the Reviewer

None

k8s-ci-robot · 2026-01-26T19:36:31Z

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: aadhil2k4
Once this PR has been reviewed and has the lgtm label, please assign illume for approval. For more information see the Code Review Process.

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linux-foundation-easycla · 2026-01-26T19:36:32Z

The committers listed above are authorized under a signed CLA.

✅ login: aadhil2k4 / name: Aadhil Ahamed (b03b74c)

k8s-ci-robot · 2026-01-26T19:36:33Z

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aadhil2k4 · 2026-01-26T19:49:32Z

@yolossn @sniok If this approach is acceptable, I can update the documentation to include the Log Level details. Please review the PR and let me know if any changes/additions are required.

Copilot

Pull request overview

This PR adds support for configuring the Headlamp backend log level via the HEADLAMP_LOG_LEVEL environment variable, addressing issue #4139. The implementation uses zerolog's SetGlobalLevel method to configure logging at application startup.

Changes:

Added a new Init() function in the logger package to configure log levels from the HEADLAMP_LOG_LEVEL environment variable
Called logger.Init() at the start of the main function in server.go to initialize logging before any other operations
Implemented error handling for invalid log level values with a fallback to info level

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
backend/pkg/logger/logger.go	Added Init function to parse HEADLAMP_LOG_LEVEL environment variable and set global zerolog log level with error handling
backend/cmd/server.go	Added logger.Init() call at the beginning of main() to initialize logging configuration

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backend/pkg/logger/logger.go

Copilot

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

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backend/pkg/logger/logger_test.go

aadhil2k4 · 2026-01-29T22:06:16Z

@illume I think this PR can be merged. Can you please check it once?

illume

Looking good.

I think this should be a backend configuration flag. This then is automatically available as an environment variable as well. Additionally there is some help available for users.

It should be documented with the other backend flags somewhere in the documentation. For example the in-cluster documentation, and backend developer documentation (How do I turn on debug or verbose logging? How do I reduce logging to only info?)

aadhil2k4 · 2026-01-31T20:57:08Z

Looking good.

I think this should be a backend configuration flag. This then is automatically available as an environment variable as well. Additionally there is some help available for users.

It should be documented with the other backend flags somewhere in the documentation. For example the in-cluster documentation, and backend developer documentation (How do I turn on debug or verbose logging? How do I reduce logging to only info?)

@illume I have a doubt, Headlamp doesnt define a Debug log level. Should I add a Debug level to the logger too ?

illume · 2026-02-01T11:41:22Z

@aadhil2k4 zlog has a default debug log level of info. Headlamp just uses the default.

Copilot

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 11 comments.

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backend/pkg/logger/logger_test.go

docs/development/backend.md

backend/pkg/config/config.go

backend/pkg/logger/logger.go

docs/development/index.md

backend/cmd/server.go

backend/pkg/config/config_test.go

illume · 2026-02-02T18:19:13Z

@aadhil2k4 thanks for that. Looking good. I'll test it a bit later.

Please remember to squash/rebase and remove the Signed-off-by from commit messages?

aadhil2k4 · 2026-02-02T18:23:51Z

@aadhil2k4 thanks for that. Looking good. I'll test it a bit later.

Please remember to squash/rebase and remove the Signed-off-by from commit messages?

Sure, I'll do it. 👍

…date tests and development docs

Copilot

Pull request overview

Copilot reviewed 7 out of 7 changed files in this pull request and generated 5 comments.

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Copilot · 2026-02-02T20:56:50Z

docs/development/index.md

+
+Backend log verbosity can be controlled using either a flag or an environment variable.
+- `--log-level`
+- `HEADLAMP_CONFIG_LOG_LEVEL`


Corrected spelling of 'HEADLAMP_CONFIG_LOG_LEVEL' to 'HEADLAMP_LOG_LEVEL'.

Suggested change

- `HEADLAMP_CONFIG_LOG_LEVEL`

- `HEADLAMP_LOG_LEVEL`

Copilot · 2026-02-02T20:56:50Z

docs/development/backend.md

+Headlamp’s backend supports configurable log levels to control verbosity.
+
+Log level can be configured using either a flag or an environment variable:
+- the log level: `--log-level` or env var `HEADLAMP_CONFIG_LOG_LEVEL`


Corrected spelling of 'HEADLAMP_CONFIG_LOG_LEVEL' to 'HEADLAMP_LOG_LEVEL'.

Suggested change

- the log level: `--log-level` or env var `HEADLAMP_CONFIG_LOG_LEVEL`

- the log level: `--log-level` or env var `HEADLAMP_LOG_LEVEL`

Copilot · 2026-02-02T20:56:50Z

backend/pkg/logger/logger.go

 var logFunc LogFunc = log

+// Init configures the global zerolog log level from environment variables.
+// The HEADLAMP_CONFIG_LOG_LEVEL environment variable controls the global log level.


Corrected spelling of 'HEADLAMP_CONFIG_LOG_LEVEL' to 'HEADLAMP_LOG_LEVEL'.

Copilot · 2026-02-02T20:56:51Z

backend/pkg/logger/logger.go

+			Str("value", logLevel).
+			Msg("Invalid HEADLAMP_CONFIG_LOG_LEVEL, defaulting to info")


Corrected spelling of 'HEADLAMP_CONFIG_LOG_LEVEL' to 'HEADLAMP_LOG_LEVEL'.

Copilot · 2026-02-02T20:56:51Z

backend/pkg/logger/logger.go

+		Str("level", level.String()).
+		Msg("Log level set from HEADLAMP_CONFIG_LOG_LEVEL")


Corrected spelling of 'HEADLAMP_CONFIG_LOG_LEVEL' to 'HEADLAMP_LOG_LEVEL'.

aadhil2k4 · 2026-02-02T21:35:56Z

@illume HEADLAMP_CONFIG_ is the naming convention for environment variables. Those are the only suggestions from Copilot. Shall I mark them as resolved?

k8s-ci-robot requested a review from sniok January 26, 2026 19:36

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aadhil2k4 force-pushed the issue_4139 branch from 5c1cc43 to b626faa Compare January 29, 2026 21:10

k8s-ci-robot added size/XXL Denotes a PR that changes 1000+ lines, ignoring generated files. and removed size/M Denotes a PR that changes 30-99 lines, ignoring generated files. labels Jan 29, 2026

aadhil2k4 force-pushed the issue_4139 branch from b626faa to e5fca8a Compare January 29, 2026 21:19

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k8s-ci-robot added needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. size/XXL Denotes a PR that changes 1000+ lines, ignoring generated files. and removed size/L Denotes a PR that changes 100-499 lines, ignoring generated files. labels Feb 2, 2026

aadhil2k4 force-pushed the issue_4139 branch from 2b7d69c to 83899e3 Compare February 2, 2026 17:32

k8s-ci-robot added size/L Denotes a PR that changes 100-499 lines, ignoring generated files. and removed needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. size/XXL Denotes a PR that changes 1000+ lines, ignoring generated files. labels Feb 2, 2026

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backend: pkg: add config flag and env var to configure log levels, up…

b03b74c

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aadhil2k4 force-pushed the issue_4139 branch from 83899e3 to b03b74c Compare February 2, 2026 20:22

illume requested a review from Copilot February 2, 2026 20:56

illume added this to the v0.40.0 milestone Feb 2, 2026

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	- the log level: `--log-level` or env var `HEADLAMP_CONFIG_LOG_LEVEL`
	- the log level: `--log-level` or env var `HEADLAMP_LOG_LEVEL`

		Str("value", logLevel).
		Msg("Invalid HEADLAMP_CONFIG_LOG_LEVEL, defaulting to info")

		Str("level", level.String()).
		Msg("Log level set from HEADLAMP_CONFIG_LOG_LEVEL")

backend: Allow configuring log level via environment variable #4458

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Summary

Related Issue

Changes

Steps to Test

Screenshots (if applicable)

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