Add minimum_severity and trace_based logger configuration parameters

[trask]

Alternative to #4611

Some related prior discussions:

• Stabilize Logger.Enabled #4208 (comment)
• Specify how Logs SDK implements Enabled #4207 (comment)

Java POC @ open-telemetry/opentelemetry-java#7529

Declarative config for this is a bit nicer than in #4611, also supports applying different minimum severity levels to different loggers:

file_format: "1.0"

logger_provider:
  logger_configurator/development:
    default_config:
      minimum_severity: WARN
      trace_based: true
    loggers:
      - name: "com.example.app.*"
        config:
          minimum_severity: INFO
      - name: "com.example.db.*"
        config:
          minimum_severity: ERROR

[pellared]

This does not support having different minimum severity levels for different processors (processing pipelines).
Isn't this can be critical/very important for OTel Collector?

From open-telemetry/opentelemetry-go-contrib#7549:

opentelemetry-collector enables users to configure its internal telemetry using otelconf. [...] For example, we need to configure leveled logging, which could theoretically be done with the minsev processor

CC @codeboten

It is possible to achieve the functionality of "logger configurator" using processors (e.g. logger filter). The question is whether we need a configuration option that is redundant? Moreover, using processors it is possible to compose more complex pipelines that are not possible using the logger configurator.

It should be possible to "implement" the declarative config of logger configurator using processors. Then the logger configurator would be a facade for configuring some processors.

PS.I think there were some similar/related discussions here #4439

If we are looking into simplicity then another alternative (mainly for default_config) could be setting the minimum severity level on the whole logger provider. This would require even "less config" but it would be not flexible.

[pellared]

Seems like there is a consensus to go forward with this proposal.

It looks like Collector already handles filtering using filterprocessor.

[pellared]

We discussed this during Go SIG meeting.
We are fine with the proposal given we want to implement this configuration using (internally) LogRecordProcessors. We do not want to add LoggerConfigurator into the Go Logs SDK, because we find it unnecessary as everything should be achievable using LogRecordProcessor. The experience for the end-user should remain the same.

CC @open-telemetry/go-triagers

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 7 days.

[carlosalberto]

Is this expected to be stable from the start?

[trask]

Is this expected to be stable from the start?

no, I checked and I think most of it is under Development sections already, did find one place where it was missed: c68bba4

[github-actions]

This PR was marked stale due to lack of activity. It will be closed in 7 days.

[Copilot]

Pull Request Overview

This PR introduces fine-grained logger configuration capabilities by adding minimum_severity and trace_based filtering parameters to the logger configuration system. This allows for more sophisticated log filtering strategies beyond simple enable/disable toggles.

• Adds two new configuration parameters: minimum_severity for severity-level filtering and trace_based for trace-sampling-based filtering
• Updates the Enabled method to incorporate the new filtering criteria
• Defines filtering logic for the Emit a LogRecord operation to ensure consistent behavior

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[carlosalberto]

Maybe have a last look @codeboten @open-telemetry/configuration-approvers ?