Add log verbosity configuration and move the log in controller.go to debug level

[RonFed]

Currently, we print a log message for each span: https://github.com/open-telemetry/opentelemetry-go-instrumentation/blob/61ff124646105a2058863b17da1815d8d42d78b3/internal/pkg/opentelemetry/controller.go#L54

We should change that to have a debug level. We don't have a configuration for verbosity. We probably should add support for configuration via:

1. command line arguments
2. InstrumentationOption
3. Enviroment variable (?)

This will need to be modified: https://github.com/open-telemetry/opentelemetry-go-instrumentation/blob/61ff124646105a2058863b17da1815d8d42d78b3/instrumentation.go#L70-L83

[RonFed]

@MrAlias @pellared I'd be happy to hear your thoughts on this.

• Can we add the logger as an Instrumentation option? I saw this comment about it: https://github.com/open-telemetry/opentelemetry-go-instrumentation/blob/02686f0a149b13fec4da73b9d40233a372fbd13b/instrumentation.go#L90-L94
• The log line mentioned in my first comment is the one I worried about since we currently have huge amounts of logs, so adding a verbosity option seems helpful (using the debug level for tests and development).

[khushijain21]

@RonFed is this open for contribution?

[RonFed]

@khushijain21 Sure

[vitorhugoro1]

@khushijain21 are you going to work on this issue? If not I will work on this.

@RonFed from the three approches you provide, which one do you think is optimal?

By my experience when trying to use with k8s, if is with command line argument seems more clear which option of log level is set.

[khushijain21]

@vitorhugoro1 yes, you can go ahead

[RonFed]

@vitorhugoro1 I think we need to support the first 2, and not sure about env var. @MrAlias What do you think?

[pellared]

Regarding env var I think we should support OTEL_LOG_LEVEL per https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/configuration/sdk-environment-variables.md#general-sdk-configuration