Clarification on `OTEL_SDK_DISABLED` scope

[kaylareopelle]

What are you trying to achieve?

Ruby received a PR to implement the OTEL_SDK_DISABLED environment variable, but we're not sure how far the functionality needs to go. The PR as it stands would skip creating providers through configuration, but someone could still manually create functional providers and tracers/meters/loggers. Is that acceptable?

Additional context.

Here's the description:

Boolean value. If “true”, a no-op SDK implementation will be used for all telemetry signals. Any other value or absence of the variable will have no effect and the SDK will remain enabled. This setting has no effect on propagators configured through the OTEL_PROPAGATORS variable.

I took a look at open-telemetry/opentelemetry-python#3648, and it seems like they always return no-ops when OTEL_SDK_DISABLED is true.

However, Java's implementation seems closer to the Ruby PR. Configuration is skipped, but I don't know enough about Java to know if that means you cannot create working tracers, etc.

[MrAlias]

cc @open-telemetry/python-approvers @open-telemetry/java-approvers

[trask]

However, Java's implementation seems closer to the Ruby PR. Configuration is skipped, but I don't know enough about Java to know if that means you cannot create working tracers, etc.

If you are using the Java autoconfigure module and set OTEL_SDK_DISABLED=true then none of the autoconfigure callbacks to customize the OpenTelemetry SDK are called, and so there's no way to add your own tracers etc.

[kaylareopelle]

If you are using the Java autoconfigure module and set OTEL_SDK_DISABLED=true then none of the autoconfigure callbacks to customize the OpenTelemetry SDK are called, and so there's no way to add your own tracers etc.

Thanks for clarifying, @trask. Is there a way for to use the Java SDK without the autoconfigure module? If so, does OTEL_SDK_DISABLED have any impact on that path?

[trask]

ya, you can use the Java SDK without the autoconfigure module, in which case OTEL_SDK_DISABLED has no effect

[kaylareopelle]

Thanks, @trask!

@open-telemetry/python-approvers - Am I reading your code correctly, will OTEL_SDK_DISABLED create no-ops for all attempts at creating tracer providers, etc.?

[danielgblanco]

@trask thinking about your response, and reading the spec, should OTEL_SDK_DISABLED also have effect with custom SDK config (i.e. without autoconfigure)?

The way I read it

a no-op SDK implementation will be used for all telemetry signals

I understand that if I pass OTEL_SDK_DISABLED then a no-op SDK would override any other config?

[trask]

@trask thinking about your response, and reading the spec, should OTEL_SDK_DISABLED also have effect with custom SDK config (i.e. without autoconfigure)?

I think this falls under (emphasis added) https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/configuration/sdk-environment-variables.md#implementation-guidelines:

Environment variables MAY be handled (implemented) directly by a component, in the SDK, or in a separate component (e.g. environment-based autoconfiguration component).

[xrmx]

Thanks, @trask!

@open-telemetry/python-approvers - Am I reading your code correctly, will OTEL_SDK_DISABLED create no-ops for all attempts at creating tracer providers, etc.?

It return no-ops when calling get_logger, get_tracer and get_meter of the sdk signals providers, so it's not a no-op tracer provider but a no-op tracer.