feat: allow disabling of install messages

[robertlaurin]

Allows controlling the severity of the opentelemetry log messages emitted independently of the logger supplied.

This still allows for a user to override the OpenTelemetry.logger entirely via the accessor OpenTelemetry.logger =, if you wish to supply a logger and still respect the OTEL_LOG_LEVEL supplied environment variable this is done through the configuration.

OpenTelemetry::SDK.configure { |c| c.logger = Logger.new(....) }

[ahayworth]

OTEL_RUBY_INSTRUMENTATION_INSTALL_MESSAGES

Is there a general log-level argument we could use instead? OTEL_DEBUG=1 or OTEL_LOG_LEVEL=debug or something - I would expect this would be off by default (as an end user) but be something I could opt into when needed.

(Unless this is required by the spec, of course).

[robertlaurin]

OTEL_RUBY_INSTRUMENTATION_INSTALL_MESSAGES

Is there a general log-level argument we could use instead? OTEL_DEBUG=1 or OTEL_LOG_LEVEL=debug or something - I would expect this would be off by default (as an end user) but be something I could opt into when needed.

(Unless this is required by the spec, of course).

Hmm, we do have OTEL_LOG_LEVEL

opentelemetry-ruby/api/lib/opentelemetry.rb

Line 31 in 943e440

@logger ||= Logger.new(STDOUT, level: ENV['OTEL_LOG_LEVEL'] || Logger::INFO)

so that could be a better choice here.

The context for this change is around users getting tired of the install message log spam, previously they would use OTEL_LOG_LEVEL but we're now setting the OpenTelemetry logger to use the Rails.logger as part of our railtie so that env var isn't working the same.

I was already a little apprehensive to add a one off config for this.

[ahayworth]

This looks great!

[amomchilov]

This is neat, thanks!