More compatibility with ActiveSupport Logger broadcast usage

[joergschiller]

#935 allows the usage of ActiveSupport::Logger.broadcast. There still seems to be an issue when using the convenience methods from logger. Logger.warn("Something happened") won't show up in AppSignal.

(There already is a detailed description what happens when adding a broadcast in #930.)

A new Rails App would create an ActiveSupport Logger in production if logging to the console is requested (which a Twelve-Factor App would do).

config/environments/production.rb:

if ENV["RAILS_LOG_TO_STDOUT"].present?
  logger = ActiveSupport::Logger.new($stdout)
  logger.formatter = config.log_formatter
  config.logger = ActiveSupport::TaggedLogging.new(logger)
end

I want to keep the console output and broadcast to an AppSignal logger:

appsignal_logger = ActiveSupport::TaggedLogging.new(Appsignal::Logger.new("rails"))
config.logger.extend(ActiveSupport::Logger.broadcast(appsignal_logger))

At first glance this seems to work. All requests are logged in AppSignal. But using the convenience methods would log to the console but not to AppSignal.

# Won't show up on appsignal.com
> Rails.logger.warn("Something happened")
Something happened
=> 19

# Will show up on appsignal.com
Rails.logger.add(Logger::WARN, "Something happened")
Something happened
=> 19

This is because the convenience methods are calling add with the log message in the third argument. But Appsignal::Logger#add won't take the message from group as a fallback if message is nil. It looks like you forgot to rename progname to group as well:

appsignal-ruby/lib/appsignal/logger.rb

Line 46 in 05dc9fe

message = progname

After the fixes in this PR Rails.logger.warn("Something happened") works for me as expected.

[luismiramirez]

Hey there @joergschiller!

Thank you so much for this contribution and for the extended information you provided with it. You're correct and this helps us a lot.

I've created a PR based on this and added you as a co author in #969

I'm closing this one in favor of #969