Add per request labels to the Ruby Logger implementation provided by Google Cloud Logger by creating a new MyCustomLogger class that inherits from Google::Cloud::Logging::Logger and mutates the Logger labels while adding new messages. Also adds #my_custom_logger method to return an new instance of the custom logger.

my_custom_logger.rb

require "google/cloud/logging"

class MyCustomLogger < Google::Cloud::Logging::Logger
  def debug message = nil, labels: {}, &block
    original_labels = @labels
    @labels = labels.merge @labels if @labels
    super message, &block
    @labels = original_labels
  end
  
  def info message = nil, labels: {}, &block
    original_labels = @labels
    @labels = labels.merge @labels if @labels
    super message, &block
    @labels = original_labels
  end
  
  def warn message = nil, labels: {}, &block
    original_labels = @labels
    @labels = labels.merge @labels if @labels
    super message, &block
    @labels = original_labels
  end
  
  def error message = nil, labels: {}, &block
    original_labels = @labels
    @labels = labels.merge @labels if @labels
    super message, &block
    @labels = original_labels
  end
  
  def fatal message = nil, labels: {}, &block
    original_labels = @labels
    @labels = labels.merge @labels if @labels
    super message, &block
    @labels = original_labels
  end
  
  def unknown message = nil, labels: {}, &block
    original_labels = @labels
    @labels = labels.merge @labels if @labels
    super message, &block
    @labels = original_labels
  end
end

module Google
  module Cloud
    module Logging
      class Project
        def my_custom_logger log_name, resource, labels = {}
          MyCustomLogger.new shared_async_writer, log_name, resource, labels
        end
      end
    end
  end
end