Print Rails info at startup (#4383)

lib/sidekiq/cli.rb

@@ -38,6 +38,7 @@ module Sidekiq
       if environment == "development" && $stdout.tty? && Sidekiq.log_formatter.is_a?(Sidekiq::Logger::Formatters::Pretty)
         print_banner
       end
+      logger.info "Booted Rails #{::Rails.version} application in #{environment} environment" if rails_app?
 
       self_read, self_write = IO.pipe
       sigs = %w[INT TERM TTIN TSTP]
@@ -378,5 +379,9 @@ module Sidekiq
       [weight.to_i, 1].max.times { opts[:queues] << queue }
       opts[:strict] = false if weight.to_i > 0
     end
+
+    def rails_app?
+      defined?(::Rails)
+    end
   end
 end

test/test_cli.rb

@@ -322,6 +322,15 @@ describe Sidekiq::CLI do
           end
         end
       end
+
+      it 'prints rails info' do
+        subject.stub(:environment, 'production') do
+          subject.stub(:launch, nil) do
+            subject.run
+          end
+          assert_includes @logdev.string, "Booted Rails #{::Rails.version} application in production environment"
+        end
+      end
     end
 
     describe 'signal handling' do