PERF: move message bus to the front of the middleware stack

Organise all initializers so they are properly ordered and use the same naming scheme

config/initializers/006-mini_profiler.rb

@@ -0,0 +1,106 @@
+# If Mini Profiler is included via gem
+if Rails.configuration.respond_to?(:load_mini_profiler) && Rails.configuration.load_mini_profiler
+  require 'rack-mini-profiler'
+  require 'flamegraph'
+
+  begin
+    require 'memory_profiler' if RUBY_VERSION >= "2.1.0"
+  rescue => e
+     STDERR.put "#{e} failed to require mini profiler"
+  end
+
+  # initialization is skipped so trigger it
+  Rack::MiniProfilerRails.initialize!(Rails.application)
+end
+
+if defined?(Rack::MiniProfiler)
+
+  # note, we may want to add some extra security here that disables mini profiler in a multi hosted env unless user global admin
+  #   raw_connection means results are not namespaced
+  #
+  # namespacing gets complex, cause mini profiler is in the rack chain way before multisite
+  Rack::MiniProfiler.config.storage_instance = Rack::MiniProfiler::RedisStore.new(connection:  DiscourseRedis.raw_connection)
+
+  skip = [
+    /^\/message-bus/,
+    /topics\/timings/,
+    /assets/,
+    /\/user_avatar\//,
+    /\/letter_avatar\//,
+    /\/highlight-js\//,
+    /qunit/,
+    /srv\/status/,
+    /commits-widget/,
+    /^\/cdn_asset/,
+    /^\/logs/,
+    /^\/site_customizations/,
+    /^\/uploads/,
+    /^\/javascripts\//,
+    /^\/images\//,
+    /^\/stylesheets\//,
+    /^\/favicon\/proxied/
+  ]
+
+  # For our app, let's just show mini profiler always, polling is chatty so nuke that
+  Rack::MiniProfiler.config.pre_authorize_cb = lambda do |env|
+    path = env['PATH_INFO']
+
+    (env['HTTP_USER_AGENT'] !~ /iPad|iPhone|Nexus 7|Android/) &&
+    !skip.any?{|re| re =~ path}
+  end
+
+  # without a user provider our results will use the ip address for namespacing
+  #  with a load balancer in front this becomes really bad as some results can
+  #  be stored associated with ip1 as the user and retrieved using ip2 causing 404s
+  Rack::MiniProfiler.config.user_provider = lambda do |env|
+    request = Rack::Request.new(env)
+    id = request.cookies["_t"] || request.ip || "unknown"
+    id = id.to_s
+    # some security, lets not have these tokens floating about
+    Digest::MD5.hexdigest(id)
+  end
+
+  Rack::MiniProfiler.config.position = 'left'
+  Rack::MiniProfiler.config.backtrace_ignores ||= []
+  Rack::MiniProfiler.config.backtrace_ignores << /lib\/rack\/message_bus.rb/
+  Rack::MiniProfiler.config.backtrace_ignores << /config\/initializers\/silence_logger/
+  Rack::MiniProfiler.config.backtrace_ignores << /config\/initializers\/quiet_logger/
+
+
+  # Rack::MiniProfiler.counter_method(ActiveRecord::QueryMethods, 'build_arel')
+  # Rack::MiniProfiler.counter_method(Array, 'uniq')
+  # require "#{Rails.root}/vendor/backports/notification"
+
+  # inst = Class.new
+  # class << inst
+  #   def start(name,id,payload)
+  #     if Rack::MiniProfiler.current && name !~ /(process_action.action_controller)|(render_template.action_view)/
+  #       @prf ||= {}
+  #       @prf[id] ||= []
+  #       @prf[id] << Rack::MiniProfiler.start_step("#{payload[:serializer] if name =~ /serialize.serializer/} #{name}")
+  #     end
+  #   end
+
+  #   def finish(name,id,payload)
+  #     if Rack::MiniProfiler.current && name !~ /(process_action.action_controller)|(render_template.action_view)/
+  #       t = @prf[id].pop
+  #       @prf.delete id unless t
+  #       Rack::MiniProfiler.finish_step t
+  #     end
+  #   end
+  # end
+  # disabling for now cause this slows stuff down too much
+  # ActiveSupport::Notifications.subscribe(/.*/, inst)
+
+  # Rack::MiniProfiler.profile_method ActionView::PathResolver, 'find_templates'
+end
+
+
+if ENV["PRINT_EXCEPTIONS"]
+  trace      = TracePoint.new(:raise) do |tp|
+    puts tp.raised_exception
+    puts tp.raised_exception.backtrace.join("\n")
+    puts
+  end
+  trace.enable
+end