Chapter 3: Implement current attributes

lib/active_monitoring/current.rb

@@ -0,0 +1,31 @@
+require_relative "core_extensions/action_controller"
+require_relative "core_extensions/active_record"
+require_relative "sql_query"
+require_relative "current"
+
+module ActiveMonitoring
+  class Current
+    class << self
+      def request_id
+        store[:request_id]
+      end
+
+      def request_id=(value)
+        store[:request_id] = value
+      end
+
+      def location
+        store[:location]
+      end
+
+      def location=(value)
+        store[:location] = value
+      end
+
+      def store
+        Thread.current[:active_monitoring_store] ||= {}
+        Thread.current[:active_monitoring_store]
+      end
+    end
+  end
+end

lib/active_monitoring/engine.rb

@@ -1,6 +1,7 @@
 require_relative "core_extensions/action_controller"
 require_relative "core_extensions/active_record"
 require_relative "sql_query"
+require_relative "current"
 
 module ActiveMonitoring
   class Engine < ::Rails::Engine
@@ -13,6 +14,11 @@ class Engine < ::Rails::Engine
     ActiveSupport.on_load(:action_controller) do
       ActionController::Base.prepend(::ActiveMonitoring::CoreExtensions::ActionController::Instrumentation)
 
+      ActiveMonitoring::Notifications.subscribe("start_processing.action_controller") do |_, _, _, _, payload|
+        Current.request_id = payload[:request_id]
+        Current.location = "#{payload[:controller]}##{payload[:action]}"
+      end
+
       ActiveMonitoring::Notifications.subscribe("process_action.action_controller") do |name, start, finish, _id, payload|
         Metric.create(
           name: name,
@@ -28,7 +34,9 @@ class Engine < ::Rails::Engine
           Metric.create(
             name: name,
             value: finish - start,
+            request_id: Current.request_id,
             sql_query: payload[:sql],
+            location: Current.location,
             created_at: finish
           )
         end

spec/requests/metrics_spec.rb

@@ -8,27 +8,6 @@
     expect(response.body).to eq("ok")
   end
 
-  scenario "Instruments start_processing.action_controller" do
-    travel_to(Time.zone.local(2020, 1, 1))
-    events = []
-    ActiveMonitoring::Notifications.subscribe("start_processing.action_controller") do |name, start, finish, id, payload|
-      events << { name: name, start: start, finish: finish, id: id, payload: payload }
-    end
-
-    post books_path
-
-    expect(events).to include(
-      a_hash_including(
-        name: "start_processing.action_controller",
-        start: Time.zone.local(2020, 1, 1),
-        finish: Time.zone.local(2020, 1, 1),
-        payload: a_hash_including(
-          request_id: response.headers["X-Request-Id"]
-        )
-      )
-    )
-  end
-
   scenario "Instruments process_action.action_controller" do
     travel_to(Time.zone.local(2020, 1, 1))
 
@@ -55,7 +34,9 @@
         name: "sql.active_record",
         value: 0,
         created_at: Time.zone.local(2020, 1, 1),
-        sql_query: %(INSERT INTO "books" ("name", "created_at", "updated_at") VALUES (?, ?, ?))
+        sql_query: %(INSERT INTO "books" ("name", "created_at", "updated_at") VALUES (?, ?, ?)),
+        request_id: response.headers["X-Request-Id"],
+        location: "BooksController#create"
       )
     )
   end