Instrument statesman for easy hook into from monitoring tools

lib/statesman/callback.rb

@@ -19,7 +19,16 @@ def initialize(options = { from: nil, to: nil, callback: nil })
     end
 
     def call(*args)
-      callback.call(*args)
+      ActiveSupport::Notifications.instrument "callback.statesman", {
+        subject: args.first.class.name,
+        subject_id: args.first.id,
+        to_state: to,
+        from_state: from,
+        callback: callback.to_s,
+        resource: self.class.name,
+      } do
+        callback.call(*args)
+      end
     end
 
     def applies_to?(options = { from: nil, to: nil })

lib/statesman/guard.rb

@@ -6,7 +6,16 @@
 module Statesman
   class Guard < Callback
     def call(*args)
-      raise GuardFailedError.new(from, to) unless super(*args)
+      ActiveSupport::Notifications.instrument "guard.statesman", {
+        subject: args.first.class.name,
+        subject_id: args.first.id,
+        to_state: to,
+        from_state: from,
+        callback: callback.to_s,
+        resource: self.class.name,
+      } do
+        raise GuardFailedError.new(from, to) unless super(*args)
+      end
     end
   end
 end

lib/statesman/machine.rb

@@ -279,14 +279,20 @@ def history
     end
 
     def transition_to!(new_state, metadata = {})
-      initial_state = current_state
-      new_state = new_state.to_s
-
-      validate_transition(from: initial_state,
-                          to: new_state,
-                          metadata: metadata)
-
-      @storage_adapter.create(initial_state, new_state, metadata)
+      ActiveSupport::Notifications.instrument "transition.statesman", {
+        to_state: new_state,
+        from_state: current_state,
+        resource: self.class.name,
+      } do
+        initial_state = current_state
+        new_state = new_state.to_s
+
+        validate_transition(from: initial_state,
+                            to: new_state,
+                            metadata: metadata)
+
+        @storage_adapter.create(initial_state, new_state, metadata)
+      end
 
       true
     rescue TransitionFailedError => e
@@ -298,13 +304,25 @@ def transition_to!(new_state, metadata = {})
     end
 
     def execute_on_failure(phase, initial_state, new_state, exception)
-      callbacks = callbacks_for(phase, from: initial_state, to: new_state)
-      callbacks.each { |cb| cb.call(@object, exception) }
+      ActiveSupport::Notifications.instrument "execute_on_failure.statesman", {
+        to_state: new_state,
+        from_state: initial_state,
+        resource: self.class.name,
+      } do
+        callbacks = callbacks_for(phase, from: initial_state, to: new_state)
+        callbacks.each { |cb| cb.call(@object, exception) }
+      end
     end
 
     def execute(phase, initial_state, new_state, transition)
-      callbacks = callbacks_for(phase, from: initial_state, to: new_state)
-      callbacks.each { |cb| cb.call(@object, transition) }
+      ActiveSupport::Notifications.instrument "execute.statesman", {
+        to_state: new_state,
+        from_state: initial_state,
+        resource: self.class.name,
+      } do
+        callbacks = callbacks_for(phase, from: initial_state, to: new_state)
+        callbacks.each { |cb| cb.call(@object, transition) }
+      end
     end
 
     def transition_to(new_state, metadata = {})