EC2: Correct previous instance state (#5528)

moto/ec2/models/instances.py

@@ -334,6 +334,8 @@ class Instance(TaggedEC2Resource, BotoInstance, CloudFormationModel):
         return self.id
 
     def start(self):
+        previous_state = copy.copy(self._state)
+
         for nic in self.nics.values():
             nic.start()
 
@@ -343,7 +345,11 @@ class Instance(TaggedEC2Resource, BotoInstance, CloudFormationModel):
         self._reason = ""
         self._state_reason = StateReason()
 
+        return previous_state
+
     def stop(self):
+        previous_state = copy.copy(self._state)
+
         for nic in self.nics.values():
             nic.stop()
 
@@ -358,6 +364,8 @@ class Instance(TaggedEC2Resource, BotoInstance, CloudFormationModel):
             "Client.UserInitiatedShutdown",
         )
 
+        return previous_state
+
     def is_running(self):
         return self._state.name == "running"
 
@@ -365,6 +373,8 @@ class Instance(TaggedEC2Resource, BotoInstance, CloudFormationModel):
         self.terminate()
 
     def terminate(self):
+        previous_state = copy.copy(self._state)
+
         for nic in self.nics.values():
             nic.stop()
 
@@ -413,6 +423,8 @@ class Instance(TaggedEC2Resource, BotoInstance, CloudFormationModel):
                 ].id
             )
 
+        return previous_state
+
     def reboot(self):
         self._state.name = "running"
         self._state.code = 16
@@ -709,16 +721,16 @@ class InstanceBackend:
     def start_instances(self, instance_ids):
         started_instances = []
         for instance in self.get_multi_instances_by_id(instance_ids):
-            instance.start()
-            started_instances.append(instance)
+            previous_state = instance.start()
+            started_instances.append((instance, previous_state))
 
         return started_instances
 
     def stop_instances(self, instance_ids):
         stopped_instances = []
         for instance in self.get_multi_instances_by_id(instance_ids):
-            instance.stop()
-            stopped_instances.append(instance)
+            previous_state = instance.stop()
+            stopped_instances.append((instance, previous_state))
 
         return stopped_instances
 
@@ -731,8 +743,8 @@ class InstanceBackend:
         for instance in self.get_multi_instances_by_id(instance_ids):
             if instance.disable_api_termination == "true":
                 raise OperationNotPermitted4(instance.id)
-            instance.terminate()
-            terminated_instances.append(instance)
+            previous_state = instance.terminate()
+            terminated_instances.append((instance, previous_state))
 
         return terminated_instances
 

moto/ec2/responses/instances.py

@@ -721,12 +721,12 @@ EC2_TERMINATE_INSTANCES = """
 <TerminateInstancesResponse xmlns="http://ec2.amazonaws.com/doc/2013-10-15/">
   <requestId>59dbff89-35bd-4eac-99ed-be587EXAMPLE</requestId>
   <instancesSet>
-    {% for instance in instances %}
+    {% for instance, previous_state in instances %}
       <item>
         <instanceId>{{ instance.id }}</instanceId>
         <previousState>
-          <code>16</code>
-          <name>running</name>
+          <code>{{ previous_state.code }}</code>
+          <name>{{ previous_state.name }}</name>
         </previousState>
         <currentState>
           <code>32</code>
@@ -741,12 +741,12 @@ EC2_STOP_INSTANCES = """
 <StopInstancesResponse xmlns="http://ec2.amazonaws.com/doc/2013-10-15/">
   <requestId>59dbff89-35bd-4eac-99ed-be587EXAMPLE</requestId>
   <instancesSet>
-    {% for instance in instances %}
+    {% for instance, previous_state in instances %}
       <item>
         <instanceId>{{ instance.id }}</instanceId>
         <previousState>
-          <code>16</code>
-          <name>running</name>
+          <code>{{ previous_state.code }}</code>
+          <name>{{ previous_state.name }}</name>
         </previousState>
         <currentState>
           <code>64</code>
@@ -761,12 +761,12 @@ EC2_START_INSTANCES = """
 <StartInstancesResponse xmlns="http://ec2.amazonaws.com/doc/2013-10-15/">
   <requestId>59dbff89-35bd-4eac-99ed-be587EXAMPLE</requestId>
   <instancesSet>
-    {% for instance in instances %}
+    {% for instance, previous_state in instances %}
       <item>
         <instanceId>{{ instance.id }}</instanceId>
         <previousState>
-          <code>16</code>
-          <name>running</name>
+          <code>{{ previous_state.code }}</code>
+          <name>{{ previous_state.name }}</name>
         </previousState>
         <currentState>
           <code>0</code>

tests/test_ec2/test_instances.py

@@ -88,7 +88,12 @@ def test_instance_launch_and_terminate():
         "An error occurred (DryRunOperation) when calling the TerminateInstance operation: Request would have succeeded, but DryRun flag is set"
     )
 
-    client.terminate_instances(InstanceIds=[instance_id])
+    response = client.terminate_instances(InstanceIds=[instance_id])
+    response["TerminatingInstances"].should.have.length_of(1)
+    instance = response["TerminatingInstances"][0]
+    instance["InstanceId"].should.equal(instance_id)
+    instance["PreviousState"].should.equal({"Code": 16, "Name": "running"})
+    instance["CurrentState"].should.equal({"Code": 32, "Name": "shutting-down"})
 
     reservations = client.describe_instances(InstanceIds=[instance_id])["Reservations"]
     instance = reservations[0]["Instances"][0]
@@ -947,8 +952,7 @@ def test_instance_start_and_stop():
         "StartingInstances"
     ]
     started_instances[0]["CurrentState"].should.equal({"Code": 0, "Name": "pending"})
-    # TODO: The PreviousState is hardcoded to 'running' atm
-    # started_instances[0]["PreviousState"].should.equal({'Code': 80, 'Name': 'stopped'})
+    started_instances[0]["PreviousState"].should.equal({"Code": 80, "Name": "stopped"})
 
 
 @mock_ec2