Enhanced ecs_taskdefinition module.

Added support to explicitly manage task definitions be revision. If the
revision expectations of the ansible task cannot be met, an error is
thrown.

If revision is not explicitly specified, enhanced module to be
idempotent with respect to task definitions. It will search for an
active revision of the task definition that matches the containers and
volumes specified. If none can be found, a new revision will be created.

lib/ansible/modules/extras/cloud/amazon/ecs_taskdefinition.py

@@ -137,6 +137,33 @@ class EcsTaskManager:
             containerDefinitions=container_definitions, volumes=volumes)
         return response['taskDefinition']
 
+    def describe_task_definitions(self, family):
+        data = {
+            "taskDefinitionArns": [],
+            "nextToken":  None
+        }
+
+        def fetch():
+            # Boto3 is weird about params passed, so only pass nextToken if we have a value
+            params = {
+                'familyPrefix': family
+            }
+
+            if data['nextToken']:
+                params['nextToken'] = data['nextToken']
+
+            result = self.ecs.list_task_definitions(**params)
+            data['taskDefinitionArns'] += result['taskDefinitionArns']
+            data['nextToken'] = result.get('nextToken', None)
+            return data['nextToken'] is not None
+
+        # Fetch all the arns, possibly across multiple pages
+        while fetch():
+            pass
+
+        # Return the full descriptions of the task definitions, sorted ascending by revision
+        return list(sorted([self.ecs.describe_task_definition(taskDefinition=arn)['taskDefinition'] for arn in data['taskDefinitionArns']], key=lambda td: td['revision']))
+
     def deregister_task(self, taskArn):
         response = self.ecs.deregister_task_definition(taskDefinition=taskArn)
         return response['taskDefinition']
@@ -145,12 +172,12 @@ def main():
 
     argument_spec = ec2_argument_spec()
     argument_spec.update(dict(
-        state=dict(required=True, choices=['present', 'absent'] ),
+        state=dict(required=True, choices=['present', 'absent']),
-        arn=dict(required=False, type='str' ),
+        arn=dict(required=False, type='str'),
-        family=dict(required=False, type='str' ),
+        family=dict(required=False, type='str'),
-        revision=dict(required=False, type='int' ),
+        revision=dict(required=False, type='int'),
-        containers=dict(required=False, type='list' ),
+        containers=dict(required=False, type='list'),
-        volumes=dict(required=False, type='list' )
+        volumes=dict(required=False, type='list')
     ))
 
     module = AnsibleModule(argument_spec=argument_spec, supports_check_mode=True)
@@ -162,52 +189,143 @@ def main():
       module.fail_json(msg='boto3 is required.')
 
     task_to_describe = None
-    # When deregistering a task, we can specify the ARN OR
+    task_mgr = EcsTaskManager(module)
-    # the family and revision.
+    results = dict(changed=False)
-    if module.params['state'] == 'absent':
+
-        if 'arn' in module.params and module.params['arn'] is not None:
-            task_to_describe = module.params['arn']
-        elif 'family' in module.params and module.params['family'] is not None and 'revision' in module.params and module.params['revision'] is not None:
-            task_to_describe = module.params['family']+":"+str(module.params['revision'])
-        else:
-            module.fail_json(msg="To use task definitions, an arn or family and revision must be specified")
-    # When registering a task, we can specify the ARN OR
-    # the family and revision.
     if module.params['state'] == 'present':
-        if not 'family' in module.params:
+        if 'containers' not in module.params or not module.params['containers']:
-            module.fail_json(msg="To use task definitions, a family must be specified")
-        if not 'containers' in module.params:
             module.fail_json(msg="To use task definitions, a list of containers must be specified")
-        task_to_describe = module.params['family']
 
-    task_mgr = EcsTaskManager(module)
+        if 'family' not in module.params or not module.params['family']:
-    existing = task_mgr.describe_task(task_to_describe)
+            module.fail_json(msg="To use task definitions, a family must be specified")
 
-    results = dict(changed=False)
+        family = module.params['family']
-    if module.params['state'] == 'present':
+        existing_definitions_in_family = task_mgr.describe_task_definitions(module.params['family'])
-        if existing and 'status' in existing and existing['status']=="ACTIVE":
+
-            results['taskdefinition']=existing
+        if 'revision' in module.params and module.params['revision']:
+            # The definition specifies revision. We must gurantee that an active revision of that number will result from this.
+            revision = int(module.params['revision'])
+
+            # A revision has been explicitly specified. Attempt to locate a matching revision
+            tasks_defs_for_revision = [td for td in existing_definitions_in_family if td['revision'] == revision]
+            existing = tasks_defs_for_revision[0] if len(tasks_defs_for_revision) > 0 else None
+
+            if existing and existing['status'] != "ACTIVE":
+                # We cannot reactivate an inactive revision
+                module.fail_json(msg="A task in family '%s' already exists for revsion %d, but it is inactive" % (family, revision))
+            elif not existing:
+                if len(existing_definitions_in_family) == 0 and revision != 1:
+                    module.fail_json(msg="You have specified a revision of %d but a created revision would be 1" % revision)
+                elif existing_definitions_in_family[-1]['revision'] + 1 != revision:
+                    module.fail_json(msg="You have specified a revision of %d but a created revision would be %d" % (revision, existing_definitions_in_family[-1]['revision'] + 1))
+        else:
+            existing = None
+
+            def _right_has_values_of_left(left, right):
+                # Make sure the values are equivalent for everything left has
+                for k, v in left.iteritems():
+                    if not ((not v and (k not in right or not right[k])) or (k in right and v == right[k])):
+                        # We don't care about list ordering because ECS can change things
+                        if isinstance(v, list) and k in right:
+                            left_list = v
+                            right_list = right[k] or []
+
+                            if len(left_list) != len(right_list):
+                                return False
+
+                            for list_val in left_list:
+                                if list_val not in right_list:
+                                    return False
+                        else:
+                            return False
+
+                # Make sure right doesn't have anything that left doesn't
+                for k, v in right.iteritems():
+                    if v and k not in left:
+                        return False
+
+                return True
+
+            def _task_definition_matches(requested_volumes, requested_containers, existing_task_definition):
+                if td['status'] != "ACTIVE":
+                    return None
+
+                existing_volumes = td.get('volumes', []) or []
+
+                if len(requested_volumes) != len(existing_volumes):
+                    # Nope.
+                    return None
+
+                if len(requested_volumes) > 0:
+                    for requested_vol in requested_volumes:
+                        found = False
+
+                        for actual_vol in existing_volumes:
+                            if _right_has_values_of_left(requested_vol, actual_vol):
+                                found = True
+                                break
+
+                        if not found:
+                            return None
+
+                existing_containers = td.get('containerDefinitions', []) or []
+
+                if len(requested_containers) != len(existing_containers):
+                    # Nope.
+                    return None
+
+                for requested_container in requested_containers:
+                    found = False
+
+                    for actual_container in existing_containers:
+                        if _right_has_values_of_left(requested_container, actual_container):
+                            found = True
+                            break
+
+                    if not found:
+                        return None
+
+                return existing_task_definition
+
+            # No revision explicitly specified. Attempt to find an active, matching revision that has all the properties requested
+            for td in existing_definitions_in_family:
+                requested_volumes = module.params.get('volumes', []) or []
+                requested_containers = module.params.get('containers', []) or []
+                existing = _task_definition_matches(requested_volumes, requested_containers, td)
+
+                if existing:
+                    break
+
+        if existing:
+            # Awesome. Have an existing one. Nothing to do.
+            results['taskdefinition'] = existing
         else:
             if not module.check_mode:
-                # doesn't exist. create it.
+                # Doesn't exist. create it.
-                volumes = []
+                volumes = module.params.get('volumes', []) or []
-                if 'volumes' in module.params:
-                    volumes = module.params['volumes']
-                if volumes is None:
-                    volumes = []
                 results['taskdefinition'] = task_mgr.register_task(module.params['family'],
-                    module.params['containers'], volumes)
+                                                                   module.params['containers'], volumes)
             results['changed'] = True
 
-    # delete the cloudtrai
     elif module.params['state'] == 'absent':
+        # When de-registering a task definition, we can specify the ARN OR the family and revision.
+        if module.params['state'] == 'absent':
+            if 'arn' in module.params and module.params['arn'] is not None:
+                task_to_describe = module.params['arn']
+            elif 'family' in module.params and module.params['family'] is not None and 'revision' in module.params and \
+                            module.params['revision'] is not None:
+                task_to_describe = module.params['family'] + ":" + str(module.params['revision'])
+            else:
+                module.fail_json(msg="To use task definitions, an arn or family and revision must be specified")
+
+        existing = task_mgr.describe_task(task_to_describe)
+
         if not existing:
             pass
         else:
-            # it exists, so we should delete it and mark changed.
+            # It exists, so we should delete it and mark changed. Return info about the task definition deleted
-            # return info about the cluster deleted
             results['taskdefinition'] = existing
-            if 'status' in existing and existing['status']=="INACTIVE":
+            if 'status' in existing and existing['status'] == "INACTIVE":
                 results['changed'] = False
             else:
                 if not module.check_mode: