From 1f46543ae263d3e6e53e8432771ff2abe816b48e Mon Sep 17 00:00:00 2001
From: William Richard <william.richard.no.s@gmail.com>
Date: Wed, 4 Apr 2018 16:01:01 -0400
Subject: [PATCH] ECS CPU, memory hard limits and host ports are all optional.

http://boto3.readthedocs.io/en/latest/reference/services/ecs.html#ECS.Client.register_task_definition
---
 moto/ecs/models.py               |  8 ++--
 tests/test_ecs/test_ecs_boto3.py | 81 ++++++++++++++++++++++++++++++++
 2 files changed, 86 insertions(+), 3 deletions(-)

diff --git a/moto/ecs/models.py b/moto/ecs/models.py
index 998975650..0c07ce107 100644
--- a/moto/ecs/models.py
+++ b/moto/ecs/models.py
@@ -502,10 +502,12 @@ class EC2ContainerServiceBackend(BaseBackend):
     def _calculate_task_resource_requirements(task_definition):
         resource_requirements = {"CPU": 0, "MEMORY": 0, "PORTS": [], "PORTS_UDP": []}
         for container_definition in task_definition.container_definitions:
-            resource_requirements["CPU"] += container_definition.get('cpu')
-            resource_requirements["MEMORY"] += container_definition.get("memory")
+            resource_requirements["CPU"] += container_definition.get('cpu', 0)
+            resource_requirements["MEMORY"] += container_definition.get(
+                "memory", container_definition.get('memoryReservation'))
             for port_mapping in container_definition.get("portMappings", []):
-                resource_requirements["PORTS"].append(port_mapping.get('hostPort'))
+                if 'hostPort' in port_mapping:
+                    resource_requirements["PORTS"].append(port_mapping.get('hostPort'))
         return resource_requirements
 
     @staticmethod
diff --git a/tests/test_ecs/test_ecs_boto3.py b/tests/test_ecs/test_ecs_boto3.py
index 5fcc297aa..7f6b835be 100644
--- a/tests/test_ecs/test_ecs_boto3.py
+++ b/tests/test_ecs/test_ecs_boto3.py
@@ -1229,6 +1229,87 @@ def test_resource_reservation_and_release():
     remaining_resources['PORTS'].should.equal(registered_resources['PORTS'])
     container_instance_description['runningTasksCount'].should.equal(0)
 
+@mock_ec2
+@mock_ecs
+def test_resource_reservation_and_release_memory_reservation():
+    client = boto3.client('ecs', region_name='us-east-1')
+    ec2 = boto3.resource('ec2', region_name='us-east-1')
+
+    test_cluster_name = 'test_ecs_cluster'
+
+    _ = client.create_cluster(
+        clusterName=test_cluster_name
+    )
+
+    test_instance = ec2.create_instances(
+        ImageId="ami-1234abcd",
+        MinCount=1,
+        MaxCount=1,
+    )[0]
+
+    instance_id_document = json.dumps(
+        ec2_utils.generate_instance_identity_document(test_instance)
+    )
+
+    _ = client.register_container_instance(
+        cluster=test_cluster_name,
+        instanceIdentityDocument=instance_id_document
+    )
+
+    _ = client.register_task_definition(
+        family='test_ecs_task',
+        containerDefinitions=[
+            {
+                'name': 'hello_world',
+                'image': 'docker/hello-world:latest',
+                'memoryReservation': 400,
+                'essential': True,
+                'environment': [{
+                    'name': 'AWS_ACCESS_KEY_ID',
+                    'value': 'SOME_ACCESS_KEY'
+                }],
+                'logConfiguration': {'logDriver': 'json-file'},
+                'portMappings': [
+                    {
+                        'containerPort': 8080
+                    }
+                ]
+            }
+        ]
+    )
+    run_response = client.run_task(
+        cluster='test_ecs_cluster',
+        overrides={},
+        taskDefinition='test_ecs_task',
+        count=1,
+        startedBy='moto'
+    )
+    container_instance_arn = run_response['tasks'][0].get('containerInstanceArn')
+    container_instance_description = client.describe_container_instances(
+        cluster='test_ecs_cluster',
+        containerInstances=[container_instance_arn]
+    )['containerInstances'][0]
+    remaining_resources, registered_resources = _fetch_container_instance_resources(container_instance_description)
+    remaining_resources['CPU'].should.equal(registered_resources['CPU'])
+    remaining_resources['MEMORY'].should.equal(registered_resources['MEMORY'] - 400)
+    remaining_resources['PORTS'].should.equal(registered_resources['PORTS'])
+    container_instance_description['runningTasksCount'].should.equal(1)
+    client.stop_task(
+        cluster='test_ecs_cluster',
+        task=run_response['tasks'][0].get('taskArn'),
+        reason='moto testing'
+    )
+    container_instance_description = client.describe_container_instances(
+        cluster='test_ecs_cluster',
+        containerInstances=[container_instance_arn]
+    )['containerInstances'][0]
+    remaining_resources, registered_resources = _fetch_container_instance_resources(container_instance_description)
+    remaining_resources['CPU'].should.equal(registered_resources['CPU'])
+    remaining_resources['MEMORY'].should.equal(registered_resources['MEMORY'])
+    remaining_resources['PORTS'].should.equal(registered_resources['PORTS'])
+    container_instance_description['runningTasksCount'].should.equal(0)
+
+
 
 @mock_ecs
 @mock_cloudformation