From 115f9513f6ed1c2d5472493dde7fa66f9a966e7c Mon Sep 17 00:00:00 2001
From: "Riccardo M. Cefala" <riccardo.cefala@mendix.com>
Date: Sat, 11 Jun 2016 12:52:19 +0200
Subject: [PATCH] add ECS ContainerInstance register and list actions

---
 moto/ecs/models.py    | 23 +++++++++++++++++++++++
 moto/ecs/responses.py | 17 +++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/moto/ecs/models.py b/moto/ecs/models.py
index f8f8f201a..45ced304e 100644
--- a/moto/ecs/models.py
+++ b/moto/ecs/models.py
@@ -113,6 +113,7 @@ class EC2ContainerServiceBackend(BaseBackend):
         self.clusters = {}
         self.task_definitions = {}
         self.services = {}
+        self.container_instances = {}
 
     def fetch_task_definition(self, task_definition_str):
         task_definition_components = task_definition_str.split(':')
@@ -235,6 +236,28 @@ class EC2ContainerServiceBackend(BaseBackend):
         else:
             raise Exception("cluster {0} or service {1} does not exist".format(cluster_name, service_name))
 
+    def register_container_instance(self, cluster_str, ec2_instance_id):
+        cluster_name = cluster_str.split('/')[-1]
+        if cluster_name in self.clusters:
+            cluster = self.clusters[cluster_name]
+        else:
+            raise Exception("{0} is not a cluster".format(cluster.name))
+        container_instance = ContainerInstance(ec2_instance_id)
+        if not self.container_instances.get(cluster_name):
+            self.container_instances[cluster_name] = {}
+        self.container_instances[cluster_name][container_instance.containerInstanceArn] = container_instance
+        return container_instance
+
+    def list_container_instances(self, cluster_str):
+        cluster_name = cluster_str.split('/')[-1]
+        return sorted(self.container_instances[cluster_name].keys())
+
+    def describe_container_instances(self, cluster_str, list_container_instances_str):
+        pass
+
+    def deregister_container_instance(self, cluster_str, container_instance_str):
+        pass
+
 
 ecs_backends = {}
 for region, ec2_backend in ec2_backends.items():
diff --git a/moto/ecs/responses.py b/moto/ecs/responses.py
index 1cf88bd4d..0adf7813c 100644
--- a/moto/ecs/responses.py
+++ b/moto/ecs/responses.py
@@ -113,3 +113,20 @@ class EC2ContainerServiceResponse(BaseResponse):
         return json.dumps({
             'service': service.response_object
         })
+
+    def register_container_instance(self):
+        cluster_str = self._get_param('cluster')
+        instance_identity_document_str = self._get_param('instanceIdentityDocument')
+        instance_identity_document = json.loads(instance_identity_document_str)
+        ec2_instance_id = instance_identity_document["instanceId"]
+        container_instance = self.ecs_backend.register_container_instance(cluster_str, ec2_instance_id)
+        return json.dumps({
+            'containerInstance' : container_instance.response_object
+        })
+
+    def list_container_instances(self):
+        cluster_str = self._get_param('cluster')
+        container_instance_arns = self.ecs_backend.list_container_instances(cluster_str)
+        return json.dumps({
+            'containerInstanceArns': container_instance_arns
+        })