From 4b1b0f8514817b5524206383476bc85fb34058e9 Mon Sep 17 00:00:00 2001
From: Andres Riancho <andres.riancho@gmail.com>
Date: Wed, 20 Aug 2014 14:51:24 -0300
Subject: [PATCH 1/2] Minor refactoring to avoid code duplication

---
 moto/ec2/models.py | 42 ++++++++++++++++++++++++++----------------
 1 file changed, 26 insertions(+), 16 deletions(-)

diff --git a/moto/ec2/models.py b/moto/ec2/models.py
index 35fbd6f60..9170cae91 100644
--- a/moto/ec2/models.py
+++ b/moto/ec2/models.py
@@ -141,37 +141,33 @@ class InstanceBackend(object):
 
     def start_instances(self, instance_ids):
         started_instances = []
-        for instance in self.all_instances():
-            if instance.id in instance_ids:
-                instance.start()
-                started_instances.append(instance)
+        for instance in self.get_multi_instances_by_id(instance_ids):
+            instance.start()
+            started_instances.append(instance)
 
         return started_instances
 
     def stop_instances(self, instance_ids):
         stopped_instances = []
-        for instance in self.all_instances():
-            if instance.id in instance_ids:
-                instance.stop()
-                stopped_instances.append(instance)
+        for instance in self.get_multi_instances_by_id(instance_ids):
+            instance.stop()
+            stopped_instances.append(instance)
 
         return stopped_instances
 
     def terminate_instances(self, instance_ids):
         terminated_instances = []
-        for instance in self.all_instances():
-            if instance.id in instance_ids:
-                instance.terminate()
-                terminated_instances.append(instance)
+        for instance in self.get_multi_instances_by_id(instance_ids):
+            instance.terminate()
+            terminated_instances.append(instance)
 
         return terminated_instances
 
     def reboot_instances(self, instance_ids):
         rebooted_instances = []
-        for instance in self.all_instances():
-            if instance.id in instance_ids:
-                instance.reboot()
-                rebooted_instances.append(instance)
+        for instance in self.get_multi_instances_by_id(instance_ids):
+            instance.reboot()
+            rebooted_instances.append(instance)
 
         return rebooted_instances
 
@@ -192,6 +188,20 @@ class InstanceBackend(object):
                 instances.append(instance)
         return instances
 
+    def get_multi_instances_by_id(self, instance_ids):
+        """
+        :param instance_ids: A string list with instance ids
+        :return: A list with instance objects
+        """
+        result = []
+
+        for reservation in self.all_reservations():
+            for instance in reservation.instances:
+                if instance.id in instance_ids:
+                    result.append(instance)
+
+        return result
+
     def get_instance_by_id(self, instance_id):
         for reservation in self.all_reservations():
             for instance in reservation.instances:

From c65ff170b2f483b4ff630d3256959751c7afe3a5 Mon Sep 17 00:00:00 2001
From: Andres Riancho <andres.riancho@gmail.com>
Date: Wed, 20 Aug 2014 14:52:23 -0300
Subject: [PATCH 2/2] Fix NotImplementedError: The describe_instance_status
 action has not been implemented #163

---
 moto/ec2/responses/instances.py  | 47 ++++++++++++++++++++++++++++++++
 tests/test_ec2/test_instances.py | 34 +++++++++++++++++++++++
 2 files changed, 81 insertions(+)

diff --git a/moto/ec2/responses/instances.py b/moto/ec2/responses/instances.py
index 106702c14..b04376127 100644
--- a/moto/ec2/responses/instances.py
+++ b/moto/ec2/responses/instances.py
@@ -65,6 +65,17 @@ class InstanceResponse(BaseResponse):
         template = Template(EC2_START_INSTANCES)
         return template.render(instances=instances)
 
+    def describe_instance_status(self):
+        instance_ids = instance_ids_from_querystring(self.querystring)
+
+        if instance_ids:
+            instances = ec2_backend.get_multi_instances_by_id(instance_ids)
+        else:
+            instances = ec2_backend.all_instances()
+
+        template = Template(EC2_INSTANCE_STATUS)
+        return template.render(instances=instances)
+
     def describe_instance_attribute(self):
         # TODO this and modify below should raise IncorrectInstanceState if
         # instance not in stopped state
@@ -359,3 +370,39 @@ EC2_INVALID_INSTANCE_ID = """<?xml version="1.0" encoding="UTF-8"?>
 <Message>The instance ID '{{ instance_id }}' does not exist</Message></Error>
 </Errors>
 <RequestID>39070fe4-6f6d-4565-aecd-7850607e4555</RequestID></Response>"""
+
+
+EC2_INSTANCE_STATUS = """<?xml version="1.0" encoding="UTF-8"?>
+<DescribeInstanceStatusResponse xmlns="http://ec2.amazonaws.com/doc/2014-05-01/">
+    <requestId>59dbff89-35bd-4eac-99ed-be587EXAMPLE</requestId>
+    <instanceStatusSet>
+      {% for instance in instances %}
+        <item>
+            <instanceId>{{ instance.id }}</instanceId>
+            <availabilityZone>us-east-1d</availabilityZone>
+            <instanceState>
+                <code>16</code>
+                <name>running</name>
+            </instanceState>
+            <systemStatus>
+                <status>ok</status>
+                <details>
+                    <item>
+                        <name>reachability</name>
+                        <status>passed</status>
+                    </item>
+                </details>
+            </systemStatus>
+            <instanceStatus>
+                <status>ok</status>
+                <details>
+                    <item>
+                        <name>reachability</name>
+                        <status>passed</status>
+                    </item>
+                </details>
+            </instanceStatus>
+        </item>
+      {% endfor %}
+    </instanceStatusSet>
+</DescribeInstanceStatusResponse>"""
\ No newline at end of file
diff --git a/tests/test_ec2/test_instances.py b/tests/test_ec2/test_instances.py
index 3ee2a2796..5b61deb8f 100644
--- a/tests/test_ec2/test_instances.py
+++ b/tests/test_ec2/test_instances.py
@@ -241,3 +241,37 @@ def test_run_instance_with_keypair():
     instance = reservation.instances[0]
 
     instance.key_name.should.equal("keypair_name")
+
+
+@mock_ec2
+def test_describe_instance_status_no_instances():
+    conn = boto.connect_ec2('the_key', 'the_secret')
+    all_status = conn.get_all_instance_status()
+    len(all_status).should.equal(0)
+
+
+@mock_ec2
+def test_describe_instance_status_with_instances():
+    conn = boto.connect_ec2('the_key', 'the_secret')
+    conn.run_instances('ami-1234abcd', key_name="keypair_name")
+
+    all_status = conn.get_all_instance_status()
+    len(all_status).should.equal(1)
+    all_status[0].instance_status.status.should.equal('ok')
+    all_status[0].system_status.status.should.equal('ok')
+
+
+@mock_ec2
+def test_describe_instance_status_with_instance_filter():
+    conn = boto.connect_ec2('the_key', 'the_secret')
+
+    # We want to filter based on this one
+    reservation = conn.run_instances('ami-1234abcd', key_name="keypair_name")
+    instance = reservation.instances[0]
+
+    # This is just to setup the test
+    conn.run_instances('ami-1234abcd', key_name="keypair_name")
+
+    all_status = conn.get_all_instance_status(instance_ids=[instance.id])
+    len(all_status).should.equal(1)
+    all_status[0].id.should.equal(instance.id)
\ No newline at end of file