From 6963866c7eece36ee9ce049ee7548994b1399971 Mon Sep 17 00:00:00 2001
From: Arthur Wang <arthur@datadoghq.com>
Date: Mon, 20 Oct 2014 15:54:00 -0400
Subject: [PATCH] Add ec2 instance state reason

- Add instance.reason and instance.state_reason
(http://docs.aws.amazon.com/AWSEC2/latest/APIReference/ApiReference-Item
Type-StateReasonType.html)
- Add ec2 filtering by state-reason-code and state-reason-message
---
 moto/ec2/models.py              | 22 ++++++++++++++++++++++
 moto/ec2/responses/instances.py |  6 +++++-
 moto/ec2/utils.py               | 17 +++++++++++++++--
 3 files changed, 42 insertions(+), 3 deletions(-)

diff --git a/moto/ec2/models.py b/moto/ec2/models.py
index 32b6b166..0540abc1 100644
--- a/moto/ec2/models.py
+++ b/moto/ec2/models.py
@@ -2,6 +2,7 @@ from __future__ import unicode_literals
 import copy
 import itertools
 from collections import defaultdict
+from datetime import datetime
 
 import six
 import boto
@@ -95,6 +96,11 @@ class InstanceState(object):
         self.name = name
         self.code = code
 
+class StateReason(object):
+    def __init__(self, message="", code=""):
+        self.message = message
+        self.code = code
+
 
 class TaggedEC2Resource(object):
     def get_tags(self, *args, **kwargs):
@@ -258,6 +264,8 @@ class Instance(BotoInstance, TaggedEC2Resource):
         self.id = random_instance_id()
         self.image_id = image_id
         self._state = InstanceState("running", 16)
+        self._reason = ""
+        self._state_reason = StateReason()
         self.user_data = user_data
         self.security_groups = security_groups
         self.instance_type = kwargs.get("instance_type", "m1.small")
@@ -317,6 +325,9 @@ class Instance(BotoInstance, TaggedEC2Resource):
         self._state.name = "running"
         self._state.code = 16
 
+        self._reason = ""
+        self._state_reason = StateReason()
+
     def stop(self, *args, **kwargs):
         for nic in self.nics.values():
             nic.stop()
@@ -324,6 +335,10 @@ class Instance(BotoInstance, TaggedEC2Resource):
         self._state.name = "stopped"
         self._state.code = 80
 
+        self._reason = "User initiated ({0})".format(datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S UTC'))
+        self._state_reason = StateReason("Client.UserInitiatedShutdown: User initiated shutdown",
+                                         "Client.UserInitiatedShutdown")
+
     def terminate(self, *args, **kwargs):
         for nic in self.nics.values():
             nic.stop()
@@ -331,10 +346,17 @@ class Instance(BotoInstance, TaggedEC2Resource):
         self._state.name = "terminated"
         self._state.code = 48
 
+        self._reason = "User initiated ({0})".format(datetime.utcnow().strftime('%Y-%m-%d %H:%M:%S UTC'))
+        self._state_reason = StateReason("Client.UserInitiatedShutdown: User initiated shutdown",
+                                         "Client.UserInitiatedShutdown")
+
     def reboot(self, *args, **kwargs):
         self._state.name = "running"
         self._state.code = 16
 
+        self._reason = ""
+        self._state_reason = StateReason()
+
     def get_tags(self):
         tags = ec2_backend.describe_tags(filters={'resource-id': [self.id]})
         return tags
diff --git a/moto/ec2/responses/instances.py b/moto/ec2/responses/instances.py
index b1833ee2..70f19a8f 100644
--- a/moto/ec2/responses/instances.py
+++ b/moto/ec2/responses/instances.py
@@ -303,7 +303,7 @@ EC2_DESCRIBE_INSTANCES = """<DescribeInstancesResponse xmlns='http://ec2.amazona
                     </instanceState>
                     <privateDnsName>ip-10.0.0.12.ec2.internal</privateDnsName>
                     <dnsName>ec2-46.51.219.63.compute-1.amazonaws.com</dnsName>
-                    <reason/>
+                    <reason>{{ instance._reason }}</reason>
                     <keyName>{{ instance.key_name }}</keyName>
                     <amiLaunchIndex>0</amiLaunchIndex>
                     <productCodes/>
@@ -337,6 +337,10 @@ EC2_DESCRIBE_INSTANCES = """<DescribeInstancesResponse xmlns='http://ec2.amazona
                       </item>
                       {% endfor %}
                     </groupSet>
+                    <stateReason>
+                      <code>{{ instance._state_reason.code }}</code>
+                      <message>{{ instance._state_reason.message }}</message>
+                    </stateReason>
                     <architecture>{{ instance.architecture }}</architecture>
                     <kernelId>{{ instance.kernel }}</kernelId>
                     <rootDeviceType>ebs</rootDeviceType>
diff --git a/moto/ec2/utils.py b/moto/ec2/utils.py
index 1a590d6d..06ff1941 100644
--- a/moto/ec2/utils.py
+++ b/moto/ec2/utils.py
@@ -266,15 +266,28 @@ def keypair_names_from_querystring(querystring_dict):
 
 filter_dict_attribute_mapping = {
     'instance-state-name': 'state',
-    'instance-id': 'id'
+    'instance-id': 'id',
+    'state-reason-code': '_state_reason.code',
+    'state-reason-message': '_state_reason.message'
 }
 
+def get_instance_value(instance, instance_attr):
+    keys = instance_attr.split('.')
+    val = instance
+    for key in keys:
+        if hasattr(val, key):
+            val = getattr(val, key)
+        elif isinstance(val, dict):
+            val = val[key]
+        else:
+            return None
+    return val
 
 def passes_filter_dict(instance, filter_dict):
     for filter_name, filter_values in filter_dict.items():
         if filter_name in filter_dict_attribute_mapping:
             instance_attr = filter_dict_attribute_mapping[filter_name]
-            instance_value = getattr(instance, instance_attr)
+            instance_value = get_instance_value(instance, instance_attr)
             if instance_value not in filter_values:
                 return False
         elif filter_name.startswith('tag:'):