Add idempotency support to ec2_group

cloud/ec2_group

@@ -49,6 +49,14 @@ options:
     required: false
     default: null
     aliases: []
+  state:
+    version_added: "1.4"
+    description:
+      - create or delete security group
+    required: false
+    default: 'present'
+    aliases: []
+
 requirements: [ "boto" ]
 '''
 
@@ -105,6 +113,7 @@ def main():
             ec2_secret_key=dict(aliases=['EC2_SECRET_KEY'], no_log=True),
             ec2_access_key=dict(aliases=['EC2_ACCESS_KEY']),
             region=dict(choices=['eu-west-1', 'sa-east-1', 'us-east-1', 'ap-northeast-1', 'us-west-2', 'us-west-1', 'ap-southeast-1', 'ap-southeast-2']),
+            state = dict(default='present', choices=['present', 'absent']),
         ),
         supports_check_mode=True,
     )
@@ -116,6 +125,7 @@ def main():
     ec2_secret_key = module.params.get('ec2_secret_key')
     ec2_access_key = module.params.get('ec2_access_key')
     region = module.params.get('region')
+    state = module.params.get('state')
 
     changed = False
 
@@ -152,8 +162,25 @@ def main():
         if curGroup.name == name and curGroup.vpc_id == vpc_id:
             group = curGroup
 
-    # if found, check the group parameters are correct
+    # Ensure requested group is absent
+    if state == 'absent':
         if group:
+            '''found a match, delete it'''
+            try:
+                group.delete()
+            except Exception, e:
+                module.fail_json(msg="Unable to delete security group '%s' - %s" % (group, e))
+            else:
+                group = None
+                changed = True
+        else:
+            '''no match found, no changes required'''
+
+    # Ensure requested group is present
+    elif state == 'present':
+        if group:
+            '''existing group found'''
+            # check the group parameters are correct
             group_in_use = False
             rs = ec2.get_all_instances()
             for r in rs:
@@ -163,21 +190,22 @@ def main():
             if group.description != description:
                 if group_in_use:
                     module.fail_json(msg="Group description does not match, but it is in use so cannot be changed.")
-            group.delete()
-            group = None
 
         # if the group doesn't exist, create it now
-    if not group:
+        else:
+            '''no match found, create it'''
             if not module.check_mode:
                 group = ec2.create_security_group(name, description, vpc_id=vpc_id)
             changed = True
+    else:
+        module.fail_json(msg="Unsupported state requested: %s" % state)
 
     # create a lookup for all existing rules on the group
-    groupRules = {}
     if group:
+        groupRules = {}
         addRulesToLookup(group.rules, 'in', groupRules)
 
-    # Now, go through all the defined rules and ensure they are there.
+        # Now, go through all provided rules and ensure they are there.
         if rules:
             for rule in rules:
                 group_id = None
@@ -194,11 +222,12 @@ def main():
                     rule['from_port'] = None
                     rule['to_port'] = None
 
+                # If rule already exists, don't later delete it
                 ruleId = "%s-%s-%s-%s-%s-%s" % ('in', rule['proto'], rule['from_port'], rule['to_port'], group_id, ip)
                 if ruleId in groupRules:
                     del groupRules[ruleId]
-                continue
+                # Otherwise, add new rule
-
+                else:
                     grantGroup = None
                     if group_id:
                         grantGroup = groups[group_id]
@@ -217,9 +246,10 @@ def main():
                     group.revoke(rule.ip_protocol, rule.from_port, rule.to_port, grant.cidr_ip, grantGroup)
                 changed = True
 
-    if not group:
+    if group:
-        module.exit_json(changed=changed, group_id=None)
         module.exit_json(changed=changed, group_id=group.id)
+    else:
+        module.exit_json(changed=changed, group_id=None)
 
 # this is magic, see lib/ansible/module_common.py
 #<<INCLUDE_ANSIBLE_MODULE_COMMON>>