Merge branch 'silkapp-ec2-eip-reuse' into devel

library/cloud/ec2_eip

@@ -75,6 +75,12 @@ options:
     default: null
     aliases: []
     version_added: "1.6"
+  reuse_existing_ip_allowed:
+    description:
+      - Reuse an EIP that is not associated to an instance (when available), instead of allocating a new one.
+    required: false
+    default: false
+    version_added: "1.6"
 
 requirements: [ "boto" ]
 author: Lorin Hochstein <lorin@nimbisservices.com>
@@ -189,13 +195,27 @@ def ip_is_associated_with_instance(ec2, public_ip, instance_id, module):
         return False
 
 
-def allocate_address(ec2, domain, module):
-    """ Allocate a new elastic IP address and return it """
+def allocate_address(ec2, domain, module, reuse_existing_ip_allowed):
+    """ Allocate a new elastic IP address (when needed) and return it """
     # If we're in check mode, nothing else to do
     if module.check_mode:
         module.exit_json(change=True)
 
-    address = ec2.allocate_address(domain=domain)
+    if reuse_existing_ip_allowed:
+      if domain:
+        domain_filter = { 'domain' : domain }
+      else:
+        domain_filter = { 'domain' : 'standard' }
+      all_addresses = ec2.get_all_addresses(filters=domain_filter)
+
+      unassociated_addresses = filter(lambda a: a.instance_id is None, all_addresses)
+      if unassociated_addresses:
+        address = unassociated_addresses[0];
+      else:
+        address = ec2.allocate_address(domain=domain)
+    else:
+      address = ec2.allocate_address(domain=domain)
+
     return address
 
 
@@ -239,6 +259,7 @@ def main():
             state = dict(required=False, default='present',
                          choices=['present', 'absent']),
             in_vpc = dict(required=False, choices=BOOLEANS, default=False),
+            reuse_existing_ip_allowed = dict(required=False, type='bool', default=False),
         )
     )
 
@@ -257,18 +278,19 @@ def main():
     state = module.params.get('state')
     in_vpc = module.params.get('in_vpc')
     domain  = "vpc" if in_vpc else None
+    reuse_existing_ip_allowed = module.params.get('reuse_existing_ip_allowed');
 
     if state == 'present':
         if public_ip is None:
             if instance_id is None:
-                address = allocate_address(ec2, domain, module)
+                address = allocate_address(ec2, domain, module, reuse_existing_ip_allowed)
                 module.exit_json(changed=True, public_ip=address.public_ip)
             else:
                 # Determine if the instance is inside a VPC or not
                 instance = find_instance(ec2, instance_id, module)
                 if instance.vpc_id != None:
                     domain = "vpc"
-                address = allocate_address(ec2, domain, module)
+                address = allocate_address(ec2, domain, module, reuse_existing_ip_allowed)
         else:
             address = find_address(ec2, public_ip, module)
         associate_ip_and_instance(ec2, address, instance_id, module)