Handle throttling and move BotoServerError handling to main. (#22383)

Unclear how useful it is to still be catching BotoServerError exceptions
generally, especially when we are now hopefully handling most instances
of throttling, but kept it as it was already in the code. Moved to main
as catching BotoServerErrors inside individual functions will bypass any
AWSRetry.backoff decorator.

Move additional imports to top.

Use python2.6 formatting

A bit of cleanup on imports

Make one more string interpolation Python 2.6 compatible.

lib/ansible/modules/cloud/amazon/ec2_elb_facts.py

@@ -80,6 +80,14 @@ EXAMPLES = '''
 
 import traceback
 
+from ansible.module_utils.basic import AnsibleModule
+from ansible.module_utils.ec2 import (
+    AWSRetry,
+    connect_to_aws,
+    ec2_argument_spec,
+    get_aws_connection_info,
+)
+
 try:
     import boto.ec2.elb
     from boto.ec2.tag import Tag
@@ -88,8 +96,9 @@ try:
 except ImportError:
     HAS_BOTO = False
 
+
 class ElbInformation(object):
-    """ Handles ELB information """
+    """Handles ELB information."""
 
     def __init__(self,
                  module,
@@ -105,17 +114,12 @@ class ElbInformation(object):
 
     def _get_tags(self, elbname):
         params = {'LoadBalancerNames.member.1': elbname}
-        try:
-            elb_tags = self.connection.get_list('DescribeTags', params, [('member', Tag)])
-            return dict((tag.Key, tag.Value) for tag in elb_tags if hasattr(tag, 'Key'))
-        except:
-            return {}
+        elb_tags = self.connection.get_list('DescribeTags', params, [('member', Tag)])
+        return dict((tag.Key, tag.Value) for tag in elb_tags if hasattr(tag, 'Key'))
 
+    @AWSRetry.backoff(tries=5, delay=5, backoff=2.0)
     def _get_elb_connection(self):
-        try:
-            return connect_to_aws(boto.ec2.elb, self.region, **self.aws_connect_params)
-        except BotoServerError as err:
-            self.module.fail_json(msg=err.message)
+        return connect_to_aws(boto.ec2.elb, self.region, **self.aws_connect_params)
 
     def _get_elb_listeners(self, listeners):
         listener_list = []
@@ -143,7 +147,7 @@ class ElbInformation(object):
         protocol, port_path = health_check.target.split(':')
         try:
             port, path = port_path.split('/', 1)
-            path = '/{}'.format(path)
+            path = '/{0}'.format(path)
         except ValueError:
             port = port_path
             path = None
@@ -161,6 +165,7 @@ class ElbInformation(object):
             health_check_dict['ping_path'] = path
         return health_check_dict
 
+    @AWSRetry.backoff(tries=5, delay=5, backoff=2.0)
     def _get_elb_info(self, elb):
         elb_info = {
             'name': elb.name,
@@ -188,10 +193,7 @@ class ElbInformation(object):
             elb_info['vpc_id'] = elb.vpc_id
 
         if elb.instances:
-            try:
-                instance_health = self.connection.describe_instance_health(elb.name)
-            except BotoServerError as err:
-                self.module.fail_json(msg=err.message)
+            instance_health = self.connection.describe_instance_health(elb.name)
             elb_info['instances_inservice'] = [inst.instance_id for inst in instance_health if inst.state == 'InService']
             elb_info['instances_inservice_count'] = len(elb_info['instances_inservice'])
             elb_info['instances_outofservice'] = [inst.instance_id for inst in instance_health if inst.state == 'OutOfService']
@@ -210,12 +212,8 @@ class ElbInformation(object):
         elb_array, token = [], None
 
         while True:
-            try:
-                all_elbs = self.connection.get_all_load_balancers(marker=token)
-                token = all_elbs.next_token
-            except BotoServerError as err:
-                self.module.fail_json(msg = "%s: %s" % (err.error_code, err.error_message),
-                    exception=traceback.format_exc())
+            all_elbs = AWSRetry.backoff(tries=5, delay=5, backoff=2.0)(self.connection.get_all_load_balancers)(marker=token)
+            token = all_elbs.next_token
 
             if all_elbs:
                 if self.names:
@@ -232,6 +230,7 @@ class ElbInformation(object):
 
         return list(map(self._get_elb_info, elb_array))
 
+
 def main():
     argument_spec = ec2_argument_spec()
     argument_spec.update(dict(
@@ -244,24 +243,28 @@ def main():
     if not HAS_BOTO:
         module.fail_json(msg='boto required for this module')
 
-    region, ec2_url, aws_connect_params = get_aws_connection_info(module)
+    try:
+
+        region, ec2_url, aws_connect_params = get_aws_connection_info(module)
+
+        if not region:
+            module.fail_json(msg="region must be specified")
 
-    if not region:
-        module.fail_json(msg="region must be specified")
+        names = module.params['names']
+        elb_information = ElbInformation(module,
+                                         names,
+                                         region,
+                                         **aws_connect_params)
 
-    names = module.params['names']
-    elb_information = ElbInformation(module,
-                              names,
-                              region,
-                              **aws_connect_params)
+        ec2_facts_result = dict(changed=False,
+                                elbs=elb_information.list_elbs())
 
-    ec2_facts_result = dict(changed=False,
-                            elbs=elb_information.list_elbs())
+    except BotoServerError as err:
+        self.module.fail_json(msg="{0}: {1}".format(err.error_code, err.error_message),
+                              exception=traceback.format_exc())
 
     module.exit_json(**ec2_facts_result)
 
-from ansible.module_utils.basic import *
-from ansible.module_utils.ec2 import *
 
 if __name__ == '__main__':
     main()