Ditto

easycloud/common/aws.py

+from botocore.exceptions import WaiterError
 from easycloud.core.metaconfmanager import MetaConfManager
+import math
 
 
 class AWSBaseConfManager(MetaConfManager):
@@ -34,3 +36,38 @@ class AWSBaseConfManager(MetaConfManager):
         # Filters (for images, Amazon has 30.000+ images available)
         self.images_filters = self.parser.get(
             "filters", "images_filters").replace(" ", "").replace("\n", "").split(",")
+
+
+class AWSEC2Utils:
+    @staticmethod
+    def wait_for_instance_operation(client, operation, instances, timeout=None):
+        """ Wait for the given operation to complete.
+        Args:
+            client (boto.EC2.Client) the AWS EC2 client.
+            operation (str): the operation to wait for (e.g., 'instance_running').
+            instances (list): the list of instance IDs.
+            timeout (float): an optional value representing the max number of
+                seconds to wait for; if None, no timeout is enforced.
+
+        See:
+        - https://boto3.amazonaws.com/v1/documentation/api/latest/guide/clients.html
+        - https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/ec2.html#waiters
+        """
+        waiter = client.get_waiter(operation)
+        if timeout is not None:
+            delay = 5
+            waiter_config = {'Delay': delay, 'MaxAttempts': math.ceil(timeout/delay)}
+        ret = True
+        check = True
+        while check:
+            try:
+                if timeout is None:
+                    waiter.wait(InstanceIds = instances)
+                else:
+                    waiter.wait(InstanceIds = instances, WaiterConfig = waiter_config)
+                check = False
+            except WaiterError:
+                if timeout is not None:
+                    check = False
+                    ret = False
+        return ret