GCP: added class to use for implementing synchronized operations (e.g., for...

GCP: added class to use for implementing synchronized operations (e.g., for waiting until the starting of an instance is done)

easycloud/common/gcp.py

 from easycloud.core.metaconfmanager import MetaConfManager
+import time
 
 
 class GCPBaseConfManager(MetaConfManager):
@@ -52,3 +53,62 @@ class GCPBaseConfManager(MetaConfManager):
             "alwaysfree", "alwaysfree_instance_types").replace(" ", "").replace("\n", "").split(",")
         self.alwaysfree_zones = self.parser.get(
             "alwaysfree", "alwaysfree_zones").replace(" ", "").replace("\n", "").split(",")
+
+
+class GCPComputeUtils:
+    @staticmethod
+    def wait_for_operation(service, project, operation, timeout=None):
+        """ Wait until the given operation is done.
+        Args:
+            service (googleapiclient.discovery.Resource): the Resource object for interacting with the Google Compute service.
+            project (str): the project identifier.
+            operation (dict): the operation to wait for as returned by the
+                original request.
+            timeout (float): an optional value representing the max number of
+                seconds to wait for; if None, no timeout is enforced.
+        Returns:
+            bool: True if the operation suceeded or False if the operation
+                failed or if it does not complete successfully before the
+                timeout.
+
+        Requires one of the following OAuth scopes:
+        - https://www.googleapis.com/auth/compute
+        - https://www.googleapis.com/auth/cloud-platform
+        and the followin IAM permissions:
+        - compute.zoneOperations.get
+
+        See:
+        - https://cloud.google.com/compute/docs/reference/rest/v1/zoneOperations/get
+        """
+        # Inspired by: https://github.com/GoogleCloudPlatform/java-docs-samples/blob/master/compute/cmdline/src/main/java/ComputeEngineSample.java
+        #FIXME: the following function has not been tested yet.
+        op = operation['name']
+        zone = None
+        if 'zone' in operation and operation['zone']:
+            zone = operation['zone'].rpartition('/')[2]
+        start_time = time.time()
+        pool_interval = 5
+        ret = True
+        try:
+            while operation is not None and operation['status'] != 'DONE':
+                time.sleep(poll_interval)
+                if timeout is not None and (time.time()-start_time) >= timeout:
+                    ret = False
+                    break
+
+                request = None
+                if zone is None:
+                    request = service.globalOperations().get(project=project,
+                                                             operation=op)
+                else:
+                    request = service.zoneOperations().get(project=project,
+                                                           zone=zone,
+                                                           operation=op)
+                operation = request.execute()
+
+                if operation is not None and ('error' in operation or 'httpErrorMessage' in operation):
+                    msg = ', '.join([ '{} (code: {})'.format(error['message'], error['code']) for error in operation['error']['errors'] ])
+                    raise Exception(msg)
+        except Exception as e:
+            raise e
+        return ret

easycloud/modules/gcp_googleapi/manager.py

@@ -4,6 +4,7 @@ EasyCloud Google Cloud Platform Manager
 
 
 import datetime
+#from easycloud.common.gcp import GCPComputeUtils
 from easycloud.core.actionbinder import bind_action
 from easycloud.core.compute import Instance, InstanceStatus, Location, LocationKind
 from easycloud.core.metamanager import MetaManager
@@ -148,12 +149,14 @@ class GCPInstance(Instance):
         self._gce_conn.instances().start(project = self._gce_proj,
                                          zone = self._zone,
                                          instance = self._gce_inst['id']).execute()
+        #TODO: call "GCPComputeUtils.wait_for_operation(self._gce_conn, self._gce_proj, res)" to perform a synchronous version of this method (where "res" is the value returned by the "start()" method)
         return True
 
     def stop(self):
         self._gce_conn.instances().stop(project = self._gce_proj,
                                         zone = self._zone,
                                         instance = self._gce_inst['id']).execute()
+        #TODO: call "GCPComputeUtils.wait_for_operation(self._gce_conn, self._gce_proj, res)" to perform a synchronous version of this method (where "res" is the value returned by the "start()" method)
         return True