cyclades: Fix bug during server creation

Commit #32a0b85, modified server creation, by refetching the object from
DB after issuing commission to quotaholder. However, the new object is
not having the 'config_url' attributed, which is added to the vm object
by the 'vmapi'. This commit, fixes this by moving the signal dispatching
code after refetching the vm. Also, this commit makes more clear the
exception handling code, when the creation job can not be enqueued to
Ganeti.

snf-cyclades-app/synnefo/api/servers.py

@@ -47,7 +47,6 @@ from synnefo.db.models import (VirtualMachine, VirtualMachineMetadata,
                                NetworkInterface)
 from synnefo.logic.backend import create_instance, delete_instance
 from synnefo.logic.utils import get_rsapi_state
-from synnefo.logic.rapi import GanetiApiError
 from synnefo.logic.backend_allocator import BackendAllocator
 from synnefo import quotas
 
@@ -359,23 +358,14 @@ def do_create_server(userid, name, password, flavor, image, metadata={},
             flavor=flavor,
             action="CREATE")
 
+        log.info("Created entry in DB for VM '%s'", vm)
+
         # Create VM's public NIC. Do not wait notification form ganeti hooks to
         # create this NIC, because if the hooks never run (e.g. building error)
         # the VM's public IP address will never be released!
         NetworkInterface.objects.create(machine=vm, network=network, index=0,
                                         ipv4=address, state="BUILDING")
 
-        log.info("Created entry in DB for VM '%s'", vm)
-
-        # dispatch server created signal
-        server_created.send(sender=vm, created_vm_params={
-            'img_id': image['backend_id'],
-            'img_passwd': password,
-            'img_format': str(image['format']),
-            'img_personality': json.dumps(personality),
-            'img_properties': json.dumps(image['metadata']),
-        })
-
         # Also we must create the VM metadata in the same transaction.
         for key, val in metadata.items():
             VirtualMachineMetadata.objects.create(
@@ -394,6 +384,17 @@ def do_create_server(userid, name, password, flavor, image, metadata={},
 
     try:
         vm = VirtualMachine.objects.select_for_update().get(id=vm.id)
+        # dispatch server created signal needed to trigger the 'vmapi', which
+        # enriches the vm object with the 'config_url' attribute which must be
+        # passed to the Ganeti job.
+        server_created.send(sender=vm, created_vm_params={
+            'img_id': image['backend_id'],
+            'img_passwd': password,
+            'img_format': str(image['format']),
+            'img_personality': json.dumps(personality),
+            'img_properties': json.dumps(image['metadata']),
+        })
+
         jobID = create_instance(vm, nic, flavor, image)
         # At this point the job is enqueued in the Ganeti backend
         vm.backendjobid = jobID
@@ -401,21 +402,18 @@ def do_create_server(userid, name, password, flavor, image, metadata={},
         transaction.commit()
         log.info("User %s created VM %s, NIC %s, Backend %s, JobID %s",
                  userid, vm, nic, backend, str(jobID))
-    except GanetiApiError as e:
-        log.exception("Can not communicate to backend %s: %s.",
-                      backend, e)
-        # Failed while enqueuing OP_INSTANCE_CREATE to backend. Restore
-        # already reserved quotas by issuing a negative commission
-        vm.operstate = "ERROR"
-        vm.backendlogmsg = "Can not communicate to backend."
-        already_deleted = vm.deleted
-        vm.deleted = True
-        vm.save()
-        if not already_deleted:
-            quotas.issue_and_accept_commission(vm, delete=True)
-        raise
     except:
-        transaction.rollback()
+        # If an exception is raised, then the user will never get the VM id.
+        # So, the VM must be marked as 'deleted'. We do not delete the VM row
+        # from DB, because the job may have been enqueued to Ganeti. We must
+        # also release the VM resources.
+        if not vm.deleted:  # just an extra check for reconciliation...
+            vm.deleted = True
+            vm.operstate = "ERROR"
+            vm.backendlogmsg = "Error while enqueuing job to Ganeti."
+            vm.save()
+            # The following call performs commit.
+            quotas.issue_and_accept_commission(vm, delete=True)
         raise
 
     return vm

snf-cyclades-app/synnefo/quotas/__init__.py

@@ -222,6 +222,7 @@ def issue_and_accept_commission(resource, delete=False):
         else:
             reject_commissions(rejected=[previous_serial.serial], strict=False)
         previous_serial.resolved = True
+        previous_serial.save()
 
     try:
         # Convert resources in the format expected by Quotaholder