Merge lp:~frankban/charms/precise/juju-gui/cancel-deployment into lp:~juju-gui/charms/precise/juju-gui/trunk

[Francesco Banconi]

GUI server: cancel deployment feature.

Added an API call for cancelling a pending
deployment.

Also updated the bundles module documentation.

For this first implementation, I discussed
with Gary a workaround to avoid scheduled
deployments to be included in the ProcessPool
executor's call queue: a time.sleep call is
added to the queue right after a new deployment.
This way, as described in the code, it is still
possible to cancel a scheduled deployment job
even if it is the first in the queue.

Tests:
run `make unittest` from the root of this branch.

QA:
- bootstrap a juju-core environment;
- deploy the GUI from this branch (`make deploy`);
- switch to the builtin server:
  `juju set juju-gui builtin-server=true`;
- ensure the GUI is working well by visiting
  https://GUI-ADDRESS .

To test the deployer support and the
"cancel deployment" feature, use the script in
http://pastebin.ubuntu.com/6100815/ e.g.:

- download and save the Python script;
- run it passing the GUI node address as first argument:
  `python start-deployer-cancel.py GUI-ADDRESS`.

The script does the following:
1) it logs in to the juju-core API server;
2) it starts/schedules three deployments;
3) it send two invalid Cancel requests;
4) it cancels the second deployment;
5) it shows the deployments status before and
   after the deployment deletion.

- if everything is ok, you should see an output like
this: http://pastebin.ubuntu.com/6100861/ ;
- you should also be able to check the deployment
  progress from the GUI;
- when the two deployments are completed (it may take
  some minutes) you should see wordpress, mysql and
  mediawiki correctly deployed and displayed in the
  topology view;
- visiting https://GUI-ADDRESS/gui-server-info you
  should see something like this:
  {
    "uptime": 970,
    "deployer": [
      {"Status": "completed", "DeploymentId": 0, "Time": 1379062144},
      {"Status": "cancelled", "DeploymentId": 1, "Time": 1379061766},
      {"Status": "completed", "DeploymentId": 2, "Time": 1379062156}
    ],
    "apiversion": "go",
    "sandbox": false,
    "version": "0.2.0",
    "debug": false,
    "apiurl": "wss://ec2-50-17-116-51.compute-1.amazonaws.com:17070"
  }

That's all, thanks a lot for QAing this branch!

https://codereview.appspot.com/13549046/

[Francesco Banconi (frankban)]

Reviewers: mp+185448_code.launchpad.net,

Message:
Please take a look.

Description:
GUI server: cancel deployment feature.

Added an API call for cancelling a pending
deployment.

Also updated the bundles module documentation.

For this first implementation, I discussed
with Gary a workaround to avoid scheduled
deployments to be included in the ProcessPool
executor's call queue: a time.sleep call is
added to the queue right after a new deployment.
This way, as described in the code, it is still
possible to cancel a scheduled deployment job
even if it is the first in the queue.

Tests:
run `make unittest` from the root of this branch.

QA:
- bootstrap a juju-core environment;
- deploy the GUI from this branch (`make deploy`);
- switch to the builtin server:
   `juju set juju-gui builtin-server=true`;
- ensure the GUI is working well by visiting
   https://GUI-ADDRESS .

To test the deployer support and the
"cancel deployment" feature, use the script in
http://pastebin.ubuntu.com/6100815/ e.g.:

- download and save the Python script;
- run it passing the GUI node address as first argument:
   `python start-deployer-cancel.py GUI-ADDRESS`.

The script does the following:
1) it logs in to the juju-core API server;
2) it starts/schedules three deployments;
3) it send two invalid Cancel requests;
4) it cancels the second deployment;
5) it shows the deployments status before and
    after the deployment deletion.

- if everything is ok, you should see an output like
this: http://pastebin.ubuntu.com/6100861/ ;
- you should also be able to check the deployment
   progress from the GUI;
- when the two deployments are completed (it may take
   some minutes) you should see wordpress, mysql and
   mediawiki correctly deployed and displayed in the
   topology view;
- visiting https://GUI-ADDRESS/gui-server-info you
   should see something like this:
   {
     "uptime": 970,
     "deployer": [
       {"Status": "completed", "DeploymentId": 0, "Time": 1379062144},
       {"Status": "cancelled", "DeploymentId": 1, "Time": 1379061766},
       {"Status": "completed", "DeploymentId": 2, "Time": 1379062156}
     ],
     "apiversion": "go",
     "sandbox": false,
     "version": "0.2.0",
     "debug": false,
     "apiurl": "wss://ec2-50-17-116-51.compute-1.amazonaws.com:17070"
   }

That's all, thanks a lot for QAing this branch!

https://code.launchpad.net/~frankban/charms/precise/juju-gui/cancel-deployment/+merge/185448

(do not edit description out of merge proposal)

Please review this at https://codereview.appspot.com/13549046/

Affected files (+243, -32 lines):
   A [revision details]
   M revision
   M server/guiserver/__init__.py
   M server/guiserver/bundles/__init__.py
   M server/guiserver/bundles/base.py
   M server/guiserver/bundles/utils.py
   M server/guiserver/bundles/views.py
   M server/guiserver/tests/bundles/test_base.py
   M server/guiserver/tests/bundles/test_utils.py
   M server/guiserver/tests/bundles/test_views.py

[Francesco Banconi (frankban)]

I forgot to mention that you need to change the PASSWORD
at line #17 of the script, setting your own admin secret,
before running the script itself.

https://codereview.appspot.com/13549046/

[Richard Harding (rharding)]

code ok, will qa next. Just have the one objection to camel cased http
params.

https://codereview.appspot.com/13549046/diff/1/server/guiserver/bundles/views.py
File server/guiserver/bundles/views.py (right):

https://codereview.appspot.com/13549046/diff/1/server/guiserver/bundles/views.py#newcode182
server/guiserver/bundles/views.py:182: deployment_id =
request.params.get('DeploymentId')
caps in the query string? why not match the var name used deployment_id?

https://codereview.appspot.com/13549046/

[Francesco Banconi (frankban)]

On 2013/09/13 13:16:21, rharding wrote:

> server/guiserver/bundles/views.py:182: deployment_id =
> request.params.get('DeploymentId')
> caps in the query string? why not match the var name used
deployment_id?

params is not really a querystring, it's the content of the Params field
included in the WebSocket message. Caps are used for consistency with
all
the other juju-core API calls.

https://codereview.appspot.com/13549046/

[lp:~frankban/charms/precise/juju-gui/cancel-deployment]

116. By Francesco Banconi on 2013-09-13

Debugging a unit test.

[Richard Harding (rharding)]

On 2013/09/13 13:24:32, frankban wrote:
> On 2013/09/13 13:16:21, rharding wrote:

> > server/guiserver/bundles/views.py:182: deployment_id =
> > request.params.get('DeploymentId')
> > caps in the query string? why not match the var name used
deployment_id?

> params is not really a querystring, it's the content of the Params
field
> included in the WebSocket message. Caps are used for consistency with
all
> the other juju-core API calls.

Ah, ok. In pyramid/charmworld request.params is a map into
request.GET/POST.

https://codereview.appspot.com/13549046/

[Richard Harding (rharding)]

LGTM

Results of the script, first run:

http://paste.mitechie.com/show/1020/

I did run it a second time and got an error:

http://paste.mitechie.com/show/1021/

I'm not sure if this is a bug here or as a follow up to not crash when
the service is already there.

https://codereview.appspot.com/13549046/

[lp:~frankban/charms/precise/juju-gui/cancel-deployment]

117. By Francesco Banconi on 2013-09-13

Debugging again.

[Francesco Banconi (frankban)]

On 2013/09/13 13:45:00, rharding wrote:
> LGTM

> Results of the script, first run:

> http://paste.mitechie.com/show/1020/

Great, thank you for QAing this branch!

> I did run it a second time and got an error:

> http://paste.mitechie.com/show/1021/

> I'm not sure if this is a bug here or as a follow up to not crash when
the
> service is already there.

Running the script a second time you also tested the validation
step failing when there is a service name clash in the
environment, and that's the correct behavior.
The subsequent KeyError is ok since the script expects
the request to be successful.

Thanks!

https://codereview.appspot.com/13549046/

[lp:~frankban/charms/precise/juju-gui/cancel-deployment]

118. By Francesco Banconi on 2013-09-13

Final debugging.

[Brad Crittenden (bac)]

LGTM

https://codereview.appspot.com/13549046/diff/1/server/guiserver/bundles/base.py
File server/guiserver/bundles/base.py (right):

https://codereview.appspot.com/13549046/diff/1/server/guiserver/bundles/base.py#newcode152
server/guiserver/bundles/base.py:152: # cancelling scheduled jobs, even
if the job is the next to be started.
It's not clear to my why you want to be able to cancel this first job.
Only giving a window of 1 second seems arbitrary. Perhaps the use case
will become clearer as I read more code.

https://codereview.appspot.com/13549046/

[Francesco Banconi (frankban)]

*** Submitted:

GUI server: cancel deployment feature.

Added an API call for cancelling a pending
deployment.

Also updated the bundles module documentation.

For this first implementation, I discussed
with Gary a workaround to avoid scheduled
deployments to be included in the ProcessPool
executor's call queue: a time.sleep call is
added to the queue right after a new deployment.
This way, as described in the code, it is still
possible to cancel a scheduled deployment job
even if it is the first in the queue.

Tests:
run `make unittest` from the root of this branch.

QA:
- bootstrap a juju-core environment;
- deploy the GUI from this branch (`make deploy`);
- switch to the builtin server:
   `juju set juju-gui builtin-server=true`;
- ensure the GUI is working well by visiting
   https://GUI-ADDRESS .

To test the deployer support and the
"cancel deployment" feature, use the script in
http://pastebin.ubuntu.com/6100815/ e.g.:

- download and save the Python script;
- run it passing the GUI node address as first argument:
   `python start-deployer-cancel.py GUI-ADDRESS`.

The script does the following:
1) it logs in to the juju-core API server;
2) it starts/schedules three deployments;
3) it send two invalid Cancel requests;
4) it cancels the second deployment;
5) it shows the deployments status before and
    after the deployment deletion.

- if everything is ok, you should see an output like
this: http://pastebin.ubuntu.com/6100861/ ;
- you should also be able to check the deployment
   progress from the GUI;
- when the two deployments are completed (it may take
   some minutes) you should see wordpress, mysql and
   mediawiki correctly deployed and displayed in the
   topology view;
- visiting https://GUI-ADDRESS/gui-server-info you
   should see something like this:
   {
     "uptime": 970,
     "deployer": [
       {"Status": "completed", "DeploymentId": 0, "Time": 1379062144},
       {"Status": "cancelled", "DeploymentId": 1, "Time": 1379061766},
       {"Status": "completed", "DeploymentId": 2, "Time": 1379062156}
     ],
     "apiversion": "go",
     "sandbox": false,
     "version": "0.2.0",
     "debug": false,
     "apiurl": "wss://ec2-50-17-116-51.compute-1.amazonaws.com:17070"
   }

That's all, thanks a lot for QAing this branch!

R=rharding, bac
CC=
https://codereview.appspot.com/13549046

https://codereview.appspot.com/13549046/diff/1/server/guiserver/bundles/base.py
File server/guiserver/bundles/base.py (right):

https://codereview.appspot.com/13549046/diff/1/server/guiserver/bundles/base.py#newcode152
server/guiserver/bundles/base.py:152: # cancelling scheduled jobs, even
if the job is the next to be started.
On 2013/09/13 14:33:19, bac wrote:
> It's not clear to my why you want to be able to cancel this first job.
  Only
> giving a window of 1 second seems arbitrary. Perhaps the use case
will become
> clearer as I read more code.

It is arbitrary indeed. This is just a way to fill the call queue so
that, when a job starts (and it is removed from the queue) he sleep is
put in the queue and the next deployment can still be cancelled. This is
just a workaround, and will be changed in the future, likely
implementing our own as...

=== modified file 'revision'
--- revision	2013-09-12 19:58:07 +0000
+++ revision	2013-09-13 14:09:53 +0000
@@ -1,1 +1,1 @@
-84
+85

=== modified file 'server/guiserver/__init__.py'
--- server/guiserver/__init__.py	2013-08-23 14:44:00 +0000
+++ server/guiserver/__init__.py	2013-09-13 14:09:53 +0000
@@ -30,7 +30,7 @@
 the HTTPS connection, allowing changes in the Juju environment to be propagated
 and shown immediately by the browser. """
 
-VERSION = (0, 1, 0)
+VERSION = (0, 2, 0)
 
 
 def get_version():

=== modified file 'server/guiserver/bundles/__init__.py'
--- server/guiserver/bundles/__init__.py	2013-09-04 15:21:54 +0000
+++ server/guiserver/bundles/__init__.py	2013-09-13 14:09:53 +0000
@@ -16,9 +16,6 @@
 
 """Juju GUI server bundles support.
 
-XXX frankban: note that the following is a work in progress. Some of the
-objects described below are not yet implemented.
-
 This package includes the objects and functions required to support deploying
 bundles in juju-core. The base pieces of the infrastructure are placed in the
 base module:
@@ -195,7 +192,9 @@
 bundle at the time. A Queue value of zero means the deployment will be started
 as soon as possible.
 
-The Status can be one of the following: 'scheduled', 'started' and 'completed'.
+The Status can be one of the following: 'scheduled', 'started', 'completed' and
+'cancelled. See the next section for an explanation of how to cancel a pending
+(scheduled) deployment.
 
 The Time field indicates the number of seconds since the epoch at the time of
 the change.
@@ -222,6 +221,40 @@
 XXX frankban: a timeout to delete completed deployments history will be
 eventually implemented.
 
+Cancelling a deployment.
+------------------------
+
+It is possible to cancel the execution of scheduled deployments by sending a
+Cancel request, e.g.:
+
+    {
+        'RequestId': 5,
+        'Type': 'Deployer',
+        'Request': 'Cancel',
+        'Params': {'DeploymentId': 42},
+    }
+
+Note that it is allowed to cancel a deployment only if it is not yet started,
+i.e. if it is in a 'scheduled' state.
+
+If any error occurs, the response is like this:
+
+    {
+        'RequestId': 5,
+        'Response': {},
+        'Error': 'some error: error details',
+    }
+
+Usually an error response is returned when either an invalid deployment id was
+provided or the request attempted to cancel an already started deployment.
+
+If the deployment is successfully cancelled, the response is the following:
+
+    {
+        'RequestId': 5,
+        'Response': {},
+    }
+
 Deployments status.
 -------------------
 
@@ -229,7 +262,7 @@
 the client can send the following request:
 
     {
-        'RequestId': 5,
+        'RequestId': 6,
         'Type': 'Deployer',
         'Request': 'Status',
     }
@@ -238,29 +271,29 @@
 the second one is a successful response:
 
     {
-        'RequestId': 5,
+        'RequestId': 6,
         'Response': {},
         'Error': 'some error: error details',
     }
 
     {
-        'RequestId': 5,
+        'RequestId': 6,
         'Response': {
             'LastChanges': [
-                {'DeploymentId': 42, 'Status': 'completed', 'Time': 1377080001,
+                {'DeploymentId': 1, 'Status': 'completed', 'Time': 1377080001,
                  'Error': 'error'},
-                {'DeploymentId': 43, 'Status': 'completed',
-                 'Time': 1377080002},
-                {'DeploymentId': 44, 'Status': 'started', 'Time': 1377080003,
+                {'DeploymentId': 2, 'Status': 'completed', 'Time': 1377080002},
+                {'DeploymentId': 3, 'Status': 'started', 'Time': 1377080003,
                  'Queue': 0},
-                {'DeploymentId': 45, 'Status': 'scheduled', 'Time': 1377080004,
+                {'DeploymentId': 4, 'Status': 'cancelled', 'Time': 1377080004},
+                {'DeploymentId': 5, 'Status': 'scheduled', 'Time': 1377080005,
                  'Queue': 1},
             ],
         },
     }
 
 In the second response above, the Error field in the first attempted deployment
-(42) contains details about an error that occurred while deploying a bundle.
+(1) contains details about an error that occurred while deploying a bundle.
 This means that bundle deployment has been completed but an error occurred
 during the process.
 """

=== modified file 'server/guiserver/bundles/base.py'
--- server/guiserver/bundles/base.py	2013-08-26 07:56:52 +0000
+++ server/guiserver/bundles/base.py	2013-09-13 14:09:53 +0000
@@ -23,7 +23,12 @@
 a detailed explanation of how these objects are used.
 """
 
-from concurrent.futures import ProcessPoolExecutor
+import time
+
+from concurrent.futures import (
+    process,
+    ProcessPoolExecutor,
+)
 from tornado import gen
 from tornado.ioloop import IOLoop
 from tornado.util import ObjectDict
@@ -37,6 +42,10 @@
 from guiserver.watchers import WatcherError
 
 
+# Controls how many more calls than processes will be queued in the call queue.
+# Set to zero to make Future.cancel() succeed more frequently (Futures in the
+# call queue cannot be cancelled).
+process.EXTRA_QUEUED_CALLS = 0
 # Juju API versions supported by the GUI server Deployer.
 # Tests use the first API version in this list.
 SUPPORTED_API_VERSIONS = ['go']
@@ -78,6 +87,8 @@
         # Queue stores the deployment identifiers corresponding to the
         # currently started/queued jobs.
         self._queue = []
+        # The futures attribute maps deployment identifiers to Futures.
+        self._futures = {}
 
     @gen.coroutine
     def validate(self, user, name, bundle):
@@ -132,9 +143,14 @@
         future = self._run_executor.submit(
             blocking.import_bundle, self._apiurl, user.password, name, bundle)
         add_future(self._io_loop, future, self._import_callback, deployment_id)
+        self._futures[deployment_id] = future
         # If a customized callback is provided, schedule it as well.
         if test_callback is not None:
             add_future(self._io_loop, future, test_callback)
+        # Submit a sleeping job in order to avoid the next deployment job to be
+        # immediately put in the executor's call queue. This allows for
+        # cancelling scheduled jobs, even if the job is the next to be started.
+        self._run_executor.submit(time.sleep, 1)
         return deployment_id
 
     def _import_callback(self, deployment_id, future):
@@ -144,12 +160,17 @@
         deployment_id identifying one specific deployment job, and the fired
         future returned by the executor.
         """
-        exception = future.exception()
-        error = None if exception is None else str(exception)
-        # Notify a deployment completed.
-        self._observer.notify_completed(deployment_id, error=error)
+        if future.cancelled():
+            # Notify a deployment has been cancelled.
+            self._observer.notify_cancelled(deployment_id)
+        else:
+            exception = future.exception()
+            error = None if exception is None else str(exception)
+            # Notify a deployment completed.
+            self._observer.notify_completed(deployment_id, error=error)
         # Remove the completed deployment job from the queue.
         self._queue.remove(deployment_id)
+        del self._futures[deployment_id]
         # Notify the new position of all remaining deployments in the queue.
         for position, deploy_id in enumerate(self._queue):
             self._observer.notify_position(deploy_id, position)
@@ -183,6 +204,18 @@
         except WatcherError:
             return
 
+    def cancel(self, deployment_id):
+        """Attempt to cancel the deployment identified by deployment_id.
+
+        Return None if the deployment has been correctly cancelled.
+        Return an error string otherwise.
+        """
+        future = self._futures.get(deployment_id)
+        if future is None:
+            return 'deployment not found or already completed'
+        if not future.cancel():
+            return 'unable to cancel the deployment'
+
     def status(self):
         """Return a list containing the last known change for each deployment.
         """
@@ -221,6 +254,7 @@
             'Import': views.import_bundle,
             'Watch': views.watch,
             'Next': views.next,
+            'Cancel': views.cancel,
             'Status': views.status,
         }
 

=== modified file 'server/guiserver/bundles/utils.py'
--- server/guiserver/bundles/utils.py	2013-08-21 16:12:45 +0000
+++ server/guiserver/bundles/utils.py	2013-09-13 14:09:53 +0000
@@ -29,6 +29,7 @@
 # Change statuses.
 SCHEDULED = 'scheduled'
 STARTED = 'started'
+CANCELLED = 'cancelled'
 COMPLETED = 'completed'
 
 
@@ -99,6 +100,12 @@
         change = create_change(deployment_id, status, queue=position)
         watcher.put(change)
 
+    def notify_cancelled(self, deployment_id):
+        """Add a change to the deployment watcher notifying it is cancelled."""
+        watcher = self.deployments[deployment_id]
+        change = create_change(deployment_id, CANCELLED)
+        watcher.close(change)
+
     def notify_completed(self, deployment_id, error=None):
         """Add a change to the deployment watcher notifying it is completed."""
         watcher = self.deployments[deployment_id]

=== modified file 'server/guiserver/bundles/views.py'
--- server/guiserver/bundles/views.py	2013-09-04 15:22:42 +0000
+++ server/guiserver/bundles/views.py	2013-09-13 14:09:53 +0000
@@ -169,6 +169,28 @@
 
 @gen.coroutine
 @require_authenticated_user
+def cancel(request, deployer):
+    """Cancel the given pending deployment.
+
+    The deployment is identified in the request by the DeploymentId parameter.
+    If the request is not valid or the deployment cannot be cancelled (e.g.
+    because it is already started) an error response is returned.
+
+    Request: 'Cancel'.
+    Parameters example: {'DeploymentId': 42}.
+    """
+    deployment_id = request.params.get('DeploymentId')
+    if deployment_id is None:
+        raise response(error='invalid request: invalid data parameters')
+    # Use the Deployer instance to cancel the deployment.
+    err = deployer.cancel(deployment_id)
+    if err is not None:
+        raise response(error='invalid request: {}'.format(err))
+    raise response()
+
+
[e-mail]
+@require_authenticated_user
 def status(request, deployer):
     """Return the current status of all the bundle deployments.
 

=== modified file 'server/guiserver/tests/bundles/test_base.py'
--- server/guiserver/tests/bundles/test_base.py	2013-08-26 07:56:52 +0000
+++ server/guiserver/tests/bundles/test_base.py	2013-09-13 14:09:53 +0000
@@ -195,13 +195,75 @@
         # Wait for the deployment to be completed.
         self.wait()
 
-    @gen_test
     def test_invalid_watcher(self):
         # None is returned if the watcher id is not valid.
         deployer = self.make_deployer()
         changes = deployer.next(42)
         self.assertIsNone(changes)
 
+    @gen_test
+    def test_cancel(self):
+        # It is possible to cancel the execution of a pending deployment.
+        deployer = self.make_deployer()
+        with self.patch_import_bundle():
+            # The test callback is passed to the first deployment because we
+            # expect the second one to be immediately cancelled.
+            deployer.import_bundle(
+                self.user, 'bundle', self.bundle, test_callback=self.stop)
+            deployment_id = deployer.import_bundle(
+                self.user, 'bundle', self.bundle)
+        watcher_id = deployer.watch(deployment_id)
+        self.assertIsNone(deployer.cancel(deployment_id))
+        # We expect two changes: the second one should notify the deployment
+        # has been cancelled.
+        yield deployer.next(watcher_id)
+        changes = yield deployer.next(watcher_id)
+        self.assert_change(changes, deployment_id, utils.CANCELLED)
+        # Wait for the deployment to be completed.
+        self.wait()
+
+    def test_cancel_unknown_deployment(self):
+        # An error is returned when trying to cancel an invalid deployment.
+        deployer = self.make_deployer()
+        error = deployer.cancel(42)
+        self.assertEqual('deployment not found or already completed', error)
+
+    @gen_test
+    def test_cancel_completed_deployment(self):
+        # An error is returned when trying to cancel a completed deployment.
+        deployer = self.make_deployer()
+        with self.patch_import_bundle():
+            deployment_id = deployer.import_bundle(
+                self.user, 'bundle', self.bundle, test_callback=self.stop)
+        watcher_id = deployer.watch(deployment_id)
+        # Assume the deployment is completed after two changes.
+        yield deployer.next(watcher_id)
+        yield deployer.next(watcher_id)
+        error = deployer.cancel(deployment_id)
+        self.assertEqual('deployment not found or already completed', error)
+        # Wait for the deployment to be completed.
+        self.wait()
+
+    @gen_test
+    def test_cancel_started_deployment(self):
+        # An error is returned when trying to cancel a deployment already
+        # started.
+        deployer = self.make_deployer()
+        with self.patch_import_bundle() as mock_import_bundle:
+            deployment_id = deployer.import_bundle(
+                self.user, 'bundle', self.bundle, test_callback=self.stop)
+        watcher_id = deployer.watch(deployment_id)
+        # Wait until the deployment is started.
+        yield deployer.next(watcher_id)
+        while True:
+            if mock_import_bundle.call_count:
+                break
+        error = deployer.cancel(deployment_id)
+        self.assertEqual('unable to cancel the deployment', error)
+        # Wait for the deployment to be completed.
+        yield deployer.next(watcher_id)
+        self.wait()
+
     def test_initial_status(self):
         # The initial deployer status is an empty list.
         deployer = self.make_deployer()

=== modified file 'server/guiserver/tests/bundles/test_utils.py'
--- server/guiserver/tests/bundles/test_utils.py	2013-08-21 16:12:45 +0000
+++ server/guiserver/tests/bundles/test_utils.py	2013-09-13 14:09:53 +0000
@@ -32,12 +32,15 @@
 from guiserver.tests import helpers
 
 
[e-mail]('time.time', mock.Mock(return_value=1234))
+mock_time = mock.patch('time.time', mock.Mock(return_value=12345))
+
+
+@mock_time
 class TestCreateChange(unittest.TestCase):
 
     def test_status(self):
         # The change includes the deployment status.
-        expected = {'DeploymentId': 0, 'Status': utils.STARTED, 'Time': 1234}
+        expected = {'DeploymentId': 0, 'Status': utils.STARTED, 'Time': 12345}
         obtained = utils.create_change(0, utils.STARTED)
         self.assertEqual(expected, obtained)
 
@@ -46,7 +49,7 @@
         expected = {
             'DeploymentId': 1,
             'Status': utils.SCHEDULED,
-            'Time': 1234,
+            'Time': 12345,
             'Queue': 42,
         }
         obtained = utils.create_change(1, utils.SCHEDULED, queue=42)
@@ -57,7 +60,7 @@
         expected = {
             'DeploymentId': 2,
             'Status': utils.COMPLETED,
-            'Time': 1234,
+            'Time': 12345,
             'Error': 'an error',
         }
         obtained = utils.create_change(2, utils.COMPLETED, error='an error')
@@ -68,7 +71,7 @@
         expected = {
             'DeploymentId': 3,
             'Status': utils.COMPLETED,
-            'Time': 1234,
+            'Time': 12345,
             'Queue': 47,
             'Error': 'an error',
         }
@@ -139,7 +142,7 @@
         self.assert_watcher(watcher1, deployment1)
         self.assert_watcher(watcher2, deployment2)
 
-    @mock.patch('time.time', mock.Mock(return_value=1234))
+    @mock_time
     def test_notify_scheduled(self):
         # It is possible to notify a new queue position for a deployment.
         deployment_id = self.observer.add_deployment()
@@ -148,13 +151,13 @@
         expected = {
             'DeploymentId': deployment_id,
             'Status': utils.SCHEDULED,
-            'Time': 1234,
+            'Time': 12345,
             'Queue': 3,
         }
         self.assertEqual(expected, watcher.getlast())
         self.assertFalse(watcher.closed)
 
-    @mock.patch('time.time', mock.Mock(return_value=12345))
+    @mock_time
     def test_notify_started(self):
         # It is possible to notify that a deployment is (about to be) started.
         deployment_id = self.observer.add_deployment()
@@ -169,7 +172,21 @@
         self.assertEqual(expected, watcher.getlast())
         self.assertFalse(watcher.closed)
 
-    @mock.patch('time.time', mock.Mock(return_value=123456))
+    @mock_time
+    def test_notify_cancelled(self):
+        # It is possible to notify that a deployment has been cancelled.
+        deployment_id = self.observer.add_deployment()
+        watcher = self.observer.deployments[deployment_id]
+        self.observer.notify_cancelled(deployment_id)
+        expected = {
+            'DeploymentId': deployment_id,
+            'Status': utils.CANCELLED,
+            'Time': 12345,
+        }
+        self.assertEqual(expected, watcher.getlast())
+        self.assertTrue(watcher.closed)
+
+    @mock_time
     def test_notify_completed(self):
         # It is possible to notify that a deployment is completed.
         deployment_id = self.observer.add_deployment()
@@ -178,12 +195,12 @@
         expected = {
             'DeploymentId': deployment_id,
             'Status': utils.COMPLETED,
-            'Time': 123456,
+            'Time': 12345,
         }
         self.assertEqual(expected, watcher.getlast())
         self.assertTrue(watcher.closed)
 
-    @mock.patch('time.time', mock.Mock(return_value=1234567))
+    @mock_time
     def test_notify_error(self):
         # It is possible to notify that an error occurred during a deployment.
         deployment_id = self.observer.add_deployment()
@@ -192,7 +209,7 @@
         expected = {
             'DeploymentId': deployment_id,
             'Status': utils.COMPLETED,
-            'Time': 1234567,
+            'Time': 12345,
             'Error': 'bad wolf',
         }
         self.assertEqual(expected, watcher.getlast())

=== modified file 'server/guiserver/tests/bundles/test_views.py'
--- server/guiserver/tests/bundles/test_views.py	2013-09-04 10:59:44 +0000
+++ server/guiserver/tests/bundles/test_views.py	2013-09-13 14:09:53 +0000
@@ -267,6 +267,43 @@
         self.deployer.next.assert_called_once_with(42)
 
 
+class TestCancel(
+        ViewsTestMixin, helpers.BundlesTestMixin, LogTrapTestCase,
+        AsyncTestCase):
+
+    def get_view(self):
+        return views.cancel
+
+    @gen_test
+    def test_invalid_deployment(self):
+        # An error response is returned if the deployment identifier is not
+        # valid.
+        request = self.make_view_request(params={'DeploymentId': 42})
+        # Set up the Deployer mock.
+        self.deployer.cancel.return_value = 'bad wolf'
+        # Execute the view.
+        response = yield self.view(request, self.deployer)
+        expected_response = {
+            'Response': {},
+            'Error': 'invalid request: bad wolf',
+        }
+        self.assertEqual(expected_response, response)
+        # Ensure the Deployer methods have been correctly called.
+        self.deployer.cancel.assert_called_once_with(42)
+
+    @gen_test
+    def test_success(self):
+        # An empty response is returned if everything is ok.
+        request = self.make_view_request(params={'DeploymentId': 42})
+        # Set up the Deployer mock.
+        self.deployer.cancel.return_value = None
+        # Execute the view.
+        response = yield self.view(request, self.deployer)
+        self.assertEqual({'Response': {}}, response)
+        # Ensure the Deployer methods have been correctly called.
+        self.deployer.cancel.assert_called_once_with(42)
+
+
 class TestStatus(
         ViewsTestMixin, helpers.BundlesTestMixin, LogTrapTestCase,
         AsyncTestCase):