Re: [Kimchi-devel] [PATCH] [Wok 1/2] Issue #122 - Make AsyncTask stoppable.

From: Paulo Vital <pvital(a)linux.vnet.ibm.com&gt; This patch gives to user a way to 'stop' a Task that is still running by setting the Task status to "killed". Since an AsyncTask is basic a thread running in the system and this thread can execute a pure Python method or a background command (by using run_command() from wok.utils), the developer must pass to AsyncTask constructor a method to be executed by the DELETE operation, called here as 'kill_cb'. If none kill_cb is passed, the task will not be able to stopped and an error message will be raised to user if DELETE operation is executed. Otherwise, the kill_cb method will be executed by kill() method (responsible to execute the DELETE operation) of AsyncTask class and its status set to 'killed'. Signed-off-by: Paulo Vital <pvital(a)linux.vnet.ibm.com&gt; --- docs/API/tasks.md | 2 ++ src/wok/asynctask.py | 18 +++++++++++++++++- src/wok/i18n.py | 1 + src/wok/model/tasks.py | 13 +++++++++++++ 4 files changed, 33 insertions(+), 1 deletion(-) diff --git a/docs/API/tasks.md b/docs/API/tasks.md index e0c404f..2068f29 100644 --- a/docs/API/tasks.md +++ b/docs/API/tasks.md @@ -27,8 +27,10 @@ server. * running: The task is running * finished: The task has finished successfully * failed: The task failed + * killed: The task was killed by user * message: Human-readable details about the Task status * target_uri: Resource URI related to the Task +* **DELETE**: Kill the Task, moving its status to 'killed' * **POST**: *See Task Actions* **Actions (POST):** diff --git a/src/wok/asynctask.py b/src/wok/asynctask.py index b98ad9a..4a4ee32 100644 --- a/src/wok/asynctask.py +++ b/src/wok/asynctask.py @@ -26,6 +26,9 @@ import traceback import uuid +from wok.exception import OperationFailed + + tasks_queue = {} @@ -41,10 +44,11 @@ def clean_old_tasks(): class AsyncTask(object): - def __init__(self, target_uri, fn, opaque=None): + def __init__(self, target_uri, fn, opaque=None, kill_cb=None): self.id = str(uuid.uuid1()) self.target_uri = target_uri self.fn = fn + self.kill_cb = kill_cb self.status = 'running' self.message = 'The request is being processing.' self.timestamp = time.time() @@ -79,3 +83,15 @@ class AsyncTask(object): except KeyError: msg = "There's no task_id %s in tasks_queue. Nothing changed." cherrypy.log.error_log.error(msg % self.id) + + def kill(self): + if self.kill_cb is None: + msg = 'There is no callback to execute DELETE operation.' + raise OperationFailed('WOKASYNC0002E', {'err': msg}) +

+ try: + self.kill_cb() + self.status = 'killed' + self.message = 'Task killed by user.' + except Exception, e: + raise OperationFailed('WOKASYNC0002E', {'err': e.message})

diff --git a/src/wok/i18n.py b/src/wok/i18n.py index ade2ae9..937477f 100644 --- a/src/wok/i18n.py +++ b/src/wok/i18n.py @@ -34,6 +34,7 @@ messages = { "WOKAPI0009E": _("You don't have permission to perform this operation."), "WOKASYNC0001E": _("Unable to find task id: %(id)s"), + "WOKASYNC0002E": _("Unable to kill task due error: %(err)s"), "WOKASYNC0003E": _("Timeout of %(seconds)s seconds expired while running task '%(task)s."), "WOKAUTH0001E": _("Authentication failed for user '%(username)s'. [Error code: %(code)s]"), diff --git a/src/wok/model/tasks.py b/src/wok/model/tasks.py index 6a2b4bf..8ae1ce4 100644 --- a/src/wok/model/tasks.py +++ b/src/wok/model/tasks.py @@ -68,3 +68,16 @@ class TaskModel(object): raise TimeoutExpired('WOKASYNC0003E', {'seconds': timeout, 'task': task.target_uri}) + + def delete(self, id): + """ + 'Stops' an AsyncTask, by executing the kill callback provided by user + when created the task. Task's status will be changed to 'killed'. + """ + try: + task = tasks_queue[id] + except KeyError: + raise NotFoundError("WOKASYNC0001E", {'id': id}) + + if task.status is 'running': + task.kill()