Re: [Kimchi-devel] [Wok] [RFC] Issue #122: Make AsyncTask stoppable.

On Jun 08 03:38PM, Aline Manera wrote: > Hi Paulo, > > On 06/06/2016 11:21 AM, Paulo Ricardo Paz Vital wrote: > > This is an RFC for "Make AsyncTask stoppable" in Wok (and any other plugin). The > > main idea is give to user a way to stop a Task that is still running, cleaning > > all references and processes and setting the Task status to "killed". > > > > To do this, the Task API need to be modified, by implementing the DELETE method > > in Task Resource. Said that, the API will look like: > > > > ### Resource: Task > > > > **URI:** /tasks/*:id* > > > > A task represents an asynchronous operation that is being performed by the > > server. > > > > **Methods:** > > > > * **GET**: Retrieve the full description of the Task > > * id: The Task ID is used to identify this Task in the API. > > * status: The current status of the Task > > * 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**: Delete the Task > > It is good to mention that this action will put the Task in the 'killed' > status. > Ok. > > * **POST**: *See Task Actions* > > > > **Actions (POST):** > > > > *No actions defined* > > > > 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 as argument to the add_task() a method > > to be executed by the DELETE operation, called here as 'kill_cb'. With this > > idea, the add_task() method and also the AsyncTask constructor will be like: > > > > def add_task(target_uri, fn, objstore, kill_cb=None, opaque=None): > > I am not sure it is a good idea to change the parameters order. > Some plugins may have using the opaque parameter as the third value so it > will cause issues. > So unless, you check all references to make sure it will not be a problem, > I'd recommend to move the kill_cb as the last parameter. > I already was expecting this, so this is not a problem to me to check and change the sequence of parameters. Will not do this only if the modifications are too many to do ;-) > > class AsyncTask(object): > > def __init__(self, id, target_uri, fn, objstore, kill_cb=None, opaque=None): > > Same I commented above. > > > If none kill_cb is passed, the task will not be able to stopped and an error (or > > warning) 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'. > > Go for it! =) > > Don't forget to add tests to test/exemplify how it will really work. > For sure. > > If you have any comments or suggestions, please feel free to reply to ML. > > > > Thanks and bestr regards, > > -- > > Paulo Ricardo Paz Vital > > Linux Technology Center, IBM Systems > > http://www.ibm.com/linux/ltc/ > > > > _______________________________________________