Added `--single` CLI option to shut down the Worker after one task.

CHANGELOG.md

@@ -15,6 +15,7 @@ changed functionality, fixed bugs).
 - Worker can be told to shut down by the Manager. The environment (for example systemd
   on Linux) is responsible for restarting Flamenco Worker after such a shutdown.
 - Added `--version` CLI option to show the version of Flamenco Worker and quit.
+- Added `--single` or `-1` CLI option to shut down the Worker after executing a single task.
 
 
 ## Version 2.0.8 (released 2017-09-07)

flamenco_worker/cli.py

@@ -31,6 +31,8 @@ def main():
                         help="Starts up in testing mode, in which only a handful of "
                              "test-specific task types are accepted. This overrides the task_types "
                              "in the configuration file.")
+    parser.add_argument('-1', '--single', action='store_true',
+                        help="Runs a single tasks, then exits.")
     args = parser.parse_args()
 
     if args.version:
@@ -55,6 +57,9 @@ def main():
         confparser.erase('worker_id')
         confparser.erase('worker_secret')
 
+    if args.single:
+        log.info('Running in single-task mode, will stop after performing one task.')
+
     # Find the Manager using UPnP/SSDP if we have no manager_url.
     if not confparser.value('manager_url'):
         from . import ssdp_discover
@@ -108,6 +113,7 @@ def main():
         push_log_max_entries=confparser.value('push_log_max_entries', int),
         push_act_max_interval=confparser.interval_secs('push_act_max_interval_seconds'),
         initial_state='testing' if args.test else 'awake',
+        run_single_task=args.single,
     )
 
     mir = may_i_run.MayIRun(

flamenco_worker/runner.py

@@ -62,6 +62,7 @@ class TaskRunner:
                 return False
 
         self._log.info('Task %s completed succesfully.', task_id)
+        self.current_command = None
         return True
 
     async def abort_current_task(self):

flamenco_worker/worker.py

@@ -56,6 +56,7 @@ class FlamencoWorker:
 
     # Indicates the state in which the Worker should start
     initial_state = attr.ib(validator=attr.validators.instance_of(str), default='awake')
+    run_single_task = attr.ib(validator=attr.validators.instance_of(bool), default=False)
 
     # When Manager tells us we may no longer run our current task, this is set to True.
     # As a result, the cancelled state isn't pushed to Manager any more. It is reset
@@ -433,6 +434,11 @@ class FlamencoWorker:
             except Exception:
                 self._log.exception('While notifying manager of failure, another error happened.')
         finally:
+            if self.run_single_task:
+                self._log.info('Running in single-task mode, exiting.')
+                self.go_to_state_shutdown()
+                return
+
             if self.state == WorkerState.AWAKE:
                 # Schedule a new task run unless shutting down or sleeping; after a little delay to
                 # not hammer the world when we're in some infinite failure loop.
@@ -637,7 +643,7 @@ class FlamencoWorker:
         using systemd on Linux with Restart=always will do this.
         """
 
-        self._log.info('Shutting down by request of the Flamenco Manager')
+        self._log.info('Shutting down by request of the Manager or due to single-task mode')
         self.state = WorkerState.SHUTTING_DOWN
 
         # Don't bother acknowledging this status, as we'll push an "offline" status anyway.