Support for set/clear timeout/interval utils actions and error handling refactor

- Added set/cler timeout/interval actions in the utils plugin to
dynamically set or stop timed actions from your custom logic

- Actions error handling refactoring. If a Response is processed with
some errors, then just log the error and return it to the caller,
without raising an exception. If instead the action execution raised an
uncaught exception, then handle the retries properly and return errors
as a list with the output from all the retries, without being too
verbose with the returning and logging the whole stack trace multiple
times.

platypush/message/request/__init__.py

@@ -190,7 +190,7 @@ class Request(Message):
                     - group: ${group_name}  # will be expanded as "Kitchen lights")
         """
 
-        def _thread_func(n_tries):
+        def _thread_func(n_tries, errors=None):
             if self.action.startswith('procedure.'):
                 context['n_tries'] = n_tries
                 response = self._execute_procedure(**context)
@@ -207,18 +207,25 @@ class Request(Message):
                 response = plugin.run(method=method_name, **args)
 
                 if response and response.is_error():
-                    raise RuntimeError('Response processed with errors: {}'.format(response))
-
-                logger.info('Processed response from plugin {}: {}'.
-                                format(plugin, str(response)))
+                    logger.warning(('Response processed with errors from ' +
+                                    'action {}.{}: {}').format(
+                                        plugin, self.action, str(response)))
+                else:
+                    logger.info('Processed response from action {}.{}: {}'.
+                                format(plugin, self.action, str(response)))
             except Exception as e:
                 # Retry mechanism
-                response = Response(output=None, errors=[str(e), traceback.format_exc()])
-                logger.exception(e)
-                if n_tries:
+                logger.warning(('Uncaught exception while processing response ' +
+                                'from action {}.{}: {}').format(
+                                    plugin, self.action, str(e)))
+
+                errors = errors or []
+                errors.append(str(e))
+                response = Response(output=None, errors=errors)
+                if n_tries-1 > 0:
                     logger.info('Reloading plugin {} and retrying'.format(module_name))
                     get_plugin(module_name, reload=True)
-                    response = _thread_func(n_tries-1)
+                    response = _thread_func(n_tries=n_tries-1, errors=errors)
             finally:
                 self._send_response(response)
                 return response

platypush/plugins/__init__.py

@@ -29,7 +29,8 @@ def action(f):
         except Exception as e:
             if isinstance(args[0], Plugin):
                 args[0].logger.exception(e)
-            errors.append(str(e) + '\n' + traceback.format_exc())
+            raise e
+            # errors.append(str(e) + '\n' + traceback.format_exc())
 
         return Response(output=output, errors=errors)
 

platypush/plugins/utils.py

@@ -1,6 +1,8 @@
+import threading
 import time
 
 from platypush.plugins import Plugin, action
+from platypush.procedure import Procedure
 
 
 class UtilsPlugin(Plugin):
@@ -8,6 +10,17 @@ class UtilsPlugin(Plugin):
     A plugin for general-purpose util methods
     """
 
+    _DEFAULT_TIMEOUT_PREFIX = '_PlatypushTimeout_'
+    _timeout_hndl_idx = 0
+    _timeout_hndl_idx_lock = threading.RLock()
+
+    _DEFAULT_INTERVAL_PREFIX = '_PlatypushInterval_'
+    _interval_hndl_idx = 0
+    _interval_hndl_idx_lock = threading.RLock()
+
+    _pending_intervals = {}
+    _pending_intervals_lock = threading.RLock()
+
     @action
     def sleep(self, seconds):
         """
@@ -19,6 +32,114 @@ class UtilsPlugin(Plugin):
 
         time.sleep(seconds)
 
+    @action
+    def set_timeout(self, seconds, actions, name=None, **args):
+        """
+        Define a set of actions to run after the specified amount of `seconds`.
+
+        :param seconds: Number of seconds before running the timeout procedure
+        :type seconds: float
+
+        :param actions: List of actions to be executed after the timeout expires
+        :type actions: list[dict]
+
+        :param name: Set an optional name for this timeout. It is advised to set
+            a name if you are planning to programmatically cancel the timeout in
+            your business logic.
+        :type name: str
+
+        :param args: Optional arguments/context to pass to the timeout function
+        """
+
+        with self._timeout_hndl_idx_lock:
+            self._timeout_hndl_idx += 1
+            if not name:
+                name = self._DEFAULT_TIMEOUT_PREFIX + str(self._timeout_hndl_idx)
+            if name in self._pending_timeouts:
+                return (None,
+                        "A timeout named '{}' is already awaiting".format(name))
+
+
+        procedure = Procedure.build(name=name, requests=actions, _async=False)
+        self._pending_timeouts[name] = procedure
+
+        def _proc_wrapper(**kwargs):
+            procedure.execute(**kwargs)
+
+        with self._pending_timeouts_lock:
+            self._pending_timeouts[name] = threading.Timer(seconds,
+                                                           _proc_wrapper,
+                                                           kwargs=args)
+        self._pending_timeouts[name].start()
+
+    @action
+    def clear_timeout(self, name):
+        timer = None
+
+        with self._pending_timeouts_lock:
+            if name not in self._pending_timeouts:
+                return
+            timer = self._pending_timeouts.pop(name)
+
+        timer.cancel()
+
+
+    @action
+    def set_interval(self, seconds, actions, name=None, **args):
+        """
+        Define a set of actions to run each specified amount of `seconds`.
+
+        :param seconds: Number of seconds between two runs of the interval
+            procedure
+        :type seconds: float
+
+        :param actions: List of actions to be executed at each interval
+        :type actions: list[dict]
+
+        :param name: Set an optional name for this interval. It is advised to
+            set a name if you are planning to programmatically cancel the
+            interval in your business logic.
+        :type name: str
+
+        :param args: Optional arguments/context to pass to the interval function
+        """
+
+        with self._interval_hndl_idx_lock:
+            self._interval_hndl_idx += 1
+            if not name:
+                name = self._DEFAULT_INTERVAL_PREFIX + \
+                    str(self._interval_hndl_idx)
+
+            if name in self._pending_intervals:
+                return (None,
+                        "An interval named '{}' is already running".format(name))
+
+
+        procedure = Procedure.build(name=name, requests=actions, _async=False)
+        self._pending_intervals[name] = procedure
+
+        def _proc_wrapper(**kwargs):
+            while True:
+                with self._pending_intervals_lock:
+                    if name not in self._pending_intervals:
+                        return
+
+                procedure.execute(**kwargs)
+                time.sleep(seconds)
+
+        with self._pending_intervals_lock:
+            self._pending_intervals[name] = threading.Thread(
+                target=_proc_wrapper, kwargs=args)
+        self._pending_intervals[name].start()
+
+    @action
+    def clear_interval(self, name):
+        interval = None
+
+        with self._pending_intervals_lock:
+            if name not in self._pending_intervals:
+                return
+            del self._pending_intervals[name]
+
 
 # vim:sw=4:ts=4:et:
-