blob: 8e63cc08f5488ad75ff8f2e44fe7db839cd15d96 [file] [log] [blame]
# Copyright 2015 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
import logging
from chromite.lib import metrics
class DroneTaskQueueException(Exception):
"""Generic task queue exception."""
class DroneTaskQueue(object):
"""A manager to run queued tasks in drones and gather results from them."""
def __init__(self):
self.results = dict()
def get_results(self):
"""Get a results dictionary keyed on drones.
@return: A dictionary of return values from drones.
results_copy = self.results.copy()
return results_copy
def execute(self, drones, wait=True):
"""Invoke methods via SSH to a drone.
@param drones: A list of drones with calls to execute.
@param wait: If True, this method will only return when all the drones
have returned the result of their respective invocations of
drone_utility. The `results` map will be cleared.
If False, the caller must clear the map before the next invocation
of `execute`, by calling `get_results`.
@return: A dictionary keyed on the drones, containing a list of return
values from the execution of drone_utility.
@raises DroneTaskQueueException: If the results map isn't empty at the
time of invocation.
if self.results:
raise DroneTaskQueueException(
'Cannot clobber results map: %s, it should be cleared '
'through get_results.' % self.results)
for drone in drones:
if not drone.get_calls():
logging.debug("Drone %s has no work, skipping."
, drone)
metric_fields = {
'drone_hostname': drone.hostname,
'call_count': len(drone.get_calls())
drone_reachable = True
drone_results = drone.execute_queued_calls()
logging.debug("Drone %s scheduled.", drone)
except IOError:
drone_reachable = False
"Drone %s is not reachable by the scheduler.", drone)
drone_reachable, fields=metric_fields)
if drone in self.results:
raise DroneTaskQueueException(
'Task queue has recorded results for drone %s: %s' %
(drone, self.results))
self.results[drone] = drone_results
return self.get_results() if wait else None