def task_check_for_new_jobs():
"""
Looks at the number of currently active threads and compares it against the
:py:data:`MAX_ENCODING_JOBS_PER_EC2_INSTANCE <media_nommer.conf.settings.MAX_ENCODING_JOBS_PER_EC2_INSTANCE>`
setting. If we are under the max, fire up another thread for encoding
additional job(s).
The interval at which :doc:`../ec2nommerd` checks for new jobs is
determined by the
:py:data:`NOMMERD_NEW_JOB_CHECK_INTERVAL <media_nommer.conf.settings.NOMMERD_NEW_JOB_CHECK_INTERVAL>`
setting.
Calls :py:func:`threaded_encode_job` for any jobs to encode.
"""
num_active_threads = NodeStateManager.get_num_active_threads()
max_threads = settings.MAX_ENCODING_JOBS_PER_EC2_INSTANCE
num_jobs_to_pop = max(0, max_threads - num_active_threads)
if num_jobs_to_pop > 0:
# We have more room for encoding threads, determine how many.
logger.debug("task_check_for_new_jobs: " \
"Popping up to %d new jobs." % num_jobs_to_pop)
# This is an iterable of BaseEncodingJob sub-classed instances for
# each job returned from the queue.
jobs = JobStateBackend.pop_new_jobs_from_queue(num_jobs_to_pop)
if jobs:
logger.debug("* Popped %d jobs from the queue." % len(jobs))
for job in jobs:
# For each job returned, render in another thread.
logger.debug("* Starting encoder thread for job: %s" % job.unique_id)
reactor.callInThread(threaded_encode_job, job)
