qw (or QueueWorker) is used to run worker processes which listen on a redis list for jobs to process.
pip install qw
git clone git://github.com/brettlangdon/qw.git
cd ./qw
python setup.py install
The manager is simply a process manager. It's job is to start/stop worker sub-processes.
The workers are processes which sit and listen for jobs on a few queues and then process those jobs.
The worker/manager take a target
which can be either a function or a string (importable function).
def target(job_id, job_data):
pass
manager = Manager(target)
# OR
manager = Manager('__main__.target')
There are a few different queues that are used. The job queues are just redis lists, manager/worker lists are sets and jobs are hashes.
A worker picks up a job from either all:jobs
, <manager>:jobs
or <worker>:jobs
, pulls the corresponding job:<job_id>
key and
processes it with the provided target
, after processing it will then remove the job:<job_id>
key as well as the job id from
the <worker>:jobs
queue.
all:managers
- a set of all managersall:jobs
- a queue that all workers can pull jobs from, the values are just the job idsjob:<job_id>
- a hash of the job data<manager>:workers
- a set of all workers belonging to a given manager<manager>:jobs
- a queue of jobs for a specific manager, workers will try to pull from here beforeall:jobs
, the values are just the job ids<worker>:jobs
- a queue of jobs for a specific worker, this is meant as a in progress queue for each worker, the workers will pull jobs into this queue from either<manager>:jobs
orall:jobs
, the values are just the job ids
qw
Workers make no assumptions about the result of processing each job. It does not place finished job into a queue or database
or anything else. Once a job has been successfully processed by a Worker, that job is removed completely from queues and from redis.
The worker itself must properly store the results into a finished queue or database if that is what is required.
from qw.manager import Manager
def job_printer(job_id, job_data):
print job_id
print job_data
manager = Manager(job_printer)
manager.start()
manager.join()
__init__(self, target, host="localhost", port=6379, db=0, num_workers=None, name=None)
start(self)
stop(self)
join(self)
__init__(self, client, target, manager_name=None, timeout=10)
run(self)
shutdown(self)
__init__(self, host="localhost", port=6379, db=0)
register_manager(self, name)
deregister_manager(self, name)
register_worker(self, manager, name)
deregister_worker(self, manager, name)
queue_job(self, job_data, manager=None, worker=None)
fetch_next_job(self, manager, worker, timeout=10)
finish_job(self, job_id, worker_name)
get_all_managers(self)
get_manager_workers(self, manager_name)
get_worker_pending_jobs(self, worker_name)
get_manager_queued_jobs(self, manager_name)
get_all_queued_jobs(self)
get_all_pending_jobs(self)
The qw-manager
tool is used to start a new manager process with the provided target
string, which gets run
for every job processed by a worker.
$ qw-manager --help
Usage:
qw-manager [--level=<log-level>] [--workers=<num-workers>] [--name=<name>] [--host=<host>] [--port=<port>] [--db=<db>] <target>
qw-manager (--help | --version)
Options:
--help Show this help message
--version Show version information
-l --level=<log-level> Set the log level (debug,info,warn,error) [default: info]
-w --workers=<num-workers> Set the number of workers to start, defaults to number of cpus
-n --name=<name> Set the manager name, defaults to hostname
-h --host=<host> Set the redis host to use [default: localhost]
-p --port=<port> Set the redis port to use [default: 6379]
-d --db=<db> Set the redis db number to use [default: 0]
The qw-client
command is useful to look at basic stats of running managers, workers and job queues
as well as to push json data in the form of a string or a file to the main queue or a manager specific queue.
$ qw-client --help
Usage:
qw-client [--host=<host>] [--port=<port>] [--db=<db>] managers
qw-client [--host=<host>] [--port=<port>] [--db=<db>] workers [<manager>]
qw-client [--host=<host>] [--port=<port>] [--db=<db>] jobs [<manager>]
qw-client [--host=<host>] [--port=<port>] [--db=<db>] queue string <data> [<manager>]
qw-client [--host=<host>] [--port=<port>] [--db=<db>] queue file <file> [<manager>]
qw-client (--help | --version)
Options:
--help Show this help message
--version Show version information
-h --host=<host> Set the redis host to use [default: localhost]
-p --port=<port> Set the redis port to use [default: 6379]
-d --db=<db> Set the redis db number to use [default: 0]