python-gearman使用

yum -y install gearmand
chkconfig gearmand on && /etc/init.d/gearmand start
# /etc/sysconfig/gearmand
指定 OPTIONS=""里的内容，添加持久性等功能

example

worker.py

#!/usr/bin/env python
# -*- encoding: utf-8; py-indent-offset: 4 -*-
import gearman
gm_worker = gearman.GearmanWorker(['localhost:4730'])
def task_listener_reverse(gearman_worker, gearman_job):
    print 'Reversing string: ' + gearman_job.data
    return gearman_job.data[::-1]
# gm_worker.set_client_id is optional
gm_worker.set_client_id('python-worker')
gm_worker.register_task('reverse', task_listener_reverse)
# Enter our work loop and call gm_worker.after_poll() after each time we timeout/see socket activity
gm_worker.work()

client.py

#!/usr/bin/env python
# -*- encoding: utf-8; py-indent-offset: 4 -*-
import gearman
def check_request_status(job_request):
    if job_request.complete:
        print "Job %s finished!  Result: %s - %s" % (job_request.job.unique, job_request.state, job_request.result)
    elif job_request.timed_out:
        print "Job %s timed out!" % job_request.unique
    elif job_request.state == JOB_UNKNOWN:
        print "Job %s connection failed!" % job_request.unique
gm_client = gearman.GearmanClient(['localhost:4730'])
completed_job_request = gm_client.submit_job("reverse", "Hello World!")
check_request_status(completed_job_request)

results

python client.py
# Job b5175e15d8e09ba6470cbedb4b6e2b1a finished!  Result: COMPLETE - !dlroW olleH
python worker.py
# Reversing string: Hello World!

API

Gearman worker

class gearman.worker.GearmanWorker(host_list=None)
	GearmanWorker :: Interface to accept jobs from a Gearman server

1 Job processing

GearmanWorker.set_client_id(client_id)
# Notify the server that we should be identified as this client ID
GearmanWorker.register_task(task, callback_function)
# Register a function with this worker
def function_callback(calling_gearman_worker, current_job):
	return current_job.data
GearmanWorker.unregister_task(task)
# Unregister a function with worker
GearmanWorker.work(poll_timeout=60.0)
# Loop indefinitely, complete tasks from all connections.

# example
gm_worker = gearman.GearmanWorker(['localhost:4730'])
# See gearman/job.py to see attributes on the GearmanJob
# Send back a reversed version of the 'data' string
def task_listener_reverse(gearman_worker, gearman_job):
    return reversed(gearman_job.data)
# gm_worker.set_client_id is optional
gm_worker.set_client_id('your_worker_client_id_name')
gm_worker.register_task('reverse', task_listener_reverse)
# Enter our work loop and call gm_worker.after_poll() after each time we timeout/see socket activity
gm_worker.work()

2 Sending in-flight job updates

GearmanWorker.send_job_data(current_job, data, poll_timeout=None)
# Send a Gearman JOB_DATA update for an inflight job
GearmanWorker.send_job_status(current_job, numerator, denominator, poll_timeout=None)
# Send a Gearman JOB_STATUS update for an inflight job
GearmanWorker.send_job_warning(current_job, data, poll_timeout=None)
# Send a Gearman JOB_WARNING update for an inflight job

# example
Callback function sending back inflight job updates:
gm_worker = gearman.GearmanWorker(['localhost:4730'])
# See gearman/job.py to see attributes on the GearmanJob
# Send back a reversed version of the 'data' string through WORK_DATA instead of WORK_COMPLETE
def task_listener_reverse_inflight(gearman_worker, gearman_job):
    reversed_data = reversed(gearman_job.data)
    total_chars = len(reversed_data)
    for idx, character in enumerate(reversed_data):
        gearman_worker.send_job_data(gearman_job, str(character))
        gearman_worker.send_job_status(gearman_job, idx + 1, total_chars)
    return None
# gm_worker.set_client_id is optional
gm_worker.register_task('reverse', task_listener_reverse_inflight)
# Enter our work loop and call gm_worker.after_poll() after each time we timeout/see socket activity
gm_worker.work()

3 Extending the worker

GearmanWorker.data_encoder
# Provide common object dumps for all communications over gearman
GearmanWorker.after_poll(any_activity)
# Polling callback to notify any outside listeners whats going on with the GearmanWorker.
Return True to continue polling, False to exit the work loop

# example
Send/receive Python objects and do work between polls:
# By default, GearmanWorker's can only send off byte-strings
# If we want to be able to send out Python objects, we can specify a data encoder
# This will automatically convert byte strings <-> Python objects for ALL commands that have the 'data' field
#
# See http://gearman.org/index.php?id=protocol for Worker commands that send/receive 'opaque data'
#
import json # Or similarly styled library
class JSONDataEncoder(gearman.DataEncoder):
    @classmethod
    def encode(cls, encodable_object):
        return json.dumps(encodable_object)
    @classmethod
    def decode(cls, decodable_string):
        return json.loads(decodable_string)
class DBRollbackJSONWorker(gearman.GearmanWorker):
    data_encoder = JSONDataEncoder
    def after_poll(self, any_activity):
        # After every select loop, let's rollback our DB connections just to be safe
        continue_working = True
        self.db_connections.rollback()
        return continue_working

Gearman client

 def check_request_status(job_request):
    if job_request.complete:
        print "Job %s finished!  Result: %s - %s" % (job_request.job.unique, job_request.state, job_request.result)
    elif job_request.timed_out:
        print "Job %s timed out!" % job_request.unique
    elif job_request.state == JOB_UNKNOWN:
        print "Job %s connection failed!" % job_request.unique
class gearman.client.GearmanClient(host_list=None, random_unique_bytes=16)
# GearmanClient :: Interface to submit jobs to a Gearman server

1 Submitting jobs

GearmanClient.submit_job(task, data, unique=None, priority=None, background=False, wait_until_complete=True, max_retries=0, poll_timeout=None)
# Submit a single job to any gearman server

# example
Sending a simple job as a blocking call:
gm_client = gearman.GearmanClient(['localhost:4730', 'otherhost:4730'])
# See gearman/job.py to see attributes on the GearmanJobRequest
# Defaults to PRIORITY_NONE, background=False (synchronous task), wait_until_complete=True
completed_job_request = gm_client.submit_job("task_name", "arbitrary binary data")
check_request_status(completed_job_request)
Sending a high priority, background, blocking call:
gm_client = gearman.GearmanClient(['localhost:4730', 'otherhost:4730'])
# See gearman/job.py to see attributes on the GearmanJobRequest
submitted_job_request = gm_client.submit_job("task_name", "arbitrary binary data", priority=gearman.PRIORITY_HIGH, background=True)
check_request_status(submitted_job_request)

GearmanClient.submit_multiple_jobs(jobs_to_submit, background=False, wait_until_complete=True, max_retries=0, poll_timeout=None)
Takes a list of jobs_to_submit with dicts of
{‘task’: task, ‘data’: data, ‘unique’: unique, ‘priority’: priority}

# example
Sending multiple jobs all at once and behave like a non-blocking call (wait_until_complete=False):
import time
gm_client = gearman.GearmanClient(['localhost:4730'])
list_of_jobs = [dict(task="task_name", data="binary data"), dict(task="other_task", data="other binary data")]
submitted_requests = gm_client.submit_multiple_jobs(list_of_jobs, background=False, wait_until_complete=False)
# Once we know our jobs are accepted, we can do other stuff and wait for results later in the function
# Similar to multithreading and doing a join except this is all done in a single process
time.sleep(1.0)
# Wait at most 5 seconds before timing out incomplete requests
completed_requests = gm_client.wait_until_jobs_completed(submitted_requests, poll_timeout=5.0)
for completed_job_request in completed_requests:
    check_request_status(completed_job_request)

GearmanClient.submit_multiple_requests(job_requests, wait_until_complete=True, poll_timeout=None)
# Take GearmanJobRequests, assign them connections, and request that they be done.
Blocks until our jobs are accepted (should be fast) OR times out
Optionally blocks until jobs are all complete
You MUST check the status of your requests after calling this function as “timed_out” or “state == JOB_UNKNOWN” maybe True

# example
Recovering from failed connections:
import time
gm_client = gearman.GearmanClient(['localhost:4730'])
list_of_jobs = [dict(task="task_name", data="task binary string"), dict(task="other_task", data="other binary string")]
failed_requests = gm_client.submit_multiple_jobs(list_of_jobs, background=False)
# Let's pretend our assigned requests' Gearman servers all failed
assert all(request.state == JOB_UNKNOWN for request in failed_requests), "All connections didn't fail!"
# Let's pretend our assigned requests' don't fail but some simply timeout
retried_connection_failed_requests = gm_client.submit_multiple_requests(failed_requests, wait_until_complete=True, poll_timeout=1.0)
timed_out_requests = [job_request for job_request in retried_requests if job_request.timed_out]
# For our timed out requests, lets wait a little longer until they're complete
retried_timed_out_requests = gm_client.submit_multiple_requests(timed_out_requests, wait_until_complete=True, poll_timeout=4.0)

GearmanClient.wait_until_jobs_accepted(job_requests, poll_timeout=None)
# Go into a select loop until all our jobs have moved to STATE_PENDING

GearmanClient.wait_until_jobs_completed(job_requests, poll_timeout=None)
# Go into a select loop until all our jobs have completed or failed

2 Retrieving job status

GearmanClient.get_job_status(current_request, poll_timeout=None)
# Fetch the job status of a single request
GearmanClient.get_job_statuses(job_requests, poll_timeout=None)
#Fetch the job status of a multiple requests

3 Extending the client

GearmanClient.data_encoder
# Provide common object dumps for all communications over gearman

# example
Send/receive Python objects (not just byte strings):
# By default, GearmanClient's can only send off byte-strings
# If we want to be able to send out Python objects, we can specify a data encoder
# This will automatically convert byte strings <-> Python objects for ALL commands that have the 'data' field
#
# See http://gearman.org/index.php?id=protocol for client commands that send/receive 'opaque data'
import pickle
class PickleDataEncoder(gearman.DataEncoder):
    @classmethod
    def encode(cls, encodable_object):
        return pickle.dumps(encodable_object)
    @classmethod
    def decode(cls, decodable_string):
        return pickle.loads(decodable_string)
class PickleExampleClient(gearman.GearmanClient):
    data_encoder = PickleDataEncoder
my_python_object = {'hello': 'there'}
gm_client = PickleExampleClient(['localhost:4730'])
gm_client.submit_job("task_name", my_python_object)

Gearman Admin client

class gearman.admin_client.GearmanAdminClient(host_list=None, poll_timeout=10.0)
GearmanAdminClient :: Interface to send/receive administrative commands to a Gearman server
This client acts as a BLOCKING client and each call will poll until it receives a satisfactory server response
http://gearman.org/index.php?id=protocol See section ‘Administrative Protocol’

1 Interacting with a server

GearmanAdminClient.send_maxqueue(task, max_size)
# Sends a request to change the maximum queue size for a given task
GearmanAdminClient.send_shutdown(graceful=True)
# Sends a request to shutdown the connected gearman server
GearmanAdminClient.get_status()
# Retrieves a list of all registered tasks and reports how many items/workers are in the queue
GearmanAdminClient.get_version()
# Retrieves the version number of the Gearman server
GearmanAdminClient.get_workers()
# Retrieves a list of workers and reports what tasks they’re operating on

# example
Checking server state:
gm_admin_client = gearman.GearmanAdminClient(['localhost:4730'])
# Inspect server state
status_response = gm_admin_client.get_status()
version_response = gm_admin_client.get_version()
workers_response = gm_admin_client.get_workers()

2 Testing server response times

GearmanAdminClient.ping_server()
# Sends off a debugging string to execute an application ping on the Gearman server

# example
Checking server response time:
gm_admin_client = gearman.GearmanAdminClient(['localhost:4730'])
response_time = gm_admin_client.ping_server()

Gearman job definitions

1 GearmanJob - Basic information about a requested job

class gearman.job.GearmanJob(connection, handle, task, unique, data)
# Represents the basics of a job... used in GearmanClient / GearmanWorker to represent job states

1.1 Server identifers

GearmanJob.connection
# GearmanConnection - Server assignment. Could be None prior to client job submission
GearmanJob.handle
# string - Job’s server handle. Handles are NOT interchangeable across different gearman servers

1.2 Job parameters

GearmanJob.task
# string - Job’s task
GearmanJob.unique
# string - Job’s unique identifier (client assigned)
GearmanJob.data
# binary - Job’s binary payload

2 GearmanJobRequest - State tracker for requested jobs

class gearman.job.GearmanJobRequest(gearman_job, initial_priority=None, background=False, max_attempts=1)
# Represents a job request... used in GearmanClient to represent job states

2.1 Tracking job submission

GearmanJobRequest.gearman_job
# GearmanJob - Job that is being tracked by this GearmanJobRequest object
GearmanJobRequest.priority
# PRIORITY_NONE [default]
# PRIORITY_LOW
# PRIORITY_HIGH
GearmanJobRequest.background
# boolean - Is this job backgrounded?
GearmanJobRequest.connection_attempts
# integer - Number of attempted connection attempts
GearmanJobRequest.max_connection_attempts
# integer - Maximum number of attempted connection attempts before raising an exception

2.2 Tracking job progress

GearmanJobRequest.result
# binary - Job’s returned binary payload - Populated if and only if JOB_COMPLETE
GearmanJobRequest.exception
# binary - Job’s exception binary payload
GearmanJobRequest.state
# JOB_UNKNOWN - Request state is currently unknown, either unsubmitted or connection failed
# JOB_PENDING - Request has been submitted, pending handle
# JOB_CREATED - Request has been accepted
# JOB_FAILED - Request received an explicit job failure (job done but errored out)
# JOB_COMPLETE - Request received an explicit job completion (job done with results)
GearmanJobRequest.timed_out
# boolean - Did the client hit its polling_timeout prior to a job finishing?
GearmanJobRequest.complete
# boolean - Does the client need to continue to poll for more updates from this job?

2.3 Tracking in-flight job updates

Certain GearmanJob’s may send back data prior to actually completing. GearmanClient uses these queues to keep track of what/when we received certain updates.
GearmanJobRequest.warning_updates
# collections.deque - Job’s warning binary payloads
GearmanJobRequest.data_updates
# collections.deque - Job’s data binary payloads
GearmanJobRequest.status¶
# dictionary - Job’s status
handle - string - Job handle
# known - boolean - Is the server aware of this request?
# running - boolean - Is the request currently being processed by a worker?
# numerator - integer
# denominator - integer
# time_received - integer - Time last updated
New in version 2.0.1: Replaces GearmanJobRequest.status_updates and GearmanJobRquest.server_status
GearmanJobRequest.status_updates
# Deprecated since version 2.0.1: Replaced by GearmanJobRequest.status
GearmanJobRequest.server_status
# Deprecated since version 2.0.1: Replaced by GearmanJobRequest.status