Workers

The module taskqueue.worker contains the abstract class BaseWorker. All your worker plugins should be derived from it.

Your custom functionality should be put into the method handle_task(). And if you want to modify the way how task results are reported or tracked then override the method report_results() of your worker subclass.

Taskqueue uses the pkg_resources library to discover registered plugins. So in order to make your plugins visible to your taskqueue installation you need to register your worker factories as entry points under the group worker.plugins:

setup(
    entry_points={
        'worker.plugins': [
            'customworker = yourpackage.yourmodule:YourWorker.factory'
        ]
    }
)

class taskqueue.worker.BaseWorker

Base class for workers.

ACCEPT = ['*/*']

Specifies list of workitem types accepted by the worker. By default workers accept workitems of any type.

cleanup(signum, frame)

Cleanup worker process.

classmethod factory()

Produce new worker callable.

handle_delivery(channel, method, header, body)

Handle AMQP message.

Parameters:

• channel (pika.channel.Channel) – AMQP channel
• method (pika.frame.Method) – message’s method
• header (pika.frame.Header) – message header
• body (string) – message body

handle_task(workitem)

Handle task.

This method is supposed to be overriden in BaseWorker subclasses.

Parameters:workitem (Workitem) – workflow work item Returns:new state of work item Return type:Workitem

is_acceptable(workitem)

Check if received workitem can be handled by worker.

Parameters:workitem (Workitem) – workitem to check Return type:boolean

report_results(channel, workitem)

Report task results back to AMQP.

Feel free to override this method.

Parameters:

• channel (pika.channel.Channel) – AMQP channel
• workitem (Workitem) – workflow work item