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Run Worker processes - Python SDK

Run a Worker Process​

How to run a Worker Process using the Temporal Python SDK.

The Worker Process is where Workflow Functions and Activity Functions are executed.

  • Each Worker Entity in the Worker Process must register the exact Workflow Types and Activity Types it may execute.
  • Each Worker Entity must also associate itself with exactly one Task Queue.
  • Each Worker Entity polling the same Task Queue must be registered with the same Workflow Types and Activity Types.

A Worker Entity is the component within a Worker Process that listens to a specific Task Queue.

Although multiple Worker Entities can be in a single Worker Process, a single Worker Entity Worker Process may be perfectly sufficient. For more information, see the Worker tuning guide.

A Worker Entity contains a Workflow Worker and/or an Activity Worker, which makes progress on Workflow Executions and Activity Executions, respectively.

To develop a Worker, use the Worker() constructor and add your Client, Task Queue, Workflows, and Activities as arguments. The following code example creates a Worker that polls for tasks from the Task Queue and executes the Workflow. When a Worker is created, it accepts a list of Workflows in the workflows parameter, a list of Activities in the activities parameter, or both.

View the source code

in the context of the rest of the application code.

from temporalio.client import Client
from temporalio.worker import Worker
# ...
# ...
async def main():
    client = await Client.connect("localhost:7233")
    worker = Worker(
        client,
        task_queue="your-task-queue",
        workflows=[YourWorkflow],
        activities=[your_activity],
    )
    await worker.run()

if __name__ == "__main__":
    asyncio.run(main())

Register types​

How to register types using the Temporal Python SDK.

All Workers listening to the same Task Queue name must be registered to handle the exact same Workflows Types and Activity Types.

If a Worker polls a Task for a Workflow Type or Activity Type it does not know about, it fails that Task. However, the failure of the Task does not cause the associated Workflow Execution to fail.

When a Worker is created, it accepts a list of Workflows in the workflows parameter, a list of Activities in the activities parameter, or both.

View the source code

in the context of the rest of the application code.

# ...
async def main():
    client = await Client.connect("localhost:7233")
    worker = Worker(
        client,
        task_queue="your-task-queue",
        workflows=[YourWorkflow],
        activities=[your_activity],
    )
    await worker.run()

if __name__ == "__main__":
    asyncio.run(main())