Unofficial Python SDK for the Temporal Workflow Engine

Status

This should be considered EXPERIMENTAL at the moment. At the moment, all I can say is that the test cases currently pass. I have not tested this for any real world use cases yet.

Installation

pip install temporal-python-sdk

Sample Code

Sample code for using this library can be found in Workflows in Python Using Temporal.

Hello World

import asyncio
import logging
from datetime import timedelta

from temporal.activity_method import activity_method
from temporal.workerfactory import WorkerFactory
from temporal.workflow import workflow_method, Workflow, WorkflowClient

logging.basicConfig(level=logging.INFO)

TASK_QUEUE = "HelloActivity-python-tq"
NAMESPACE = "default"

# Activities Interface
class GreetingActivities:
    @activity_method(task_queue=TASK_QUEUE, schedule_to_close_timeout=timedelta(seconds=1000))
    async def compose_greeting(self, greeting: str, name: str) -> str:
        raise NotImplementedError


# Activities Implementation
class GreetingActivitiesImpl:
    async def compose_greeting(self, greeting: str, name: str):
        return greeting + " " + name + "!"


# Workflow Interface
class GreetingWorkflow:
    @workflow_method(task_queue=TASK_QUEUE)
    async def get_greeting(self, name: str) -> str:
        raise NotImplementedError


# Workflow Implementation
class GreetingWorkflowImpl(GreetingWorkflow):

    def __init__(self):
        self.greeting_activities: GreetingActivities = Workflow.new_activity_stub(GreetingActivities)
        pass

    async def get_greeting(self, name):
        return await self.greeting_activities.compose_greeting("Hello", name)


async def client_main():
    client = WorkflowClient.new_client(namespace=NAMESPACE)

    factory = WorkerFactory(client, NAMESPACE)
    worker = factory.new_worker(TASK_QUEUE)
    worker.register_activities_implementation(GreetingActivitiesImpl(), "GreetingActivities")
    worker.register_workflow_implementation_type(GreetingWorkflowImpl)
    factory.start()

    greeting_workflow: GreetingWorkflow = client.new_workflow_stub(GreetingWorkflow)
    result = await greeting_workflow.get_greeting("Python")
    print(result)
    print("Stopping workers.....")
    await worker.stop()
    print("Workers stopped......")

if __name__ == '__main__':
    asyncio.run(client_main())

Roadmap

1.0

• Workflow argument passing and return values
• Activity invocation
• Activity heartbeat and Activity.getHeartbeatDetails()
• doNotCompleteOnReturn
• ActivityCompletionClient
  • complete
  • complete_exceptionally
• Activity get_namespace(), get_task_token() get_workflow_execution()
• Activity Retry
• Activity Failure Exceptions
• workflow_execution_timeout / workflow_run_timeout / workflow_task_timeout
• Workflow exceptions
• Cron workflows
• Workflow static methods:
  • await_till()
  • sleep()
  • current_time_millis()
  • now()
  • random_uuid()
  • new_random()
  • get_workflow_id()
  • get_run_id()
  • get_version()
  • get_logger()
• Activity invocation parameters
• Query method
• Signal methods
• Workflow start parameters - workflow_id etc...
• Workflow client - starting workflows synchronously
• Workflow client - starting workflows asynchronously (WorkflowClient.start)
• Get workflow result after async execution (client.wait_for_close)
• Workflow client - invoking signals
• Workflow client - invoking queries

1.1

• ActivityStub and Workflow.newUntypedActivityStub
• Remove threading, use coroutines for everything all concurrency
• Classes as arguments and return values to/from activity and workflow methods (DataConverter)
  • Type hints for DataConverter
• Parallel activity execution (STATUS: there's a working but not finalized API).

1.2

• Timers
• Custom workflow ids through start() and new_workflow_stub()
• WorkflowStub and WorkflowClient.newUntypedWorkflowStub
• ContinueAsNew
• Sticky workflows
• Child Workflows

1.3

• Support for keyword arguments

2.0

• Compatibility with Java client
• Compatibility with Golang client
• Upgrade python-betterproto

Post 2.0:

• sideEffect/mutableSideEffect
• Local activity
• Cancellation Scopes
• Explicit activity ids for activity invocations