Actor lifecycle

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Lifecycle methods

Initialization and cleanup

At the start of its runtime, the Actor needs to initialize itself, its event manager and its storages, and at the end of the runtime it needs to close these cleanly. The Apify SDK provides several options on how to manage this.

Actor.init() and Actor.exit()

The Actor.init() method initializes the Actor, the event manager which processes the Actor events from the platform event websocket, and the storage client used in the execution environment. It should be called before performing any other Actor operations.

The Actor.exit() method then exits the Actor cleanly, tearing down the event manager and the storage client. There is also the Actor.fail() method, which exits the Actor while marking it as failed.

src/main.py

import asyncio
from apify import Actor
from apify.consts import ActorExitCodes

async def main():
    await Actor.init()
    try:
        print('Actor input:', await Actor.get_input())
        await Actor.set_value('OUTPUT', 'Hello, world!')
        await Actor.exit()
    except Exception as e:
        print('Error while running Actor', e)
        await Actor.fail(exit_code=ActorExitCodes.ERROR_USER_FUNCTION_THREW, exception=e)

asyncio.run(main())

Context manager

So that you don't have to call the lifecycle methods manually, the Actor class provides a context manager, which calls the Actor.init() method on enter, the Actor.exit() method on a clean exit, and the Actor.fail() method when there is an exception during the run of the Actor.

This is the recommended way to work with the Actor class.

src/main.py

import asyncio
from apify import Actor

async def main():
    async with Actor:
        print('Actor input:', await Actor.get_input())
        await Actor.set_value('OUTPUT', 'Hello, world!')

asyncio.run(main())

Main function

Another option is to pass a function to the Actor via the Actor.main(main_func) method, which causes the Actor to initialize, run the main function, and exit, catching any runtime errors in the passed function.

src/main.py

import asyncio
from apify import Actor

async def actor_main_func():
    print('Actor input:', await Actor.get_input())
    await Actor.set_value('OUTPUT', 'Hello, world!')

async def main():
    await Actor.main(actor_main_func)

asyncio.run(main())