This document describes the current stable version of Celery (5.2). For development docs, go here.

celery.bootsteps

A directed acyclic graph of reusable components.

class celery.bootsteps.Blueprint(steps=None, name=None, on_start=None, on_close=None, on_stopped=None)

Blueprint containing bootsteps that can be applied to objects.

Parameters

• Sequence[Union[str (steps) – List of steps.

• Step]] – List of steps.

• name (str) – Set explicit name for this blueprint.

• on_start (Callable) – Optional callback applied after blueprint start.

• on_close (Callable) – Optional callback applied before blueprint close.

• on_stopped (Callable) – Optional callback applied after blueprint stopped.

GraphFormatter

alias of celery.bootsteps.StepFormatter

property alias

apply(parent, **kwargs)

Apply the steps in this blueprint to an object.

This will apply the __init__ and include methods of each step, with the object as argument:

step = Step(obj)
...
step.include(obj)

For StartStopStep the services created will also be added to the objects steps attribute.

claim_steps()

close(parent)

connect_with(other)

default_steps = {}

human_state()

info(parent)

join(timeout=None)

load_step(step)

name = None

restart(parent, method='stop', description='restarting', propagate=False)

send_all(parent, method, description=None, reverse=True, propagate=True, args=())

start(parent)

started = 0

state = None

state_to_name = {0: 'initializing', 1: 'running', 2: 'closing', 3: 'terminating'}

stop(parent, close=True, terminate=False)

class celery.bootsteps.ConsumerStep(parent, **kwargs)

Bootstep that starts a message consumer.

consumers = None

get_consumers(channel)

name = 'celery.bootsteps.ConsumerStep'

requires = ('celery.worker.consumer:Connection',)

shutdown(c)

start(c)

stop(c)

class celery.bootsteps.StartStopStep(parent, **kwargs)

Bootstep that must be started and stopped in order.

close(parent)

include(parent)

name = 'celery.bootsteps.StartStopStep'

obj = None

start(parent)

stop(parent)

terminate(parent)

class celery.bootsteps.Step(parent, **kwargs)

A Bootstep.

The __init__() method is called when the step is bound to a parent object, and can as such be used to initialize attributes in the parent object at parent instantiation-time.

property alias

conditional = False

create(parent)

Create the step.

enabled = True

include(parent)

include_if(parent)

Return true if bootstep should be included.

You can define this as an optional predicate that decides whether this step should be created.

info(obj)

instantiate(name, *args, **kwargs)

label = None

last = False

name = 'celery.bootsteps.Step'

requires = ()