celery-yaml 2.1.2

Easy configuration for celery app using Yaml file

Easy Configuration For Celery App Using a Yaml File

celery-yaml is a library to inject a --yaml option to the celery worker command in order to inject its configuration.

It also handle help to configurate this application for Pyramid application.

Usage

celery -A my_application.module_containing_my.app worker --yaml development.yaml ...

This will configure the application my_application containing an application app in a submodule module_containing_my.

The celery app must register the --yaml using the add_yaml_option on the app instance, this way:

from celery import Celery
from celery_yaml import add_yaml_option

app = Celery()
add_yaml_option(app)

Yaml format

celery:
  broker_url: 'amqp://guest:guest@localhost:5672//'
  result_backend: 'rpc://'
  imports:
      - my_application.tasks
  # see all settings in the celery docs:
  # https://docs.celeryproject.org/en/stable/userguide/configuration.html

logging:
  version: 1
  # dictConfig format
  # https://docs.python.org/3/library/logging.config.html#logging-config-dictschema

---

NOTE

The broker_url can also be override by an environment variable CELERY_BROKER_URL to avoid password in the configuration file.

Using Celery in a Pyramid App.

The extras "pyramid" must be added to install the extras depencencies.

With poetry

[tool.poetry.dependencies]
celery-yaml = { version = "^0.1.3", extras = ["pyramid"] }

Then some entry_points have to configure, such as:

[tool.poetry.plugins."paste.app_factory"]
main = "pyramid_app.wsgi:main"

[tool.poetry.plugins."celery_yaml.app"]
main = "pyramid_app.backend:app"

[tool.poetry.plugins."plaster.loader_factory"]
"file+yaml" = "plaster_yaml:Loader"

the paste.app_factory is used by Pyramid itself to build the WSGI sergivice but we add a plaster.loader_factory to configure the usage of a yaml file instead of an ini file to configure it.

Then the celery_yaml.app is used by celery-yaml as an entrypoint to the celery app.

Then, in the configuration file,

celery: &celery
  result_backend: 'rpc://'
  imports:
      - pyramid_app.tasks

app:
  "use": "egg:pyramid_app"
  "pyramid.includes": ["celery_yaml"]
  "celery":
    <<: *celery
    "use": "egg:pyramid_app"

foo: "bar"

More configuration

if the celery app as a method on_yaml_loaded then the function is called with the data and the filepath in parameter. It may be used to get mode configuration available readed from the yaml file.

Example

from celery import Celery as CeleryBase


class Celery(CeleryBase):

    def on_yaml_loaded(self, data: dict[str, Any], config_path: str):
        data['foo']  # you can access to the value of foo here

This is particullary usefull for depenency injection purpose.

Environment substitution

celery:
  broker_url: ${CELERY_BROKER_URL}
  result_backend: ${CELERY_BACKEND_RESULT}
  imports:
      - pyramid_app.tasks

database_dsn: ${DATABASE_DSN}

The CELERY_BROKER_URL and CELERY_BACKEND_RESULT environment variable are interpreted by celery, so can be outside your yaml file, but, it is not True for all the variable, using celery-yaml, you can still inject configuration in the yaml that are substituted in the configuration during the yaml load.

This is particullary usefull to keep your configuration structured but keep secrets in environment variable, for security reason. And also to build docker container that can be easily customizable.

See full example in the examples directory:

https://github.com/mardiros/celery-yaml/tree/master/examples/pyramid-app