django-uws 0.2.dev370864

Django implementation of the IVOA UWS pattern.

Django Universal Worker Service

Django implementation of the IVOA UWS pattern.

The Universal Worker Service (UWS) pattern defines how to manage asynchronous execution of jobs on a service. Any application of the pattern defines a family of related services with a common service contract. Possible uses of the pattern are also described.

Url: https://www.ivoa.net/documents/UWS/ DOI: 10.5479/ADS/bib/2016ivoa.spec.1024H

Installation

Django UWS is available via Pypi:

pip install django-uws

Django Quick start

1. add uws to your INSTALLED_APPS setting likes this:

    INSTALLED_APPS = [
        ...
        'uws',
        ...
    ]

Additionally you may want to set the following settings:

CELERY_TIMEZONE = "Europe/Amsterdam"
CELERY_USE_UTC = True
# Recommended to use an environment variable to set the broker URL.
CELERY_BROKER_URL = os.getenv("CELERY_BROKER_URL", "amqp://guest@localhost:5672")

2. Include the uws URLconf in your project urls.py like this:

    ...
    path('uws/', include('uws.urls')),  # 'uws/' can be replaced by the name of your service if necessary.
    ...

3. Run python manage.py migrate uws to create the UWS models. Optionally: python manage.py migrate uws --database uws by specifying

    DATABASE_ROUTERS = [
    ...
    "uws.database_router.UWSDatabaseRouter",
    ...
    ]

and a `uws` entry in your `DATABASES` setting

4. Add Celery configuration Create a celery.py file in the Django <project> folder (next to settings.py, wsgi.py etc.) with the following content:

import os

from celery import Celery

# Set the default Django settings module for the 'celery' program.
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "project.default_settings")

app = Celery("project") # Change to something related to your Service

app.config_from_object("django.conf:settings", namespace="CELERY")

app.autodiscover_tasks()

Worker configuration

The worker configuration still uses a Django project layout and can be merged with an existing Django application serving the API or as a standalone worker instance. Setting it up is similar to the steps for the api:

1. Create a workers (or similarly named) directory to store the code for your workers

2. Create worker files. An example would be:

from uws.classes import UWSJob
from uws.client import Client
from uws.workers import Worker

class Echo(Worker):
    """A worker echoing all parameters"""

    def __init__(self):
        self._type = "echo"

    def run(self, job: UWSJob, job_token: str, client: Client) -> None:
        data = [{"key": p.key, "value": p.value} for p in job.parameters]
        client.add_results(job.jobId, data, job_token)

3. Set the following Django settings (if not already present):

CELERY_TIMEZONE = "Europe/Amsterdam"
CELERY_USE_UTC = True
CELERY_BROKER_URL = os.getenv("CELERY_BROKER_URL", "amqp://guest@localhost:5672")

# Classes of available workers
UWS_WORKERS = ["workers.echo.Echo"]
# Web path to UWS api, recommended to use an environment variable
UWS_HOST = os.getenv("UWS_HOST", "https://example.com/uws/")

Contributing

For developer access to this repository, please send a message on the ESAP channel on Rocket Chat.

License

This project is licensed under the Apache License version 2.0.