.. _plugin-dev:
Plugin Developer Documentation
====================================
Getting Started
---------------
Signals
----------
In order to configure a plugin to able to listen and send signals using Colab
signals structure, some steps are required:
* Every plugin that needs to handle signals in colab need to use celery in order
to run taks asynchronously. This is due the fact that every time a handling
method for a signal is executed, it will be executed as a asynchronously
celery tasks, in order to not block other colab tasks. To use celery in the
plugin, file named celery.py needs to be created on the root directory of the
plugin. An example file can be seen below:
.. code-block:: python
m __future__ import absolute_import
import os
from celery import Celery
# set the default Django settings module for the 'celery' program.
os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'colab.settings')
from django.conf import settings
app = Celery('colab')
app.config_from_object('django.conf:settings')
app.autodiscover_tasks(lambda: settings.INSTALLED_APPS)
app.conf.update(
CELERY_RESULT_BACKEND='djcelery.backends.database:DatabaseBackend',
)
app.conf.update(
CELERY_RESULT_BACKEND='djcelery.backends.cache:CacheBackend',
)
* The plugin should import the method from colab.signals.tasks in order for the
plugin to use the necessary method to handle signals
* In the apps.py file it is necessary to declare a list variable containing all the
signals that the plugin will dispatch. It is suggested to name the variable
"registered_signals", but that nomenclature not strictly necessary.
* It is also necessary to declare a variable containing the name of the plugin
that will send the signal. It must be said that the name of the plugin cannot
contain any special character, such as dot or comma. It is suggested to name
the variable "short_name", but that nomenclature is not strictly
necessary.
* In order to actually register the signals, it is necessary to call the method
register_signal, which require the name of the plugin that is registering the
signals and a list of signals to be registered as parameters. This method
should be called on the app method named __init__. Since the plugin class is a
subclass of AppConfig, the constructor of the parent must be calles as weel.
.. code-block:: ṕython
def __init__(self, app_name, app_module):
super(ProxyGitlabAppConfig, self).__init__(app_name, app_module)
register_signal(self.short_name, self.signals_list)
* In order to listen for a given signal, it is required to create a handling
method. This method should be located at a file named tasks.py in the same
directory as the plugins files. It also must be said that this method need to
receive at least a \*\*kwargs parameter. An example of a handling method can
be seen below:
.. code-block:: python
# import app from celery.py
@app.task(bind=True)
def handling_method(self, **kwargs):
# DO SOMETHING
* With signals registered and handling method defined you must connect them.
To do it you must call connect_signal passing signal name, sender and handling
method as arguments. This calling must be into ready function in apps.py, as
you can see below:
.. code-block:: python
def ready(self):
connect_signal(self.signal_name, self.sender, handling_method)
* To send a broadcast signal you must call send method anywhere passing signal name
and sender as arguments. If necessary you can pass another parameters in
\*\*kwargs. As you can see below:
.. code-block:: python
send(signal_name, sender)
* If you want to run celery manually to make some tests, you should execute:
.. code-block:: shell
celery -A colab worker --loglevel=debug