Pagure provides a mechanism for loading 3rd party plugins in the form of Flask Blueprints. The plugins are loaded from a separate configuration file that is specified using the PAGURE_PLUGINS_CONFIG option. There are at least two reasons for keeping plugins initialization outside the main pagure configuration file:

  1. avoid circular dependencies errors. For example if the pagure configuration imports a plugin, which in turn imports the pagure configuration, the plugin could try to read a configuration option that has not been imported yet and thus raise an error

  2. the pagure configuration is also loaded by other processes such as Celery workers. The Celery tasks might only be interested in reading the configuration settings without having to load any external plugin

Loading the configuration

The configuration file can be loaded by setting the variable PAGURE_PLUGINS_CONFIG inside the pagure main configuration file, for example inside /etc/pagure/pagure.cfg. Alternatively, it is also possible to set the environment variable PAGURE_PLUGINS_CONFIG before starting the pagure server. If both variables are set, the environment variable takes precedence over the configuration file.

The configuration file

After Pagure has imported the configuration file defined in PAGURE_PLUGINS_CONFIG it will look for Flask Blueprints in a variable called PLUGINS defined in the same file, for example PLUGINS = [ plugin1.blueprint, plugin2.blueprint, ... ]. Pagure will then proceed to register any Blueprint into the main Flask app, in the same order as they are listed in PLUGINS.

An example configuration can be seen in files/plugins.cfg.sample inside the Pagure repository.