flask.cli AppGroup Example Code

AppGroup is a class within the flask.cli module of the Flask project. It works like the Click Group class and automatically wraps the functions using with_appcontext.

DispatchingApp, FlaskGroup, ScriptInfo, pass_script_info, and with_appcontext are several other callables with code examples from the same flask.cli package.

Example 1 from indico

indico (project website, documentation and sandbox demo) is a Flask-based web app for event management. The code is open sourced under the MIT license.

indico / indico / cli / util.py

# util.py

import traceback
from importlib import import_module

import click
from flask.cli import AppGroup, FlaskGroup, ScriptInfo
from flask_pluginengine import wrap_in_plugin_context
from werkzeug.utils import cached_property

def _create_app(info):
    from indico.web.flask.app import make_app
    return make_app()

class IndicoFlaskGroup(FlaskGroup):

    def __init__(self, **extra):
        super().__init__(create_app=_create_app, add_default_commands=False, add_version_option=False,
                         set_debug_flag=False, **extra)
        self._indico_plugin_commands = None

    def _load_plugin_commands(self):
        assert False

    def _wrap_in_plugin_context(self, plugin, cmd):
        cmd.callback = wrap_in_plugin_context(plugin, cmd.callback)
        for subcmd in getattr(cmd, 'commands', {}).values():
            self._wrap_in_plugin_context(plugin, subcmd)

    def _get_indico_plugin_commands(self, ctx):
        if self._indico_plugin_commands is not None:
            return self._indico_plugin_commands
            from indico.core import signals
            from indico.util.signals import named_objects_from_signal
            cmds = named_objects_from_signal(signals.plugin.cli.send(), plugin_attr='_indico_plugin')
            rv = {}
            for name, cmd in cmds.items():
                if cmd._indico_plugin:
                    self._wrap_in_plugin_context(cmd._indico_plugin, cmd)
                rv[name] = cmd
        except Exception as exc:
            if 'No indico config found' not in str(exc):
                click.echo(click.style('Loading plugin commands failed:', fg='red', bold=True))
                click.echo(click.style(traceback.format_exc(), fg='red'))
            rv = {}
        self._indico_plugin_commands = rv
        return rv

    def get_command(self, ctx, name):
        rv = AppGroup.get_command(self, ctx, name)
        if rv is not None:
            return rv
        return self._get_indico_plugin_commands(ctx).get(name)

    def list_commands(self, ctx):
        rv = set(click.Group.list_commands(self, ctx))
        return sorted(rv)

class LazyGroup(click.Group):

    def __init__(self, import_name, **kwargs):
        self._import_name = import_name

    def _impl(self):
        module, name = self._import_name.split(':', 1)
        return getattr(import_module(module), name)

    def get_command(self, ctx, cmd_name):
        return self._impl.get_command(ctx, cmd_name)

## ... source file continues with no further AppGroup examples...

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