State Points¶

State points are application-level lifecycle hooks that let a plugin run logic after the plugin has been accepted as a normal extension plugin.

Unlike extension points such as tep, hep or vep, a state point is not used to register new plugin capabilities. Instead, it is used to execute application-level initialization once the Flask application is ready.

What is a state point?¶

A state point is a special function that the framework detects by name. Currently, the supported state point is on_app_ready(app).

It is called after the plugin manager has scanned, loaded and registered the plugin into the Flask application. The hook receives the current Flask app instance as its only parameter.

How to define it¶

A plugin can define a state point together with register():

from flask import Blueprint

bp = Blueprint("demo", __name__)

def register():
    return {"bep": {"blueprint": bp, "prefix": "/demo"}}

def on_app_ready(app):
    with app.app_context():
        app.config.setdefault("DEMO_PLUGIN_ENABLED", True)
        app.extensions["demo_plugin"] = {"ready": True}

How it works¶

The framework will call on_app_ready(app) only for plugins that provide a regular register() entry point. A plugin that defines only on_app_ready without register() is treated as an invalid extension and will be rejected during loading.

Typical use cases¶

Use a state point when you need to:

initialize shared services or clients
inject configuration into the application
register application-wide globals or template helpers
attach objects to app.extensions for later reuse

Example¶

def on_app_ready(app):
    with app.app_context():
        app.config.setdefault("PLUGIN_TITLE", "Demo")
        app.extensions["plugin"] = {
            "title": app.config["PLUGIN_TITLE"],
            "ready": True,
        }
        app.jinja_env.globals["plugin_title"] = app.config["PLUGIN_TITLE"]