Piccolo ORM outside of multi-app structure.

[gnat]

It's a bit of a hangup to use Piccolo in a multi-app layout, many ASGI servers support having a single app.py file you can just point to and serve instantly (Sanic Server, Uvicorn, etc).

It would be really great if Piccolo had better support to load config from any variable you choose, and more flexibility about where it can find config (not just loaded from modules)- so you can do migrations as a single app.

A bit of a hack, but I have it working like this:

• /project
  • app.py
  • /tables
    • tables.py
    • /migrations

import os
from piccolo.conf.apps import AppRegistry
from piccolo.engine.postgres import PostgresEngine
from piccolo.conf.apps import AppConfig, table_finder

class AppRegistryLocal(AppRegistry):
    def __init__(self, local):
        app_config = local
        self.apps = [app_config.app_name]
        self.app_configs = {}
        app_names = []
        self.app_configs[app_config.app_name] = app_config
        app_names.append(app_config.app_name)
        self._validate_app_names(app_names)

CURRENT_DIRECTORY = os.path.dirname(os.path.abspath(__file__))

APP_CONFIG = AppConfig(
    app_name="app",
    migrations_folder_path=os.path.join(
        CURRENT_DIRECTORY, "tables", "migrations"
    ),
    table_classes=table_finder(modules=["tables.tables"]),
    migration_dependencies=[],
    commands=[],
)

DB = PostgresEngine(config={
    "database": "piccolo",
    "user": "root",
    "password": "",
    "host": "localhost",
    "port": 26257,
})

APP_REGISTRY = AppRegistryLocal(local=APP_CONFIG)

Using this layout, piccolo can be run like so:

• export PICCOLO_CONF=app; piccolo migrations new app --auto
• export PICCOLO_CONF=app; piccolo migrations forwards app

[gnat]

Thoughts? More intuitive patterns?

This would be especially convenient for teams wanting to migrate an existing app to Piccolo without restructuring- fewer barriers to adoption.

Would be great to at least see AppRegistry be able to take configuration from any variable before 1.0.

[gnat]

Note, when you run your web server you also have to use export PICCOLO_CONF=app; so Finder will work... rough edge that may need some smoothing out for this to work well.

[dantownsend]

The easiest hack would be to put all of your code in piccolo_conf.py.

What makes things awkward at the moment is if you wanted to rename piccolo_conf.py to app.py then you have to use the PICCOLO_CONF=app environment variable to tell Piccolo where to look.

There could be another way besides environment variables - a .piccolo file or something.