A more customisable CLI and REPL

Is there an existing issue for this?

• I have searched the existing issues

Is your feature request related to a problem? Please describe.

No response

Describe the solution you'd like

Sanic CLI currently has options for different run configurations.
Requested:

• Ability to add custom commands for application related workflows. With application context available to the command.

Usage can be similar to how inspector commands are created currently.

Sanic REPL currently provides 4 objects by default In the repl context.
Requested:

• Ability to add/inject additional objects to the repl context.
• Ability to prepare REPL context. (e.g. pre importing modules, models)

Thanks

Additional context

No response

REPL was one of the best feature added for developer experience imo. Being able to have some models/classes pre-imported or adding custom utility objects would be great. I'd love to contribute too.

[ahopkins]

The CLI bit I was planning for a long time. The how of it was always the concern, but I figured that out. Stay tuned.

I like the REPL injection idea also.

[ahopkins]

See #3019

If the REPL idea is something you'd like to work on @goodki-d, LMK.

Yes! I'd love to work on it. I have some approaches in mind

[ahopkins]

Excellent. What was your thought? It's going to be a bit of a challenge as you are diving deep into the process manager internals. Maybe ping me on the Discord server and we can brainstorm?

Sure, lets connect on discord!

I was not sure about the process manager here. I assumed REPL was running on the main process.

sanic/sanic/cli/app.py

Lines 183 to 186 in a575f5c

	@app.main_process_ready
	async def start_repl(app):
	SanicREPL(app, self.args.repl).run()
	await app._startup()

---

I was thinking If we could merge the user supplied variables with the currently available locals

- super().__init__(locals=locals_available)
+ super().__init__(locals={**locals_available, **user_locals})

and generating the variable description to show dynamically.

For the user API, I was thinking of something like

from sanic import Sanic
app = Sanic(...)

# variable == module/class/object/callable
app.repl.add_local(variable, "<name>", "desc")

[ahopkins]

Merged in #3042