Default to `Docker()` storage?

[cicdw]

Question: now that initializing Docker storage sets sensible defaults for base_image and prefect_version, and additionally installs kubernetes extras, should we default to an unmodified Docker() class for every Flow? I.e.,

f = Flow()
f.storage # populated with Docker() storage

I don't believe this has any consequences for users not deploying their Flows to Cloud (because flow.serialize defaults to using build=False), but does allow simple Flows with no extraneous dependencies to be deployed with ease.

This would require us to introduce one additional configuration setting for the registry_url, as we don't want to set any public defaults here, but could read a default value from a user's config or environment variable.

cc: @jlowin @joshmeek

[jlowin]

Makes sense to me.

I'm concerned that we're starting to have a creeping pattern of "we want this thing to be instantiated automatically, but we need to provide init arguments" and our config is going to become crowded (and stale). Perhaps there's a clean way to mark init arguments as being read from config values (or, more likely, env vars), similar to how we use default_from_attrs to mark run arguments as being read from attrs.

Something like:

class MyClass:
	@defaults_from_config(a="defaults.myclass.a", b="another_thing.myclass.b")
    def __init__(self, a=1, b=2):
        pass

This way, a and b have Pythonic defaults, but can use prefect.config.defaults.myclass.a and prefect.config.another_thing.myclass.b if those keys are defined.

Maybe too crazy / overengineered?

[cicdw]

Hmmmmm I'm definitely intrigued by this. So the idea here is that we don't have to populate these default values in our config.toml file because they are set in code, however they can be overwritten via user config if desired?

[joshmeek]

Yeah I'm on board with this

[cicdw]

OK so I decided I'm uncomfortable with a default registry_url for security reasons. However, I have a new idea:

• have the default storage class be configurable from config.toml
• let flow.deploy accept arbitrary **kwargs that are then passed into the initialization method of the default storage which is only attached to the flow at deploy time

This would allow for the following lightning fast deploy:

from prefect import Flow

Flow("speedy").deploy("My Project", registry_url="cicdw", image_name="speedy-flow")

cc: @joshmeek @jlowin

[cicdw]

This was closed with #1337