Fix CLI command to enable starting the proxy from within Docker

[whummer]

Update environment check to use SDK Docker client and enable starting the proxy from within Docker.

The main use case is the ability to run the proxy container from within the LocalStack main container as part of an init script. /cc @RobertLucian

[RobertLucian]

LGTM!

That being said, while we're at it, do you mind also adding rolo as a dependency to the localstack-extension-aws-replicator package, and locking its version to <=0.6? If not, I'll have a separate PR created after this.

[whummer]

That being said, while we're at it, do you mind also adding rolo as a dependency to the localstack-extension-aws-replicator package, and locking its version to <=0.6? If not, I'll have a separate PR created after this.

@RobertLucian not sure this is required at this point. Things are a bit in flux right now, admittedly (couple of package renamings and refactorings recently), but with the upcoming LocalStack 3.6.0 release this week things should stabilize again. I would suggest to better be forward-compatible and ask customers to upgrade to the latest version, which should make the rolo version pin unnecessary. Thoughts?

[alexrashed]

Just chiming in here concerning the rolo pin:
We definitely need to find ways to define compatibilities between LS versions and extensions, but extensions are installed into a vent which is then directly linked to the LocalStack venv. This means that LocalStack and it's transitive dependencies (like rolo) are "provided" and should not be set as install dependencies for extensions.
Setting a limit on rolo could therefore break the extension for certain versions of LocalStack.

[whummer]

Thanks @alexrashed for the additional insights here! Agreed that LS runtime dependencies should not be included or pinned by extensions, makes total sense. 👍 (That's why we have rolo only as a test dependency in this extension - although some of the dependencies may actually be cleaned up in setup.cfg, we have a long-standing TODO in there which I was hoping to tackle some time soon). For now, we'll just get it merged and released as-is - @RobertLucian we can then work with the customer to upgrade to the latest release version. 👍

[RobertLucian]

@alexrashed @whummer got it. The only problem I've noticed is that installing the latest rolo version that got released 2 days ago (0.7.0) breaks the AWS replicator extension with the Error: cannot import name 'Dispatcher' from 'rolo.router' (/usr/local/lib/python3.10/site-packages/rolo/router.py) error. Downgrading that to 0.6.1 fixes it.

What's the best way to ensure that the AWS Replicator extension works as expected and is straightforward to install and run?