Allow --build-command to be passed for docker builds

[milesj]

What is the problem this feature would solve? Please describe.

We're trying to improve the performance of our Docker based builds for DOAP, and was looking into Depot (https://depot.dev), which is a drop-in replacement for Docker. So docker build -> depot build.

Unfortunately the doctl app dev build command doesn't support a custom build command for docker builds.

✘ build command overrides are ignored for dockerfile-based builds

Describe the solution you'd like

It would be nice if we could substitute docker for depot. Whether it's something like --build-command 'depot build' or a completely unique option like --use-depot.

Additional context

[kamaln7]

Hey @milesj. Thanks for the suggestion! Depot looks very interesting.

Currently Docker builds are tightly coupled with the docker engine API and are hardwired to use the docket socket. Compatible engines like podman are supported because of that. I took a quick look at Depot's documentation and it seems to be a drop-in CLI replacement but not an engine replacement i.e. it doesn't expose a compatible socket.

If that is correct, it would require some work to add support for it. I'll let the doctl project maintainers confirm if they'd accept a PR that adds support for depot

[bentranter]

Hey @milesj, just to follow up on what @kamaln7 said, while we don't have the bandwidth right now to add support, we'd definitely accept a contribution to add support for Depot!