feat: Allow copa to use buildkit from dockerd

[cpuguy83]

This adds support for connection drivers for connecting to buildkit.

• unix:// addrs are for connecting directly to buildkitd as before
• docker:// will connect to docker's built-in buildkit instance
• docker-container:// takes a container name and proxies the buildkit socket using buildctl in the container (similar to buildx)
• buildx:// will read a specific buildx instance config and try to connect to that (defaults to the currently selected buildx instance) - currently only supports docker-container backed buildx instances
• An empty addr will attempt the default docker address, then try buildx, and then fallback to the default buildkit addr.

Fixes #177

[codecov]

Codecov Report

Patch coverage: 13.98% and project coverage change: -6.22% ⚠️

Comparison is base (6e08cb6) 34.72% compared to head (e307f53) 28.51%.

❗ Current head e307f53 differs from pull request most recent head 57c66e8. Consider uploading reports for the commit 57c66e8 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #233      +/-   ##
==========================================
- Coverage   34.72%   28.51%   -6.22%     
==========================================
  Files          12       16       +4     
  Lines        1146     1487     +341     
==========================================
+ Hits          398      424      +26     
- Misses        727     1037     +310     
- Partials       21       26       +5     

Files Changed	Coverage Δ
pkg/buildkit/buildkit.go	0.00% <0.00%> (ø)
pkg/patch/patch.go	7.44% <0.00%> (-0.51%)	⬇️
pkg/buildkit/connhelpers/buildx.go	7.07% <7.07%> (ø)
pkg/buildkit/connhelpers/docker.go	22.22% <22.22%> (ø)
pkg/buildkit/drivers.go	22.72% <22.72%> (ø)
pkg/patch/cmd.go	53.57% <100.00%> (ø)

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[sozercan]

@cpuguy83 should we remove the buildkit instance for some of the e2e tests or have a matrix of them (one using docker builtin and another one using standalone buildkit)?

copacetic/.github/workflows/build.yml

Line 142 in 3e22d49

docker run --detach --rm --privileged -p 0.0.0.0:$BUILDKIT_PORT:$BUILDKIT_PORT/tcp --name buildkitd --entrypoint buildkitd "moby/buildkit:v$BUILDKIT_VERSION" --addr tcp://0.0.0.0:$BUILDKIT_PORT

[cpuguy83]

I updated this with to fixes issues.
Also added a 2nd commit which adds some extra drivers (details in the commit and PR description).

[cpuguy83]

should we remove the buildkit instance for some of the e2e tests or have a matrix of them (one using docker builtin and another one using standalone buildkit)?

@sozercan Sounds good. I'll have to take a look at how e2e is setup tomorrow.

[salaxander]

No review comments this is just super cool that's all

[cpuguy83]

Pushed updates for adding a test matrix.
I do have problems getting this to work on a devcontainer locally, but that seems to be true even with just a normal buildkit tcp connection.
Mainly the issue is after copa patches everything it tries to export an image.
Unfortunately there are no messages... we'll see how this does in CI after some approves the run.

[cpuguy83]

Finally have CI working the way I'd like it to.

Moved the patch tests into go integration tests.
Tests run in parallel and the test matrix is used to setup different buildkit envs.
So we can add different envs without blowing up the test matrix for a run.

codecov is not happy.
I'm not sure I can really make it happy enough to turn it green.
Some of this code is interacting with the system so it's not really feasible to write unit tests for it.

[sozercan]

do we want to align on sh or bash?

[cpuguy83]

There's nothing bashy-in here, really the line is to make my editor load the right toolset.
Otherwise totally fine to throw either sh or bash in there.

[sozercan]

Thank you! LGTM