Always pass --load flag to docker buildx build command

[mattt]

Related to #1620

Some customers have observed the replicate/setup-cog action failing to push new versions of images to Replicate.

In logs for such failing GitHub Actions runs, the following is printed:

No output specified with docker-container driver. Build result will only remain in the build cache. To push result image into registry use --push or to load image into docker use --load

We currently do pass --load, but only when building on macOS:

cog/pkg/docker/build.go

Line 25 in 03216b6

args = append(args, "--platform", "linux/amd64", "--load")

I believe this code was leftover from when cog build didn't always imply docker buildx build, and BuildKit was used only when building linux/amd64 on linux/arm64/v8.

From https://docs.docker.com/reference/cli/docker/buildx/create/#docker-driver:

docker driver - Uses the builder that is built into the Docker daemon. With this driver, the --load flag is implied by default on buildx build. However, building multi-platform images or exporting cache is not currently supported.

docker-container driver - Uses a BuildKit container that will be spawned via Docker. With this driver, both building multi-platform images and exporting cache are supported.

This PR adds the --load flag to the docker buildx build command invocation for all code paths. Since that's the implied default for the docker driver, this change shouldn't affect anyone getting the correct behavior.

[jlalmes]

RE. #1620 - I am running cog build & cog push on a GitHub action (ubuntu-latest-8-cores), so don't believe this PR solves the issue 🤔

[mattt]

@jlalmes Correct. These changes haven't been released yet, so this won't work until they are. Working to get those out tomorrow.

[joe-aivatarz]

I updated cog to v0.9.6 and still getting this error on ubuntu-22.04 using replicate/setup-cog github action:
WARNING: No output specified with docker-container driver. Build result will only remain in the build cache. To push result image into registry use --push or to load image into docker use --load
Validating model schema...
Unable to find image 'r8.im/joe-aivatarz/comfyui-runner:latest' locally
docker: Error response from daemon: manifest for r8.im/joe-aivatarz/comfyui-runner:latest not found: manifest unknown: Failed to fetch "latest".

[zeke]

@joe-aivatarz this PR has not been included in a Cog release yet, but we're working on it.