Multi Platform Build pushes platforms linux/amd64 and linux/arm64 but both binaries are amd64

[zioproto]

Behaviour

I am running a GitHub action exactly like the example provided:

My code:
https://github.com/zioproto/tfmod-scaffold/blob/debug/.github/workflows/debug.yaml

The example:
https://github.com/docker/build-push-action/blob/master/docs/advanced/multi-platform.md

I am testing the produced image on a Mac M1pro with Docker Desktop

Steps to reproduce this issue

I stripped down my Dockerfile to the bare minimum.

https://github.com/zioproto/tfmod-scaffold/blob/debug/Dockerfile

When I test the container like this:

% docker run --platform=linux/arm64 --rm zioproto/debug:latest go version
Unable to find image 'zioproto/debug:latest' locally
latest: Pulling from zioproto/debug
d836772a1c1f: Already exists
66a9e63c657a: Already exists
d1989b6e74cf: Already exists
c28818711e1e: Already exists
98c059399382: Already exists
664eea083347: Already exists
b4cc10248836: Already exists
Digest: sha256:176743a658639afd7d62b6e4551e99bf0e67cf98add713867c9d77d5b19c03d8
Status: Downloaded newer image for zioproto/debug:latest
go version go1.19 linux/amd64

I always get golang for amd64 go version go1.19 linux/amd64

The base image I am using has proper support for arm64

% docker run --rm mcr.microsoft.com/oss/go/microsoft/golang:1.19 go version
go version go1.19 linux/arm64
% docker run --rm  --platform=linux/arm64 mcr.microsoft.com/oss/go/microsoft/golang:1.19 go version
go version go1.19 linux/arm64
% docker run --rm  --platform=linux/amd64 mcr.microsoft.com/oss/go/microsoft/golang:1.19 go version
Unable to find image 'mcr.microsoft.com/oss/go/microsoft/golang:1.19' locally
1.19: Pulling from oss/go/microsoft/golang
d836772a1c1f: Already exists
66a9e63c657a: Already exists
d1989b6e74cf: Already exists
c28818711e1e: Already exists
98c059399382: Already exists
664eea083347: Already exists
b4cc10248836: Already exists
Digest: sha256:df429a4c9d180b0feedfe2b71be356cd6aa2ef96b35e810e76d74d31577fec3d
Status: Downloaded newer image for mcr.microsoft.com/oss/go/microsoft/golang:1.19
go version go1.19 linux/amd64
% docker run --rm  --platform=linux/amd64 zioproto/debug go version
Unable to find image 'zioproto/debug:latest' locally
latest: Pulling from zioproto/debug
d836772a1c1f: Already exists
66a9e63c657a: Already exists
d1989b6e74cf: Already exists
c28818711e1e: Already exists
98c059399382: Already exists
664eea083347: Already exists
b4cc10248836: Already exists
Digest: sha256:176743a658639afd7d62b6e4551e99bf0e67cf98add713867c9d77d5b19c03d8
Status: Downloaded newer image for zioproto/debug:latest
go version go1.19 linux/amd64
% docker run --rm  --platform=linux/arm64 zioproto/debug go version
Unable to find image 'zioproto/debug:latest' locally
latest: Pulling from zioproto/debug
Digest: sha256:176743a658639afd7d62b6e4551e99bf0e67cf98add713867c9d77d5b19c03d8
Status: Downloaded newer image for zioproto/debug:latest
go version go1.19 linux/amd64

Expected behaviour

I expected the arm64 image to have a arm64 binary

Configuration

• Repository URL (if public): https://github.com/zioproto/tfmod-scaffold/blob/debug/.github/workflows/debug.yaml
• Build URL (if public): https://github.com/zioproto/tfmod-scaffold/actions/runs/2846124880

[zioproto]

Cc: @lonegunmanb

[crazy-max]

Looking at your Dockerfile:

ARG GOLANG_IMAGE_TAG=1.19
FROM --platform=${BUILDPLATFORM} mcr.microsoft.com/oss/go/microsoft/golang:${GOLANG_IMAGE_TAG} as build

FROM --platform=${BUILDPLATFORM} mcr.microsoft.com/oss/go/microsoft/golang:${GOLANG_IMAGE_TAG} as runner

If you use $BUILDPLATFORM arg in global scope it will pull the image for the platform matching the host (on GHA runner ubuntu-latest it's linux/amd64) so it's expected.

So just remove --platform=${BUILDPLATFORM} and it will pull the target platform (defined in platforms input). Fyi by default it's --platform=${TARGETPLATFORM}.

Closing this issue since that should answer your question, but feel free to re-open if it doesn't. Thanks.

[zioproto]

I confirm that removing --platform=${BUILDPLATFORM} in the Dockerfile fixed the issue.

Thank you !