FKAS go.mod is importing an actual CAPM3 release

[mquhuy]

What steps did you take and what happened:
https://github.com/metal3-io/cluster-api-provider-metal3/blob/main/hack/fake-apiserver/go.mod#L7

What did you expect to happen:
Should have used v0.0.0, and added a replace line to refer to ./../../api

Anything else you would like to add:
This happens because our image build workflow uses the absolute context, hence we cannot build with anything outside of the hack/fake-apiserver directory.

This could be solved by mounting the api/ to the build container, but that requires enabling buildkit. We might want to do that anyway, as docker build will go away soon.

/kind bug

[tuminoid]

/triage accepted

[tuminoid]

Just providing further context on this.

This directive in the action mounts just the specified directory in the container via the reusable action, so ../../.. does not point to /api as it does not exist in build context.

Building the PR #2379 would result in (simulated with "gh act" and relaxed workflow files):

| Building Docker image quay.io/metal3-io/metal3-fkas with tags kashif_fix-fakeapi-gomod,kashif_fix-fakeapi-gomod_2025-03-06_7f1a1622c979e7f757a1276f6cf54c1dd9af663b...
| BuildCommand docker build -f hack/fake-apiserver/Dockerfile -t quay.io/metal3-io/metal3-fkas:kashif_fix-fakeapi-gomod -t quay.io/metal3-io/metal3-fkas:kashif_fix-fakeapi-gomod_2025-03-06_7f1a1622c979e7f757a1276f6cf54c1dd9af663b hack/fake-apiserver
[+] Building 1.9s (10/16)                                        docker:default
|  => [internal] load build definition from Dockerfile                       0.1s
|  => => transferring dockerfile: 2.15kB                                     0.0s
|  => [internal] load metadata for gcr.io/distroless/static:nonroot@sha256:  0.5s
|  => [internal] load metadata for docker.io/library/golang:1.23.7@sha256:1  0.0s
|  => [internal] load .dockerignore                                          0.1s
|  => => transferring context: 2B                                            0.0s
|  => [base 1/4] FROM docker.io/library/golang:1.23.7@sha256:1acb493b9f9dfd  0.0s
|  => [stage-3 1/4] FROM gcr.io/distroless/static:nonroot@sha256:9ecc53c269  0.0s
|  => [internal] load build context                                          0.1s
|  => => transferring context: 66.01kB                                       0.0s
|  => CACHED [base 2/4] WORKDIR /workspace                                   0.0s
|  => [base 3/4] COPY go.mod go.sum ./                                       0.1s
|  => ERROR [base 4/4] RUN go mod download                                   1.0s
| ------
|  > [base 4/4] RUN go mod download:
| 0.908 go: github.com/metal3-io/cluster-api-provider-metal3/[email protected] (replaced by ./../../api): reading /api/go.mod: open /api/go.mod: no such file or directory
| ------
| Dockerfile:32
| --------------------
|   30 |     # Cache deps before building and copying source so that we don't need to re-download as much
|   31 |     # and so that source changes don't invalidate our downloaded layer
|   32 | >>> RUN go mod download
|   33 |     
|   34 |     # Build Fkas
| --------------------
| ERROR: failed to solve: process "/bin/sh -c go mod download" did not complete successfully: exit code: 1

[tuminoid]

Local docker build breaks exactly the same, no need to even use the container build workflow. Build context matters.