On an Apple Silicon dev box, every `POST /workspaces` failed immediately
with:
no matching manifest for linux/arm64/v8 in the manifest list entries:
no match for platform in manifest: not found
because the GHCR workspace-template-* images ship only a linux/amd64
manifest today. `ImagePull` and `ContainerCreate` asked for the daemon's
native arch and missed. The Canvas surfaced this as
docker image "ghcr.io/molecule-ai/workspace-template-autogen:latest"
not found after pull attempt — verify GHCR visibility for autogen
— confusing because the image IS visible, just not for linux/arm64.
### Fix
Add an auto-detect helper `defaultImagePlatform()` in
`internal/provisioner/provisioner.go` that returns `"linux/amd64"` on
Apple Silicon hosts and `""` (no preference) everywhere else, with an
env override `MOLECULE_IMAGE_PLATFORM` for operators who want to pin
or disable explicitly. The result is passed to both `ImagePull`
(`PullOptions.Platform`) and `ContainerCreate` (4th arg
`*ocispec.Platform`) so the pulled amd64 manifest matches the
create-time platform spec. Docker Desktop transparently runs it
under QEMU emulation on M-series Macs — slow (2–5× native) but
functional.
SaaS production (linux/amd64 EC2, `MOLECULE_ENV=production`) never
hits the `runtime.GOARCH == "arm64"` branch, so the current behaviour
on real tenants is byte-for-byte unchanged. Opt-in escape hatch for
operators who want it off:
export MOLECULE_IMAGE_PLATFORM="" # disable auto-force
export MOLECULE_IMAGE_PLATFORM=linux/arm64 # pin alternate
`ocispec` is `github.com/opencontainers/image-spec/specs-go/v1` —
already in go.sum v1.1.1 as a transitive dependency of
`github.com/docker/docker`, not a new import.
### Tests
`internal/provisioner/platform_test.go` exercises every branch:
- `TestDefaultImagePlatform_EnvOverride_ExplicitValue` — env wins
- `TestDefaultImagePlatform_EnvOverride_EmptyValue` — empty string
disables the auto-force (operator escape hatch)
- `TestDefaultImagePlatform_AutoDetect` — linux/amd64 on arm64 Mac,
"" on every other host
- `TestParseOCIPlatform` — 7 table-driven cases covering well-formed
platforms, malformed inputs, and nil handling
### End-to-end verification
Before this commit, `POST /workspaces` on my Apple Silicon box:
workspace status transitioned: provisioning → failed (~1s)
log: image pull for ... failed: no matching manifest for linux/arm64/v8
After this commit, fresh DB + fresh platform:
workspace status transitioned: provisioning → online (~25s)
log: attempting pull (platform=linux/amd64)
pulled ghcr.io/molecule-ai/workspace-template-langgraph:latest
docker ps: ws-7aa08951-00d Up 27 seconds
The existing provisioner race-tested test suite (`go test -race
./internal/provisioner/`) still passes — the platform pointer defaults
to nil on linux/amd64 hosts, so the CI-resolved test expectations
don't change.
Closes#1875 (arm64 image blocker).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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