Multiarch Go Builds + Google Cloud Build

cloudbuild.yaml

steps:
- name: 'gcr.io/cloud-builders/docker'
  id: 'amd64'
  args:
  - 'build'
  - '--build-arg=CGO_ENABLED=0'
  - '--build-arg=GOARCH=amd64'
  - '--tag=gcr.io/$PROJECT_ID/village:amd64'
  - '.'
  waitFor: ['-']

- name: 'gcr.io/cloud-builders/docker'
  id: 'push-amd64'
  args:
  - 'push'
  - 'gcr.io/$PROJECT_ID/village:amd64'
  waitFor: ['amd64']

- name: 'gcr.io/cloud-builders/docker'
  id: 'arm'
  args:
  - 'build'
  - '--build-arg=GOARCH=arm'
  - '--build-arg=GOARM=6'
  - '--tag=gcr.io/$PROJECT_ID/village:arm32v6'
  - '.'
  waitFor: ['-']

- name: 'gcr.io/cloud-builders/docker'
  id: 'push-arm'
  args:
  - 'push'
  - 'gcr.io/$PROJECT_ID/village:arm32v6'
  waitFor: ['arm']

- name: 'gcr.io/cloud-builders/docker'
  id: 'manifest'
  env:
  - 'DOCKER_CLI_EXPERIMENTAL=enabled'
  args:
  - 'manifest'
  - 'create'
  - 'gcr.io/$PROJECT_ID/village:$COMMIT_SHA'
  - 'gcr.io/$PROJECT_ID/village:arm32v6'
  - 'gcr.io/$PROJECT_ID/village:amd64' 
  waitFor: ['push-amd64', 'push-arm']

- name: 'gcr.io/cloud-builders/docker'
  id: 'annotate-manifest'
  env:
  - 'DOCKER_CLI_EXPERIMENTAL=enabled'
  args:
  - 'manifest'
  - 'annotate'
  - 'gcr.io/$PROJECT_ID/village:$COMMIT_SHA'
  - 'gcr.io/$PROJECT_ID/village:arm32v6'
  - '--os=linux'
  - '--arch=arm'
  waitFor: ['manifest']

- name: 'gcr.io/cloud-builders/docker'
  id: 'push-manifest'
  env:
  - 'DOCKER_CLI_EXPERIMENTAL=enabled'
  args:
  - 'manifest'
  - 'push'
  - 'gcr.io/$PROJECT_ID/village:$COMMIT_SHA'
  waitFor: ['annotate-manifest']

images:
  - 'gcr.io/$PROJECT_ID/village:amd64'
  - 'gcr.io/$PROJECT_ID/village:arm32v6'

Dockerfile

FROM golang:alpine as builder

RUN apk update && apk add git && apk add tzdata

COPY . $GOPATH/src/github.com/bamnet/village
WORKDIR $GOPATH/src/github.com/bamnet/village

ARG CGO_ENABLED=0
ARG GOARCH=amd64
ARG GOARM=6
RUN env CGO_ENABLED=${CGO_ENABLED} GOARCH=${GOARCH} GOARM=${GOARM} go build -o /go/bin/show

FROM scratch
COPY --from=builder /usr/local/go/lib/time/zoneinfo.zip /usr/local/go/lib/time/
COPY --from=builder /go/bin/show /go/bin/show
ENTRYPOINT ["/go/bin/show"]
CMD []