Multiarch images (#324)

taken from #214

Configured to only build multiarch when also publishing (when running in `main` or for a release)

## Build time

- amd64 & arm64: 07:42
- amd64 only: 04:26

Build time via kaniko building only amd64: ~ 6/7 min

Reviewed-on: https://codeberg.org/Codeberg/pages-server/pulls/324
Reviewed-by: crapStone <codeberg@crapstone.dev>
Co-authored-by: pat-s <patrick.schratz@gmail.com>
Co-committed-by: pat-s <patrick.schratz@gmail.com>

.woodpecker/build.yml

@@ -29,10 +29,11 @@ steps:
 
   docker-dryrun:
     depends_on: vendor
-    image: plugins/kaniko:1.8.8
+    image: woodpeckerci/plugin-docker-buildx:3.2.1
     settings:
       dockerfile: Dockerfile
-      no_push: true
+      platforms: linux/amd64
+      dry-run: true
       tags: latest
     when:
       - event: [push, pull_request]
@@ -98,10 +99,11 @@ steps:
 
   docker-next:
     depends_on: vendor
-    image: plugins/kaniko:1.8.8
+    image: woodpeckerci/plugin-docker-buildx:3.2.1
     settings:
       registry: codeberg.org
       dockerfile: Dockerfile
+      platforms: linux/amd64,arm64
       repo: codeberg.org/codeberg/pages-server
       tags: next
       username:
@@ -114,10 +116,11 @@ steps:
 
   docker-tag:
     depends_on: vendor
-    image: plugins/kaniko:1.8.8
+    image: woodpeckerci/plugin-docker-buildx:3.2.1
     settings:
       registry: codeberg.org
       dockerfile: Dockerfile
+      platforms: linux/amd64,arm64
       repo: codeberg.org/codeberg/pages-server
       tags: [latest, '${CI_COMMIT_TAG}']
       username:

Dockerfile

@@ -1,14 +1,35 @@
-FROM techknowlogick/xgo as build
+# Set the default Go version as a build argument
+ARG XGO="go-1.21.x"
 
-WORKDIR /workspace
+# Use xgo (a Go cross-compiler tool) as build image
+FROM --platform=$BUILDPLATFORM techknowlogick/xgo:${XGO} as build
 
-COPY . .
+# Set the working directory and copy the source code
-RUN CGO_ENABLED=1 go build -tags 'sqlite sqlite_unlock_notify netgo' -ldflags '-s -w -extldflags "-static" -linkmode external' .
+WORKDIR /go/src/codeberg.org/codeberg/pages
+COPY . /go/src/codeberg.org/codeberg/pages
 
+# Set the target architecture (can be set using --build-arg), buildx set it automatically
+ARG TARGETOS TARGETARCH
+
+# Build the binary using xgo
+RUN --mount=type=cache,target=/root/.cache/go-build \
+    --mount=type=cache,target=/go/pkg \
+    GOOS=${TARGETOS} GOARCH=${TARGETARCH} CGO_ENABLED=1 \
+    xgo -x -v --targets=${TARGETOS}/${TARGETARCH} -tags='sqlite sqlite_unlock_notify netgo' -ldflags='-s -w -extldflags "-static" -linkmode external' -out pages .
+
+# Use a scratch image as the base image for the final container,
+# which will contain only the built binary and the CA certificates
 FROM scratch
-COPY --from=build /workspace/pages /pages
+
+# Copy the built binary and the CA certificates from the build container to the final container
+COPY --from=build /go/src/codeberg.org/codeberg/pages/ /pages
 COPY --from=build \
     /etc/ssl/certs/ca-certificates.crt \
     /etc/ssl/certs/ca-certificates.crt
 
+# Expose ports 80 and 443 for the built binary to listen on
+EXPOSE 80/tcp
+EXPOSE 443/tcp
+
+# Set the entrypoint for the container to the built binary
 ENTRYPOINT ["/pages"]