Publish arm image too (#21)

base image (https://hub.docker.com/_/docker/tags?page=1&name=20.10-dind) do support amd64 and arm64

so we can do too

Reviewed-on: https://codeberg.org/woodpecker-plugins/plugin-docker-buildx/pulls/21

.gitignore

@@ -1,5 +1,6 @@
 /release/
-/drone-docker-buildx*
+
+docker-buildx
 
 coverage.out
 CHANGELOG.md

.woodpecker/main.yml

@@ -1,20 +1,26 @@
+branches: main
+
+variables:
+    - &platforms 'linux/amd64,linux/arm64'
+
 pipeline:
   dryrun:
-    image: plugins/kaniko
+    image: woodpeckerci/plugin-docker-buildx:v20.10.18
     settings:
+      platforms: *platforms
       repo: woodpeckerci/plugin-docker-buildx
-      tags: latest
-      dockerfile: Dockerfile
-      no_push: true
+      dockerfile: Dockerfile.multiarch
+      dry_run: true
     when:
       event: pull_request
 
   publish:
-    image: plugins/kaniko
+    image: woodpeckerci/plugin-docker-buildx:v20.10.18
     settings:
+      platforms: *platforms
       repo: woodpeckerci/plugin-docker-buildx
       tags: latest, ${CI_COMMIT_TAG}
-      dockerfile: Dockerfile
+      dockerfile: Dockerfile.multiarch
       username:
         from_secret: docker_username
       password:

Dockerfile.multiarch

@@ -1,9 +1,12 @@
-FROM golang:1.18-alpine as build
+FROM --platform=$BUILDPLATFORM golang:1.18 as build
 
 COPY . /src
 WORKDIR /src
 
-RUN CGO_ENABLED=0 go build -v -a -tags netgo -o docker-buildx ./cmd/docker-buildx
+ARG TARGETOS TARGETARCH
+RUN --mount=type=cache,target=/root/.cache/go-build \
+    --mount=type=cache,target=/go/pkg \
+    make build
 
 FROM docker:20.10-dind
 

Makefile

@@ -0,0 +1,6 @@
+TARGETOS ?= linux
+TARGETARCH ?= amd64
+LDFLAGS := -s -w -extldflags "-static"
+
+build:
+	CGO_ENABLED=0 GOOS=${TARGETOS} GOARCH=${TARGETARCH} go build -ldflags '${LDFLAGS}' -v -a -tags netgo -o docker-buildx ./cmd/docker-buildx