From 2ce69222ef271b16939166528eaa87a29d234132 Mon Sep 17 00:00:00 2001
From: Andrew Gouin <andrew@gouin.io>
Date: Mon, 16 Oct 2023 08:33:29 -0600
Subject: [PATCH] Docker image - cross compile (#372)

* Docker images for branches

* Cross compile

* export vars
---
 .github/workflows/release.yaml |  5 ++++-
 Dockerfile                     | 28 +++++++++++++++++++++-------
 local.Dockerfile               | 33 +++++++++++++++++++++++++++++++++
 3 files changed, 58 insertions(+), 8 deletions(-)
 create mode 100644 local.Dockerfile

diff --git a/.github/workflows/release.yaml b/.github/workflows/release.yaml
index 14c35645..8c97d7c6 100644
--- a/.github/workflows/release.yaml
+++ b/.github/workflows/release.yaml
@@ -4,6 +4,8 @@ on:
   push:
     tags:
       - '**'
+    branches:
+      - '**'
 
 env:
   REGISTRY: ghcr.io
@@ -42,12 +44,13 @@ jobs:
             # set latest tag for default branch
             type=raw,value=latest,enable={{is_default_branch}}
             type=ref,event=tag
+            type=ref,event=branch
 
       - name: Build and push Docker image
         uses: docker/build-push-action@v3
         with:
           context: .
-          platforms: linux/amd64
+          platforms: linux/amd64,linux/arm64
           file: Dockerfile
           push: true
           tags: ${{ steps.meta.outputs.tags }}
diff --git a/Dockerfile b/Dockerfile
index b8ca27d8..f03e29bc 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,5 +1,15 @@
-# Build the manager binary
-FROM golang:1.20 as builder
+FROM --platform=$BUILDPLATFORM golang:1.20-alpine AS builder
+
+RUN apk add --update --no-cache gcc libc-dev
+
+ARG TARGETARCH
+ARG BUILDARCH
+
+RUN if [ "${TARGETARCH}" = "arm64" ] && [ "${BUILDARCH}" != "arm64" ]; then \
+        wget -c https://musl.cc/aarch64-linux-musl-cross.tgz -O - | tar -xzvv --strip-components 1 -C /usr; \
+    elif [ "${TARGETARCH}" = "amd64" ] && [ "${BUILDARCH}" != "amd64" ]; then \
+        wget -c https://musl.cc/x86_64-linux-musl-cross.tgz -O - | tar -xzvv --strip-components 1 -C /usr; \
+    fi
 
 WORKDIR /workspace
 # Copy the Go Modules manifests
@@ -17,12 +27,16 @@ COPY internal/ internal/
 
 ARG VERSION
 
-# Build
-RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64 go build -ldflags "-X github.com/strangelove-ventures/cosmos-operator/internal/version.version=$VERSION" -a -o manager .
+RUN if [ "${TARGETARCH}" = "arm64" ] && [ "${BUILDARCH}" != "arm64" ]; then \
+        export CC=aarch64-linux-musl-gcc CXX=aarch64-linux-musl-g++;\
+    elif [ "${TARGETARCH}" = "amd64" ] && [ "${BUILDARCH}" != "amd64" ]; then \
+        export CC=x86_64-linux-musl-gcc CXX=x86_64-linux-musl-g++; \
+    fi; \
+    export GOOS=linux GOARCH=$TARGETARCH CGO_ENABLED=1 LDFLAGS='-linkmode external -extldflags "-static"'; \
+    go build -ldflags "-X github.com/strangelove-ventures/cosmos-operator/internal/version.version=$VERSION $LDFLAGS" -a -o manager .
 
-# Use distroless as minimal base image to package the manager binary
-# Refer to https://github.com/GoogleContainerTools/distroless for more details
-FROM gcr.io/distroless/static:nonroot
+# Build final image from scratch
+FROM scratch
 
 LABEL org.opencontainers.image.source=https://github.com/strangelove-ventures/cosmos-operator
 
diff --git a/local.Dockerfile b/local.Dockerfile
new file mode 100644
index 00000000..0ef37e31
--- /dev/null
+++ b/local.Dockerfile
@@ -0,0 +1,33 @@
+FROM golang:1.20-alpine AS builder
+
+RUN apk add --update --no-cache gcc libc-dev
+
+WORKDIR /workspace
+# Copy the Go Modules manifests
+COPY go.mod go.mod
+COPY go.sum go.sum
+# cache deps before building and copying source so that we don't need to re-download as much
+# and so that source changes don't invalidate our downloaded layer
+RUN go mod download
+
+# Copy the go source
+COPY *.go .
+COPY api/ api/
+COPY controllers/ controllers/
+COPY internal/ internal/
+
+ARG VERSION
+
+RUN export CGO_ENABLED=1 LDFLAGS='-linkmode external -extldflags "-static"'; \
+    go build -ldflags "-X github.com/strangelove-ventures/cosmos-operator/internal/version.version=$VERSION $LDFLAGS" -a -o manager .
+
+# Build final image from scratch
+FROM scratch
+
+LABEL org.opencontainers.image.source=https://github.com/strangelove-ventures/cosmos-operator
+
+WORKDIR /
+COPY --from=builder /workspace/manager .
+USER 65532:65532
+
+ENTRYPOINT ["/manager"]