From 2b1d77927958884d39f8245519d77467f973f4f2 Mon Sep 17 00:00:00 2001
From: Graham McIntire <graham@mcintire.me>
Date: Tue, 13 Jan 2026 14:07:21 -0600
Subject: [PATCH] Add multi-architecture build support (amd64, arm64)

---
 .gitlab-ci.yml | 54 +++++++++++++++-----------------------------------
 Dockerfile     | 22 +++++++++++++++++---
 2 files changed, 35 insertions(+), 41 deletions(-)

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 4ae7ecc..1e56458 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -55,7 +55,7 @@ build:test:
     - main
     - tags
 
-# Build and push for main branch
+# Build and push for main branch (multi-architecture)
 build:main:
   stage: build
   image: docker:24-dind
@@ -63,14 +63,17 @@ build:main:
     - docker:24-dind
   before_script:
     - docker login -u $DOCKERHUB_USERNAME -p $DOCKERHUB_TOKEN
+    # Enable buildx for multi-arch
+    - docker buildx create --use --name multiarch-builder
+    - docker buildx inspect --bootstrap
   script:
     - |
-      docker build \
+      docker buildx build \
+        --platform linux/amd64,linux/arm64 \
         --tag $REGISTRY/$IMAGE_NAME:latest \
         --tag $REGISTRY/$IMAGE_NAME:main-$CI_COMMIT_SHORT_SHA \
+        --push \
         .
-    - docker push $REGISTRY/$IMAGE_NAME:latest
-    - docker push $REGISTRY/$IMAGE_NAME:main-$CI_COMMIT_SHORT_SHA
     - echo "IMAGE_TAG=latest" >> build.env
   artifacts:
     reports:
@@ -78,42 +81,10 @@ build:main:
   only:
     - main
 
-# Release build for tags (versioned releases)
-release:
+# Release build for tags (multi-architecture)
+release:multiarch:
   stage: release
   image: docker:24-dind
-  services:
-    - docker:24-dind
-  before_script:
-    - docker login -u $DOCKERHUB_USERNAME -p $DOCKERHUB_TOKEN
-  script:
-    - |
-      # Extract version from tag (assumes tags like v0.1.0)
-      VERSION=${CI_COMMIT_TAG#v}
-
-      docker build \
-        --tag $REGISTRY/$IMAGE_NAME:$VERSION \
-        --tag $REGISTRY/$IMAGE_NAME:$CI_COMMIT_TAG \
-        --tag $REGISTRY/$IMAGE_NAME:latest \
-        .
-
-      docker push $REGISTRY/$IMAGE_NAME:$VERSION
-      docker push $REGISTRY/$IMAGE_NAME:$CI_COMMIT_TAG
-      docker push $REGISTRY/$IMAGE_NAME:latest
-
-      echo "Released version: $VERSION"
-      echo "IMAGE_TAG=$VERSION" >> release.env
-  artifacts:
-    reports:
-      dotenv: release.env
-  only:
-    - tags
-  except:
-    - branches
-
-build:multiarch:
-  stage: build
-  image: docker:24-dind
   services:
     - docker:24-dind
   before_script:
@@ -128,8 +99,15 @@ build:multiarch:
       docker buildx build \
         --platform linux/amd64,linux/arm64 \
         --tag $REGISTRY/$IMAGE_NAME:$VERSION \
+        --tag $REGISTRY/$IMAGE_NAME:$CI_COMMIT_TAG \
         --tag $REGISTRY/$IMAGE_NAME:latest \
         --push \
         .
+
+      echo "Released version: $VERSION"
+      echo "IMAGE_TAG=$VERSION" >> release.env
+  artifacts:
+    reports:
+      dotenv: release.env
   only:
     - tags
diff --git a/Dockerfile b/Dockerfile
index df02c71..dd8cd4f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,11 +1,23 @@
 # Build stage
 FROM rust:1.83-alpine AS builder
 
+# Build arguments provided by Docker buildx
+ARG TARGETPLATFORM
+
 WORKDIR /app
 
 # Install build dependencies
 RUN apk add --no-cache musl-dev protobuf-dev
 
+# Determine Rust target based on platform and add it
+RUN case "$TARGETPLATFORM" in \
+    "linux/amd64") RUST_TARGET="x86_64-unknown-linux-musl" ;; \
+    "linux/arm64") RUST_TARGET="aarch64-unknown-linux-musl" ;; \
+    *) echo "Unsupported platform: $TARGETPLATFORM" && exit 1 ;; \
+    esac && \
+    echo "$RUST_TARGET" > /tmp/rust-target && \
+    rustup target add "$RUST_TARGET"
+
 # Copy manifests and build files
 COPY Cargo.toml Cargo.lock build.rs ./
 COPY proto ./proto
@@ -14,7 +26,8 @@ COPY proto ./proto
 RUN mkdir src && echo "fn main() {}" > src/main.rs
 
 # Build dependencies (cached layer)
-RUN cargo build --release --target x86_64-unknown-linux-musl
+RUN RUST_TARGET=$(cat /tmp/rust-target) && \
+    cargo build --release --target "$RUST_TARGET"
 
 # Remove dummy src
 RUN rm -rf src
@@ -23,7 +36,10 @@ RUN rm -rf src
 COPY src ./src
 
 # Build the actual application
-RUN touch src/main.rs && cargo build --release --target x86_64-unknown-linux-musl
+RUN RUST_TARGET=$(cat /tmp/rust-target) && \
+    touch src/main.rs && \
+    cargo build --release --target "$RUST_TARGET" && \
+    cp "target/$RUST_TARGET/release/towerops-agent" /tmp/towerops-agent
 
 # Runtime stage
 FROM alpine:3.19
@@ -35,7 +51,7 @@ RUN apk add --no-cache ca-certificates
 RUN mkdir -p /data
 
 # Copy binary from builder
-COPY --from=builder /app/target/x86_64-unknown-linux-musl/release/towerops-agent /usr/local/bin/
+COPY --from=builder /tmp/towerops-agent /usr/local/bin/towerops-agent
 
 # Volume for database
 VOLUME ["/data"]