feat(multiplatform): Improve multiplatform support (#5)

Dockerfile

@@ -1,7 +1,7 @@
 # syntax=docker/dockerfile:1
 
-# Build stage
-FROM golang:1.21 AS build
+# Build stage: use native architecture and Go's cross-compilation
+FROM --platform=$BUILDPLATFORM golang:1.21 AS build
 
 # Set by docker automatically
 ARG TARGETOS TARGETARCH
@@ -11,23 +11,21 @@ ARG GOARCH=$TARGETARCH
 # Set destination for COPY
 WORKDIR /app
 
-# Download Go modules
+# For better layer caching, copy and install dependencies first then build app
 COPY go.mod go.sum ./
 RUN go mod download
 
-# Copy the source code. Note the slash at the end, as explained in
+# Note the slash at the end, as explained in
 # https://docs.docker.com/engine/reference/builder/#copy
 COPY . ./
-
-# Build
-RUN CGO_ENABLED=0 go build -o ./bin/testbed ./src
+RUN make build
 
 # Final stage
 FROM alpine:3.18
 
 WORKDIR /bin
 
-COPY --from=build /app/bin/testbed .
+COPY --from=build /app/bin/testbed ./
 
 # Run
-CMD ["/bin/testbed", "--debug"]
+ENTRYPOINT [ "/bin/testbed" ]

Makefile

@@ -1,13 +1,13 @@
 GO_DIR = ./src
 BIN_DIR = ./bin
+TMP_DIR = ./tmp
 
 .PHONE: all
-all: clean test build
+all: clean format test build
 
 .PHONY: clean
 clean:
-	rm -rf $(BIN_DIR)
-	rm -f *.out
+	rm -rf $(BIN_DIR) $(TMP_DIR)
 	go mod tidy
 
 .PHONY: format
@@ -21,11 +21,11 @@ test:
 
 .PHONY: build
 build:
-	go build -o $(BIN_DIR)/testbed $(GO_DIR)
+	CGO_ENABLED=0 go build -o $(BIN_DIR)/testbed $(GO_DIR)
 
 .PHONY: coverprofile
 coverprofile:
-	go test -coverprofile=coverage.out ./...
-	go tool cover -html=coverage.out
-	go tool cover -func=coverage.out
-	rm -f coverage.out
+	mkdir $(TMP_DIR) || true
+	go test -coverprofile=$(TMP_DIR)/coverage.out ./...
+	go tool cover -html=$(TMP_DIR)/coverage.out
+	go tool cover -func=$(TMP_DIR)/coverage.out

src/main.go

@@ -25,7 +25,7 @@ func parseFlags() *flagSet {
 	return &fs
 }
 
-// SetupLog shows a basic example on how to setup 
+// SetupLog shows a basic example on how to setup
 // package zap to do structured, leveled logging in Go.
 func setupLog(debug bool) (logger *zap.Logger) {
 	if debug {