fix: Handle WebP encoding without CGO dependency

docker/dockerfile-api

@@ -29,6 +29,7 @@ ARG STORAGE_DIR=storage
 ARG LOGS_DIR=logs
 ARG MEDIA_DIR=media
 ARG FIXTURES_DIR=fixture
+ARG TZ=Asia/Singapore
 
 # ----------------------------------------------------------------------------------------------------------------------
 #                                           BUILDER STAGE
@@ -41,10 +42,17 @@ ARG BINARY_NAME
 ARG APP_VERSION
 ARG BUILD_TAGS
 
+# Install system dependencies required to build with CGO and libwebp support.
+RUN apk add --no-cache \
+        build-base=0.5-r3 \
+        pkgconf=2.4.3-r0 \
+        libwebp-dev=1.5.0-r0
+
 # Configure Go build cache and module cache under our APP_DIR.
 ENV GOPATH=${APP_DIR}/.gopath
 ENV GOMODCACHE=${APP_DIR}/.gopath/pkg/mod
 ENV GOCACHE=${APP_DIR}/.gocache
+ENV CGO_ENABLED=1
 
 # Create the Go module & build cache directories.
 RUN mkdir -p ${GOMODCACHE} ${GOCACHE}
@@ -59,14 +67,13 @@ RUN go mod download
 # Copy remaining source code into the builder.
 COPY . .
 
-# Compile a statically-linked binary.
+# Compile the application binary with CGO enabled so WebP encoding is available.
 #
-#       * CGO_ENABLED=0: disable CGO for static builds.
 #       * -tags: apply build tags.
 #       * -o: output binaries path/name.
 #       * -ldflags: strip symbols and inject version.
 #
-RUN CGO_ENABLED=0 go build \
+RUN go build \
     -tags "${BUILD_TAGS}" \
     -o ${APP_DIR}/${BINARY_NAME} \
     -ldflags="-s -w -X main.Version=${APP_VERSION}" \
@@ -89,9 +96,12 @@ ARG MEDIA_DIR
 ARG FIXTURES_DIR
 ARG APP_HOST_PORT
 
-# Install timezone data so Go’s time.* functions work correctly.
-RUN apk add --no-cache tzdata
-ENV TZ=Asia/Singapore
+# Timezone configuration (default to Asia/Singapore).
+ARG TZ=Asia/Singapore
+
+# Install timezone data and runtime dependencies for the CGO-enabled binary.
+RUN apk add --no-cache tzdata=2025b-r0 libwebp=1.5.0-r0
+ENV TZ=${TZ}
 
 # Create the system group for our non-root user.
 RUN addgroup -S ${APP_GROUP}

pkg/images/image.go

@@ -26,7 +26,6 @@ import (
 	_ "golang.org/x/image/webp"
 
 	"github.com/andybalholm/brotli"
-	"github.com/chai2010/webp"
 	"github.com/gen2brain/avif"
 	"github.com/klauspost/compress/zstd"
 )
@@ -533,8 +532,7 @@ func Save(path string, img stdimage.Image, ext string, quality int) error {
 		encoder := &png.Encoder{CompressionLevel: png.DefaultCompression}
 		return encoder.Encode(fh, img)
 	case ".webp":
-		options := &webp.Options{Lossless: false, Quality: float32(quality)}
-		return webp.Encode(fh, img, options)
+		return encodeWebp(fh, img, quality)
 	default:
 		options := &jpeg.Options{Quality: quality}
 		return jpeg.Encode(fh, img, options)

pkg/images/image_test.go

@@ -867,6 +867,10 @@ func TestSaveJPEG(t *testing.T) {
 func TestSaveWebP(t *testing.T) {
 	t.Parallel()
 
+	if !webpEncodeSupported() {
+		t.Skip("webp encoding requires cgo")
+	}
+
 	dir := t.TempDir()
 	path := filepath.Join(dir, "photo.webp")
 

pkg/images/webp_encode_cgo.go

@@ -0,0 +1,19 @@
+//go:build cgo
+
+package images
+
+import (
+	stdimage "image"
+	"io"
+
+	"github.com/chai2010/webp"
+)
+
+func encodeWebp(w io.Writer, img stdimage.Image, quality int) error {
+	options := &webp.Options{Lossless: false, Quality: float32(quality)}
+	return webp.Encode(w, img, options)
+}
+
+func webpEncodeSupported() bool {
+	return true
+}

pkg/images/webp_encode_stub.go

@@ -0,0 +1,17 @@
+//go:build !cgo
+
+package images
+
+import (
+	"errors"
+	stdimage "image"
+	"io"
+)
+
+func encodeWebp(_ io.Writer, _ stdimage.Image, _ int) error {
+	return errors.New("webp encoding requires cgo support")
+}
+
+func webpEncodeSupported() bool {
+	return false
+}