[feat](build): add versioned Docker image build script and version injection

- Introduced `tools/build_server_image.sh` for building versioned server images with support for multi-arch builds.
- Added `VERSION` injection via `-ldflags` in Dockerfile and Go binaries for both server and client.
- Updated workflows and Makefile to ensure consistent version tagging during builds.

.github/workflows/docker-publish.yml

@@ -56,4 +56,6 @@ jobs:
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
           cache-from: type=gha
-          cache-to: type=gha,mode=max
+          cache-to: type=gha,mode=max
+          build-args: |
+            VERSION=${{ github.sha }}

Dockerfile.server

@@ -18,6 +18,8 @@ FROM golang:1.25-alpine AS builder
 # 기본값을 지정해두면 로컬 docker build 시에도 별도 인자 없이 빌드 가능합니다.
 ARG TARGETOS=linux
 ARG TARGETARCH=amd64
+# Git 태그/커밋 정보를 main.version 에 주입하기 위한 VERSION 인자 (기본 dev)
+ARG VERSION=dev
 
 WORKDIR /src
 
@@ -32,7 +34,8 @@ RUN go mod download
 COPY . .
 
 # 서버 바이너리 빌드 (멀티 아키텍처: TARGETOS/TARGETARCH 기반)
-RUN CGO_ENABLED=0 GOOS=${TARGETOS} GOARCH=${TARGETARCH} go build -o /out/hop-gate-server ./cmd/server
+# -ldflags 를 통해 main.version 에 VERSION 값을 주입합니다.
+RUN CGO_ENABLED=0 GOOS=${TARGETOS} GOARCH=${TARGETARCH} go build -ldflags "-X main.version=${VERSION}" -o /out/hop-gate-server ./cmd/server
 
 # ---------- Runtime stage ----------
 FROM alpine:3.20

Makefile

@@ -18,7 +18,9 @@ BIN_DIR := ./bin
 SERVER_BIN := $(BIN_DIR)/hop-gate-server
 CLIENT_BIN := $(BIN_DIR)/hop-gate-client
 
-VERSION ?= $(shell git describe --tags --dirty --always 2>/dev/null || echo dev)
+# VERSION 은 현재 커밋의 7글자 SHA 를 사용합니다 (예: 1a2b3c4).
+# git 정보가 없으면 dev 로 fallback 합니다.
+VERSION ?= $(shell git rev-parse --short=7 HEAD 2>/dev/null || echo dev)
 
 # .env 파일 로드
 include .env

cmd/client/main.go

@@ -15,6 +15,10 @@ import (
 	"github.com/dalbodeule/hop-gate/internal/proxy"
 )
 
+// version 은 빌드 시 -ldflags "-X main.version=xxxxxxx" 로 덮어쓰이는 필드입니다.
+// 기본값 "dev" 는 로컬 개발용입니다.
+var version = "dev"
+
 func getEnvOrPanic(logger logging.Logger, key string) string {
 	value, exists := os.LookupEnv(key)
 	if !exists || strings.TrimSpace(value) == "" {
@@ -124,6 +128,7 @@ func main() {
 
 	logger.Info("hop-gate client starting", logging.Fields{
 		"stack":                 "prometheus-loki-grafana",
+		"version":               version,
 		"server_addr":           finalCfg.ServerAddr,
 		"domain":                finalCfg.Domain,
 		"local_target":          finalCfg.LocalTarget,

cmd/server/main.go

@@ -29,6 +29,10 @@ import (
 	"github.com/dalbodeule/hop-gate/internal/store"
 )
 
+// version 은 빌드 시 -ldflags "-X main.version=xxxxxxx" 로 덮어쓰이는 필드입니다.
+// 기본값 "dev" 는 로컬 개발용입니다.
+var version = "dev"
+
 type dtlsSessionWrapper struct {
 	sess         dtls.Session
 	mu           sync.Mutex
@@ -815,6 +819,7 @@ func main() {
 
 	logger.Info("hop-gate server starting", logging.Fields{
 		"stack":        "prometheus-loki-grafana",
+		"version":      version,
 		"http_listen":  cfg.HTTPListen,
 		"https_listen": cfg.HTTPSListen,
 		"dtls_listen":  cfg.DTLSListen,

tools/build_server_image.sh

@@ -0,0 +1,43 @@
+. #!/usr/bin/env bash
+
+set -euo pipefail
+
+# Build hop-gate server image from Dockerfile.server.
+# VERSION is derived from current git commit (7-char SHA).
+
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"
+REPO_ROOT="${SCRIPT_DIR}/.."
+cd "${REPO_ROOT}"
+
+VERSION="$(git rev-parse --short=7 HEAD 2>/dev/null || echo dev)"
+
+# Default image name; can be overridden by first argument.
+# Usage:
+#   ./tools/build_server_image.sh                 # builds ghcr.io/dalbodeule/hop-gate:<hash> and :latest
+#   ./tools/build_server_image.sh my/image/name   # builds my/image/name:<hash> and :latest
+IMAGE_NAME="${1:-ghcr.io/dalbodeule/hop-gate}"
+
+echo "Building hop-gate server image"
+echo "  context : ${REPO_ROOT}"
+echo "  image   : ${IMAGE_NAME}:${VERSION}"
+echo "  version : ${VERSION}"
+
+# Use docker buildx if available; fallback to docker build.
+if command -v docker >/dev/null 2>&1 && docker buildx version >/dev/null 2>&1; then
+  BUILD_CMD=(docker buildx build)
+else
+  BUILD_CMD=(docker build)
+fi
+
+# Optional environment variables:
+#   PLATFORM=linux/amd64,linux/arm64   (for buildx)
+#   PUSH=1                              (for buildx --push)
+
+"${BUILD_CMD[@]}" \
+  ${PLATFORM:+--platform "${PLATFORM}"} \
+  -f Dockerfile.server \
+  --build-arg VERSION="${VERSION}" \
+  -t "${IMAGE_NAME}:${VERSION}" \
+  -t "${IMAGE_NAME}:latest" \
+  ${PUSH:+--push} \
+  .