# 多阶段构建：api-gateway 生产镜像
# 用法：docker build -t edu/api-gateway:latest -f services/api-gateway/Dockerfile .
# 构建上下文必须是仓库根目录（需访问 packages/shared-go 与 go.work）

# ============ Builder ============
FROM golang:1.25-alpine AS builder
WORKDIR /app

# 使用国内 Go 模块代理（容器内无法访问 proxy.golang.org）
ENV GOPROXY=https://goproxy.cn,direct
ENV GOSUMDB=off

# git 与 ca-certificates 为 go mod 下载所需
RUN apk add --no-cache git ca-certificates

# 利用 go.work 时需拷贝根 go.work 与 shared-go 包
# 注意：go.work 引用了 push-gateway，但本构建仅需要 api-gateway + shared-go，
# 故生成精简版 go.work 避免加载缺失模块
COPY go.work.sum ./
COPY packages/shared-go ./packages/shared-go
COPY services/api-gateway/go.mod services/api-gateway/go.sum ./services/api-gateway/
# 生成仅含 api-gateway + shared-go 的精简 go.work
RUN printf 'go 1.25.0\n\nuse (\n  ./packages/shared-go\n  ./services/api-gateway\n)\n' > go.work
RUN cd services/api-gateway && go mod download

# 拷源码并构建
COPY services/api-gateway ./services/api-gateway
COPY packages/shared-go ./packages/shared-go
# 静态编译，CGO_DISABLED 便于 alpine 运行
# 注入 version 便于可观测性资源属性
RUN CGO_ENABLED=0 GOOS=linux go build \
    -ldflags="-s -w -X main.version=docker" \
    -o /app/bin/api-gateway \
    ./services/api-gateway

# ============ Runtime ============
FROM alpine:3.20 AS runner
WORKDIR /app

RUN apk add --no-cache ca-certificates tzdata wget

# 非 root 用户
RUN addgroup -g 1001 -S app && adduser -S app -u 1001 -G app

COPY --from=builder /app/bin/api-gateway /app/api-gateway

USER app
EXPOSE 8080

# 健康检查
HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 \
  CMD wget --quiet --spider http://localhost:8080/healthz || exit 1

ENTRYPOINT ["/app/api-gateway"]