# syntax=docker/dockerfile:1
# ---------- 构建阶段：带完整 Go 工具链 ----------
FROM golang:1.26-alpine AS build
WORKDIR /src
# 先只复制依赖描述文件，依赖不变时这一层可以复用缓存
COPY go.mod ./
RUN go mod download
COPY . .
# 静态编译，去掉调试信息减小体积
RUN CGO_ENABLED=0 go build -trimpath -ldflags="-s -w" -o /out/api .

# ---------- 运行阶段：只放二进制 ----------
FROM gcr.io/distroless/static-debian12:nonroot
COPY --from=build /out/api /api
ENV PORT=8080
EXPOSE 8080
USER nonroot:nonroot
# exec 形式，进程是 PID 1，能直接收到 SIGTERM
ENTRYPOINT ["/api"]