# ==========================
# Stage 1: Build the Go binary
# ==========================
FROM golang:1.21-alpine AS builder

# 设置工作目录
WORKDIR /build

# 复制 go.mod 和 go.sum，先做依赖缓存
COPY go.mod go.sum ./

# 下载依赖（缓存层）
RUN go mod download

# 复制源代码
COPY app/ ./app

# 编译可执行文件
RUN go build -o sentinel ./app/main.go

# ==========================
# Stage 2: 生成最终运行镜像
# ==========================
FROM alpine:3.18

# 安装 ca-certificates，如果程序需要访问 HTTPS
RUN apk add --no-cache ca-certificates

# 设置工作目录
WORKDIR /app

# 复制从 builder 构建好的二进制
COPY --from=builder /build/sentinel .

# 设置默认执行命令
CMD ["./sentinel"]