What is multi-staging in the build process?

This is the use of multiple builds to achieve the final result, often to reduce the size of the final container image. In the first stage (builder stage), the application with all dependencies is built, and in the second stage (runner stage), only the necessary build artifacts from the first stage are copied.

Example Dockerfile:

# Build stage
FROM alpine:latest as builder
WORKDIR /app
COPY . .
RUN go build -o myapp

# Runtime stage
FROM alpine:latest
WORKDIR /app
COPY --from=builder /app/myapp .
CMD ["./myapp"]