How to implement multi-stage building in Docker?

Docker multi-stage builds is a technique that allows defining multiple build stages in a single Dockerfile, reducing the image size and improving build efficiency.

The steps for implementing Docker multi-stage builds are as follows:

1. In the Dockerfile, multiple build stages are defined with each stage using the FROM instruction to specify a base image and carry out the corresponding build steps within it.

# 第一个构建阶段
FROM base_image as builder
# 执行构建步骤

# 第二个构建阶段
FROM base_image
COPY --from=builder /app /app
# 执行其他构建步骤

1. Generate the necessary files or build the application in the first stage and then copy these files to the second stage of building.
2. Copy files from the first build stage to the second build stage using the –from option.
3. To ultimately retain only the results of the second build stage when building an image, you can specify the target stage with the –target option in the docker build command.

docker build --target builder -t final_image .

Using Docker multi-stage builds can optimize image size and build efficiency, making it a recommended technique for building complex applications or images.