Docker中的构建上下文

## Docker Build 命令中的参数

docker build -t imagename:tagname .


The docker build command builds Docker images from a Dockerfile and a “context”. A build’s context is the set of files located in the specified PATH or URL. The build process can refer to any of the files in the context. For example, your build can use a COPY instruction to reference a file in the context.

## 为什么会有构建上下文

Sending build context to Docker daemon  55.09MB


COPY ./package.json /app/