前言 Docker 是一个广受欢迎的开发平台，它允许用户通过容器化技术来构建、打包和部署应用程序。尽管 Docker 提供了强大的功能和灵活性，但对于初学者而言，在项目中配置 Docker 可能会遇到一些挑战。
不过，Docker 官方为了降低使用门槛，推出了一个便捷的命令docker init。这个命令旨在快速初始化 Docker 配置，从而简化将 Docker 集成到项目中的流程。通过使用这个命令，用户可以轻松地为项目设置必要的 Docker 支持，进而享受到 Docker 带来的便利和效率提升。
docker init 简介 docker init 命令会根据用户指定的选项生成运行容器的一些文件，极大的加快了项目的容器化：
.dockerignore : docker 构建时忽略的文件列表 Dockerfile: 镜像的核心文件 Compose.yaml: docker compose 的配置文件 README.Docker.md 如果你的项目中已有以上文件，会让你选择是否覆盖旧文件避免文件冲突问题。
docker init 提供了一组项目的模板文件，包括了 Go、Python、ASP.NET Core 等常见的服务器应用程序及一个其它类型应用程序模板。开发者使用 init 命令时，可以根据选择的模板生成相应的文件，使开发者可以快速的构建并启动容器。
使用 接下来介绍如何使用 docker init 进行项目容器的初始化，这里以前文的 go 项目为例子进行介绍。
进入项目根目录执行 init 命令，选择 go 模板，会让你选择使用的 go 版本，主程序的位置及应用所使用的端口： 执行完可以看到会生成相应的文件及如何构建并运行的命令。
查看生成的 Dockerfile 和 Compose.yaml 文件：
# syntax=docker/dockerfile:1 # Comments are provided throughout this file to help you get started. # If you need more help, visit the Dockerfile reference guide at # https://docs.docker.com/go/dockerfile-reference/ # Want to help us make this template better? Share your feedback here: https://forms.gle/ybq9Krt8jtBL3iCk7 ################################################################################ # Create a stage for building the application. ARG GO_VERSION=1.21.0 FROM --platform=$BUILDPLATFORM golang:${GO_VERSION} AS build WORKDIR /src # Download dependencies as a separate step to take advantage of Docker's caching. # Leverage a cache mount to /go/pkg/mod/ to speed up subsequent builds. # Leverage bind mounts to go.sum and go.mod to avoid having to copy them into # the container. RUN --mount=type=cache,target=/go/pkg/mod/ \ --mount=type=bind,source=go.sum,target=go.sum \ --mount=type=bind,source=go.mod,target=go.mod \ go mod download -x # This is the architecture you’re building for, which is passed in by the builder. # Placing it here allows the previous steps to be cached across architectures. ARG TARGETARCH # Build the application. # Leverage a cache mount to /go/pkg/mod/ to speed up subsequent builds. # Leverage a bind mount to the current directory to avoid having to copy the # source code into the container. RUN --mount=type=cache,target=/go/pkg/mod/ \ --mount=type=bind,target=. \ CGO_ENABLED=0 GOARCH=$TARGETARCH go build -o /bin/server ./retry/server ################################################################################ # Create a new stage for running the application that contains the minimal # runtime dependencies for the application. This often uses a different base # image from the build stage where the necessary files are copied from the build # stage. # # The example below uses the alpine image as the foundation for running the app. # By specifying the "latest" tag, it will also use whatever happens to be the # most recent version of that image when you build your Dockerfile. If # reproducability is important, consider using a versioned tag # (e.g., alpine:3.17.2) or SHA (e.g., alpine@sha256:c41ab5c992deb4fe7e5da09f67a8804a46bd0592bfdf0b1847dde0e0889d2bff). FROM alpine:latest AS final # Install any runtime dependencies that are needed to run your application. # Leverage a cache mount to /var/cache/apk/ to speed up subsequent builds. RUN --mount=type=cache,target=/var/cache/apk \ apk --update add \ ca-certificates \ tzdata \ && \ update-ca-certificates # Create a non-privileged user that the app will run under. # See https://docs.docker.com/go/dockerfile-user-best-practices/ ARG UID=10001 RUN adduser \ --disabled-password \ --gecos "" \ --home "/nonexistent" \ --shell "/sbin/nologin" \ --no-create-home \ --uid "${UID}" \ appuser USER appuser # Copy the executable from the "build" stage. COPY --from=build /bin/server /bin/ # Expose the port that the application listens on. EXPOSE 9000 # What the container should run when it is started. ENTRYPOINT [ "/bin/server" ] 可以看到 Dockerfile 是一个常见的多阶段构建镜像流程。
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