From 0db00b966966beabf670f165071a4e44f19956f8 Mon Sep 17 00:00:00 2001 From: khs1994 Date: Sat, 10 Mar 2018 09:16:43 +0800 Subject: [PATCH] Update Dockerfile multistage-builds #320 --- image/demo/multistage-builds/Dockerfile | 4 ++-- image/multistage-builds.md | 26 +++++++++++++++++++++++-- 2 files changed, 26 insertions(+), 4 deletions(-) diff --git a/image/demo/multistage-builds/Dockerfile b/image/demo/multistage-builds/Dockerfile index c54c11d..1475e9e 100644 --- a/image/demo/multistage-builds/Dockerfile +++ b/image/demo/multistage-builds/Dockerfile @@ -1,4 +1,4 @@ -FROM golang:1.9-alpine +FROM golang:1.9-alpine as builder RUN apk --no-cache add git @@ -10,7 +10,7 @@ COPY app.go . RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o app . -FROM alpine:latest +FROM alpine:latest as prod RUN apk --no-cache add ca-certificates diff --git a/image/multistage-builds.md b/image/multistage-builds.md index 44a93d8..fac70ca 100644 --- a/image/multistage-builds.md +++ b/image/multistage-builds.md @@ -134,7 +134,7 @@ go/helloworld 1 f55d3e16affc 2 minutes ago 295MB 编写 `Dockerfile` 文件 ```docker -FROM golang:1.9-alpine +FROM golang:1.9-alpine as builder RUN apk --no-cache add git @@ -146,7 +146,7 @@ COPY app.go . RUN CGO_ENABLED=0 GOOS=linux go build -a -installsuffix cgo -o app . -FROM alpine:latest +FROM alpine:latest as prod RUN apk --no-cache add ca-certificates @@ -175,3 +175,25 @@ go/helloworld 1 f55d3e16affc 2 minutes ago 295MB ``` 很明显使用多阶段构建的镜像体积小，同时也完美解决了上边提到的问题。 + +#### 只构建某一阶段的镜像 + +我们可以使用 `as` 来为某一阶段命名，例如 + +```dockerfile +FROM golang:1.9-alpine as builder +``` + +例如当我们只想构建 `builder` 阶段的镜像时，我们可以在使用 `docker build` 命令时加上 `--target` 参数即可 + +```bash +$ docker build --target builder -t username/imagename:tag . +``` + +#### 构建时从其他镜像复制文件 + +上面例子中我们使用 `COPY --from=0 /go/src/github.com/go/helloworld/app .` 从上一阶段的镜像中复制文件，我们也可以复制任意镜像中的文件。 + +```dockerfile +$ COPY --from=nginx:latest /etc/nginx/nginx.conf /nginx.conf +```