多级坞文件跳过级

Question

我正在尝试构建一个带有以下阶段的多级dockerfile，但所有阶段都将被执行。

即使我在docker构建中指定了EXECUTION_ENV=local，我也总是执行git克隆。

文档：

ARG GIT_TOKEN=abc:1a2b3
ARG EXECUTION_ENV=local

# get dependencies from github
FROM alpine/git as gitclone-ci
WORKDIR /usr/src/
RUN git clone https://{GIT_USER_TOKEN}@github.com/something.git \
    && git clone https://{GIT_USER_TOKEN}@github.com/somethingelse.git

## in local dependencies are already available in the parent folder
FROM alpine/git as gitclone-local
WORKDIR /usr/src/
COPY ../something /usr/src/something 
COPY ../somethingelse /usr/src/somethingelse

FROM node:latest as builder
WORKDIR /usr/src
COPY --from=gitclone-${EXECUTION_ENV} /usr/src .
COPY package* ./
COPY src/ src/
RUN ["npm", "install"]

Docker尝试：

docker build -t somecontainer --build-arg GIT_TOKEN=abc:123 --build-arg EXECUTION_ENV=local.

docker build -t somecontainer --target builder --build-arg GIT_TOKEN=abc:123 --build-arg EXECUTION_ENV=local.

注：如果在停靠守护进程中启用"features": { "buildkit": true}并运行cmd docker build -t somecontainer --build-arg GIT_TOKEN=abc:123 --build-arg EXECUTION_ENV=local.，则会得到以下错误

failed to solve with frontend dockerfile.v0: failed to create LLB definition: failed to parse stage name "gitclone-$EXECUTION_ENV": invalid reference format: repository name must be lowercase

Answer 1

跳过阶段只适用于BuildKit。请参阅讨论这里和文章这里。

至于您所得到的错误，您应该使用或不使用BuildKit，因为您不能在COPY指令中使用构建参数。不同的是，对于BuildKit，Docker甚至拒绝启动构建，如果没有它，构建将在COPY指令上失败。

您需要做的是使用FROM指令解析构建args这一事实，为要复制的映像创建额外的别名：

ARG GIT_TOKEN=abc:1a2b3
ARG EXECUTION_ENV=local

# get dependencies from github
FROM alpine/git as gitclone-ci
WORKDIR /usr/src/
RUN git clone https://{GIT_USER_TOKEN}@github.com/something.git \
    && git clone https://{GIT_USER_TOKEN}@github.com/somethingelse.git

## in local dependencies are already available in the parent folder
FROM alpine/git as gitclone-local
WORKDIR /usr/src/
COPY ../something /usr/src/something 
COPY ../somethingelse /usr/src/somethingelse

FROM gitclone-${EXECUTION_ENV} as intermediate

FROM node:latest as builder
WORKDIR /usr/src
COPY --from=intermediate /usr/src .
COPY package* ./
COPY src/ src/
RUN ["npm", "install"]