修复 docker build 错误 "ERROR: No build stage in current context"

若 docker build 时遇到了错误 "ERROR: No build stage in current context"，则有可能是没有将 FROM 命令语句放置在第一行。

问题

例如，Dockerfile 文件如下：

MAINTAINER FengYin Xu
# builder stage
FROM node:16-alpine as builder
ARG APP_HOME=/home/web/app
# Create app directory
WORKDIR ${APP_HOME}
# Install app dependencies
# A wildcard is used to ensure both package.json AND package-lock.json are copied
# where available (npm@5+)
COPY package*.json ${APP_HOME}/
RUN npm install
# build production package
COPY . ${APP_HOME}/
RUN npm run build

以上 Dockerfile 在 docker build . 时会遇到错误：

解决方案

解决方案很简单，将 FROM 命令语句移动到最前面，作为第一行即可。

# builder stage
FROM node:16-alpine as builder
MAINTAINER FengYin Xu
ARG APP_HOME=/home/web/app
# Create app directory
WORKDIR ${APP_HOME}
# Install app dependencies
# A wildcard is used to ensure both package.json AND package-lock.json are copied
# where available (npm@5+)
COPY package*.json ${APP_HOME}/
RUN npm install
# build production package
COPY . ${APP_HOME}/
RUN npm run build

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