arg

• ARG

  FROM xxx
  ARG app_env
  ENV APP_ENV $app_env

docker build ./ --build-arg app_env=production

example

• Dockerfile

  ```dockerfile

  FROM daocloud.io/library/node:6.1.0

ARG app_env ENV APP_ENV $app_env

Set workspace

ENV REACT_ROOT /www/crms RUN mkdir -p $REACT_ROOT WORKDIR $REACT_ROOT

ADD docker_run.sh .

COPY example.env.production.local example.env.production.local

COPY example.env.preproduction.local example.env.preproduction.local

RUN /bin/bash docker_run.sh

RUN if [ ${APP_ENV} = production ]; then cp example.env.production.local .env.production.local else cp example.env.preproduction.local .env.preproduction.local fi

Install app dependencies

COPY package.json package.json RUN npm install

Bundle app source

COPY . .

Build and optimize react app

RUN npm run build --production

run react

EXPOSE 5000 RUN npm install -g serve CMD serve -s build

- docker_run.sh
```shell
if [ -z $APP_ENV ]; then
    APP_ENV='dev'
    echo "export APP_ENV=${APP_ENV}" >> ${HOME}/.bashrc
fi

source ~/.bashrc

if [ "$APP_ENV" = "dev" ]; then
  echo "APP_ENV:${APP_ENV}"
    cp example.env.preproduction.local .env.production.local

elif [ "$APP_ENV" = "production" ]; then
  echo "APP_ENV:${APP_ENV}"
    cp example.env.production.local .env.production.local

else
    echo "unknown APP_ENV:${APP_ENV}"
fi

echo "ECHO get APP_ENV finish, then to npm install"