将自定义环境变量传递到 dockerized react-admin 应用程序中

Question

I'm using react-admin in a project which shall run in a Docker swarm.

As we have multiple environments I defined an environment variable REACT_APP_API_ENDPOINT which points to our application's API with which react-admin shall interact.

So far I have learned that this variable must be "baked into react-admin" on build time. So I added the following to my Dockerfile :

ARG REACT_APP_API_ENDPOINT
ENV REACT_APP_API_ENDPOINT $REACT_APP_API_ENDPOINT

If this is true are my following assumptions correct?

• I must set the value for REACT_APP_API_ENDPOINT when running the docker build command .
• I will need one Docker image per environment.

Or is there a more feasible and dynamic way to pass that variable to react-admin?

Answer 1

1.

dockerfile

ARG REACT_APP_API_ENDPOINT

docker build --build-arg REACT_APP_API_ENDPOINT=192.168.0.1

2. You will need build container per environment

Answer 2

I finally got it working.

Dockerfile

ARG REACT_APP_API_ENDPOINT
ENV REACT_APP_API_ENDPOINT $REACT_APP_API_ENDPOINT

Then, to build the container:
docker build -t myimage --build-arg REACT_APP_API_ENDPOINT=<URL> .

It looks a bit weird to me but I couldn't figure out any other way as React does need custom variables like REACT_APP_MY_VARIABLE at build time.

Answer 3

At start i thought passing environment variables in a docker-compose file will work, but using RUN printenv inside Dockerfile (which prints systems environment variables), i found that the variables i was passing in, were not available when React was building production files. The key here is to pass environment variables inside Dockerfile, when the image is created, before React build files are created. Hence, a Dockerfile like this should work:

FROM node:13.12.0-alpine as build
WORKDIR /app
ENV PATH /app/node_modules/.bin:$PATH
#declaring react custom environment variable
ENV REACT_APP_API_HOST http://localhost:8080
COPY package.json ./
COPY package-lock.json ./
RUN npm ci --silent
COPY . ./
RUN npm run build