How dockerize create-react-app can access to azure release pipeline variables in docker environment

Question

Here is the complete flow of problem

1) Azure Build pipeline creates an artefact (docker image) using following DockerFile

FROM hub.docker.prod.private.com/library/node:10.16-alpine as buildImage
RUN mkdir -p /usr/src/app
WORKDIR /usr/src/app

ENV PATH /app/node_modules/.bin:$PATH
ENV REACT_APP_SERVER_URL=${REACT_APP_SERVER_URL}
ENV REACT_APP_AD_APP_ID=${REACT_APP_AD_APP_ID}
ENV REACT_APP_REDIRECT_URL=${REACT_APP_REDIRECT_URL}
ENV REACT_APP_AUTHORITY=${REACT_APP_AUTHORITY}

COPY package.json /usr/src/app/
RUN npm install
RUN npm install react-scripts@3.0.1 -g
COPY . /usr/src/app
RUN npm run build

FROM hub.docker.prod.private.com/library/nginx:1.15.12-alpine
COPY --from=buildImage /usr/src/app/build /usr/share/nginx/html
RUN rm /etc/nginx/conf.d/default.conf
COPY nginx/nginx.conf /etc/nginx/conf.d
EXPOSE 80
CMD ["nginx", "-g", "daemon off;"]

2) And pushes docker image into Azure container registry ( ACR ).

3) Multistage Release pipeline pulls image from ACR and deploy on azure app service(s) ( QA -> Stage -> Prod ).

4) Release pipeline is using variable values from variable group defined in release pipeline and I am expecting these variable should available in docker environment so that it replaces ENV variable placeholders in DockerFile .

But after deployment all environment variables that being used inside application remains undefined, can you please correct me if it is possible to use docker environment the way I mentioned above.

Answer 1

But after deployment all environment variables that being used inside application remains undefined, can you please correct me if it is possible to use docker environment the way I mentioned above.

The way mentioned above wasn't possible to work. During the deployment process, Release Variables won't automatically replace the original values with stage-scope release variables in DockerFile.

As a workaround, you can try Replace Tokens task from Replace Tokens , add this task in your three stages before deploy task. So the task order in your three stages should be similar to: Replace Tokens task to set release variables in DockerFile=>docker build and push=>deploy task.

To use this task, your Dockerfile should be:

ENV REACT_APP_SERVER_URL=#{REACT_APP_SERVER_URL}#
ENV REACT_APP_AD_APP_ID=#{REACT_APP_AD_APP_ID}#
ENV REACT_APP_REDIRECT_URL=#{REACT_APP_REDIRECT_URL}#
ENV REACT_APP_AUTHORITY=#{REACT_APP_AUTHORITY}#

Details about how this task works check my another issue .

If you don't want to make any change to the Dockerfile itself, another way is to pass the value in command-line arguments. You can check this similar post for more details.