Copying environment variables into Dockerfile

Question

I am trying to create a .env-file in the Dockerfile using the following line:

RUN env | grep "REACT_APP" >> .env

I'm getting this error:

The command '/bin/sh -c env | grep "REACT_APP" >> .env' returned a non-zero code: 1

Does anyone know how to solve this?

EDIT:

Full Dockerfile:

FROM node:11.2-alpine
EXPOSE 5000

ENV NPM_CONFIG_LOGLEVEL warn

RUN ['/bin/sh', '-c', 'env | grep "REACT_APP" >> .env']

RUN npm install -g serve
CMD serve -s build -n

# Separate layer for dependencies, it will speedup build
COPY package.json package.json
RUN npm install

COPY . .

RUN npm run build --production

#TODO: Maybe there is another way to include it to build?
#Legacy redirects via native serve options (https://github.com/zeit/serve-handler#redirects-array)
RUN cp serve.json build/

Answer 1

Apparently you don't have REACT_APP defined at all. As the command:

RUN env| grep REACT_APP >> .env

Will fail with the following error, in case you don't have it defined already.

The command '/bin/sh -c env| grep REACT_APP >> .env' returned a non-zero code: 1

Also no need to write it as

RUN ['/bin/sh', '-c', 'env | grep "REACT_APP" >> .env']

This format RUN env| grep REACT_APP >> .env RUN env| grep REACT_APP >> .env will suffice

Answer 2

RUN command is launched "as-is", not through the shell. If you wish to use features like shell redirects you have to run it in the shell:

RUN ["/bin/bash", "-c", "env | grep \"REACT_APP\" >> .env"]

bash , dash , sh - choose the shell you have in your image. Not every image has BASH inside.

Answer 3

You are could be getting the error because you may not have "REACT_APP" env set.

can you try it as follows,

ENV REACT_APP test
RUN env | grep "REACT_APP" >> .env

You cant use bash as alphine image only support sh