set NODE_ENV variable in production via docker file

Question

I am trying to use below code below code in nodejs

if (process.env.NODE_ENV !== 'production')

I tried to set NODE_ENV variable from docker file like below.

FROM collinestes/docker-node-oracle:10-slim
ENV NODE_ENV=production
EXPOSE  8085
CMD ["npm","start"]

If i to run my docker image it does not start and throws error. If i remove NODE_ENV all runs fine. Is it the right way to setting NODE_ENV from dockerfile?

Solution 1

Remove the equal sign

ENV NODE_ENV production

Solution 2

Your Dockerfile should work, are you sure there isn't anything else inside the application, maybe package.json could be override it ?

I have tested it and it works correctly

$ echo $NODE_ENV
production

Also I would suggest to set the NODE_ENV variable while running the container as it would be easier to modify, I am aware that you can override it anyway if needed but setting it on the run-time will make your image with less layers. you can use the command below

-e can be used to pass an environment variable and can be passed multiple times if you have more than one variable

docker run -e NODE_ENV=production $IMAGENAME

Comments

[djheru]

What is the error?

[Hacker]

But i have other variables like ENV UV_THREADPOOL_SIZE=5 which does not have any issue.

[Hacker]

npm start has babel-node --presets es2015 index.js and when i have that variable in docker file it throws up error like babel-node not found

[Mostafa Hussein]

So maybe you need to configure PATH to make it work. This is just my guessing as I don't know more information about your actual Dockerfile

[Mostafa Hussein]

Syntax is not the problem in this case, ENV supports both styles as shown in here: docs.docker.com/engine/reference/builder/#env

[Hacker]

If i use prod instead of production, it works fine.

[Mostafa Hussein]

So it seems your application uses prod not production, am i correct ?

[Hacker]

Yeah. So i had to change my code also top prod. If i use production in dockerfile, it does not work.

[Hacker]

I changed in docker file and code also to prod and all worked fine.

[Mostafa Hussein]

I cannot tell without knowing the framework. have you reviewed the framework's documentation or github issues ? maybe they have something special regarding the node env variable ?

[Nick N]

Using AWS ECS Docker instances, I ended up adding an Environment Variable in the Task Definition key NODE_ENV and value production. Things worked fine. Somehow I stumbled onto this page with my issue, so documenting it for others.