Node.js Docker image environment variables

Question

I have a Node.js application which is built into the docker image. In this application I have a config file with some API urls (API key, for example) which might change from time to time. Is it possible to launch the docker image with some additional parameter and then access this param from the node.js code (I assume this could be done through using environment vars) so as not to rebuild the image every time the value of this param should be changed. This is the pseudo code which I assume can be used:

docker run -p 8080:8080 paramApiKey="12345" mydockerimage

and then I'd like to access it from the node.js app:

var apiKey = process.env.paramApiKey

Can this somehow be achieved?

taxicala · Accepted Answer · 2015-11-05 17:11:48Z

4

In order to define environment variables with docker at the time you use the run command, you have to use the -e flag and the format is should be "name=value", meaning that your ENV variable should be "paramApiKey=12345" so that you can access it by doing process.env.paramApiKey in your application.

That being said, your command would look like:

docker run -p 8080:8080 -e "paramApiKey=12345" mydockerimage

answered Nov 5, 2015 at 17:11

taxicala

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4 Comments

Sachacr Over a year ago

Have you an idea for handling a long list of environment variables ?

JakubM Over a year ago

@Sachacr: Put them to a file and use --env-file, see docs.docker.com/engine/reference/commandline/run/…

George Katsanos Over a year ago

what if some variables are stuff like passwords and JWT Secret hashes?

George Katsanos Over a year ago

and how would you tell cloud.docker.com to use them? for example: cloud.docker.com/app/gkatsanos/repository/docker/gkatsanos/…

Dmitry Sokurenko · Accepted Answer · 2015-11-05 17:06:57Z

1

Sure, just try:

docker run -p 8080:8080 -e "paramApiKey=12345" mydockerimage

answered Nov 5, 2015 at 17:06

Dmitry Sokurenko

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