disable env variable substitution in docker compose env files

[simonm11]

I updated docker and notice a significant change of behavior when using my env files in docker-compose

I have the following:

env_file:
      - ./file.env

and, in file.env

property=${something}

Before updating, doing echo $property in my running container would produce the string ${something}. Which was what I wanted.

Now (docker 19.03.12), $property is empty because docker is trying to find $something from my system env variables.

What caused this change of behavior? Is there a way to disable it or work around it?

[ImDevinC]

This looks similar to the issue I reported awhile ago, unfortunately no response yet: #7601

[simonm11]

did you find some kind of work around in the meanwhile?

[dominikbraun]

What caused this change of behavior?

Possibly #7150.

[simonm11]

Is it a bug or an intended feature ?

[ImDevinC]

@simonm11 I found that removing the {} from my variable seemed to help. IE: Changing ${SAMPLE_ARG} to $SAMPLE_ARG. I'm sure there are some situations where the brackets will be needed, but I lucked out in my case where they weren't needed

[nicomelchiori]

Hi @ImDevinC, we are having same issue.

We update docker-compose from 1.25.4 to 1.27.4 and start trying to subtitute ${xxx} variables. Unfortunatly we can't remove brackets as you mentioned in previous comment.
Is there any way to tell compose to not to replace variables?

[ImDevinC]

It's been awhile since I've visited this, but I've been using the workaround above for my solution, just remove the {} from your variable so instead of ${xxx} you can use $xxx

[nicomelchiori]

Unfortunately Spring needs brackets to replace the variables when it starts the application, as docker replacement occurred before the variable is erased at the moment Spring needs it. We will continue using 1.25.5
It would be great if it could be disabled in docker-compose
Thanks anyway.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[saschabrockel]

The bug still exists. We just had the bug with BookStack where also a property with a dollar sign is used.

[stale]

This issue has been automatically marked as not stale anymore due to the recent activity.