How can i use variable to assigne a service name

Docker Engine Compose
, ,
1

Hi

Say I have a .env file that contains the variables I want to pass to the docker-compose.yml file.

.env

STACK_VERSION=8.6.2
SERVICE_NAME=es-sim03
......
......

docker-compose.yml

version: '3.7'
services:
  ${SERVICE_NAME}:
    image: docker.elastic.co/elasticsearch/elasticsearch:${STACK_VERSION}
......
......

How can I use the variable for this service? The above code block show an error:

services Additional property ${SERVICE_NAME} is not allowed

2

No, you can’t. Service names are supposed to be literal strings.

You can use --project-name (short version: -p ) to specify the project name, which will be prefixed to the container, volume, and network names for a particular compose deployment to prevent naming conflicts with other deployments using the same docker-compose.yml

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3

Thanks Metin

It is really helpful.

4

Just to give you the full picture:

You could render your compose files through templating of some sort (you would need to solve this yourself) and pass it to docker compose, like this: {command to render template} | docker compose -f - up -d

The -f - uses the compose file it receives via stdin.

Somewhere in the forum, I gave an example that uses envsubst for simple templating.

Update: this is the somewhere

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5

It same as the old reply “Little complex to understand” LOL. Still will give it a try.

6

If you want, you can quote the parts that are unclear to you, write what you understood or assume, then I can try to rephrase the quoted part.

1 Like
7

You can not use a variable for service name as previously written by @meyay, but you can most definitely use a variable for tags i.e.

service_name:${TAG}
8

hello,
No, you can’t. Service names are supposed to be literal strings.
You can use different names.

9

Hey, just wanted to make sure there is still no way to use environment variables in service names nowadays. I would need to specify different service names for several instances of a multi container app running on the same network.

Thanks

10

No, it is not supported. And will not if nobody asks for the feature :slight_smile:

You can do that here:

My opinion is that when I need a more complex compose file where even service names can be changed, I use a template system. I wouldn’t complicate the compose file parser more. Even now there are some issues with handling variables i compose files when using docker compose config

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