Compose: Incorrect environment variable interpolation

[fogine]

When the .env file has the following setup:

POSTGRES_DB=test
POSTGRES_USER=test

with the following docker-compose.yml section:

  service_name:
    environment:
      POSTGRES_DB: ${POSTGRES_DB:-${POSTGRES_USER}}
      POSTGRES_USER: ${POSTGRES_USER:-postgres}

When the container is run the POSTGRES_DB is incorrectly evaluated to value "test}" .
Expected correct POSTGRES_DB value is "test".

When either .env file is not present or the docker-compose.yml file doesn't use nested variable interpolation, the POSTGRES_DB is correctly evaluated to "test".

> docker-compose version
docker-compose version 1.17.1, build unknown                                                                                                                                                                                                  
docker-py version: 2.6.1
CPython version: 3.6.3
OpenSSL version: OpenSSL 1.1.0g  2 Nov 2017

> uname -a
Linux username 4.14.6-1-ARCH #1 SMP PREEMPT Thu Dec 14 21:26:16 UTC 2017 x86_64 GNU/Linux

> docker  version
Client:                                                                                                                                                                                                                                       
 Version:      17.11.0-ce
 API version:  1.34
 Go version:   go1.9.2
 Git commit:   1caf76ce6b
 Built:        Sun Dec 10 10:15:57 2017                                                                                                                                                                                                       
 OS/Arch:      linux/amd64                                                                                                                                                                                                                    

Server:
 Version:      17.11.0-ce
 API version:  1.34 (minimum version 1.12)
 Go version:   go1.9.2
 Git commit:   1caf76ce6b
 Built:        Sun Dec 10 10:16:13 2017
 OS/Arch:      linux/amd64
 Experimental: false

[fogine]

There are other cases of incorrect variable interpolation with nested placeholders which does NOT involve the .env file at all.

[shin-]

Thanks for the report! Unfortunately, Compose's implementation doesn't actually support nested interpolation ; as a result, this is behaving as intended, with the first closing brace delimiting the variable statement, the second closing brace is treated as a regular character.

[fogine]

Then please consider this a feature request.

[stale[bot]]

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.

[stale[bot]]

This issue has been automatically closed because it had not recent activity during the stale period.