Import docker compose file in another compose file - docker

Question

Is it possible to "import" or link a docker-compose file into another docker-compose file?
Suppose I have two files:
# docker-compose-1.yml
services:
A:
# config
B:
# config
# docker-compose-2.yml
services:
C:
# config
import: docker-compose-1.yml
By running docker-compose -f docker-compose-2.yml up, I would like to start containers A, B (specified in the imported file) and C. Is this possible, without having to link both files with the -f parameter?

Answer 1

By extending
It's possible to extend or use multiple docker-compose files and their services and link them in just one file. You can take a look at this link to understand how is the other usages of multiple compose files. But you can't include the file yet without linking related files together as you mentioned.
Here, I defined a common-services.yaml:
version: '2'
services:
nginx_a:
image: nginx:latest
container_name: nginx
ports:
- 81:80
- 1443:443
And then, I created a docker-compose.yml and included the common-services.yml file and its own service as well.
services:
nginx:
extends:
file: common-services.yml
service: nginx_a
nginx_b:
image: nginx:latest
container_name: nginx_b
volumes:
ports:
- 82:80
- 2443:443
By .env technique
And if you want to avoid chaining usage of multiple files, there is also a technique with .env files. I will rewrite the previous example with .env technique.
COMPOSE_PATH_SEPARATOR=:
COMPOSE_FILE=common-services.yml:docker-compose.yml
Let's add another service as an example in the common-services.yml
version: '2'
services:
ngin_a:
image: nginx:latest
container_name: nginx_a
ports:
- 81:80
- 1443:443
redis_c:
image: redis:latest
container_name: redis_c
ports:
- 6381:6380
And finally, load all of them in the docker-compose file without even mention to those services.
version: '2'
services:
nginx_b:
image: nginx:latest
container_name: nginx_b
ports:
- 82:80
- 2443:443
env_file:
- .env
In the end, you will have three running services.