Conection docker projects by a specific network

gistfile1.txt

# Setup to development testing without touch CMS API:
# /triller_cms/settings/base.py
TRILLER_CMS_OLD_API_URL = 'https://development-social.triller.co/v1.5/'
#TRILLER_CMS_API_URL = 'http://api.staging.triller.co/v1.5/cms-api'
TRILLER_CMS_API_URL = ''

# triller_cms/settings/development.py
#TRILLER_CMS_API_URL = os.getenv('CMS_API_URL', 'https://development-social.triller.co/v1.5/cms-api')

# triller_cms/settings/docker.py
#TRILLER_CMS_API_URL = 'http://172.21.0.3:5000/v1.5/cms-api'
#TRILLER_CMS_API_URL = 'https://development-social.triller.co/v1.5/cms-api/'

# triller_cms/settings/test.py
#TRILLER_CMS_API_URL = os.getenv('CMS_API_URL', 'https://development-social.triller.co/v1.5/cms-api')

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# Fisrt create a network
docker network create my-pre-existing-network

CMS:
adding at docker-compose.yml
networks:
  - default

networks:
  default:
    external:
       name: my-pre-existing-network
       
API:
adding at docker-compose.yml
networks:
  default:
    external:
       name: my-pre-existing-network