Feature Request: Add command to print config

[hamiltont]

docker-compose has the config command to print the full configuration

This is invaluable for many scenarios:

• checking passed build args
• confirming that multiple YAML files have combined properly
• ensuring that your CI/CD variables are making it into the YAML properly (e.g. GitLab CI/CD env variables don't properly support $, so variables like $apr1$hash get mangled before they enter the YAML file)
• recording a record of each deployment

Could swarm have a config command as well?

My team has basically 100% migrated to swarm, but we keep docker-compose installed in our CI/CD environment specifically for this one subcommand

Example docker-compose config output

docker-compose config
 networks:
   internal: {}
   web-ingress: {}
 services:
   dashboard:
     build:
       args:
         BUILD_FLAGS: VUE_APP_API_URL=https://api.dev.mydomain.com VUE_APP_COOKIE_DOMAIN=dev.mydomain.com
       context: /builds/mygroup/my-project
     image: 543066533799.dkr.ecr.us-east-1.amazonaws.com/mycontainer:64e3da5d
     networks:
       internal: {}
       web-ingress: {}
     ports:
     - published: 80
       target: 80
 version: '3.7'

[SMFloris]

@hamiltont , I submitted a PR that fixes this ( #2740 ). Please feel free to test it and provide any feedback you can.

This is how one can test this easily:

# first build docker
make -f docker.Makefile cross
# symlink the binary
ln -s $PWD/build/docker-darwin-amd64 /usr/local/bin/docker-local
# test the output of the merge/interpolation
docker-local stack config -c compose1.yml -c compose2.yml
# try piping it back to docker stack deploy
docker-local stack deploy -c compose1.yml -c compose2.yml --skip-interpolation | docker stack deploy -c -

[hamiltont]

@SMFloris awesome! Will try to test this week sometime

[vibro]

👋 Any updates on this? I recently updated docker-compose and ran into the issue this is trying to resolve. Thanks!

[meyerson]

👋 This would be nice to have @gtardif @ndeloof