Idea: Provide jaas run with compose file and service name for service creation

[MarcPer]

Expected Behavior

Command docker stack deploy gets service information from a docker-compose.yml file. The idea is for jaas run to be able to get the service specification from the same source.

Current Behavior

jaas run requires all service information to be passed directly via the command line (except for the env files).

Possible Solution

A new flag for jaas with the path to a compose file and the service name. For example

# jaas run -f docker-compose.yml=my_service --command "./run-migrations.sh"

Context

The most common use case of jaas for me is running Database migrations, just before deploying a stack that depends on them. These migrations are always part of the code that is to be deployed and the one-shot service needs the same environment and secrets as the actual swarm service.

So, the service is for me always necessarily configured already by docker-compose.yml and it holds all the information that jaas needs to run. If jaas could read it from the source, there wouldn't be a need for duplicating it.

[alexellis]

What is the docker-compose.yml file going to look like, and what fields are expected to be parsed?

Would you be OK with a "jaas"-format YAML file?

I am not sure why a string of command-line options is not workable? Where does it fail / let you down?