[Compose file] allow names for non-external volumes

[dnephin]

Proposed syntax:

volumes:
  data:
    name: something
    driver: drivername

This will fix a bunch of issues:

• docker stack deploy failed if volume name with special character like "@" used in the compose file  moby/moby#33529
• Docker Compose Variable substitution - can't use a variable in a yaml/compose key moby/moby#33540
• templated volume name syntax not supported in compose v3 format? moby/moby#30770

Probably others I haven't found yet.

We should also deprecate external: name: foo (external: bool would remain undeprecated).

cc @shin- What do you think?

Also, should we go ahead and do this with secrets, configs and networks as well, to keep them consistent?

[dnephin]

cc @vdemeester as well

[shin-]

Seems reasonable. external is ignored in docker stack anyway, right?

[xask00]

In reference to moby/moby#30770

Will this change make templated names for volumes possible in the compose YML file used by docker stack deploy like below -

volumes:
  data:
    name: {{.Service.Name}}-{{.Task.Slot}}-vol
    driver: cloudstor:aws

equivalent of the command line -

docker service create \
  --replicas 5 \
  --name ping2 \
  --mount type=volume,volume-driver=cloudstor:aws,source={{.Service.Name}}-{{.Task.Slot}}-vol,destination=/mydata \
  alpine ping docker.com

[dnephin]

Yes, that is one of the problems that will be fixed by this change.

[xask00]

@dnephin thanks for confirming

[eliaoggian]

I Think this fix will be great! When will this be implemented?

Thanks!

[shouze]

@eliaoggian yes see #306 need to wait for 3.4 version of the schema with some other changes. I guess we can't expect a GA until 17.09 @dnephin right?