True "default" profile support for services in Docker Compose

[luke6Lh43]

Description

It would be very useful if Docker Compose supported a true "default" profile for services. The idea is:

A service with a "default" profile would be started if no profiles are specified via --profile on the CLI.
If any profile is specified, services with the "default" profile would not be started, unless explicitly included in the profile list.

Current behavior:
There is a workaround where setting profiles: [""] causes a service to be started by default when no profile is given, but not when any profile is specified. I have tested this on Docker Desktop for Mac (v2.39.2-desktop.1) and it works. However, there are StackOverflow discussions suggesting this does not work reliably across all platforms or Compose versions.

Desired behavior:

Add first-class support for a "default" (or similar) profile in Docker Compose. Services tagged with this profile would start only when no profile is specified, and not when any profile is given. This would make configuration more explicit and portable, and avoid reliance on undocumented/undocumented "profiles: [""]" workarounds.

Workaround working on MacOS

services:
  service1:
    image: busybox
    container_name: service1
    command: ["sleep", "3600"]
    # No profile, always starts by default

  service2:
    image: busybox
    container_name: service2
    command: ["sleep", "3600"]
    profiles: ["foo", ""]

  service3:
    image: busybox
    container_name: service3
    command: ["sleep", "3600"]
    profiles: ["bar"]

Test 1:

[~/developer/test]$ docker compose up -d  
[+] Running 3/3
 ✔ Network test_default  Created                                                                                                                                                    0.0s 
 ✔ Container service1    Started                                                                                                                                                    0.1s 
 ✔ Container service2    Started   

Test 2:

[~/developer/test]$ docker compose --profile bar up -d
[+] Running 3/3
 ✔ Network test_default  Created                                                                                                                                                    0.0s 
 ✔ Container service3    Started                                                                                                                                                    0.1s 
 ✔ Container service1    Started 

[ndeloof]

The behavior you suggest to disable "default" services when a profile is enabled would be a breaking change.

From your illustration example, you can get the expected result running docker compose up service3 - this will automatically enable bar profile, and only run target service (and dependencies, if needed)

[glours]

I agree with @ndeloof this will introduce a breakin change in the way profiles currently works.
There is already multiple possibilities to manage this kind of situation, by starting a service with a specific profile like mentioned by @ndeloof, by using dependencies between services as described in the documentation