Docker compose pull should not pull image that's overrided with build option

[kscc25]

Scenario: I have two compose files

The base one is docker-compose.yml:

version: '2'

services:
  webapp:
    image: hello-world
  redis:
    image: redis:latest

The extended one is docker-compose.override.yml to override webapp service with build option:

version: '2'

services:

  webapp:
    extends:
      file: docker-compose.yml
      service: webapp
    build:
      context: .
  redis:
    extends:
      file: docker-compose.yml
      service: redis

The command I run:

docker-compose -f docker-compose.override.yml pull

Actualy result: both hello-world and redis images are pulled

Expected result: only redis image is pulled because the hello-world image is eventually built later with docker-compose build.

[lindt]

You defined both. The image and how it's built.
build is just used, if there is no pre-built image available.

[kscc25]

I realize that if I have both build and image in the same docker compose file, the image is still pulled:

version: '2'

services:

  webapp:
    build:
      context: .
    image: hello-world1
  redis:
    image: redis:latest

I do not see any reason to pull hello-world1 image on docker-compose pull command. Furthermore, the image hello-world1 is used for local usage only so I will have unwanted error Error: image library/hello-world1 not found.

I suggest to not pull service image whenever the build option is provided.

[aanand]

I do not see any reason to pull hello-world1 image on docker-compose pull command.

This was actually one of the use cases that first prompted us to support both build and image simultaneously. Some teams have pre-baked images for services that take time to build, so that developers can just pull them instead of going through the build process. Then, as and when they need to make changes to a service, they can run docker-compose build <service>.

To avoid a failed pull, you can either specify the services to pull (docker-compose pull redis) or ignore failures (docker-compose pull --ignore-pull-failures).