Dockercompose trigger doesn't recognize the implicit `latest` tag

[david-uhlig]

Docker Compose assumes the latest tag when the image: attribute is missing a tag or digest, e.g. given

# ~/docker/proxy/compose.yaml
services:
  nginx:
    image: nginx
  labels:
    wud.watch: true
    wud.watch.digest: true
    wud.tag.include: ^latest$

The command docker compose pull nginx would pull the nginx:latest image from the Docker Hub default repository.

WUD's watcher successfully detects when the image needs updating. However, WUD's dockercompose trigger fails to pull the image and restart the container.

# ~/docker/wud/compose.yaml
services:
  whatsupdocker:
    image: getwud/wud
    volumes:
      - /var/run/docker.sock:/var/run/docker.sock
      - ../proxy/compose.yaml:/docker/proxy/compose.yaml
    ports:
      - 3000:3000
    environment:
      # Local Docker watcher - Scan every hour
      - WUD_WATCHER_LOCAL_CRON=0 * * * *
      - WUD_WATCHER_LOCAL_SOCKET=/var/run/docker.sock
      - WUD_WATCHER_LOCAL_WATCHBYDEFAULT=false
      - WUD_TRIGGER_DOCKERCOMPOSE_PROXY_FILE=/docker/proxy/compose.yaml

This happens because in

wud/app/triggers/providers/dockercompose/Dockercompose.js

Lines 12 to 25 in 7e579d2

	function doesContainerBelongToCompose(compose, container) {
	// Get registry configuration
	const registry = getState().registry[container.image.registry.name];
	// Rebuild image definition string
	const currentImage = registry.getImageFullName(
	container.image,
	container.image.tag.value,
	);
	return Object.keys(compose.services).some((key) => {
	const service = compose.services[key];
	return service.image.includes(currentImage);
	});
	}

currentImage will end with the explicit :latest tag, but service.image might not, as it refers to the real value of the image attribute in the compose.yaml file. Hence, there won't be a match in L23 unless the image explicitly includes the :latest tag.

The expected behavior:

1. WUD should pull the image and update the container, regardless of the optional :latest tag.
2. It should not update the compose.yaml file from image: nginx to image: nginx:latest.

A temporary workaround is to explicitly add the :latest tag to all such images.

See also: #775

[PrivatePuffin]

I think you misunderstand what the docker-compose trigger is for...

Docker-Compose trigger, updates SEMVER tags within compose files.
It does not update:

• Non-Semver tags
• Digests

Non-semver tags are not changed (the times it does suggest other non-semver tags, is buggy behavior and 99% of the times completely wrong).

So:
No semver tag change == no docker-compose update
So this is working as intended.

The only issue is the fact that the dockerfile doesn't match the running container (technically), but even then it wouldn't do non-semver changes.

[david-uhlig]

According to the documentation, the docker-compose trigger does more than updating the container tag in the compose.yml. It also pulls the updated image and refreshes the container.

With the given configuration, which tells WUD to look for digest changes on the latest tag:

# ~/docker/proxy/compose.yaml
services:
  nginx:
    image: nginx # Implicit latest tag
  labels:
    wud.watch: true
    wud.watch.digest: true
    wud.tag.include: ^latest$

1. The WUD watcher does detect digest changes.
2. The docker-compose trigger will not activate because it doesn't recognize the implicit latest tag on image: nginx.

However, when adding the latest tag explicitly:

# ~/docker/proxy/compose.yaml
services:
  nginx:
    image: nginx:latest # Explicit latest tag
  labels:
    wud.watch: true
    wud.watch.digest: true
    wud.tag.include: ^latest$

1. The WUD watcher does detect digest changes.
2. The docker-compose trigger will activate, pull the image and refresh the container.

From the Docker Compose perspective, both configs are equivalent. Therefore, it feels unintuitive, that WUD would treat them differently. Furthermore, there is currently no way in WUD, to pull and refresh updated Docker Compose services with the implicit latest tag.

[PrivatePuffin]

Ahh yes, so we do have a bug indeed.

In both cases it should either pull digests or not pull digests.
Imgo, it should not refresh containers on digest pull if there are no docker-compose changes being made.
If people want that behavior they should setup the docker trigger instead.

[PrivatePuffin]

I can confirm in-code that it's buggy anyway, because the code will order a refresh of any container in any compose-file on trigger. regardless of update status.

[PrivatePuffin]

Above PR should ensure docker-compose trigger works as expected:
Update compose file and ensure running containers match the compose file.

Nothing more.

---

If you want digest-only updates to running containers, you can use the docker trigger with the digest threshold when #859 is merged. (which fixed the fact docker couldn't be used to ensure this behavior)

[david-uhlig]

Respectfully, I disagree.

It is common to have compose.yml configurations with mixed service declarations like:

# ~/docker/proxy/compose.yaml
services:
  nginx:
    image: nginx
    labels:
      wud.watch: true
      wud.watch.digest: true
      wud.tag.include: ^latest$

  mariadb:
    image: mariadb:lts
    labels:
      wud.watch: true
      wud.watch.digest: true
      wud.tag.include: ^lts$

  redis:
    image: redis:8.2.3
    labels:
      wud.watch: true

Following your suggestion would mean that the nginx and mariadb services would be configured by the Docker trigger, while the redis service would be configured by the Docker Compose trigger. When someone later changes the redis service to a non-SemVer tag (e.g. 8.2), the redis service would suddenly be configured by the Docker trigger as well.

That would be confusing behaviour for me. For my part:

• All Docker Compose services should be configured through the Docker Compose trigger, regardless of their tag.
• The tag should only be updated if it changes.
• Container pulling and refreshing should occur regardless of whether the tag is updated.

All of the above is the current standard behaviour for the Docker Compose trigger, except for my reported bug. If you want to change the behaviour, it deserves its own report, in my humble opinion.

[PrivatePuffin]

• All Docker Compose services should be configured through the Docker Compose trigger, regardless of their tag.

Docker-Compose Is a trigger just intended to handle docker-compose files. Nothing more, nothing less
The oversight in the code is that some non-modified container are still getting forced-updated.

That was never intended in-code or in -doce.

You can disagree with that all you want, but docker-compose trigger is never designed as a digest-update tool.

---

However, I agree that docker-compose SHOULD cover digest updates (see my other issue report).
But only IF its explicit in the compose-file (in which case, it should update the compose-file with the new digest AND update the running container in the same way)

What you are expecting is to update the container, without an update specification specified in either the trigger or compose-file. Thats unacceptable behaviour.

[PrivatePuffin]

Following your suggestion would mean that the nginx and mariadb services would be configured by the Docker trigger, while the redis service would be configured by the Docker Compose trigger.

Yes, because literally all code except the docker-compose mistake works that way.

[PrivatePuffin]

All of the above is the current standard behaviour for the Docker Compose trigger,

Precisely, in all cases docker-compose is bugged vs other updating code.
Mostly because tiggers are a special case, when it comes to code.

[PrivatePuffin]

If you want to change the behaviour, it deserves its own report, in my humble opinion.

I dont need to file an issue to file a PR, thank you very much.

[david-uhlig]

I might have missed that you've become the maintainer of this software. Unless that's the case, we should let him decide. I would appreciate it if you could revise your communication style, it's disrespectful.

[s-b-e-n-s-o-n]

This has been fixed in WUD-CE as of 9.0.0-ce — docker-compose trigger now only updates services with actual image changes, and normalizes implicit latest tags.

[s-b-e-n-s-o-n]

This is addressed in WUD Community Edition (whatsupdocker-ce). The docker-compose trigger now normalizes implicit latest tags — image: nginx is treated as equivalent to image: nginx:latest so it no longer triggers a false version mismatch.