Zarf does not respect docker contexts

[mjnagel]

Environment

Device and OS: MBP, macOS
App version: v0.34.0
Kubernetes distro being used: k3d (not relevant here)
Other:

Steps to reproduce

I'm encounter an issue on my mac when I attempt to use the local docker fallback for a local image. Relevant piece of this is that my docker socket is provided by colima and is not the default path.

1. Make a zarf.yaml that references an image that does not exist remotely but is local.
2. Attempt to create this package
3. Zarf will fallback to pulling from the local docker.

Expected result

Zarf respects my docker context/uses it (note my active context is colima here):

❯ docker context ls
NAME       DESCRIPTION                               DOCKER ENDPOINT                                     ERROR
colima *   colima                                    unix:///Users/mjnagel/.colima/default/docker.sock   
cooper     Remote cooper Docker host                 ssh://cooper                                        
default    Current DOCKER_HOST based configuration   unix:///var/run/docker.sock                         

Actual Result

Zarf only considers the DOCKER_HOST environment variable:

          ERROR:  Failed to create package: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the                                                                                                  
                  docker daemon running?                                                                                                                                                                                

Severity/Priority

Low, by setting DOCKER_HOST to my active context I can make this work, although I don't believe I've been able to make docker-over-ssh work with the DOCKER_HOST env/zarf.

[AustinAbro321]

Thanks for the issue @mjnagel!

While, I'm not opposed to supporting this docker context's are more a feature of the CLI than the daemon. If we wanted to solve this we would have to get the url of the docker sock for that context.
To do this we can either:

• Figure out how to call the docker CLI from go using https://github.com/docker/cli. This can be trickier than it first seems, but if there is an easy way to get the host from calls to the cli package this would be best.
• Follow some of the docker logic summarized below to get the current context. Using the current context we would than have to look at the path ~/.docker/contexts/meta/33341cc9809c9410f1149a11fc4a79a53562069c7ff0c652fa18b8c83e3ec34b/meta.json and open that file to get the hostname of the docker sock

2. The "DOCKER_CONTEXT" environment variable.
3. The current context as configured through the in "currentContext"
field in the CLI configuration file ("~/.docker/config.json").

[mjnagel]

@AustinAbro321 interesting mention of CLI vs daemon. I may have to validate and test out a few other tools, but I think in my experience docker contexts are typically honored by other tools. k3d is the one that immediately comes to mind - clusters will be spun up on your active docker context rather than looking at the default socket only/DOCKER_HOST. From a quick skim of their code it seems like they are leveraging the go docker cli like what you mentioned in option 1.

Definitely not familiar with complexity of this on the zarf side, but it would be a pretty nice QoL improvement - especially as mentioned in my case trying to use Docker over SSH. This works for the rest of my operations (k3d, docker builds, etc) but fails with zarf's local docker fallback. If there were any workarounds this might not be so bad but I'm unaware of a way to handle this outside of Zarf itself respecting my context.

[mjnagel]

Re-running through previous testing steps, I am able to set my docker host this way to point to my docker over ssh host:

export DOCKER_HOST=ssh://mjnagel@1.2.3.4

Docker CLI commands, k3d commands, etc all work. However when I try to use zarf expecting the local docker fallback to work I encounter this issue:

 WARNING  Falling back to local 'docker', failed to find the manifest on a remote: GET
          https://index.docker.io/v2/mjnagel/test123/manifests/latest: MANIFEST_UNKNOWN: manifest
          unknown; unknown tag=latest
     ERROR:  failed to create package: error during connect: Get "http://mjnagel%401.2.3.4/v1.24/images/docker.io/mjnagel/test123:latest/json": dial tcp: lookup mjnagel@1.2.3.4: no such host

Perhaps the more troublesome problem here is that Zarf does not support docker over SSH for this local fallback - even if you put aside the context issue.

[ericwyles]

I have ran into this too and if zarf worked with docker over SSH (even if just by setting DOCKER_HOST) that would be great. I like to use docker over ssh to a linux machine to test some amd64 only stuff from my arm64 mac.

[AustinAbro321]

@mjnagel Could you make a separate issue for supporting docker over SSH

[mjnagel]

@AustinAbro321 done, #2943