How do you share a volume between containers?

[lofty crow]

Hi everyone!

I'm trying to write a Dagger function to run my e2e tests. Nothing too special, just a few containers, using .AsService() and .WithServiceBinding("svc", svc).

The particularity in my setup is that I need to provision a shared volume where these different services will read and write contents. This is something that I've achieved in other environments successfully, e.g.: k8s + shared volume within a pod, k8s + persistentvolume (ReadWriteMany) or in Docker Compose by sharing a volume with multiple services.

Is there an equivalent in the Dagger space? AFAIK mounted directories and cache volumes while very useful they're not quite the same thing.

Thank you in advance!

[shrewd bear]

Hey there! Sharing a cache volume across the different services would be the equivalent of sharing a volume in compose

[lofty crow]

Really? I must have done something wrong then, I had one service add contents to the volume but it read as empty from another container. I'll try again, thank you! Will report back.

[shrewd bear]

Sure! LMK if you're still having issues and I can give it a look

[lofty crow]

I think that I misunderstood how cache mounts work when the ownership is changed. I've put an example together: https://github.com/sevein/dagger-cache-volume-visibility-test but now I can see how I can work around it.

Thank you!