Exposing Ports

[river yacht]

Hi All,
How do we expose ports using dagger, i've not been able to find any docs for this, if someone can guide me that would be great

[hidden pewter]

Hi @river yacht, currently dagger does not support long-running containers (aka "services"). It's planned though, we had an early support in the cue sdk but this needs to be ported to the new API. Once done, a service will be able to expose a port.

If you describe your use case here, maybe we can find a workaround.

[river yacht]

@hidden pewter my use case is very simple, i'm just trying to replicate the behaviour that we have with EXPOSE instruction in a Dockerfile, basically, when building my container images using dagger i want to have the resulting image such that the container runtime expose x ports.

[digital basin]

@river yacht EXPOSE in Dockerfiles is mostly for documentation purposes, it doesn't actually have any effects when the container is started since you still need to send the -p flag regardless. Having said that, you might want to follow this discussion as well https://discord.com/channels/707636530424053791/1042501877906022481 since that's related. cc @proper dirge

ref: https://github.com/dagger/dagger/issues/3886

[river yacht]

Thanks @digital basin

[vital locust]

Thanks, that was useful for my usecase too.

[heavy grotto]

I think you can either :

1. just skip expose, since tools en generally don’t use it nowadays.

2. try a hack like this:

justExpose := c.Container().Build(c.Directory().WithNewFile("Dockerfile", "FROM scratch\nEXPOSE 8080"))
ctr := justExpose.<the rest of your build here>

[river yacht]

Thanks @heavy grotto