agent: return port attributes from devcontainer

[johnstcn]

We're currently missing portAttributes in the devcontainers response:

https://containers.dev/implementors/json_reference/#port-attributes

Fetch this from the devcontainer metadata Docker container label and return it in the response.

[mafredri]

To clarify the scope of the issue and help drive the implementation, I'd like to ask:

• What is the goal with adding portAttributes on the response?
• How will it be used once there?

[johnstcn]

What is the goal with adding portAttributes on the response?

There are a few attributes that will be useful for us, such as label and protocol.

label will be useful in both the UI and for referring to ports in some way later.
protocol is unclear at the moment, so TBD.

It's more of a "in case we need it" than anything else.

[defelmnq]

After some discussions with @mafredri - we'd need some more details @johnstcn :

from devcontainers.json reference documentation - there's two ways to describe ports :

• forwardPorts which is the recommended way. Once the container is running, the forwarded ports do not appear in the docker inspect command, excepted in the Labels.devcontainersmetadata.
• appPort which is not the recommended way, but shows the port in docker inspect port section.

Here's an example from what we can do on devcontainers.json part :

	"appPort": ["127.0.0.1:9998:9998"],
	"forwardPorts": [9999],
	"portsAttributes": {
		"9998": { "label": "Foobar" }
	}

Purely talking about the scope of this ticket , we could rely on the metadata and return the ports and associated fields - still we're curious about if we really do want to do it or not ? As the forwardPorts part seems not to be handled by docker but more a devcontainers related process - it will probably not be usable, even if the info is shared.

Are we missing some context ?