Make `labgrid-client` work with local-only configuration

[flxzt]

Currently it is only possible to use the labgrid-client tool with the distributed infrastructure - deployed exporter, coordinator, and so on.

When trying to use labgrid-client with only a local environment configuration where no remote place is specified and no coordinator address is supplied, the client errors out with message:

No RemotePlace found in configuration file

IMHO it would be nice to close the feature gap of the client for local usage by either use the locally defined resources directly for some of it's commands like io, or console, or start coordinator&exporter on-demand internally in some way.

[luke-hackwell]

Hi, I've been experimenting to get labgrid-client to work without the coordinator deployed. I'd like to get some opinions of if this design could be useful.

You can see a rough implementation in this commit. The diff looks large, but there aren't actually that many meaningful changes.

I've split the client into a remote and local part. The remote part works as the client does now. The local part can interact with devices, but can't do anything with places.

The existing ClientSession class has been split into a base ClientSession and subclasses of RemoteSession and LocalSession. The base ClientSession implements functions that interact with devices and other common functionality. RemoteSession implements functionality for places on top of this. RemoteSession and LocalSession implement the _get_target method, which allows the LocalSession to get targets without the need for places.

CL args have been split between remote and local. A new CL target labgrid-client-local has been made that contains only commands to run in local mode. In local mode the client will run based on the resources and drivers specified in the main target of the config file.

To try this:

labgrid-local-client -c ssh.yaml ssh

ssh.yaml

targets:
  main:
    resources:
      NetworkService:
        address: "localhost"
        username: "lukhac01"
    drivers:
      SSHDriver: {}

I've only tested the ssh command, but it seems like the others should also work (apart from the console command because it is async).

[luke-hackwell]

I also tried spinning up a local coordinator. In this case you'd have to create places, add matches, export resources and such behind the scenes, which seems like more effort and a worse design than the other approach

[luke-hackwell]

Hi @Emantor, are there any thoughts on this?

[Emantor]

I don't think using a spearate command for the local client is strictly necessary, We should be able to detect whether a ClientSession is required at all by looking into the configuration file early and figuring out if it contains a RemotePlace resource. If it does not we should be able to operate without a ClientSession.