Delegate Communcation Streams

[joshmeranda]

Add support for delegate stream communication. Currently only single messages and broadcasts are supported, but streams would be useful when the gateway needs to continuously check the agent for data with minimal network data.

For example, when monitoring the progress of a data import (as in #1014) we currently store the progress of targets on the agent and have to continuously poll the agent to keep the user up-to-date. But a stream would allow the agent to inform the gateway every time there is an update to the target status, which would remove the need for the gateway to check the agent for import status.

[kralicky]

Can you elaborate a bit on this part? maybe give an example scenario.

when the gateway needs to continuously check the agent for data with minimal network data.

[joshmeranda]

Another benefit is avoiding spam gateway logs from the delegate server:

2023-05-04T15:00:13-04:00 DEBUG gateway.delegate gateway/delegate.go:91 delegating rpc request {"target": "2a4789ce-737d-4e0f-a92a-7fbc84f91a22", "request": "/remoteread.RemoteReadAgent/GetTargetStatus"}
2023-05-04T15:00:14-04:00 DEBUG gateway.delegate gateway/delegate.go:91 delegating rpc request {"target": "2a4789ce-737d-4e0f-a92a-7fbc84f91a22", "request": "/remoteread.RemoteReadAgent/GetTargetStatus"}
2023-05-04T15:00:15-04:00 DEBUG gateway.delegate gateway/delegate.go:91 delegating rpc request {"target": "2a4789ce-737d-4e0f-a92a-7fbc84f91a22", "request": "/remoteread.RemoteReadAgent/GetTargetStatus"}
2023-05-04T15:00:15-04:00 DEBUG gateway.delegate gateway/delegate.go:91 delegating rpc request {"target": "2a4789ce-737d-4e0f-a92a-7fbc84f91a22", "request": "/remoteread.RemoteReadAgent/GetTargetStatus"}
2023-05-04T15:00:16-04:00 DEBUG gateway.delegate gateway/delegate.go:91 delegating rpc request {"target": "2a4789ce-737d-4e0f-a92a-7fbc84f91a22", "request": "/remoteread.RemoteReadAgent/GetTargetStatus"}
2023-05-04T15:00:16-04:00 DEBUG gateway.delegate gateway/delegate.go:91 delegating rpc request {"target": "2a4789ce-737d-4e0f-a92a-7fbc84f91a22", "request": "/remoteread.RemoteReadAgent/GetTargetStatus"}
2023-05-04T15:00:17-04:00 DEBUG gateway.delegate gateway/delegate.go:91 delegating rpc request {"target": "2a4789ce-737d-4e0f-a92a-7fbc84f91a22", "request": "/remoteread.RemoteReadAgent/GetTargetStatus"}
2023-05-04T15:00:17-04:00 DEBUG gateway.delegate gateway/delegate.go:91 delegating rpc request {"target": "2a4789ce-737d-4e0f-a92a-7fbc84f91a22", "request": "/remoteread.RemoteReadAgent/GetTargetStatus"}
2023-05-04T15:00:18-04:00 DEBUG gateway.delegate gateway/delegate.go:91 delegating rpc request {"target": "2a4789ce-737d-4e0f-a92a-7fbc84f91a22", "request": "/remoteread.RemoteReadAgent/GetTargetStatus"}

[kralicky]

Well, I suppose we could just remove that log statement 😛