How does communication between the CLI and the Agent work?

Disclaimer: Looked briefly at bidirectional communication with Hashicorp plugin model but tabled that for now https://github.com/hashicorp/go-plugin/tree/main/examples/bidirectional

Goal here is to make the API somewhat clean to that we can move to this model later if needed.

Terminology

Since the CLI is the one that initiates the communication, we will call it the client and the agent the server.

Flows

• Client asks server if communication is required for a given channel
• If no, client proceeds with the command
• If yes, client start a communication session with the server until the server is satisfied

Communication session

• Client sends an initial Information request to the server
• Server sends back an InformationRequest
• Client processes the InformationRequest with a handler (CLI prompt) and returns an Answer
• The Answer is sent back to the server
• If satisfied, the server communicates back that it is done
• Otherwise, we repeat the process until the server is satisfied