[Design] Elastic Agent Control Protocol v2 gRPC.

[ph]

Goals

• Allow health reportings per Inputs, or outputs.
• Allow processes to route logs event through the gRPC endpoint.
• Allow Elastic Agent to Collect Input or Output specific metric
• Allow Elastic Agent to offer services to runnings process (k,v services).
• Support v1 and v2 clients.
• List of metrics collected by the Elastic Agent about his managed processes.

Deliverables

• A new protocol file.
• Sequence Diagram that describe:
  • Initiale handshake
  • How configuration are sent to the process
  • How Action are sent to the running process
• State diagram for the health status for Elastic Agent and the runnings processes
• High-level diagram interaction of the different components.
• Define behavior of Agent when a process or health
• A client/server Go implementation

WIP at elastic/elastic-agent-client#29