55 lines
1.8 KiB
Markdown
55 lines
1.8 KiB
Markdown
# RPC
|
|
|
|
This section is a work in progress.
|
|
|
|
The RPC subsystem is exclusicely in Server Agents. It is comprised of two main components:
|
|
|
|
1. the "RPC Server" (for lack of a better term) handles multiplexing of many different
|
|
requests on a single TCP port.
|
|
2. RPC endpoints handle RPC requests and return responses.
|
|
|
|
The RPC subsystems handles requests from:
|
|
|
|
1. Client Agents in the local DC
|
|
2. (if the server is a leader) other Server Agents in the local DC
|
|
3. Server Agents in other Datacenters
|
|
4. in-process requests from other components running in the same process (ex: the HTTP API
|
|
or DNS interface).
|
|
|
|
## Routing
|
|
|
|
The "RPC Server" accepts requests to the [server port] and routes the requests based on
|
|
configuration of the Server and the the first byte in the request. The diagram below shows
|
|
all the possible routing flows.
|
|
|
|
[server port]: https://www.consul.io/docs/agent/options#server_rpc_port
|
|
|
|
|
|
|
|
<sup>[source](./routing.mmd)</sup>
|
|
|
|
The main entrypoint to RPC routing is `handleConn` in [agent/consul/rpc.go].
|
|
|
|
[agent/consul/rpc.go]: https://github.com/hashicorp/consul/blob/main/agent/consul/rpc.go
|
|
|
|
|
|
## RPC Endpoints
|
|
|
|
This section is a work in progress, it will eventually cover topics like:
|
|
|
|
- net/rpc - (in the stdlib)
|
|
- new grpc endpoints
|
|
- [Streaming](./streaming)
|
|
- [agent/structs](https://github.com/hashicorp/consul/tree/main/agent/structs) - contains definitions of all the internal RPC protocol request and response structures.
|
|
|
|
|
|
## RPC connections and load balancing
|
|
|
|
This section is a work in progress, it will eventually cover topics like:
|
|
|
|
Routing RPC request to Consul servers and for connection pooling.
|
|
|
|
- [agent/router](https://github.com/hashicorp/consul/tree/main/agent/router)
|
|
- [agent/pool](https://github.com/hashicorp/consul/tree/main/agent/pool)
|
|
|