New RPC Endpoint Checklist

Prefer adding a new message to changing any existing RPC messages.

Code

Request struct and *RequestType constant in nomad/structs/structs.go. Append the constant, old constant values must remain unchanged
In nomad/fsm.go, add a dispatch case to the switch statement in (n *nomadFSM) Apply
- *nomadFSM method to decode the request and call the state method
State method for modifying objects in a Txn in nomad/state/state_store.go
- nomad/state/state_store_test.go
Handler for the request in nomad/foo_endpoint.go
- RPCs are resolved by matching the method name for bound structs net/rpc
- Check ACLs for security, list endpoints filter by ACL
- Register new RPC struct in nomad/server.go
- Check ACLs to enforce security
Wrapper for the HTTP request in command/agent/foo_endpoint.go
- Backwards compatibility requires a new endpoint, an upgraded client or server may be forwarding this request to an old server, without support for the new RPC
- RPCs triggered by an internal process may not need support
- Check ACLs as an optimization
nomad/core_sched.go sends many RPCs
- ServersMeetMinimumVersion asserts that the server cluster is upgraded, so use this to gaurd sending the new RPC, else send the old RPC
- Version must match the actual release version!