Implementing an SBI client in Go

NRF Discovery in the Client Path

A consumer NF's SBI client logic starts with NRF discovery. When SMF needs to call AUSF for the first time, it sends an Nnrf_NFDiscovery request specifying the target NF type and any filter criteria (PLMN, slice, supported services). The NRF returns one or more matching NF profiles with FQDNs. SMF picks one (often based on a load hint or simple round-robin), then opens an HTTPS connection. Subsequent calls reuse that connection. Cache the discovery result for some TTL to avoid hammering NRF on every SBI call. Standard production cache durations are a few minutes with subscribe-notify for…