What causes "profiling: no grpc.Server provided" in grpc/grpc-go?

Create the *grpc.Server first, then pass it: profiling.Init(&profiling.ProfilingConfig{Server: s, Enabled: true, StreamStatsSize: N}).

grpc/grpc-go · error

profiling: no grpc.Server provided

Error message

profiling: no grpc.Server provided

What it means

Returned by profiling.Init when the supplied ProfilingConfig has a nil Server field. The profiling package needs a *grpc.Server to register its ProfilingService handler on; without one there is no way to expose the profiling RPCs, so Init bails out before initializing stats.

Solutions

Create the *grpc.Server first, then pass it: profiling.Init(&profiling.ProfilingConfig{Server: s, Enabled: true, StreamStatsSize: N}).
If you only want in-process stats and not the RPC service, note that this package requires a server; call internal/profiling directly instead.
Guard with a nil check so the program logs and continues rather than returning a hard error during startup.

Example fix

// before
profiling.Init(&profiling.ProfilingConfig{Enabled: true, StreamStatsSize: 1024})
// after
s := grpc.NewServer()
profiling.Init(&profiling.ProfilingConfig{Enabled: true, StreamStatsSize: 1024, Server: s})

Defensive patterns

Strategy: validation

Validate before calling

if pc.Server == nil {
    log.Printf("skipping profiling.Init: no grpc.Server provided")
    return
}
if err := profiling.Init(pc); err != nil { log.Fatal(err) }

Try / catch

if err := profiling.Init(pc); err != nil { if errors.Is(err, service.ErrorNilServer) { /* server was nil; init order bug */ log.Printf("profiling not started: %v", err) } else { return err } }

Prevention

Always construct *grpc.Server before profiling.Init.
Wire profiling.Init in the same function that calls RegisterService to keep ordering obvious.
Add a unit test asserting profiling.Init fails fast when Server is nil (documented contract).

When it happens

Trigger: Calling profiling.Init(&profiling.ProfilingConfig{Enabled: true, StreamStatsSize: 1000}) without setting Server. Common when an app constructs the config before the *grpc.Server is created and forgets to wire it back.

Common situations: Order-of-initialization bug: profiling.Init invoked before grpc.NewServer. Refactor that introduced a NewProfilingConfig helper that never receives the server. Test code that wants stats but not the RPC service.

Related errors

AI-assisted analysis of grpc/grpc-go@0c51461d27 (2026-08-11). Data as JSON: /api/errors/84374e432af8a7fe. Report an issue: GitHub.

Appendix: source

Thrown at profiling/service/service.go:61

// ProfilingConfig defines configuration options for the Init method.
type ProfilingConfig struct {
	// Setting this to true will enable profiling.
	Enabled bool

	// Profiling uses a circular buffer (ring buffer) to store statistics for
	// only the last few RPCs so that profiling stats do not grow unbounded. This
	// parameter defines the upper limit on the number of RPCs for which
	// statistics should be stored at any given time. An average RPC requires
	// approximately 2-3 KiB of memory for profiling-related statistics, so
	// choose an appropriate number based on the amount of memory you can afford.
	StreamStatsSize uint32

	// To expose the profiling service and its methods, a *grpc.Server must be
	// provided.
	Server *grpc.Server
}

var errorNilServer = errors.New("profiling: no grpc.Server provided")

// Init takes a *ProfilingConfig to initialize profiling (turned on/off
// depending on the value set in pc.Enabled) and register the profiling service
// in the server provided in pc.Server.
func Init(pc *ProfilingConfig) error {
	if pc.Server == nil {
		return errorNilServer
	}

	if err := profiling.InitStats(pc.StreamStatsSize); err != nil {
		return err
	}

	ppb.RegisterProfilingServer(pc.Server, getProfilingServerInstance())

	// Do this last after everything has been initialized and allocated.
	profiling.Enable(pc.Enabled)

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