What causes "rpc: can't find service ${service}" in micro/go-micro?

Register the service on the server before accepting requests: server.Handle(handler)

rpc: can't find service ${service}

Error message

rpc: can't find service ${service}

What it means

The endpoint was well-formed, but the service name (the part before the dot) is not present in the router's serviceMap. No handler with that name was registered via Handle/NewHandler on this server. The request is rejected and the server continues reading.

Source

Thrown at server/rpc_router.go:436

	}

	// We read the header successfully. If we see an error now,
	// we can still recover and move on to the next request.
	keepReading = true

	serviceMethod := strings.Split(req.msg.Endpoint, ".")
	if len(serviceMethod) != 2 {
		err = errors.New("rpc: service/endpoint request ill-formed: " + req.msg.Endpoint)
		return
	}

	// Look up the request.
	router.mu.Lock()
	service = router.serviceMap[serviceMethod[0]]
	router.mu.Unlock()

	if service == nil {
		err = errors.New("rpc: can't find service " + serviceMethod[0])
		return
	}

	mtype = service.method[serviceMethod[1]]
	if mtype == nil {
		err = errors.New("rpc: can't find method " + serviceMethod[1])
	}

	return
}

func (router *router) NewHandler(h interface{}, opts ...HandlerOption) Handler {
	return NewRpcHandler(h, opts...)
}

func (router *router) Handle(h Handler) error {
	router.mu.Lock()
	defer router.mu.Unlock()

View on GitHub (pinned to 24529f1404)

Solutions

Register the service on the server before accepting requests: server.Handle(handler)
Verify the endpoint's service name matches h.Name() exactly, including case
Confirm the client is dialing the server instance that actually registers this service
List registered services at startup and log them to compare with client requests

Example fix

// before (client)
msg.Endpoint = "OrderSvc.Place" // never registered
// after (server)
router.NewHandler(NewOrderService("OrderSvc"))
// client
msg.Endpoint = "OrderSvc.Place"

Defensive patterns

Strategy: try-catch

Try / catch

reply, err := client.Call(ctx, "OrderSvc.Place", args)
if err != nil {
	if strings.Contains(err.Error(), "can't find service") {
		// fail fast: wrong server or service not registered; do not retry blindly
		log.Fatalf("service not registered: %v", err)
	}
	return err
}

Prevention

Register all services before the server starts accepting connections
Share a single source of truth (constants) for service names between client and server
Log the set of registered service names at server startup
Verify client dial target points at the server hosting the service

When it happens

Trigger: Calling an RPC whose service name was never registered, registered under a different name, or registered on a different router/server instance; typo in the service portion of the endpoint.

Common situations: Service renamed during refactoring while clients still use the old name; handler registration skipped due to failed startup ordering; client pointed at the wrong server/port that hosts other services; case mismatch (service names must be exported).

Related errors

AI-assisted analysis of micro/go-micro@24529f1404 (2026-09-01). Data as JSON: /api/errors/08e8d5b1687123ae. Report an issue: GitHub.