micro/go-micro · error

rpc: service/endpoint request ill-formed: ${endpoint}

Error message

rpc: service/endpoint request ill-formed: ${endpoint}

What it means

This error means the RPC request's Endpoint field did not contain exactly one dot separating service name from method name. The router splits req.msg.Endpoint on '.' and requires exactly two parts; anything else is ill-formed and cannot be routed. The connection is kept alive (keepReading=true) so the client can send further requests.

Source

Thrown at server/rpc_router.go:426

	err = cc.ReadHeader(msg, msg.Type)
	if err != nil {
		req = nil
		if err == io.EOF || err == io.ErrUnexpectedEOF {
			return
		}
		err = errors.New("rpc: router cannot decode request: " + err.Error())

		return
	}

	// 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])
	}

View on GitHub (pinned to 24529f1404)

Solutions

1. Send the endpoint as exactly "ServiceName.MethodName" with a single dot
2. Trim any package path or namespace prefix from the service name before sending
3. Log req.msg.Endpoint on the client before dispatch to confirm the wire format
4. If using a custom codec, ensure it does not mangle or split the endpoint field

Example fix

// before
msg.Endpoint = "mypackage/MyService.Calculate"
// after
msg.Endpoint = "MyService.Calculate"

func validEndpoint(ep string) bool {
	parts := strings.Split(ep, ".")
	return len(parts) == 2 && parts[0] != "" && parts[1] != ""
}
if !validEndpoint(msg.Endpoint) { return fmt.Errorf("bad endpoint: %q", msg.Endpoint) }

When it happens

Trigger: Sending a request whose endpoint string has no dot ("MyService"), more than one dot ("pkg/MyService.Method" or "Service.Method.Extra"), or an empty endpoint.

Common situations: Hand-rolled RPC clients that forget the Service.Method format; endpoints copied from code paths containing package qualifiers or slashes; a client library upgrade that changed endpoint encoding; empty endpoint due to unset config field.

Related errors

• go.micro.client
• streamer not implemented
• connection header set to close
• rpc Register: type ${sname} is not exported
• rpc: service already defined: ${sname}

AI-assisted analysis of micro/go-micro@24529f1404 (2026-09-01). Data as JSON: /api/errors/c4f75a780dcd85e8. Report an issue: GitHub.