Move fetching response from channel to request() method

Also parse error on bad status in request method.
This pattern was scattered all over the place.

internal/lvgen/procedures.tmpl

@@ -140,17 +140,11 @@ func (l *Libvirt) {{.Name}}({{range $ix, $arg := .Args}}{{if $ix}}, {{end}}{{.Na
 		return
 	}
 {{end}}
-	var resp <-chan response
-	resp, err = l.request({{.Num}}, constants.Program, &buf)
+{{if .RetStruct}}	var r response{{end}}
+	{{if .RetStruct}}r{{else}}_{{end}}, err = l.request({{.Num}}, constants.Program, &buf)
 	if err != nil {
 		return
 	}
-
-	r := <-resp
-	if r.Status != StatusOK {
-		err = decodeError(r.Payload)
-		return
-	}
 {{if .RetStruct}}
 	// Return value unmarshaling
 	rdr := bytes.NewReader(r.Payload)

libvirt.go

@@ -152,19 +152,12 @@ func (l *Libvirt) Events(dom string) (<-chan DomainEvent, error) {
 		return nil, err
 	}
 
-	resp, err := l.request(constants.QEMUConnectDomainMonitorEventRegister, constants.ProgramQEMU, &buf)
+	res, err := l.request(constants.QEMUConnectDomainMonitorEventRegister, constants.ProgramQEMU, &buf)
 	if err != nil {
-		return nil, err
-	}
-
-	res := <-resp
-	if res.Status != StatusOK {
-		err = decodeError(res.Payload)
 		if err == ErrUnsupported {
 			return nil, ErrEventsNotSupported
 		}
-
-		return nil, decodeError(res.Payload)
+		return nil, err
 	}
 
 	dec := xdr.NewDecoder(bytes.NewReader(res.Payload))
@@ -250,17 +243,11 @@ func (l *Libvirt) Run(dom string, cmd []byte) ([]byte, error) {
 		return nil, err
 	}
 
-	resp, err := l.request(constants.QEMUDomainMonitor, constants.ProgramQEMU, &buf)
+	res, err := l.request(constants.QEMUDomainMonitor, constants.ProgramQEMU, &buf)
 	if err != nil {
 		return nil, err
 	}
 
-	res := <-resp
-	// check for libvirt errors
-	if res.Status != StatusOK {
-		return nil, decodeError(res.Payload)
-	}
-
 	// check for QEMU process errors
 	if err = getQEMUError(res); err != nil {
 		return nil, err

rpc.go

@@ -131,41 +131,22 @@ func (l *Libvirt) connect() error {
 
 	// libvirt requires that we call auth-list prior to connecting,
 	// event when no authentication is used.
-	resp, err := l.request(constants.ProcAuthList, constants.Program, &buf)
+	_, err = l.request(constants.ProcAuthList, constants.Program, &buf)
 	if err != nil {
 		return err
 	}
 
-	r := <-resp
-	if r.Status != StatusOK {
-		return decodeError(r.Payload)
-	}
-
-	resp, err = l.request(constants.ProcConnectOpen, constants.Program, &buf)
+	_, err = l.request(constants.ProcConnectOpen, constants.Program, &buf)
 	if err != nil {
 		return err
 	}
 
-	r = <-resp
-	if r.Status != StatusOK {
-		return decodeError(r.Payload)
-	}
-
 	return nil
 }
 
 func (l *Libvirt) disconnect() error {
-	resp, err := l.request(constants.ProcConnectClose, constants.Program, nil)
-	if err != nil {
-		return err
-	}
-
-	r := <-resp
-	if r.Status != StatusOK {
-		return decodeError(r.Payload)
-	}
-
-	return nil
+	_, err := l.request(constants.ProcConnectClose, constants.Program, nil)
+	return err
 }
 
 // listen processes incoming data and routes
@@ -281,16 +262,11 @@ func (l *Libvirt) removeStream(id uint32) error {
 		return err
 	}
 
-	resp, err := l.request(constants.QEMUConnectDomainMonitorEventDeregister, constants.ProgramQEMU, &buf)
+	_, err = l.request(constants.QEMUConnectDomainMonitorEventDeregister, constants.ProgramQEMU, &buf)
 	if err != nil {
 		return err
 	}
 
-	res := <-resp
-	if res.Status != StatusOK {
-		return decodeError(res.Payload)
-	}
-
 	l.em.Lock()
 	delete(l.events, id)
 	l.em.Unlock()
@@ -314,9 +290,9 @@ func (l *Libvirt) deregister(id uint32) {
 }
 
 // request performs a libvirt RPC request.
-// The returned channel is used by the caller to receive the asynchronous
-// call response. The channel is closed once a response has been sent.
-func (l *Libvirt) request(proc uint32, program uint32, payload *bytes.Buffer) (<-chan response, error) {
+// returns response returned by server.
+// if response is not OK, decodes error from it and returns it.
+func (l *Libvirt) request(proc uint32, program uint32, payload *bytes.Buffer) (response, error) {
 	serial := l.serial()
 	c := make(chan response)
 
@@ -344,22 +320,27 @@ func (l *Libvirt) request(proc uint32, program uint32, payload *bytes.Buffer) (<
 	defer l.mu.Unlock()
 	err := binary.Write(l.w, binary.BigEndian, p)
 	if err != nil {
-		return nil, err
+		return response{}, err
 	}
 
 	// write payload
 	if payload != nil {
 		err = binary.Write(l.w, binary.BigEndian, payload.Bytes())
 		if err != nil {
-			return nil, err
+			return response{}, err
 		}
 	}
 
 	if err := l.w.Flush(); err != nil {
-		return nil, err
+		return response{}, err
 	}
 
-	return c, nil
+	resp := <-c
+	if resp.Status != StatusOK {
+		return resp, decodeError(resp.Payload)
+	}
+
+	return resp, nil
 }
 
 // encode XDR encodes the provided data.