Merge pull request #104 from BetaXOi/query-schema

qmp: support command 'query-qmp-schema'

qemu/qmp.go

@@ -84,6 +84,9 @@ type QMPConfig struct {
 	// logger is used by the qmpStart function and all the go routines
 	// it spawns to log information.
 	Logger QMPLog
+
+	// specify the capacity of buffer used by receive QMP response.
+	MaxCapacity int
 }
 
 type qmpEventFilter struct {
@@ -242,8 +245,19 @@ type MigrationStatus struct {
 	XbzrleCache  MigrationXbzrleCache     `json:"xbzrle-cache,omitempty"`
 }
 
+// SchemaInfo represents all QMP wire ABI
+type SchemaInfo struct {
+	MetaType string `json:"meta-type"`
+	Name     string `json:"name"`
+}
+
 func (q *QMP) readLoop(fromVMCh chan<- []byte) {
 	scanner := bufio.NewScanner(q.conn)
+	if q.cfg.MaxCapacity > 0 {
+		buffer := make([]byte, q.cfg.MaxCapacity)
+		scanner.Buffer(buffer, q.cfg.MaxCapacity)
+	}
+
 	for scanner.Scan() {
 		line := scanner.Bytes()
 		if q.cfg.Logger.V(1) {
@@ -260,6 +274,7 @@ func (q *QMP) readLoop(fromVMCh chan<- []byte) {
 
 		fromVMCh <- sendLine
 	}
+	q.cfg.Logger.Infof("sanner return error: %v", scanner.Err())
 	close(fromVMCh)
 }
 
@@ -1509,3 +1524,24 @@ func (q *QMP) ExecuteMigrationIncoming(ctx context.Context, uri string) error {
 	}
 	return q.executeCommand(ctx, "migrate-incoming", args, nil)
 }
+
+// ExecQueryQmpSchema query all QMP wire ABI and returns a slice
+func (q *QMP) ExecQueryQmpSchema(ctx context.Context) ([]SchemaInfo, error) {
+	response, err := q.executeCommandWithResponse(ctx, "query-qmp-schema", nil, nil, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	// convert response to json
+	data, err := json.Marshal(response)
+	if err != nil {
+		return nil, fmt.Errorf("unable to extract memory devices information: %v", err)
+	}
+
+	var schemaInfo []SchemaInfo
+	if err = json.Unmarshal(data, &schemaInfo); err != nil {
+		return nil, fmt.Errorf("unable to convert json to schemaInfo: %v", err)
+	}
+
+	return schemaInfo, nil
+}

qemu/qmp_test.go

@@ -1588,3 +1588,38 @@ func TestMainLoopEventBeforeGreeting(t *testing.T) {
 	q.Shutdown()
 	<-disconnectedCh
 }
+
+func TestQMPExecQueryQmpSchema(t *testing.T) {
+	connectedCh := make(chan *QMPVersion)
+	disconnectedCh := make(chan struct{})
+	buf := newQMPTestCommandBuffer(t)
+	schemaInfo := []SchemaInfo{
+		{
+			MetaType: "command",
+			Name:     "object-add",
+		},
+		{
+			MetaType: "event",
+			Name:     "VSOCK_RUNNING",
+		},
+	}
+	buf.AddCommand("query-qmp-schema", nil, "return", schemaInfo)
+	cfg := QMPConfig{
+		Logger:      qmpTestLogger{},
+		MaxCapacity: 1024,
+	}
+	q := startQMPLoop(buf, cfg, connectedCh, disconnectedCh)
+	checkVersion(t, connectedCh)
+	info, err := q.ExecQueryQmpSchema(context.Background())
+	if err != nil {
+		t.Fatalf("Unexpected error: %v\n", err)
+	}
+	if len(schemaInfo) != 2 {
+		t.Fatalf("Expected schema infos length equals to 2\n")
+	}
+	if reflect.DeepEqual(info, schemaInfo) == false {
+		t.Fatalf("Expected %v equals to %v\n", info, schemaInfo)
+	}
+	q.Shutdown()
+	<-disconnectedCh
+}