Add listen events command (#171)

Signed-off-by: Congqi Xia <[email protected]>

eventlog/event_log.proto

@@ -0,0 +1,26 @@
+syntax = "proto3";
+package milvus.proto.eventlog;
+
+option go_package = "github.com/milvus-io/birdwatcher/eventlog";
+
+service EventLogService {
+    rpc Listen(ListenRequest) returns(stream Event) {}
+}
+
+message ListenRequest {
+}
+
+message Event {
+    Level level = 1;
+    int32 type = 2;
+    bytes data = 3;
+    int64 ts = 4;
+}
+
+enum Level {
+    Undefined = 0;
+    Debug = 1;
+    Info = 2;
+    Warn = 3;
+    Error = 4;
+}

eventlog/listener.go

@@ -0,0 +1,67 @@
+package eventlog
+
+import (
+	"context"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
+)
+
+type Listener struct {
+	conn   *grpc.ClientConn
+	client EventLogServiceClient
+	stream EventLogService_ListenClient
+	closed chan struct{}
+}
+
+func NewListener(ctx context.Context, addr string) (*Listener, error) {
+	opts := []grpc.DialOption{
+		grpc.WithTransportCredentials(insecure.NewCredentials()),
+		grpc.WithBlock(),
+		grpc.WithTimeout(time.Second),
+	}
+
+	conn, err := grpc.DialContext(ctx, addr, opts...)
+	if err != nil {
+		return nil, err
+	}
+
+	client := NewEventLogServiceClient(conn)
+	return &Listener{
+		conn:   conn,
+		client: client,
+	}, nil
+}
+
+func (l *Listener) Start(ctx context.Context) (<-chan *Event, error) {
+	ch := make(chan *Event, 100)
+	s, err := l.client.Listen(ctx, &ListenRequest{})
+	if err != nil {
+		return nil, err
+	}
+
+	go func() {
+		defer close(ch)
+		for {
+			evt, err := s.Recv()
+			if err != nil {
+				return
+			}
+			select {
+			case ch <- evt:
+			case <-l.closed:
+				return
+			}
+		}
+	}()
+
+	return ch, nil
+}
+
+func (l *Listener) Stop() {
+	close(l.closed)
+	if l.stream != nil {
+		l.stream.CloseSend()
+	}
+}

go.mod

@@ -9,6 +9,7 @@ require (
 	github.com/c-bata/go-prompt v0.2.6
 	github.com/cockroachdb/errors v1.9.1
 	github.com/confluentinc/confluent-kafka-go v1.9.1
+	github.com/fatih/color v1.7.0
 	github.com/gin-gonic/gin v1.9.1
 	github.com/golang/protobuf v1.5.2
 	github.com/gosuri/uilive v0.0.4