Add resolved udp connection type, continually resolve dns names in background

config/config.go

@@ -384,7 +384,7 @@ func (rc *ReporterConfig) NewReporter(
 	metrics *jaeger.Metrics,
 	logger jaeger.Logger,
 ) (jaeger.Reporter, error) {
-	sender, err := rc.newTransport()
+	sender, err := rc.newTransport(logger)
 	if err != nil {
 		return nil, err
 	}
@@ -401,7 +401,7 @@ func (rc *ReporterConfig) NewReporter(
 	return reporter, err
 }
 
-func (rc *ReporterConfig) newTransport() (jaeger.Transport, error) {
+func (rc *ReporterConfig) newTransport(logger jaeger.Logger) (jaeger.Transport, error) {
 	switch {
 	case rc.CollectorEndpoint != "":
 		httpOptions := []transport.HTTPOption{transport.HTTPBatchSize(1), transport.HTTPHeaders(rc.HTTPHeaders)}
@@ -410,6 +410,9 @@ func (rc *ReporterConfig) newTransport() (jaeger.Transport, error) {
 		}
 		return transport.NewHTTPTransport(rc.CollectorEndpoint, httpOptions...), nil
 	default:
-		return jaeger.NewUDPTransport(rc.LocalAgentHostPort, 0)
+		return jaeger.NewUDPTransportWithParams(jaeger.UDPTransportParams{
+			HostPort: rc.LocalAgentHostPort,
+			Logger:   logger,
+		})
 	}
 }

config/config_test.go

@@ -561,15 +561,15 @@ func TestInvalidSamplerType(t *testing.T) {
 func TestUDPTransportType(t *testing.T) {
 	rc := &ReporterConfig{LocalAgentHostPort: "localhost:1234"}
 	expect, _ := jaeger.NewUDPTransport(rc.LocalAgentHostPort, 0)
-	sender, err := rc.newTransport()
+	sender, err := rc.newTransport(log.NullLogger)
 	require.NoError(t, err)
 	require.IsType(t, expect, sender)
 }
 
 func TestHTTPTransportType(t *testing.T) {
 	rc := &ReporterConfig{CollectorEndpoint: "http://1.2.3.4:5678/api/traces"}
 	expect := transport.NewHTTPTransport(rc.CollectorEndpoint)
-	sender, err := rc.newTransport()
+	sender, err := rc.newTransport(log.NullLogger)
 	require.NoError(t, err)
 	require.IsType(t, expect, sender)
 }
@@ -581,7 +581,7 @@ func TestHTTPTransportTypeWithAuth(t *testing.T) {
 		Password:          "auth_pass",
 	}
 	expect := transport.NewHTTPTransport(rc.CollectorEndpoint)
-	sender, err := rc.newTransport()
+	sender, err := rc.newTransport(log.NullLogger)
 	require.NoError(t, err)
 	require.IsType(t, expect, sender)
 }

transport_udp.go

@@ -19,6 +19,7 @@ import (
 	"fmt"
 
 	"github.com/uber/jaeger-client-go/internal/reporterstats"
+	"github.com/uber/jaeger-client-go/log"
 	"github.com/uber/jaeger-client-go/thrift"
 	j "github.com/uber/jaeger-client-go/thrift-gen/jaeger"
 	"github.com/uber/jaeger-client-go/utils"
@@ -57,35 +58,61 @@ type udpSender struct {
 	failedToEmitSpans    int64
 }
 
-// NewUDPTransport creates a reporter that submits spans to jaeger-agent.
+// UDPTransportParams allows specifying options for initializing a UDPTransport. An instance of this struct should
+// be passed to NewUDPTransportWithParams.
+type UDPTransportParams struct {
+	HostPort      string
+	MaxPacketSize int
+	Logger        log.Logger
+}
+
+// NewUDPTransportWithParams creates a reporter that submits spans to jaeger-agent.
 // TODO: (breaking change) move to transport/ package.
-func NewUDPTransport(hostPort string, maxPacketSize int) (Transport, error) {
-	if len(hostPort) == 0 {
-		hostPort = fmt.Sprintf("%s:%d", DefaultUDPSpanServerHost, DefaultUDPSpanServerPort)
+func NewUDPTransportWithParams(params UDPTransportParams) (Transport, error) {
+	if len(params.HostPort) == 0 {
+		params.HostPort = fmt.Sprintf("%s:%d", DefaultUDPSpanServerHost, DefaultUDPSpanServerPort)
 	}
-	if maxPacketSize == 0 {
-		maxPacketSize = utils.UDPPacketMaxLength
+
+	if params.MaxPacketSize == 0 {
+		params.MaxPacketSize = utils.UDPPacketMaxLength
+	}
+
+	if params.Logger == nil {
+		params.Logger = log.StdLogger
 	}
 
 	protocolFactory := thrift.NewTCompactProtocolFactory()
 
 	// Each span is first written to thriftBuffer to determine its size in bytes.
-	thriftBuffer := thrift.NewTMemoryBufferLen(maxPacketSize)
+	thriftBuffer := thrift.NewTMemoryBufferLen(params.MaxPacketSize)
 	thriftProtocol := protocolFactory.GetProtocol(thriftBuffer)
 
-	client, err := utils.NewAgentClientUDP(hostPort, maxPacketSize)
+	client, err := utils.NewAgentClientUDPWithParams(utils.AgentClientUDPParams{
+		HostPort:      params.HostPort,
+		MaxPacketSize: params.MaxPacketSize,
+		Logger:        params.Logger,
+	})
 	if err != nil {
 		return nil, err
 	}
 
 	return &udpSender{
 		client:         client,
-		maxSpanBytes:   maxPacketSize - emitBatchOverhead,
+		maxSpanBytes:   params.MaxPacketSize - emitBatchOverhead,
 		thriftBuffer:   thriftBuffer,
 		thriftProtocol: thriftProtocol,
 	}, nil
 }
 
+// NewUDPTransport creates a reporter that submits spans to jaeger-agent.
+// TODO: (breaking change) move to transport/ package.
+func NewUDPTransport(hostPort string, maxPacketSize int) (Transport, error) {
+	return NewUDPTransportWithParams(UDPTransportParams{
+		HostPort:      hostPort,
+		MaxPacketSize: maxPacketSize,
+	})
+}
+
 // SetReporterStats implements reporterstats.Receiver.
 func (s *udpSender) SetReporterStats(rs reporterstats.ReporterStats) {
 	s.reporterStats = rs