Opentracing support

vendor/github.com/uber/jaeger-client-go/utils/udp_client.go

@@ -0,0 +1,104 @@
+// Copyright (c) 2016 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+package utils
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"net"
+
+	"github.com/apache/thrift/lib/go/thrift"
+
+	"github.com/uber/jaeger-client-go/thrift-gen/agent"
+	"github.com/uber/jaeger-client-go/thrift-gen/jaeger"
+	"github.com/uber/jaeger-client-go/thrift-gen/zipkincore"
+)
+
+// UDPPacketMaxLength is the max size of UDP packet we want to send, synced with jaeger-agent
+const UDPPacketMaxLength = 65000
+
+// AgentClientUDP is a UDP client to Jaeger agent that implements agent.Agent interface.
+type AgentClientUDP struct {
+	agent.Agent
+	io.Closer
+
+	connUDP       *net.UDPConn
+	client        *agent.AgentClient
+	maxPacketSize int                   // max size of datagram in bytes
+	thriftBuffer  *thrift.TMemoryBuffer // buffer used to calculate byte size of a span
+}
+
+// NewAgentClientUDP creates a client that sends spans to Jaeger Agent over UDP.
+func NewAgentClientUDP(hostPort string, maxPacketSize int) (*AgentClientUDP, error) {
+	if maxPacketSize == 0 {
+		maxPacketSize = UDPPacketMaxLength
+	}
+
+	thriftBuffer := thrift.NewTMemoryBufferLen(maxPacketSize)
+	protocolFactory := thrift.NewTCompactProtocolFactory()
+	client := agent.NewAgentClientFactory(thriftBuffer, protocolFactory)
+
+	destAddr, err := net.ResolveUDPAddr("udp", hostPort)
+	if err != nil {
+		return nil, err
+	}
+
+	connUDP, err := net.DialUDP(destAddr.Network(), nil, destAddr)
+	if err != nil {
+		return nil, err
+	}
+	if err := connUDP.SetWriteBuffer(maxPacketSize); err != nil {
+		return nil, err
+	}
+
+	clientUDP := &AgentClientUDP{
+		connUDP:       connUDP,
+		client:        client,
+		maxPacketSize: maxPacketSize,
+		thriftBuffer:  thriftBuffer}
+	return clientUDP, nil
+}
+
+// EmitZipkinBatch implements EmitZipkinBatch() of Agent interface
+func (a *AgentClientUDP) EmitZipkinBatch(spans []*zipkincore.Span) error {
+	return errors.New("Not implemented")
+}
+
+// EmitBatch implements EmitBatch() of Agent interface
+func (a *AgentClientUDP) EmitBatch(batch *jaeger.Batch) error {
+	a.thriftBuffer.Reset()
+	a.client.SeqId = 0 // we have no need for distinct SeqIds for our one-way UDP messages
+	if err := a.client.EmitBatch(batch); err != nil {
+		return err
+	}
+	if a.thriftBuffer.Len() > a.maxPacketSize {
+		return fmt.Errorf("Data does not fit within one UDP packet; size %d, max %d, spans %d",
+			a.thriftBuffer.Len(), a.maxPacketSize, len(batch.Spans))
+	}
+	_, err := a.connUDP.Write(a.thriftBuffer.Bytes())
+	return err
+}
+
+// Close implements Close() of io.Closer and closes the underlying UDP connection.
+func (a *AgentClientUDP) Close() error {
+	return a.connUDP.Close()
+}