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// Copyright (c) 2017 Uber Technologies, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package utils
import (
"context"
"errors"
"fmt"
"io"
"net"
"time"
"github.com/uber/jaeger-client-go/log"
"github.com/uber/jaeger-client-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 udpConn
client *agent.AgentClient
maxPacketSize int // max size of datagram in bytes
thriftBuffer *thrift.TMemoryBuffer // buffer used to calculate byte size of a span
}
type udpConn interface {
Write([]byte) (int, error)
SetWriteBuffer(int) error
Close() error
}
// AgentClientUDPParams allows specifying options for initializing an AgentClientUDP. An instance of this struct should
// be passed to NewAgentClientUDPWithParams.
type AgentClientUDPParams struct {
HostPort string
MaxPacketSize int
Logger log.Logger
DisableAttemptReconnecting bool
AttemptReconnectInterval time.Duration
}
// NewAgentClientUDPWithParams creates a client that sends spans to Jaeger Agent over UDP.
func NewAgentClientUDPWithParams(params AgentClientUDPParams) (*AgentClientUDP, error) {
// validate hostport
if _, _, err := net.SplitHostPort(params.HostPort); err != nil {
return nil, err
}
if params.MaxPacketSize == 0 {
params.MaxPacketSize = UDPPacketMaxLength
}
if params.Logger == nil {
params.Logger = log.StdLogger
}
if !params.DisableAttemptReconnecting && params.AttemptReconnectInterval == 0 {
params.AttemptReconnectInterval = time.Second * 30
}
thriftBuffer := thrift.NewTMemoryBufferLen(params.MaxPacketSize)
protocolFactory := thrift.NewTCompactProtocolFactory()
client := agent.NewAgentClientFactory(thriftBuffer, protocolFactory)
var connUDP udpConn
var err error
if params.DisableAttemptReconnecting {
destAddr, err := net.ResolveUDPAddr("udp", params.HostPort)
if err != nil {
return nil, err
}
connUDP, err = net.DialUDP(destAddr.Network(), nil, destAddr)
if err != nil {
return nil, err
}
} else {
// host is hostname, setup resolver loop in case host record changes during operation
connUDP, err = newReconnectingUDPConn(params.HostPort, params.AttemptReconnectInterval, net.ResolveUDPAddr, net.DialUDP, params.Logger)
if err != nil {
return nil, err
}
}
if err := connUDP.SetWriteBuffer(params.MaxPacketSize); err != nil {
return nil, err
}
return &AgentClientUDP{
connUDP: connUDP,
client: client,
maxPacketSize: params.MaxPacketSize,
thriftBuffer: thriftBuffer,
}, nil
}
// NewAgentClientUDP creates a client that sends spans to Jaeger Agent over UDP.
func NewAgentClientUDP(hostPort string, maxPacketSize int) (*AgentClientUDP, error) {
return NewAgentClientUDPWithParams(AgentClientUDPParams{
HostPort: hostPort,
MaxPacketSize: maxPacketSize,
})
}
// EmitZipkinBatch implements EmitZipkinBatch() of Agent interface
func (a *AgentClientUDP) EmitZipkinBatch(context.Context, []*zipkincore.Span) error {
return errors.New("Not implemented")
}
// EmitBatch implements EmitBatch() of Agent interface
func (a *AgentClientUDP) EmitBatch(ctx context.Context, batch *jaeger.Batch) error {
a.thriftBuffer.Reset()
if err := a.client.EmitBatch(ctx, 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()
}