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// Copyright The OpenTelemetry Authors
//
// 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 jaeger // import "go.opentelemetry.io/otel/exporters/jaeger"
import (
"context"
"fmt"
"io"
"net"
"strings"
"time"
"github.com/go-logr/logr"
genAgent "go.opentelemetry.io/otel/exporters/jaeger/internal/gen-go/agent"
gen "go.opentelemetry.io/otel/exporters/jaeger/internal/gen-go/jaeger"
"go.opentelemetry.io/otel/exporters/jaeger/internal/third_party/thrift/lib/go/thrift"
)
const (
// udpPacketMaxLength is the max size of UDP packet we want to send, synced with jaeger-agent.
udpPacketMaxLength = 65000
// emitBatchOverhead is the additional overhead bytes used for enveloping the datagram,
// synced with jaeger-agent https://github.com/jaegertracing/jaeger-client-go/blob/master/transport_udp.go#L37
emitBatchOverhead = 70
)
// agentClientUDP is a UDP client to Jaeger agent that implements gen.Agent interface.
type agentClientUDP struct {
genAgent.Agent
io.Closer
connUDP udpConn
client *genAgent.AgentClient
maxPacketSize int // max size of datagram in bytes
thriftBuffer *thrift.TMemoryBuffer // buffer used to calculate byte size of a span
thriftProtocol thrift.TProtocol
}
type udpConn interface {
Write([]byte) (int, error)
SetWriteBuffer(int) error
Close() error
}
type agentClientUDPParams struct {
Host string
Port string
MaxPacketSize int
Logger logr.Logger
AttemptReconnecting bool
AttemptReconnectInterval time.Duration
}
// newAgentClientUDP creates a client that sends spans to Jaeger Agent over UDP.
func newAgentClientUDP(params agentClientUDPParams) (*agentClientUDP, error) {
hostPort := net.JoinHostPort(params.Host, params.Port)
// validate hostport
if _, _, err := net.SplitHostPort(hostPort); err != nil {
return nil, err
}
if params.MaxPacketSize <= 0 || params.MaxPacketSize > udpPacketMaxLength {
params.MaxPacketSize = udpPacketMaxLength
}
if params.AttemptReconnecting && params.AttemptReconnectInterval <= 0 {
params.AttemptReconnectInterval = time.Second * 30
}
thriftBuffer := thrift.NewTMemoryBufferLen(params.MaxPacketSize)
protocolFactory := thrift.NewTCompactProtocolFactoryConf(&thrift.TConfiguration{})
thriftProtocol := protocolFactory.GetProtocol(thriftBuffer)
client := genAgent.NewAgentClientFactory(thriftBuffer, protocolFactory)
var connUDP udpConn
var err error
if params.AttemptReconnecting {
// host is hostname, setup resolver loop in case host record changes during operation
connUDP, err = newReconnectingUDPConn(hostPort, params.MaxPacketSize, params.AttemptReconnectInterval, net.ResolveUDPAddr, net.DialUDP, params.Logger)
if err != nil {
return nil, err
}
} else {
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(params.MaxPacketSize); err != nil {
return nil, err
}
return &agentClientUDP{
connUDP: connUDP,
client: client,
maxPacketSize: params.MaxPacketSize,
thriftBuffer: thriftBuffer,
thriftProtocol: thriftProtocol,
}, nil
}
// EmitBatch buffers batch to fit into UDP packets and sends the data to the agent.
func (a *agentClientUDP) EmitBatch(ctx context.Context, batch *gen.Batch) error {
var errs []error
processSize, err := a.calcSizeOfSerializedThrift(ctx, batch.Process)
if err != nil {
// drop the batch if serialization of process fails.
return err
}
maxPacketSize := a.maxPacketSize
if maxPacketSize > udpPacketMaxLength-emitBatchOverhead {
maxPacketSize = udpPacketMaxLength - emitBatchOverhead
}
totalSize := processSize
var spans []*gen.Span
for _, span := range batch.Spans {
spanSize, err := a.calcSizeOfSerializedThrift(ctx, span)
if err != nil {
errs = append(errs, fmt.Errorf("thrift serialization failed: %v", span))
continue
}
if spanSize+processSize >= maxPacketSize {
// drop the span that exceeds the limit.
errs = append(errs, fmt.Errorf("span too large to send: %v", span))
continue
}
if totalSize+spanSize >= maxPacketSize {
if err := a.flush(ctx, &gen.Batch{
Process: batch.Process,
Spans: spans,
}); err != nil {
errs = append(errs, err)
}
spans = spans[:0]
totalSize = processSize
}
totalSize += spanSize
spans = append(spans, span)
}
if len(spans) > 0 {
if err := a.flush(ctx, &gen.Batch{
Process: batch.Process,
Spans: spans,
}); err != nil {
errs = append(errs, err)
}
}
if len(errs) == 1 {
return errs[0]
} else if len(errs) > 1 {
joined := a.makeJoinedErrorString(errs)
return fmt.Errorf("multiple errors during transform: %s", joined)
}
return nil
}
// makeJoinedErrorString join all the errors to one error message.
func (a *agentClientUDP) makeJoinedErrorString(errs []error) string {
var errMsgs []string
for _, err := range errs {
errMsgs = append(errMsgs, err.Error())
}
return strings.Join(errMsgs, ", ")
}
// flush will send the batch of spans to the agent.
func (a *agentClientUDP) flush(ctx context.Context, batch *gen.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
}
// calcSizeOfSerializedThrift calculate the serialized thrift packet size.
func (a *agentClientUDP) calcSizeOfSerializedThrift(ctx context.Context, thriftStruct thrift.TStruct) (int, error) {
a.thriftBuffer.Reset()
err := thriftStruct.Write(ctx, a.thriftProtocol)
return a.thriftBuffer.Len(), err
}
// Close implements Close() of io.Closer and closes the underlying UDP connection.
func (a *agentClientUDP) Close() error {
return a.connUDP.Close()
}
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