/
trace.go
99 lines (84 loc) 路 3.21 KB
/
trace.go
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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 server
import (
"context"
"fmt"
"github.com/opentracing/opentracing-go"
"github.com/opentracing/opentracing-go/ext"
"github.com/uber/jaeger-client-go"
"github.com/uber/jaeger-client-go/crossdock/common"
"github.com/uber/jaeger-client-go/crossdock/log"
"github.com/uber/jaeger-client-go/crossdock/thrift/tracetest"
)
func (s *Server) doStartTrace(req *tracetest.StartTraceRequest) (*tracetest.TraceResponse, error) {
span := s.Tracer.StartSpan(req.ServerRole)
if req.Sampled {
ext.SamplingPriority.Set(span, 1)
}
span.SetBaggageItem(BaggageKey, req.Baggage)
defer span.Finish()
ctx := opentracing.ContextWithSpan(context.Background(), span)
return s.prepareResponse(ctx, req.ServerRole, req.Downstream)
}
func (s *Server) doJoinTrace(ctx context.Context, req *tracetest.JoinTraceRequest) (*tracetest.TraceResponse, error) {
return s.prepareResponse(ctx, req.ServerRole, req.Downstream)
}
func (s *Server) prepareResponse(ctx context.Context, role string, reqDwn *tracetest.Downstream) (*tracetest.TraceResponse, error) {
observedSpan, err := observeSpan(ctx, s.Tracer)
if err != nil {
return nil, err
}
resp := tracetest.NewTraceResponse()
resp.Span = observedSpan
if reqDwn != nil {
downstreamResp, err := s.callDownstream(ctx, role, reqDwn)
if err != nil {
return nil, err
}
resp.Downstream = downstreamResp
}
return resp, nil
}
func (s *Server) callDownstream(ctx context.Context, role string, downstream *tracetest.Downstream) (*tracetest.TraceResponse, error) {
switch downstream.Transport {
case tracetest.Transport_HTTP:
return s.callDownstreamHTTP(ctx, downstream)
case tracetest.Transport_DUMMY:
return &tracetest.TraceResponse{NotImplementedError: "DUMMY transport not implemented"}, nil
default:
return nil, errUnrecognizedProtocol
}
}
func (s *Server) callDownstreamHTTP(ctx context.Context, target *tracetest.Downstream) (*tracetest.TraceResponse, error) {
req := &tracetest.JoinTraceRequest{
ServerRole: target.ServerRole,
Downstream: target.Downstream,
}
url := fmt.Sprintf("http://%s:%s/join_trace", target.Host, target.Port)
log.Printf("Calling downstream service '%s' at %s", target.ServiceName, url)
return common.PostJSON(ctx, url, req)
}
func observeSpan(ctx context.Context, tracer opentracing.Tracer) (*tracetest.ObservedSpan, error) {
span := opentracing.SpanFromContext(ctx)
if span == nil {
return nil, errNoSpanObserved
}
sc := span.Context().(jaeger.SpanContext)
observedSpan := tracetest.NewObservedSpan()
observedSpan.TraceId = sc.TraceID().String()
observedSpan.Sampled = sc.IsSampled()
observedSpan.Baggage = span.BaggageItem(BaggageKey)
return observedSpan, nil
}