/
opentracing.go
62 lines (57 loc) · 1.78 KB
/
opentracing.go
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package opentracing
import (
"context"
"github.com/opentracing/opentracing-go"
"github.com/opentracing/opentracing-go/ext"
"github.com/opentracing/opentracing-go/log"
"google.golang.org/grpc"
"google.golang.org/grpc/grpclog"
"google.golang.org/grpc/metadata"
)
//MDReaderWriter metadata Reader and Writer
type MDReaderWriter struct {
metadata.MD
}
var (
grpcTag = opentracing.Tag{Key: string(ext.Component), Value: "gRPC"}
)
// OpentracingServerInterceptor rewrite server's interceptor with open tracing
func OpentracingServerInterceptor(tracer opentracing.Tracer) grpc.UnaryServerInterceptor {
return func(
ctx context.Context,
req interface{},
info *grpc.UnaryServerInfo,
handler grpc.UnaryHandler,
) (interface{}, error) {
md, ok := metadata.FromIncomingContext(ctx)
if !ok {
md = metadata.MD{}
}
parentSpanContext, err := tracer.Extract(opentracing.HTTPHeaders, metadataTextMap(md))
if err != nil && err != opentracing.ErrSpanContextNotFound {
grpclog.Infof("grpc_opentracing: failed parsing trace information: %v", err)
}
serverSpan := tracer.StartSpan(info.FullMethod,
// 这里实现的关联父级span,如果partentSpanContext为空,则是顶级
ext.RPCServerOption(parentSpanContext),
grpcTag,
)
injectOpentracingIdsToTags(serverSpan, Extract(ctx))
newCtx := opentracing.ContextWithSpan(ctx, serverSpan)
rsp, err := handler(newCtx, req)
tags := Extract(newCtx)
for key, val := range tags.Values() {
// Don't tag errors, log them instead.
if vErr, ok := val.(error); ok {
serverSpan.LogKV(key, vErr.Error())
} else {
serverSpan.SetTag(key, val)
}
}
if err != nil {
ext.Error.Set(serverSpan, true)
serverSpan.LogFields(log.String("event", "error"), log.String("message", err.Error()))
}
return rsp, err
}
}