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kratos/examples/blog/pkg/middleware/trace.go

79 lines
2.1 KiB

package tracing
import (
"context"
"github.com/go-kratos/kratos/v2/middleware"
"github.com/go-kratos/kratos/v2/transport/grpc"
"github.com/go-kratos/kratos/v2/transport/http"
"github.com/opentracing/opentracing-go"
"github.com/opentracing/opentracing-go/ext"
"github.com/opentracing/opentracing-go/log"
"google.golang.org/grpc/metadata"
)
// Option is tracing option.
type Option func(*options)
type options struct {
tracer opentracing.Tracer
}
// WithTracer sets a custom tracer to be used for this middleware, otherwise the opentracing.GlobalTracer is used.
func WithTracer(tracer opentracing.Tracer) Option {
return func(o *options) {
o.tracer = tracer
}
}
// Server returns a new server middleware for OpenTracing.
func Server(opts ...Option) middleware.Middleware {
options := options{
tracer: opentracing.GlobalTracer(),
}
for _, o := range opts {
o(&options)
}
return func(handler middleware.Handler) middleware.Handler {
return func(ctx context.Context, req interface{}) (reply interface{}, err error) {
var (
component string
operation string
spanContext opentracing.SpanContext
)
if info, ok := http.FromServerContext(ctx); ok {
// HTTP span
component = "HTTP"
operation = info.Request.RequestURI
spanContext, _ = options.tracer.Extract(
opentracing.HTTPHeaders,
opentracing.HTTPHeadersCarrier(info.Request.Header),
)
} else if info, ok := grpc.FromServerContext(ctx); ok {
// gRPC span
component = "gRPC"
operation = info.FullMethod
if md, ok := metadata.FromIncomingContext(ctx); ok {
spanContext, _ = options.tracer.Extract(
opentracing.HTTPHeaders,
opentracing.HTTPHeadersCarrier(md),
)
}
}
span := options.tracer.StartSpan(
operation,
ext.RPCServerOption(spanContext),
opentracing.Tag{Key: string(ext.Component), Value: component},
)
defer span.Finish()
if reply, err = handler(ctx, req); err != nil {
ext.Error.Set(span, true)
span.LogFields(
log.String("event", "error"),
log.String("message", err.Error()),
)
}
return
}
}
}