mirror of
https://github.com/coredns/coredns.git
synced 2025-11-03 18:53:13 -05:00
d8714e64e4
* Rename middleware to plugin first pass; mostly used 'sed', few spots where I manually changed text. This still builds a coredns binary. * fmt error * Rename AddMiddleware to AddPlugin * Readd AddMiddleware to remain backwards compat
85 lines
1.8 KiB
Go
85 lines
1.8 KiB
Go
// Package trace implements OpenTracing-based tracing
|
|
package trace
|
|
|
|
import (
|
|
"fmt"
|
|
"sync"
|
|
"sync/atomic"
|
|
|
|
"github.com/coredns/coredns/plugin"
|
|
// Plugin the trace package.
|
|
_ "github.com/coredns/coredns/plugin/pkg/trace"
|
|
|
|
"github.com/miekg/dns"
|
|
ot "github.com/opentracing/opentracing-go"
|
|
zipkin "github.com/openzipkin/zipkin-go-opentracing"
|
|
"golang.org/x/net/context"
|
|
)
|
|
|
|
type trace struct {
|
|
Next plugin.Handler
|
|
ServiceEndpoint string
|
|
Endpoint string
|
|
EndpointType string
|
|
tracer ot.Tracer
|
|
serviceName string
|
|
clientServer bool
|
|
every uint64
|
|
count uint64
|
|
Once sync.Once
|
|
}
|
|
|
|
func (t *trace) Tracer() ot.Tracer {
|
|
return t.tracer
|
|
}
|
|
|
|
// OnStartup sets up the tracer
|
|
func (t *trace) OnStartup() error {
|
|
var err error
|
|
t.Once.Do(func() {
|
|
switch t.EndpointType {
|
|
case "zipkin":
|
|
err = t.setupZipkin()
|
|
default:
|
|
err = fmt.Errorf("unknown endpoint type: %s", t.EndpointType)
|
|
}
|
|
})
|
|
return err
|
|
}
|
|
|
|
func (t *trace) setupZipkin() error {
|
|
|
|
collector, err := zipkin.NewHTTPCollector(t.Endpoint)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
recorder := zipkin.NewRecorder(collector, false, t.ServiceEndpoint, t.serviceName)
|
|
t.tracer, err = zipkin.NewTracer(recorder, zipkin.ClientServerSameSpan(t.clientServer))
|
|
|
|
return err
|
|
}
|
|
|
|
// Name implements the Handler interface.
|
|
func (t *trace) Name() string {
|
|
return "trace"
|
|
}
|
|
|
|
// ServeDNS implements the plugin.Handle interface.
|
|
func (t *trace) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
|
|
trace := false
|
|
if t.every > 0 {
|
|
queryNr := atomic.AddUint64(&t.count, 1)
|
|
|
|
if queryNr%t.every == 0 {
|
|
trace = true
|
|
}
|
|
}
|
|
if span := ot.SpanFromContext(ctx); span == nil && trace {
|
|
span := t.Tracer().StartSpan("servedns")
|
|
defer span.Finish()
|
|
ctx = ot.ContextWithSpan(ctx, span)
|
|
}
|
|
return plugin.NextOrFailure(t.Name(), t.Next, ctx, w, r)
|
|
}
|