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Grpc tracing (#544)

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* checkpoint

* Pass context through ServeDNS, enable gRPC tracing

* Fix types and make tracer available to proxy. go fmt

* Fix imports

* Use the DoNotStartTrace option

* Change to SpanFilter from DoNotStartTrace

* Use new name (IncludeSpan)

* Final names

* Add tests; fix possible client/conn leaks in grpc

* go fmt
This commit is contained in:
John Belamaric 2017-03-01 10:41:54 -05:00 • committed by GitHub
parent 0a4903571e
commit 9ea8cde36e
8 changed files with 140 additions and 16 deletions
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5
core/dnsserver/server.go
View file

@ -155,6 +155,10 @@ func (s *Server) Address() string { return s.Addr }
// defined in the request so that the correct zone
// (configuration and middleware stack) will handle the request.
func (s *Server) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
s.ServeDNSWithContext(context.Background(), w, r)
}
func (s *Server) ServeDNSWithContext(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) {
defer func() {
// In case the user doesn't enable error middleware, we still
// need to make sure that we stay alive up here
@ -171,7 +175,6 @@ func (s *Server) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
q := r.Question[0].Name
b := make([]byte, len(q))
off, end := 0, false
ctx := context.Background()
var dshandler *Config

28
middleware/proxy/grpc.go
View file

@ -5,16 +5,22 @@ import (
"crypto/tls"
"log"
"github.com/grpc-ecosystem/grpc-opentracing/go/otgrpc"
"github.com/coredns/coredns/middleware/proxy/pb"
"github.com/coredns/coredns/middleware/trace"
"github.com/coredns/coredns/request"
"github.com/miekg/dns"
opentracing "github.com/opentracing/opentracing-go"
"google.golang.org/grpc"
"google.golang.org/grpc/credentials"
)
type grpcClient struct {
dialOpt grpc.DialOption
dialOpts []grpc.DialOption
clients map[string]pb.DnsServiceClient
conns []*grpc.ClientConn
upstream *staticUpstream
@ -24,9 +30,9 @@ func newGrpcClient(tls *tls.Config, u *staticUpstream) *grpcClient {
g := &grpcClient{upstream: u}
if tls == nil {
g.dialOpt = grpc.WithInsecure()
g.dialOpts = append(g.dialOpts, grpc.WithInsecure())
} else {
g.dialOpt = grpc.WithTransportCredentials(credentials.NewTLS(tls))
g.dialOpts = append(g.dialOpts, grpc.WithTransportCredentials(credentials.NewTLS(tls)))
}
g.clients = map[string]pb.DnsServiceClient{}
@ -54,18 +60,32 @@ func (g *grpcClient) Exchange(ctx context.Context, addr string, state request.Re
func (g *grpcClient) Protocol() string { return "grpc" }
func (g *grpcClient) OnShutdown(p *Proxy) error {
g.clients = map[string]pb.DnsServiceClient{}
for i, conn := range g.conns {
err := conn.Close()
if err != nil {
log.Printf("[WARNING] Error closing connection %d: %s\n", i, err)
}
}
g.conns = []*grpc.ClientConn{}
return nil
}
func (g *grpcClient) OnStartup(p *Proxy) error {
dialOpts := g.dialOpts
if p.Trace != nil {
if t, ok := p.Trace.(trace.Trace); ok {
onlyIfParent := func(parentSpanCtx opentracing.SpanContext, method string, req, resp interface{}) bool {
return parentSpanCtx != nil
}
intercept := otgrpc.OpenTracingClientInterceptor(t.Tracer(), otgrpc.IncludingSpans(onlyIfParent))
dialOpts = append(dialOpts, grpc.WithUnaryInterceptor(intercept))
} else {
log.Printf("[WARNING] Wrong type for trace middleware reference: %s", p.Trace)
}
}
for _, host := range g.upstream.Hosts {
conn, err := grpc.Dial(host.Name, g.dialOpt)
conn, err := grpc.Dial(host.Name, dialOpts...)
if err != nil {
log.Printf("[WARNING] Skipping gRPC host '%s' due to Dial error: %s\n", host.Name, err)
} else {

54
middleware/proxy/grpc_test.go Normal file
View file

@ -0,0 +1,54 @@
package proxy
import (
"testing"
"time"
)
func pool() []*UpstreamHost {
return []*UpstreamHost{
{
Name: "localhost:10053",
},
{
Name: "localhost:10054",
},
}
}
func TestStartupShutdown(t *testing.T) {
upstream := &staticUpstream{
from: ".",
Hosts: pool(),
Policy: &Random{},
Spray: nil,
FailTimeout: 10 * time.Second,
MaxFails: 1,
}
g := newGrpcClient(nil, upstream)
upstream.ex = g
p := &Proxy{Trace: nil}
p.Upstreams = &[]Upstream{upstream}
err := g.OnStartup(p)
if err != nil {
t.Errorf("Error starting grpc client exchanger: %s", err)
return
}
if len(g.clients) != len(pool()) {
t.Errorf("Expected %d grpc clients but found %d", len(pool()), len(g.clients))
}
err = g.OnShutdown(p)
if err != nil {
t.Errorf("Error stopping grpc client exchanger: %s", err)
return
}
if len(g.clients) != 0 {
t.Errorf("Shutdown didn't remove clients, found %d", len(g.clients))
}
if len(g.conns) != 0 {
t.Errorf("Shutdown didn't remove conns, found %d", len(g.conns))
}
}

4
middleware/proxy/proxy.go
View file

@ -28,6 +28,10 @@ type Proxy struct {
// midway.
Upstreams *[]Upstream
// Trace is the Trace middleware, if it is installed
// This is used by the grpc exchanger to trace through the grpc calls
Trace middleware.Handler
}
// Upstream manages a pool of proxy upstream hosts. Select should return a

3
middleware/proxy/setup.go
View file

@ -20,7 +20,8 @@ func setup(c *caddy.Controller) error {
return middleware.Error("proxy", err)
}
P := &Proxy{}
t := dnsserver.GetMiddleware(c, "trace")
P := &Proxy{Trace: t}
dnsserver.GetConfig(c).AddMiddleware(func(next middleware.Handler) middleware.Handler {
P.Next = next
P.Upstreams = &upstreams

4
middleware/trace/setup.go
View file

@ -34,9 +34,9 @@ func setup(c *caddy.Controller) error {
return nil
}
func traceParse(c *caddy.Controller) (*Trace, error) {
func traceParse(c *caddy.Controller) (*trace, error) {
var (
tr = &Trace{Endpoint: defEP, EndpointType: defEpType, every: 1, serviceName: defServiceName}
tr = &trace{Endpoint: defEP, EndpointType: defEpType, every: 1, serviceName: defServiceName}
err error
)

25
middleware/trace/trace.go
View file

@ -15,12 +15,17 @@ import (
)
// Trace holds the tracer and endpoint info
type Trace struct {
type Trace interface {
middleware.Handler
Tracer() ot.Tracer
}
type trace struct {
Next middleware.Handler
ServiceEndpoint string
Endpoint string
EndpointType string
Tracer ot.Tracer
tracer ot.Tracer
serviceName string
clientServer bool
every uint64
@ -28,8 +33,12 @@ type Trace struct {
Once sync.Once
}
func (t *trace) Tracer() ot.Tracer {
return t.tracer
}
// OnStartup sets up the tracer
func (t *Trace) OnStartup() error {
func (t *trace) OnStartup() error {
var err error
t.Once.Do(func() {
switch t.EndpointType {
@ -42,7 +51,7 @@ func (t *Trace) OnStartup() error {
return err
}
func (t *Trace) setupZipkin() error {
func (t *trace) setupZipkin() error {
collector, err := zipkin.NewHTTPCollector(t.Endpoint)
if err != nil {
@ -50,7 +59,7 @@ func (t *Trace) setupZipkin() error {
}
recorder := zipkin.NewRecorder(collector, false, t.ServiceEndpoint, t.serviceName)
t.Tracer, err = zipkin.NewTracer(recorder, zipkin.ClientServerSameSpan(t.clientServer))
t.tracer, err = zipkin.NewTracer(recorder, zipkin.ClientServerSameSpan(t.clientServer))
if err != nil {
return err
}
@ -58,12 +67,12 @@ func (t *Trace) setupZipkin() error {
}
// Name implements the Handler interface.
func (t *Trace) Name() string {
func (t *trace) Name() string {
return "trace"
}
// ServeDNS implements the middleware.Handle interface.
func (t *Trace) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
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)
@ -73,7 +82,7 @@ func (t *Trace) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg)
}
}
if span := ot.SpanFromContext(ctx); span == nil && trace {
span := t.Tracer.StartSpan("servedns")
span := t.Tracer().StartSpan("servedns")
defer span.Finish()
ctx = ot.ContextWithSpan(ctx, span)
}

33
middleware/trace/trace_test.go Normal file
View file

@ -0,0 +1,33 @@
package trace
import (
"testing"
"github.com/mholt/caddy"
)
// CreateTestTrace creates a trace middleware to be used in tests
func CreateTestTrace(config string) (*caddy.Controller, *trace, error) {
c := caddy.NewTestController("dns", config)
m, err := traceParse(c)
return c, m, err
}
func TestTrace(t *testing.T) {
_, m, err := CreateTestTrace(`trace`)
if err != nil {
t.Errorf("Error parsing test input: %s", err)
return
}
if m.Name() != "trace" {
t.Errorf("Wrong name from GetName: %s", m.Name())
}
err = m.OnStartup()
if err != nil {
t.Errorf("Error starting tracing middleware: %s", err)
return
}
if m.Tracer() == nil {
t.Errorf("Error, no tracer created")
}
}