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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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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 {