Opentracing support

vendor/github.com/opentracing-contrib/go-observer/LICENSE

@@ -0,0 +1,201 @@
+                                 Apache License
+                           Version 2.0, January 2004
+                        http://www.apache.org/licenses/
+
+   TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
+
+   1. Definitions.
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+      the conditions stated in this License.
+
+   5. Submission of Contributions. Unless You explicitly state otherwise,
+      any Contribution intentionally submitted for inclusion in the Work
+      by You to the Licensor shall be under the terms and conditions of
+      this License, without any additional terms or conditions.
+      Notwithstanding the above, nothing herein shall supersede or modify
+      the terms of any separate license agreement you may have executed
+      with Licensor regarding such Contributions.
+
+   6. Trademarks. This License does not grant permission to use the trade
+      names, trademarks, service marks, or product names of the Licensor,
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+      origin of the Work and reproducing the content of the NOTICE file.
+
+   7. Disclaimer of Warranty. Unless required by applicable law or
+      agreed to in writing, Licensor provides the Work (and each
+      Contributor provides its Contributions) on an "AS IS" BASIS,
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+
+   END OF TERMS AND CONDITIONS
+
+   APPENDIX: How to apply the Apache License to your work.
+
+      To apply the Apache License to your work, attach the following
+      boilerplate notice, with the fields enclosed by brackets "{}"
+      replaced with your own identifying information. (Don't include
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+
+   Copyright (c) 2017 opentracing-contrib
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

vendor/github.com/opentracing-contrib/go-observer/observer.go

@@ -0,0 +1,39 @@
+// This project is licensed under the Apache License 2.0, see LICENSE.
+
+package otobserver
+
+import opentracing "github.com/opentracing/opentracing-go"
+
+// Observer can be registered with a Tracer to recieve notifications
+// about new Spans. Tracers are not required to support the Observer API.
+// The actual registration depends on the implementation, which might look
+// like the below e.g :
+// observer := myobserver.NewObserver()
+// tracer := client.NewTracer(..., client.WithObserver(observer))
+//
+type Observer interface {
+	// Create and return a span observer. Called when a span starts.
+	// If the Observer is not interested in the given span, it must return (nil, false).
+	// E.g :
+	//     func StartSpan(opName string, opts ...opentracing.StartSpanOption) {
+	//         var sp opentracing.Span
+	//         sso := opentracing.StartSpanOptions{}
+	//         spanObserver, ok := observer.OnStartSpan(span, opName, sso);
+	//         if ok {
+	//             // we have a valid SpanObserver
+	//         }
+	//         ...
+	//     }
+	OnStartSpan(sp opentracing.Span, operationName string, options opentracing.StartSpanOptions) (SpanObserver, bool)
+}
+
+// SpanObserver is created by the Observer and receives notifications about
+// other Span events.
+type SpanObserver interface {
+	// Callback called from opentracing.Span.SetOperationName()
+	OnSetOperationName(operationName string)
+	// Callback called from opentracing.Span.SetTag()
+	OnSetTag(key string, value interface{})
+	// Callback called from opentracing.Span.Finish()
+	OnFinish(options opentracing.FinishOptions)
+}

vendor/github.com/opentracing-contrib/go-stdlib/LICENSE

@@ -0,0 +1,27 @@
+Copyright (c) 2016, opentracing-contrib
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+* Redistributions of source code must retain the above copyright notice, this
+  list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright notice,
+  this list of conditions and the following disclaimer in the documentation
+  and/or other materials provided with the distribution.
+
+* Neither the name of go-stdlib nor the names of its
+  contributors may be used to endorse or promote products derived from
+  this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/github.com/opentracing-contrib/go-stdlib/nethttp/client.go

@@ -0,0 +1,294 @@
+// +build go1.7
+
+package nethttp
+
+import (
+	"context"
+	"io"
+	"net/http"
+	"net/http/httptrace"
+
+	"github.com/opentracing/opentracing-go"
+	"github.com/opentracing/opentracing-go/ext"
+	"github.com/opentracing/opentracing-go/log"
+)
+
+type contextKey int
+
+const (
+	keyTracer contextKey = iota
+)
+
+const defaultComponentName = "net/http"
+
+// Transport wraps a RoundTripper. If a request is being traced with
+// Tracer, Transport will inject the current span into the headers,
+// and set HTTP related tags on the span.
+type Transport struct {
+	// The actual RoundTripper to use for the request. A nil
+	// RoundTripper defaults to http.DefaultTransport.
+	http.RoundTripper
+}
+
+type clientOptions struct {
+	operationName      string
+	componentName      string
+	disableClientTrace bool
+}
+
+// ClientOption contols the behavior of TraceRequest.
+type ClientOption func(*clientOptions)
+
+// OperationName returns a ClientOption that sets the operation
+// name for the client-side span.
+func OperationName(operationName string) ClientOption {
+	return func(options *clientOptions) {
+		options.operationName = operationName
+	}
+}
+
+// ComponentName returns a ClientOption that sets the component
+// name for the client-side span.
+func ComponentName(componentName string) ClientOption {
+	return func(options *clientOptions) {
+		options.componentName = componentName
+	}
+}
+
+// ClientTrace returns a ClientOption that turns on or off
+// extra instrumentation via httptrace.WithClientTrace.
+func ClientTrace(enabled bool) ClientOption {
+	return func(options *clientOptions) {
+		options.disableClientTrace = !enabled
+	}
+}
+
+// TraceRequest adds a ClientTracer to req, tracing the request and
+// all requests caused due to redirects. When tracing requests this
+// way you must also use Transport.
+//
+// Example:
+//
+// 	func AskGoogle(ctx context.Context) error {
+// 		client := &http.Client{Transport: &nethttp.Transport{}}
+// 		req, err := http.NewRequest("GET", "http://google.com", nil)
+// 		if err != nil {
+// 			return err
+// 		}
+// 		req = req.WithContext(ctx) // extend existing trace, if any
+//
+// 		req, ht := nethttp.TraceRequest(tracer, req)
+// 		defer ht.Finish()
+//
+// 		res, err := client.Do(req)
+// 		if err != nil {
+// 			return err
+// 		}
+// 		res.Body.Close()
+// 		return nil
+// 	}
+func TraceRequest(tr opentracing.Tracer, req *http.Request, options ...ClientOption) (*http.Request, *Tracer) {
+	opts := &clientOptions{}
+	for _, opt := range options {
+		opt(opts)
+	}
+	ht := &Tracer{tr: tr, opts: opts}
+	ctx := req.Context()
+	if !opts.disableClientTrace {
+		ctx = httptrace.WithClientTrace(ctx, ht.clientTrace())
+	}
+	req = req.WithContext(context.WithValue(ctx, keyTracer, ht))
+	return req, ht
+}
+
+type closeTracker struct {
+	io.ReadCloser
+	sp opentracing.Span
+}
+
+func (c closeTracker) Close() error {
+	err := c.ReadCloser.Close()
+	c.sp.LogFields(log.String("event", "ClosedBody"))
+	c.sp.Finish()
+	return err
+}
+
+// RoundTrip implements the RoundTripper interface.
+func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
+	rt := t.RoundTripper
+	if rt == nil {
+		rt = http.DefaultTransport
+	}
+	tracer, ok := req.Context().Value(keyTracer).(*Tracer)
+	if !ok {
+		return rt.RoundTrip(req)
+	}
+
+	tracer.start(req)
+
+	ext.HTTPMethod.Set(tracer.sp, req.Method)
+	ext.HTTPUrl.Set(tracer.sp, req.URL.String())
+
+	carrier := opentracing.HTTPHeadersCarrier(req.Header)
+	tracer.sp.Tracer().Inject(tracer.sp.Context(), opentracing.HTTPHeaders, carrier)
+	resp, err := rt.RoundTrip(req)
+
+	if err != nil {
+		tracer.sp.Finish()
+		return resp, err
+	}
+	ext.HTTPStatusCode.Set(tracer.sp, uint16(resp.StatusCode))
+	if req.Method == "HEAD" {
+		tracer.sp.Finish()
+	} else {
+		resp.Body = closeTracker{resp.Body, tracer.sp}
+	}
+	return resp, nil
+}
+
+// Tracer holds tracing details for one HTTP request.
+type Tracer struct {
+	tr   opentracing.Tracer
+	root opentracing.Span
+	sp   opentracing.Span
+	opts *clientOptions
+}
+
+func (h *Tracer) start(req *http.Request) opentracing.Span {
+	if h.root == nil {
+		parent := opentracing.SpanFromContext(req.Context())
+		var spanctx opentracing.SpanContext
+		if parent != nil {
+			spanctx = parent.Context()
+		}
+		operationName := h.opts.operationName
+		if operationName == "" {
+			operationName = "HTTP Client"
+		}
+		root := h.tr.StartSpan(operationName, opentracing.ChildOf(spanctx))
+		h.root = root
+	}
+
+	ctx := h.root.Context()
+	h.sp = h.tr.StartSpan("HTTP "+req.Method, opentracing.ChildOf(ctx))
+	ext.SpanKindRPCClient.Set(h.sp)
+
+	componentName := h.opts.componentName
+	if componentName == "" {
+		componentName = defaultComponentName
+	}
+	ext.Component.Set(h.sp, componentName)
+
+	return h.sp
+}
+
+// Finish finishes the span of the traced request.
+func (h *Tracer) Finish() {
+	if h.root != nil {
+		h.root.Finish()
+	}
+}
+
+// Span returns the root span of the traced request. This function
+// should only be called after the request has been executed.
+func (h *Tracer) Span() opentracing.Span {
+	return h.root
+}
+
+func (h *Tracer) clientTrace() *httptrace.ClientTrace {
+	return &httptrace.ClientTrace{
+		GetConn:              h.getConn,
+		GotConn:              h.gotConn,
+		PutIdleConn:          h.putIdleConn,
+		GotFirstResponseByte: h.gotFirstResponseByte,
+		Got100Continue:       h.got100Continue,
+		DNSStart:             h.dnsStart,
+		DNSDone:              h.dnsDone,
+		ConnectStart:         h.connectStart,
+		ConnectDone:          h.connectDone,
+		WroteHeaders:         h.wroteHeaders,
+		Wait100Continue:      h.wait100Continue,
+		WroteRequest:         h.wroteRequest,
+	}
+}
+
+func (h *Tracer) getConn(hostPort string) {
+	ext.HTTPUrl.Set(h.sp, hostPort)
+	h.sp.LogFields(log.String("event", "GetConn"))
+}
+
+func (h *Tracer) gotConn(info httptrace.GotConnInfo) {
+	h.sp.SetTag("net/http.reused", info.Reused)
+	h.sp.SetTag("net/http.was_idle", info.WasIdle)
+	h.sp.LogFields(log.String("event", "GotConn"))
+}
+
+func (h *Tracer) putIdleConn(error) {
+	h.sp.LogFields(log.String("event", "PutIdleConn"))
+}
+
+func (h *Tracer) gotFirstResponseByte() {
+	h.sp.LogFields(log.String("event", "GotFirstResponseByte"))
+}
+
+func (h *Tracer) got100Continue() {
+	h.sp.LogFields(log.String("event", "Got100Continue"))
+}
+
+func (h *Tracer) dnsStart(info httptrace.DNSStartInfo) {
+	h.sp.LogFields(
+		log.String("event", "DNSStart"),
+		log.String("host", info.Host),
+	)
+}
+
+func (h *Tracer) dnsDone(httptrace.DNSDoneInfo) {
+	h.sp.LogFields(log.String("event", "DNSDone"))
+}
+
+func (h *Tracer) connectStart(network, addr string) {
+	h.sp.LogFields(
+		log.String("event", "ConnectStart"),
+		log.String("network", network),
+		log.String("addr", addr),
+	)
+}
+
+func (h *Tracer) connectDone(network, addr string, err error) {
+	if err != nil {
+		h.sp.LogFields(
+			log.String("message", "ConnectDone"),
+			log.String("network", network),
+			log.String("addr", addr),
+			log.String("event", "error"),
+			log.Error(err),
+		)
+	} else {
+		h.sp.LogFields(
+			log.String("event", "ConnectDone"),
+			log.String("network", network),
+			log.String("addr", addr),
+		)
+	}
+}
+
+func (h *Tracer) wroteHeaders() {
+	h.sp.LogFields(log.String("event", "WroteHeaders"))
+}
+
+func (h *Tracer) wait100Continue() {
+	h.sp.LogFields(log.String("event", "Wait100Continue"))
+}
+
+func (h *Tracer) wroteRequest(info httptrace.WroteRequestInfo) {
+	if info.Err != nil {
+		h.sp.LogFields(
+			log.String("message", "WroteRequest"),
+			log.String("event", "error"),
+			log.Error(info.Err),
+		)
+		ext.Error.Set(h.sp, true)
+	} else {
+		h.sp.LogFields(log.String("event", "WroteRequest"))
+	}
+}

vendor/github.com/opentracing-contrib/go-stdlib/nethttp/doc.go

@@ -0,0 +1,3 @@
+// Package nethttp provides OpenTracing instrumentation for the
+// net/http package.
+package nethttp

vendor/github.com/opentracing-contrib/go-stdlib/nethttp/server.go

@@ -0,0 +1,96 @@
+// +build go1.7
+
+package nethttp
+
+import (
+	"net/http"
+
+	opentracing "github.com/opentracing/opentracing-go"
+	"github.com/opentracing/opentracing-go/ext"
+)
+
+type statusCodeTracker struct {
+	http.ResponseWriter
+	status int
+}
+
+func (w *statusCodeTracker) WriteHeader(status int) {
+	w.status = status
+	w.ResponseWriter.WriteHeader(status)
+}
+
+type mwOptions struct {
+	opNameFunc    func(r *http.Request) string
+	componentName string
+}
+
+// MWOption controls the behavior of the Middleware.
+type MWOption func(*mwOptions)
+
+// OperationNameFunc returns a MWOption that uses given function f
+// to generate operation name for each server-side span.
+func OperationNameFunc(f func(r *http.Request) string) MWOption {
+	return func(options *mwOptions) {
+		options.opNameFunc = f
+	}
+}
+
+// MWComponentName returns a MWOption that sets the component name
+// name for the server-side span.
+func MWComponentName(componentName string) MWOption {
+	return func(options *mwOptions) {
+		options.componentName = componentName
+	}
+}
+
+// Middleware wraps an http.Handler and traces incoming requests.
+// Additionally, it adds the span to the request's context.
+//
+// By default, the operation name of the spans is set to "HTTP {method}".
+// This can be overriden with options.
+//
+// Example:
+// 	 http.ListenAndServe("localhost:80", nethttp.Middleware(tracer, http.DefaultServeMux))
+//
+// The options allow fine tuning the behavior of the middleware.
+//
+// Example:
+//   mw := nethttp.Middleware(
+//      tracer,
+//      http.DefaultServeMux,
+//      nethttp.OperationName(func(r *http.Request) string {
+//	        return "HTTP " + r.Method + ":/api/customers"
+//      }),
+//   )
+func Middleware(tr opentracing.Tracer, h http.Handler, options ...MWOption) http.Handler {
+	opts := mwOptions{
+		opNameFunc: func(r *http.Request) string {
+			return "HTTP " + r.Method
+		},
+	}
+	for _, opt := range options {
+		opt(&opts)
+	}
+	fn := func(w http.ResponseWriter, r *http.Request) {
+		ctx, _ := tr.Extract(opentracing.HTTPHeaders, opentracing.HTTPHeadersCarrier(r.Header))
+		sp := tr.StartSpan(opts.opNameFunc(r), ext.RPCServerOption(ctx))
+		ext.HTTPMethod.Set(sp, r.Method)
+		ext.HTTPUrl.Set(sp, r.URL.String())
+
+		// set component name, use "net/http" if caller does not specify
+		componentName := opts.componentName
+		if componentName == "" {
+			componentName = defaultComponentName
+		}
+		ext.Component.Set(sp, componentName)
+
+		w = &statusCodeTracker{w, 200}
+		r = r.WithContext(opentracing.ContextWithSpan(r.Context(), sp))
+
+		h.ServeHTTP(w, r)
+
+		ext.HTTPStatusCode.Set(sp, uint16(w.(*statusCodeTracker).status))
+		sp.Finish()
+	}
+	return http.HandlerFunc(fn)
+}