vendor: add new opentracing deps for session tracing

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor.conf

@@ -26,8 +26,11 @@ github.com/RackSec/srslog 456df3a81436d29ba874f3590eeeee25d666f8a5
 github.com/imdario/mergo 0.2.1
 golang.org/x/sync fd80eb99c8f653c847d294a001bdf2a3a6f768f5
 
+# buildkit
 github.com/moby/buildkit b14fd548fe80c0399b105aeec5dbd96ccd2f7720
 github.com/tonistiigi/fsutil dc68c74458923f357474a9178bd198aa3ed11a5f
+github.com/grpc-ecosystem/grpc-opentracing 8e809c8a86450a29b90dcc9efbf062d0fe6d9746
+github.com/opentracing/opentracing-go 1361b9cd60be79c4c3a7fa9841b3c132e40066a7
 
 #get libnetwork packages
 

vendor/github.com/grpc-ecosystem/grpc-opentracing/LICENSE

@@ -0,0 +1,27 @@
+Copyright (c) 2016, gRPC Ecosystem
+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 grpc-opentracing 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/grpc-ecosystem/grpc-opentracing/PATENTS

@@ -0,0 +1,23 @@
+Additional IP Rights Grant (Patents)
+
+"This implementation" means the copyrightable works distributed by
+Google as part of the GRPC project.
+
+Google hereby grants to You a perpetual, worldwide, non-exclusive,
+no-charge, royalty-free, irrevocable (except as stated in this section)
+patent license to make, have made, use, offer to sell, sell, import,
+transfer and otherwise run, modify and propagate the contents of this
+implementation of GRPC, where such license applies only to those patent
+claims, both currently owned or controlled by Google and acquired in
+the future, licensable by Google that are necessarily infringed by this
+implementation of GRPC.  This grant does not include claims that would be
+infringed only as a consequence of further modification of this
+implementation.  If you or your agent or exclusive licensee institute or
+order or agree to the institution of patent litigation against any
+entity (including a cross-claim or counterclaim in a lawsuit) alleging
+that this implementation of GRPC or any code incorporated within this
+implementation of GRPC constitutes direct or contributory patent
+infringement, or inducement of patent infringement, then any patent
+rights granted to you under this License for this implementation of GRPC
+shall terminate as of the date such litigation is filed.
+Status API Training Shop Blog About

vendor/github.com/grpc-ecosystem/grpc-opentracing/README.rst

@@ -0,0 +1,25 @@
+################
+GRPC-OpenTracing
+################
+
+This package enables distributed tracing in GRPC clients and servers via `The OpenTracing Project`_: a set of consistent, expressive, vendor-neutral APIs for distributed tracing and context propagation.
+
+Once a production system contends with real concurrency or splits into many services, crucial (and formerly easy) tasks become difficult: user-facing latency optimization, root-cause analysis of backend errors, communication about distinct pieces of a now-distributed system, etc. Distributed tracing follows a request on its journey from inception to completion from mobile/browser all the way to the microservices. 
+
+As core services and libraries adopt OpenTracing, the application builder is no longer burdened with the task of adding basic tracing instrumentation to their own code. In this way, developers can build their applications with the tools they prefer and benefit from built-in tracing instrumentation. OpenTracing implementations exist for major distributed tracing systems and can be bound or swapped with a one-line configuration change.
+
+*******************
+Further Information
+*******************
+
+If you’re interested in learning more about the OpenTracing standard, join the conversation on our `mailing list`_ or `Gitter`_.
+
+If you want to learn more about the underlying API for your platform, visit the `source code`_. 
+
+If you would like to implement OpenTracing in your project and need help, feel free to send us a note at `community@opentracing.io`_.
+
+.. _The OpenTracing Project: http://opentracing.io/
+.. _source code: https://github.com/opentracing/
+.. _mailing list: http://opentracing.us13.list-manage.com/subscribe?u=180afe03860541dae59e84153&id=19117aa6cd
+.. _Gitter: https://gitter.im/opentracing/public
+.. _community@opentracing.io: community@opentracing.io

vendor/github.com/grpc-ecosystem/grpc-opentracing/go/otgrpc/README.md

@@ -0,0 +1,57 @@
+# OpenTracing support for gRPC in Go
+
+The `otgrpc` package makes it easy to add OpenTracing support to gRPC-based
+systems in Go.
+
+## Installation
+
+```
+go get github.com/grpc-ecosystem/grpc-opentracing/go/otgrpc
+```
+
+## Documentation
+
+See the basic usage examples below and the [package documentation on
+godoc.org](https://godoc.org/github.com/grpc-ecosystem/grpc-opentracing/go/otgrpc).
+
+## Client-side usage example
+
+Wherever you call `grpc.Dial`:
+
+```go
+// You must have some sort of OpenTracing Tracer instance on hand.
+var tracer opentracing.Tracer = ...
+...
+
+// Set up a connection to the server peer.
+conn, err := grpc.Dial(
+    address,
+    ... // other options
+    grpc.WithUnaryInterceptor(
+        otgrpc.OpenTracingClientInterceptor(tracer)),
+    grpc.WithStreamInterceptor(
+        otgrpc.OpenTracingStreamClientInterceptor(tracer)))
+
+// All future RPC activity involving `conn` will be automatically traced.
+```
+
+## Server-side usage example
+
+Wherever you call `grpc.NewServer`:
+
+```go
+// You must have some sort of OpenTracing Tracer instance on hand.
+var tracer opentracing.Tracer = ...
+...
+
+// Initialize the gRPC server.
+s := grpc.NewServer(
+    ... // other options
+    grpc.UnaryInterceptor(
+        otgrpc.OpenTracingServerInterceptor(tracer)),
+    grpc.StreamInterceptor(
+        otgrpc.OpenTracingStreamServerInterceptor(tracer)))
+
+// All future RPC activity involving `s` will be automatically traced.
+```
+

vendor/github.com/grpc-ecosystem/grpc-opentracing/go/otgrpc/client.go

@@ -0,0 +1,239 @@
+package otgrpc
+
+import (
+	"github.com/opentracing/opentracing-go"
+	"github.com/opentracing/opentracing-go/ext"
+	"github.com/opentracing/opentracing-go/log"
+	"golang.org/x/net/context"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+	"io"
+	"runtime"
+	"sync/atomic"
+)
+
+// OpenTracingClientInterceptor returns a grpc.UnaryClientInterceptor suitable
+// for use in a grpc.Dial call.
+//
+// For example:
+//
+//     conn, err := grpc.Dial(
+//         address,
+//         ...,  // (existing DialOptions)
+//         grpc.WithUnaryInterceptor(otgrpc.OpenTracingClientInterceptor(tracer)))
+//
+// All gRPC client spans will inject the OpenTracing SpanContext into the gRPC
+// metadata; they will also look in the context.Context for an active
+// in-process parent Span and establish a ChildOf reference if such a parent
+// Span could be found.
+func OpenTracingClientInterceptor(tracer opentracing.Tracer, optFuncs ...Option) grpc.UnaryClientInterceptor {
+	otgrpcOpts := newOptions()
+	otgrpcOpts.apply(optFuncs...)
+	return func(
+		ctx context.Context,
+		method string,
+		req, resp interface{},
+		cc *grpc.ClientConn,
+		invoker grpc.UnaryInvoker,
+		opts ...grpc.CallOption,
+	) error {
+		var err error
+		var parentCtx opentracing.SpanContext
+		if parent := opentracing.SpanFromContext(ctx); parent != nil {
+			parentCtx = parent.Context()
+		}
+		if otgrpcOpts.inclusionFunc != nil &&
+			!otgrpcOpts.inclusionFunc(parentCtx, method, req, resp) {
+			return invoker(ctx, method, req, resp, cc, opts...)
+		}
+		clientSpan := tracer.StartSpan(
+			method,
+			opentracing.ChildOf(parentCtx),
+			ext.SpanKindRPCClient,
+			gRPCComponentTag,
+		)
+		defer clientSpan.Finish()
+		ctx = injectSpanContext(ctx, tracer, clientSpan)
+		if otgrpcOpts.logPayloads {
+			clientSpan.LogFields(log.Object("gRPC request", req))
+		}
+		err = invoker(ctx, method, req, resp, cc, opts...)
+		if err == nil {
+			if otgrpcOpts.logPayloads {
+				clientSpan.LogFields(log.Object("gRPC response", resp))
+			}
+		} else {
+			SetSpanTags(clientSpan, err, true)
+			clientSpan.LogFields(log.String("event", "error"), log.String("message", err.Error()))
+		}
+		if otgrpcOpts.decorator != nil {
+			otgrpcOpts.decorator(clientSpan, method, req, resp, err)
+		}
+		return err
+	}
+}
+
+// OpenTracingStreamClientInterceptor returns a grpc.StreamClientInterceptor suitable
+// for use in a grpc.Dial call. The interceptor instruments streaming RPCs by creating
+// a single span to correspond to the lifetime of the RPC's stream.
+//
+// For example:
+//
+//     conn, err := grpc.Dial(
+//         address,
+//         ...,  // (existing DialOptions)
+//         grpc.WithStreamInterceptor(otgrpc.OpenTracingStreamClientInterceptor(tracer)))
+//
+// All gRPC client spans will inject the OpenTracing SpanContext into the gRPC
+// metadata; they will also look in the context.Context for an active
+// in-process parent Span and establish a ChildOf reference if such a parent
+// Span could be found.
+func OpenTracingStreamClientInterceptor(tracer opentracing.Tracer, optFuncs ...Option) grpc.StreamClientInterceptor {
+	otgrpcOpts := newOptions()
+	otgrpcOpts.apply(optFuncs...)
+	return func(
+		ctx context.Context,
+		desc *grpc.StreamDesc,
+		cc *grpc.ClientConn,
+		method string,
+		streamer grpc.Streamer,
+		opts ...grpc.CallOption,
+	) (grpc.ClientStream, error) {
+		var err error
+		var parentCtx opentracing.SpanContext
+		if parent := opentracing.SpanFromContext(ctx); parent != nil {
+			parentCtx = parent.Context()
+		}
+		if otgrpcOpts.inclusionFunc != nil &&
+			!otgrpcOpts.inclusionFunc(parentCtx, method, nil, nil) {
+			return streamer(ctx, desc, cc, method, opts...)
+		}
+
+		clientSpan := tracer.StartSpan(
+			method,
+			opentracing.ChildOf(parentCtx),
+			ext.SpanKindRPCClient,
+			gRPCComponentTag,
+		)
+		ctx = injectSpanContext(ctx, tracer, clientSpan)
+		cs, err := streamer(ctx, desc, cc, method, opts...)
+		if err != nil {
+			clientSpan.LogFields(log.String("event", "error"), log.String("message", err.Error()))
+			SetSpanTags(clientSpan, err, true)
+			clientSpan.Finish()
+			return cs, err
+		}
+		return newOpenTracingClientStream(cs, method, desc, clientSpan, otgrpcOpts), nil
+	}
+}
+
+func newOpenTracingClientStream(cs grpc.ClientStream, method string, desc *grpc.StreamDesc, clientSpan opentracing.Span, otgrpcOpts *options) grpc.ClientStream {
+	finishChan := make(chan struct{})
+
+	isFinished := new(int32)
+	*isFinished = 0
+	finishFunc := func(err error) {
+		// The current OpenTracing specification forbids finishing a span more than
+		// once. Since we have multiple code paths that could concurrently call
+		// `finishFunc`, we need to add some sort of synchronization to guard against
+		// multiple finishing.
+		if !atomic.CompareAndSwapInt32(isFinished, 0, 1) {
+			return
+		}
+		close(finishChan)
+		defer clientSpan.Finish()
+		if err != nil {
+			clientSpan.LogFields(log.String("event", "error"), log.String("message", err.Error()))
+			SetSpanTags(clientSpan, err, true)
+		}
+		if otgrpcOpts.decorator != nil {
+			otgrpcOpts.decorator(clientSpan, method, nil, nil, err)
+		}
+	}
+	go func() {
+		select {
+		case <-finishChan:
+			// The client span is being finished by another code path; hence, no
+			// action is necessary.
+		case <-cs.Context().Done():
+			finishFunc(cs.Context().Err())
+		}
+	}()
+	otcs := &openTracingClientStream{
+		ClientStream: cs,
+		desc:         desc,
+		finishFunc:   finishFunc,
+	}
+
+	// The `ClientStream` interface allows one to omit calling `Recv` if it's
+	// known that the result will be `io.EOF`. See
+	// http://stackoverflow.com/q/42915337
+	// In such cases, there's nothing that triggers the span to finish. We,
+	// therefore, set a finalizer so that the span and the context goroutine will
+	// at least be cleaned up when the garbage collector is run.
+	runtime.SetFinalizer(otcs, func(otcs *openTracingClientStream) {
+		otcs.finishFunc(nil)
+	})
+	return otcs
+}
+
+type openTracingClientStream struct {
+	grpc.ClientStream
+	desc       *grpc.StreamDesc
+	finishFunc func(error)
+}
+
+func (cs *openTracingClientStream) Header() (metadata.MD, error) {
+	md, err := cs.ClientStream.Header()
+	if err != nil {
+		cs.finishFunc(err)
+	}
+	return md, err
+}
+
+func (cs *openTracingClientStream) SendMsg(m interface{}) error {
+	err := cs.ClientStream.SendMsg(m)
+	if err != nil {
+		cs.finishFunc(err)
+	}
+	return err
+}
+
+func (cs *openTracingClientStream) RecvMsg(m interface{}) error {
+	err := cs.ClientStream.RecvMsg(m)
+	if err == io.EOF {
+		cs.finishFunc(nil)
+		return err
+	} else if err != nil {
+		cs.finishFunc(err)
+		return err
+	}
+	if !cs.desc.ServerStreams {
+		cs.finishFunc(nil)
+	}
+	return err
+}
+
+func (cs *openTracingClientStream) CloseSend() error {
+	err := cs.ClientStream.CloseSend()
+	if err != nil {
+		cs.finishFunc(err)
+	}
+	return err
+}
+
+func injectSpanContext(ctx context.Context, tracer opentracing.Tracer, clientSpan opentracing.Span) context.Context {
+	md, ok := metadata.FromOutgoingContext(ctx)
+	if !ok {
+		md = metadata.New(nil)
+	} else {
+		md = md.Copy()
+	}
+	mdWriter := metadataReaderWriter{md}
+	err := tracer.Inject(clientSpan.Context(), opentracing.HTTPHeaders, mdWriter)
+	// We have no better place to record an error than the Span itself :-/
+	if err != nil {
+		clientSpan.LogFields(log.String("event", "Tracer.Inject() failed"), log.Error(err))
+	}
+	return metadata.NewOutgoingContext(ctx, md)
+}

vendor/github.com/grpc-ecosystem/grpc-opentracing/go/otgrpc/errors.go

@@ -0,0 +1,69 @@
+package otgrpc
+
+import (
+	"github.com/opentracing/opentracing-go"
+	"github.com/opentracing/opentracing-go/ext"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+// A Class is a set of types of outcomes (including errors) that will often
+// be handled in the same way.
+type Class string
+
+const (
+	Unknown Class = "0xx"
+	// Success represents outcomes that achieved the desired results.
+	Success Class = "2xx"
+	// ClientError represents errors that were the client's fault.
+	ClientError Class = "4xx"
+	// ServerError represents errors that were the server's fault.
+	ServerError Class = "5xx"
+)
+
+// ErrorClass returns the class of the given error
+func ErrorClass(err error) Class {
+	if s, ok := status.FromError(err); ok {
+		switch s.Code() {
+		// Success or "success"
+		case codes.OK, codes.Canceled:
+			return Success
+
+		// Client errors
+		case codes.InvalidArgument, codes.NotFound, codes.AlreadyExists,
+			codes.PermissionDenied, codes.Unauthenticated, codes.FailedPrecondition,
+			codes.OutOfRange:
+			return ClientError
+
+		// Server errors
+		case codes.DeadlineExceeded, codes.ResourceExhausted, codes.Aborted,
+			codes.Unimplemented, codes.Internal, codes.Unavailable, codes.DataLoss:
+			return ServerError
+
+		// Not sure
+		case codes.Unknown:
+			fallthrough
+		default:
+			return Unknown
+		}
+	}
+	return Unknown
+}
+
+// SetSpanTags sets one or more tags on the given span according to the
+// error.
+func SetSpanTags(span opentracing.Span, err error, client bool) {
+	c := ErrorClass(err)
+	code := codes.Unknown
+	if s, ok := status.FromError(err); ok {
+		code = s.Code()
+	}
+	span.SetTag("response_code", code)
+	span.SetTag("response_class", c)
+	if err == nil {
+		return
+	}
+	if client || c == ServerError {
+		ext.Error.Set(span, true)
+	}
+}

vendor/github.com/grpc-ecosystem/grpc-opentracing/go/otgrpc/options.go

@@ -0,0 +1,76 @@
+package otgrpc
+
+import "github.com/opentracing/opentracing-go"
+
+// Option instances may be used in OpenTracing(Server|Client)Interceptor
+// initialization.
+//
+// See this post about the "functional options" pattern:
+// http://dave.cheney.net/2014/10/17/functional-options-for-friendly-apis
+type Option func(o *options)
+
+// LogPayloads returns an Option that tells the OpenTracing instrumentation to
+// try to log application payloads in both directions.
+func LogPayloads() Option {
+	return func(o *options) {
+		o.logPayloads = true
+	}
+}
+
+// SpanInclusionFunc provides an optional mechanism to decide whether or not
+// to trace a given gRPC call. Return true to create a Span and initiate
+// tracing, false to not create a Span and not trace.
+//
+// parentSpanCtx may be nil if no parent could be extraction from either the Go
+// context.Context (on the client) or the RPC (on the server).
+type SpanInclusionFunc func(
+	parentSpanCtx opentracing.SpanContext,
+	method string,
+	req, resp interface{}) bool
+
+// IncludingSpans binds a IncludeSpanFunc to the options
+func IncludingSpans(inclusionFunc SpanInclusionFunc) Option {
+	return func(o *options) {
+		o.inclusionFunc = inclusionFunc
+	}
+}
+
+// SpanDecoratorFunc provides an (optional) mechanism for otgrpc users to add
+// arbitrary tags/logs/etc to the opentracing.Span associated with client
+// and/or server RPCs.
+type SpanDecoratorFunc func(
+	span opentracing.Span,
+	method string,
+	req, resp interface{},
+	grpcError error)
+
+// SpanDecorator binds a function that decorates gRPC Spans.
+func SpanDecorator(decorator SpanDecoratorFunc) Option {
+	return func(o *options) {
+		o.decorator = decorator
+	}
+}
+
+// The internal-only options struct. Obviously overkill at the moment; but will
+// scale well as production use dictates other configuration and tuning
+// parameters.
+type options struct {
+	logPayloads bool
+	decorator   SpanDecoratorFunc
+	// May be nil.
+	inclusionFunc SpanInclusionFunc
+}
+
+// newOptions returns the default options.
+func newOptions() *options {
+	return &options{
+		logPayloads:   false,
+		inclusionFunc: nil,
+	}
+}
+
+func (o *options) apply(opts ...Option) {
+	for _, opt := range opts {
+		opt(o)
+	}
+}

vendor/github.com/grpc-ecosystem/grpc-opentracing/go/otgrpc/package.go

@@ -0,0 +1,5 @@
+// Package otgrpc provides OpenTracing support for any gRPC client or server.
+//
+// See the README for simple usage examples:
+// https://github.com/grpc-ecosystem/grpc-opentracing/blob/master/go/otgrpc/README.md
+package otgrpc

vendor/github.com/grpc-ecosystem/grpc-opentracing/go/otgrpc/server.go

@@ -0,0 +1,141 @@
+package otgrpc
+
+import (
+	"github.com/opentracing/opentracing-go"
+	"github.com/opentracing/opentracing-go/ext"
+	"github.com/opentracing/opentracing-go/log"
+	"golang.org/x/net/context"
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/metadata"
+)
+
+// OpenTracingServerInterceptor returns a grpc.UnaryServerInterceptor suitable
+// for use in a grpc.NewServer call.
+//
+// For example:
+//
+//     s := grpc.NewServer(
+//         ...,  // (existing ServerOptions)
+//         grpc.UnaryInterceptor(otgrpc.OpenTracingServerInterceptor(tracer)))
+//
+// All gRPC server spans will look for an OpenTracing SpanContext in the gRPC
+// metadata; if found, the server span will act as the ChildOf that RPC
+// SpanContext.
+//
+// Root or not, the server Span will be embedded in the context.Context for the
+// application-specific gRPC handler(s) to access.
+func OpenTracingServerInterceptor(tracer opentracing.Tracer, optFuncs ...Option) grpc.UnaryServerInterceptor {
+	otgrpcOpts := newOptions()
+	otgrpcOpts.apply(optFuncs...)
+	return func(
+		ctx context.Context,
+		req interface{},
+		info *grpc.UnaryServerInfo,
+		handler grpc.UnaryHandler,
+	) (resp interface{}, err error) {
+		spanContext, err := extractSpanContext(ctx, tracer)
+		if err != nil && err != opentracing.ErrSpanContextNotFound {
+			// TODO: establish some sort of error reporting mechanism here. We
+			// don't know where to put such an error and must rely on Tracer
+			// implementations to do something appropriate for the time being.
+		}
+		if otgrpcOpts.inclusionFunc != nil &&
+			!otgrpcOpts.inclusionFunc(spanContext, info.FullMethod, req, nil) {
+			return handler(ctx, req)
+		}
+		serverSpan := tracer.StartSpan(
+			info.FullMethod,
+			ext.RPCServerOption(spanContext),
+			gRPCComponentTag,
+		)
+		defer serverSpan.Finish()
+
+		ctx = opentracing.ContextWithSpan(ctx, serverSpan)
+		if otgrpcOpts.logPayloads {
+			serverSpan.LogFields(log.Object("gRPC request", req))
+		}
+		resp, err = handler(ctx, req)
+		if err == nil {
+			if otgrpcOpts.logPayloads {
+				serverSpan.LogFields(log.Object("gRPC response", resp))
+			}
+		} else {
+			SetSpanTags(serverSpan, err, false)
+			serverSpan.LogFields(log.String("event", "error"), log.String("message", err.Error()))
+		}
+		if otgrpcOpts.decorator != nil {
+			otgrpcOpts.decorator(serverSpan, info.FullMethod, req, resp, err)
+		}
+		return resp, err
+	}
+}
+
+// OpenTracingStreamServerInterceptor returns a grpc.StreamServerInterceptor suitable
+// for use in a grpc.NewServer call. The interceptor instruments streaming RPCs by
+// creating a single span to correspond to the lifetime of the RPC's stream.
+//
+// For example:
+//
+//     s := grpc.NewServer(
+//         ...,  // (existing ServerOptions)
+//         grpc.StreamInterceptor(otgrpc.OpenTracingStreamServerInterceptor(tracer)))
+//
+// All gRPC server spans will look for an OpenTracing SpanContext in the gRPC
+// metadata; if found, the server span will act as the ChildOf that RPC
+// SpanContext.
+//
+// Root or not, the server Span will be embedded in the context.Context for the
+// application-specific gRPC handler(s) to access.
+func OpenTracingStreamServerInterceptor(tracer opentracing.Tracer, optFuncs ...Option) grpc.StreamServerInterceptor {
+	otgrpcOpts := newOptions()
+	otgrpcOpts.apply(optFuncs...)
+	return func(srv interface{}, ss grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
+		spanContext, err := extractSpanContext(ss.Context(), tracer)
+		if err != nil && err != opentracing.ErrSpanContextNotFound {
+			// TODO: establish some sort of error reporting mechanism here. We
+			// don't know where to put such an error and must rely on Tracer
+			// implementations to do something appropriate for the time being.
+		}
+		if otgrpcOpts.inclusionFunc != nil &&
+			!otgrpcOpts.inclusionFunc(spanContext, info.FullMethod, nil, nil) {
+			return handler(srv, ss)
+		}
+
+		serverSpan := tracer.StartSpan(
+			info.FullMethod,
+			ext.RPCServerOption(spanContext),
+			gRPCComponentTag,
+		)
+		defer serverSpan.Finish()
+		ss = &openTracingServerStream{
+			ServerStream: ss,
+			ctx:          opentracing.ContextWithSpan(ss.Context(), serverSpan),
+		}
+		err = handler(srv, ss)
+		if err != nil {
+			SetSpanTags(serverSpan, err, false)
+			serverSpan.LogFields(log.String("event", "error"), log.String("message", err.Error()))
+		}
+		if otgrpcOpts.decorator != nil {
+			otgrpcOpts.decorator(serverSpan, info.FullMethod, nil, nil, err)
+		}
+		return err
+	}
+}
+
+type openTracingServerStream struct {
+	grpc.ServerStream
+	ctx context.Context
+}
+
+func (ss *openTracingServerStream) Context() context.Context {
+	return ss.ctx
+}
+
+func extractSpanContext(ctx context.Context, tracer opentracing.Tracer) (opentracing.SpanContext, error) {
+	md, ok := metadata.FromIncomingContext(ctx)
+	if !ok {
+		md = metadata.New(nil)
+	}
+	return tracer.Extract(opentracing.HTTPHeaders, metadataReaderWriter{md})
+}

vendor/github.com/grpc-ecosystem/grpc-opentracing/go/otgrpc/shared.go

@@ -0,0 +1,42 @@
+package otgrpc
+
+import (
+	"strings"
+
+	opentracing "github.com/opentracing/opentracing-go"
+	"github.com/opentracing/opentracing-go/ext"
+	"google.golang.org/grpc/metadata"
+)
+
+var (
+	// Morally a const:
+	gRPCComponentTag = opentracing.Tag{string(ext.Component), "gRPC"}
+)
+
+// metadataReaderWriter satisfies both the opentracing.TextMapReader and
+// opentracing.TextMapWriter interfaces.
+type metadataReaderWriter struct {
+	metadata.MD
+}
+
+func (w metadataReaderWriter) Set(key, val string) {
+	// The GRPC HPACK implementation rejects any uppercase keys here.
+	//
+	// As such, since the HTTP_HEADERS format is case-insensitive anyway, we
+	// blindly lowercase the key (which is guaranteed to work in the
+	// Inject/Extract sense per the OpenTracing spec).
+	key = strings.ToLower(key)
+	w.MD[key] = append(w.MD[key], val)
+}
+
+func (w metadataReaderWriter) ForeachKey(handler func(key, val string) error) error {
+	for k, vals := range w.MD {
+		for _, v := range vals {
+			if err := handler(k, v); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}

vendor/github.com/grpc-ecosystem/grpc-opentracing/python/README.md

@@ -0,0 +1,4 @@
+The repo has moved.
+-------------------
+
+https://github.com/opentracing-contrib/python-grpc

vendor/github.com/grpc-ecosystem/grpc-opentracing/python/examples/protos/command_line.proto

@@ -0,0 +1,15 @@
+syntax = "proto3";
+
+package command_line;
+
+service CommandLine {
+  rpc Echo(CommandRequest) returns (CommandResponse) {}
+}
+
+message CommandRequest {
+  string text = 1;
+}
+
+message CommandResponse {
+  string text = 1;
+}

vendor/github.com/grpc-ecosystem/grpc-opentracing/python/examples/protos/store.proto

@@ -0,0 +1,37 @@
+syntax = "proto3";
+
+package store;
+
+service Store {
+  rpc AddItem(AddItemRequest) returns (Empty) {}
+  rpc AddItems(stream AddItemRequest) returns (Empty) {}
+  rpc RemoveItem(RemoveItemRequest) returns (RemoveItemResponse) {}
+  rpc RemoveItems(stream RemoveItemRequest) returns (RemoveItemResponse) {}
+  rpc ListInventory(Empty) returns (stream QuantityResponse) {}
+  rpc QueryQuantity(QueryItemRequest) returns (QuantityResponse) {}
+  rpc QueryQuantities(stream QueryItemRequest) 
+                          returns (stream QuantityResponse) {}
+}
+
+message Empty {}
+
+message AddItemRequest {
+  string name = 1;
+}
+
+message RemoveItemRequest {
+  string name = 1;
+}
+
+message RemoveItemResponse {
+  bool was_successful = 1;
+}
+
+message QueryItemRequest {
+  string name = 1;
+}
+
+message QuantityResponse {
+  string name = 1;
+  int32 count = 2;
+}

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

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2016 The OpenTracing Authors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

vendor/github.com/opentracing/opentracing-go/README.md

@@ -0,0 +1,163 @@
+[![Gitter chat](http://img.shields.io/badge/gitter-join%20chat%20%E2%86%92-brightgreen.svg)](https://gitter.im/opentracing/public) [![Build Status](https://travis-ci.org/opentracing/opentracing-go.svg?branch=master)](https://travis-ci.org/opentracing/opentracing-go) [![GoDoc](https://godoc.org/github.com/opentracing/opentracing-go?status.svg)](http://godoc.org/github.com/opentracing/opentracing-go)
+[![Sourcegraph Badge](https://sourcegraph.com/github.com/opentracing/opentracing-go/-/badge.svg)](https://sourcegraph.com/github.com/opentracing/opentracing-go?badge)
+
+# OpenTracing API for Go
+
+This package is a Go platform API for OpenTracing.
+
+## Required Reading
+
+In order to understand the Go platform API, one must first be familiar with the
+[OpenTracing project](http://opentracing.io) and
+[terminology](http://opentracing.io/documentation/pages/spec.html) more specifically.
+
+## API overview for those adding instrumentation
+
+Everyday consumers of this `opentracing` package really only need to worry
+about a couple of key abstractions: the `StartSpan` function, the `Span`
+interface, and binding a `Tracer` at `main()`-time. Here are code snippets
+demonstrating some important use cases.
+
+#### Singleton initialization
+
+The simplest starting point is `./default_tracer.go`. As early as possible, call
+
+```go
+    import "github.com/opentracing/opentracing-go"
+    import ".../some_tracing_impl"
+
+    func main() {
+        opentracing.InitGlobalTracer(
+            // tracing impl specific:
+            some_tracing_impl.New(...),
+        )
+        ...
+    }
+```
+
+##### Non-Singleton initialization
+
+If you prefer direct control to singletons, manage ownership of the
+`opentracing.Tracer` implementation explicitly.
+
+#### Creating a Span given an existing Go `context.Context`
+
+If you use `context.Context` in your application, OpenTracing's Go library will
+happily rely on it for `Span` propagation. To start a new (blocking child)
+`Span`, you can use `StartSpanFromContext`.
+
+```go
+    func xyz(ctx context.Context, ...) {
+        ...
+        span, ctx := opentracing.StartSpanFromContext(ctx, "operation_name")
+        defer span.Finish()
+        span.LogFields(
+            log.String("event", "soft error"),
+            log.String("type", "cache timeout"),
+            log.Int("waited.millis", 1500))
+        ...
+    }
+```
+
+#### Starting an empty trace by creating a "root span"
+
+It's always possible to create a "root" `Span` with no parent or other causal
+reference.
+
+```go
+    func xyz() {
+        ...
+        sp := opentracing.StartSpan("operation_name")
+        defer sp.Finish()
+        ...
+    }
+```
+
+#### Creating a (child) Span given an existing (parent) Span
+
+```go
+    func xyz(parentSpan opentracing.Span, ...) {
+        ...
+        sp := opentracing.StartSpan(
+            "operation_name",
+            opentracing.ChildOf(parentSpan.Context()))
+        defer sp.Finish()
+        ...
+    }
+```
+
+#### Serializing to the wire
+
+```go
+    func makeSomeRequest(ctx context.Context) ... {
+        if span := opentracing.SpanFromContext(ctx); span != nil {
+            httpClient := &http.Client{}
+            httpReq, _ := http.NewRequest("GET", "http://myservice/", nil)
+
+            // Transmit the span's TraceContext as HTTP headers on our
+            // outbound request.
+            opentracing.GlobalTracer().Inject(
+                span.Context(),
+                opentracing.HTTPHeaders,
+                opentracing.HTTPHeadersCarrier(httpReq.Header))
+
+            resp, err := httpClient.Do(httpReq)
+            ...
+        }
+        ...
+    }
+```
+
+#### Deserializing from the wire
+
+```go
+    http.HandleFunc("/", func(w http.ResponseWriter, req *http.Request) {
+        var serverSpan opentracing.Span
+        appSpecificOperationName := ...
+        wireContext, err := opentracing.GlobalTracer().Extract(
+            opentracing.HTTPHeaders,
+            opentracing.HTTPHeadersCarrier(req.Header))
+        if err != nil {
+            // Optionally record something about err here
+        }
+
+        // Create the span referring to the RPC client if available.
+        // If wireContext == nil, a root span will be created.
+        serverSpan = opentracing.StartSpan(
+            appSpecificOperationName,
+            ext.RPCServerOption(wireContext))
+
+        defer serverSpan.Finish()
+
+        ctx := opentracing.ContextWithSpan(context.Background(), serverSpan)
+        ...
+    }
+```
+
+#### Conditionally capture a field using `log.Noop`
+
+In some situations, you may want to dynamically decide whether or not
+to log a field.  For example, you may want to capture additional data,
+such as a customer ID, in non-production environments:
+
+```go
+    func Customer(order *Order) log.Field {
+        if os.Getenv("ENVIRONMENT") == "dev" {
+            return log.String("customer", order.Customer.ID)
+        }
+        return log.Noop()
+    }
+```
+
+#### Goroutine-safety
+
+The entire public API is goroutine-safe and does not require external
+synchronization.
+
+## API pointers for those implementing a tracing system
+
+Tracing system implementors may be able to reuse or copy-paste-modify the `basictracer` package, found [here](https://github.com/opentracing/basictracer-go). In particular, see `basictracer.New(...)`.
+
+## API compatibility
+
+For the time being, "mild" backwards-incompatible changes may be made without changing the major version number. As OpenTracing and `opentracing-go` mature, backwards compatibility will become more of a priority.

vendor/github.com/opentracing/opentracing-go/ext/tags.go

@@ -0,0 +1,210 @@
+package ext
+
+import opentracing "github.com/opentracing/opentracing-go"
+
+// These constants define common tag names recommended for better portability across
+// tracing systems and languages/platforms.
+//
+// The tag names are defined as typed strings, so that in addition to the usual use
+//
+//     span.setTag(TagName, value)
+//
+// they also support value type validation via this additional syntax:
+//
+//    TagName.Set(span, value)
+//
+var (
+	//////////////////////////////////////////////////////////////////////
+	// SpanKind (client/server or producer/consumer)
+	//////////////////////////////////////////////////////////////////////
+
+	// SpanKind hints at relationship between spans, e.g. client/server
+	SpanKind = spanKindTagName("span.kind")
+
+	// SpanKindRPCClient marks a span representing the client-side of an RPC
+	// or other remote call
+	SpanKindRPCClientEnum = SpanKindEnum("client")
+	SpanKindRPCClient     = opentracing.Tag{Key: string(SpanKind), Value: SpanKindRPCClientEnum}
+
+	// SpanKindRPCServer marks a span representing the server-side of an RPC
+	// or other remote call
+	SpanKindRPCServerEnum = SpanKindEnum("server")
+	SpanKindRPCServer     = opentracing.Tag{Key: string(SpanKind), Value: SpanKindRPCServerEnum}
+
+	// SpanKindProducer marks a span representing the producer-side of a
+	// message bus
+	SpanKindProducerEnum = SpanKindEnum("producer")
+	SpanKindProducer     = opentracing.Tag{Key: string(SpanKind), Value: SpanKindProducerEnum}
+
+	// SpanKindConsumer marks a span representing the consumer-side of a
+	// message bus
+	SpanKindConsumerEnum = SpanKindEnum("consumer")
+	SpanKindConsumer     = opentracing.Tag{Key: string(SpanKind), Value: SpanKindConsumerEnum}
+
+	//////////////////////////////////////////////////////////////////////
+	// Component name
+	//////////////////////////////////////////////////////////////////////
+
+	// Component is a low-cardinality identifier of the module, library,
+	// or package that is generating a span.
+	Component = stringTagName("component")
+
+	//////////////////////////////////////////////////////////////////////
+	// Sampling hint
+	//////////////////////////////////////////////////////////////////////
+
+	// SamplingPriority determines the priority of sampling this Span.
+	SamplingPriority = uint16TagName("sampling.priority")
+
+	//////////////////////////////////////////////////////////////////////
+	// Peer tags. These tags can be emitted by either client-side of
+	// server-side to describe the other side/service in a peer-to-peer
+	// communications, like an RPC call.
+	//////////////////////////////////////////////////////////////////////
+
+	// PeerService records the service name of the peer.
+	PeerService = stringTagName("peer.service")
+
+	// PeerAddress records the address name of the peer. This may be a "ip:port",
+	// a bare "hostname", a FQDN or even a database DSN substring
+	// like "mysql://username@127.0.0.1:3306/dbname"
+	PeerAddress = stringTagName("peer.address")
+
+	// PeerHostname records the host name of the peer
+	PeerHostname = stringTagName("peer.hostname")
+
+	// PeerHostIPv4 records IP v4 host address of the peer
+	PeerHostIPv4 = ipv4Tag("peer.ipv4")
+
+	// PeerHostIPv6 records IP v6 host address of the peer
+	PeerHostIPv6 = stringTagName("peer.ipv6")
+
+	// PeerPort records port number of the peer
+	PeerPort = uint16TagName("peer.port")
+
+	//////////////////////////////////////////////////////////////////////
+	// HTTP Tags
+	//////////////////////////////////////////////////////////////////////
+
+	// HTTPUrl should be the URL of the request being handled in this segment
+	// of the trace, in standard URI format. The protocol is optional.
+	HTTPUrl = stringTagName("http.url")
+
+	// HTTPMethod is the HTTP method of the request, and is case-insensitive.
+	HTTPMethod = stringTagName("http.method")
+
+	// HTTPStatusCode is the numeric HTTP status code (200, 404, etc) of the
+	// HTTP response.
+	HTTPStatusCode = uint16TagName("http.status_code")
+
+	//////////////////////////////////////////////////////////////////////
+	// DB Tags
+	//////////////////////////////////////////////////////////////////////
+
+	// DBInstance is database instance name.
+	DBInstance = stringTagName("db.instance")
+
+	// DBStatement is a database statement for the given database type.
+	// It can be a query or a prepared statement (i.e., before substitution).
+	DBStatement = stringTagName("db.statement")
+
+	// DBType is a database type. For any SQL database, "sql".
+	// For others, the lower-case database category, e.g. "redis"
+	DBType = stringTagName("db.type")
+
+	// DBUser is a username for accessing database.
+	DBUser = stringTagName("db.user")
+
+	//////////////////////////////////////////////////////////////////////
+	// Message Bus Tag
+	//////////////////////////////////////////////////////////////////////
+
+	// MessageBusDestination is an address at which messages can be exchanged
+	MessageBusDestination = stringTagName("message_bus.destination")
+
+	//////////////////////////////////////////////////////////////////////
+	// Error Tag
+	//////////////////////////////////////////////////////////////////////
+
+	// Error indicates that operation represented by the span resulted in an error.
+	Error = boolTagName("error")
+)
+
+// ---
+
+// SpanKindEnum represents common span types
+type SpanKindEnum string
+
+type spanKindTagName string
+
+// Set adds a string tag to the `span`
+func (tag spanKindTagName) Set(span opentracing.Span, value SpanKindEnum) {
+	span.SetTag(string(tag), value)
+}
+
+type rpcServerOption struct {
+	clientContext opentracing.SpanContext
+}
+
+func (r rpcServerOption) Apply(o *opentracing.StartSpanOptions) {
+	if r.clientContext != nil {
+		opentracing.ChildOf(r.clientContext).Apply(o)
+	}
+	SpanKindRPCServer.Apply(o)
+}
+
+// RPCServerOption returns a StartSpanOption appropriate for an RPC server span
+// with `client` representing the metadata for the remote peer Span if available.
+// In case client == nil, due to the client not being instrumented, this RPC
+// server span will be a root span.
+func RPCServerOption(client opentracing.SpanContext) opentracing.StartSpanOption {
+	return rpcServerOption{client}
+}
+
+// ---
+
+type stringTagName string
+
+// Set adds a string tag to the `span`
+func (tag stringTagName) Set(span opentracing.Span, value string) {
+	span.SetTag(string(tag), value)
+}
+
+// ---
+
+type uint32TagName string
+
+// Set adds a uint32 tag to the `span`
+func (tag uint32TagName) Set(span opentracing.Span, value uint32) {
+	span.SetTag(string(tag), value)
+}
+
+// ---
+
+type uint16TagName string
+
+// Set adds a uint16 tag to the `span`
+func (tag uint16TagName) Set(span opentracing.Span, value uint16) {
+	span.SetTag(string(tag), value)
+}
+
+// ---
+
+type boolTagName string
+
+// Add adds a bool tag to the `span`
+func (tag boolTagName) Set(span opentracing.Span, value bool) {
+	span.SetTag(string(tag), value)
+}
+
+type ipv4Tag string
+
+// Set adds IP v4 host address of the peer as an uint32 value to the `span`, keep this for backward and zipkin compatibility
+func (tag ipv4Tag) Set(span opentracing.Span, value uint32) {
+	span.SetTag(string(tag), value)
+}
+
+// SetString records IP v4 host address of the peer as a .-separated tuple to the `span`. E.g., "127.0.0.1"
+func (tag ipv4Tag) SetString(span opentracing.Span, value string) {
+	span.SetTag(string(tag), value)
+}

vendor/github.com/opentracing/opentracing-go/globaltracer.go

@@ -0,0 +1,32 @@
+package opentracing
+
+var (
+	globalTracer Tracer = NoopTracer{}
+)
+
+// SetGlobalTracer sets the [singleton] opentracing.Tracer returned by
+// GlobalTracer(). Those who use GlobalTracer (rather than directly manage an
+// opentracing.Tracer instance) should call SetGlobalTracer as early as
+// possible in main(), prior to calling the `StartSpan` global func below.
+// Prior to calling `SetGlobalTracer`, any Spans started via the `StartSpan`
+// (etc) globals are noops.
+func SetGlobalTracer(tracer Tracer) {
+	globalTracer = tracer
+}
+
+// GlobalTracer returns the global singleton `Tracer` implementation.
+// Before `SetGlobalTracer()` is called, the `GlobalTracer()` is a noop
+// implementation that drops all data handed to it.
+func GlobalTracer() Tracer {
+	return globalTracer
+}
+
+// StartSpan defers to `Tracer.StartSpan`. See `GlobalTracer()`.
+func StartSpan(operationName string, opts ...StartSpanOption) Span {
+	return globalTracer.StartSpan(operationName, opts...)
+}
+
+// InitGlobalTracer is deprecated. Please use SetGlobalTracer.
+func InitGlobalTracer(tracer Tracer) {
+	SetGlobalTracer(tracer)
+}

vendor/github.com/opentracing/opentracing-go/gocontext.go

@@ -0,0 +1,57 @@
+package opentracing
+
+import "golang.org/x/net/context"
+
+type contextKey struct{}
+
+var activeSpanKey = contextKey{}
+
+// ContextWithSpan returns a new `context.Context` that holds a reference to
+// `span`'s SpanContext.
+func ContextWithSpan(ctx context.Context, span Span) context.Context {
+	return context.WithValue(ctx, activeSpanKey, span)
+}
+
+// SpanFromContext returns the `Span` previously associated with `ctx`, or
+// `nil` if no such `Span` could be found.
+//
+// NOTE: context.Context != SpanContext: the former is Go's intra-process
+// context propagation mechanism, and the latter houses OpenTracing's per-Span
+// identity and baggage information.
+func SpanFromContext(ctx context.Context) Span {
+	val := ctx.Value(activeSpanKey)
+	if sp, ok := val.(Span); ok {
+		return sp
+	}
+	return nil
+}
+
+// StartSpanFromContext starts and returns a Span with `operationName`, using
+// any Span found within `ctx` as a ChildOfRef. If no such parent could be
+// found, StartSpanFromContext creates a root (parentless) Span.
+//
+// The second return value is a context.Context object built around the
+// returned Span.
+//
+// Example usage:
+//
+//    SomeFunction(ctx context.Context, ...) {
+//        sp, ctx := opentracing.StartSpanFromContext(ctx, "SomeFunction")
+//        defer sp.Finish()
+//        ...
+//    }
+func StartSpanFromContext(ctx context.Context, operationName string, opts ...StartSpanOption) (Span, context.Context) {
+	return startSpanFromContextWithTracer(ctx, GlobalTracer(), operationName, opts...)
+}
+
+// startSpanFromContextWithTracer is factored out for testing purposes.
+func startSpanFromContextWithTracer(ctx context.Context, tracer Tracer, operationName string, opts ...StartSpanOption) (Span, context.Context) {
+	var span Span
+	if parentSpan := SpanFromContext(ctx); parentSpan != nil {
+		opts = append(opts, ChildOf(parentSpan.Context()))
+		span = tracer.StartSpan(operationName, opts...)
+	} else {
+		span = tracer.StartSpan(operationName, opts...)
+	}
+	return span, ContextWithSpan(ctx, span)
+}

vendor/github.com/opentracing/opentracing-go/log/field.go

@@ -0,0 +1,269 @@
+package log
+
+import (
+	"fmt"
+	"math"
+)
+
+type fieldType int
+
+const (
+	stringType fieldType = iota
+	boolType
+	intType
+	int32Type
+	uint32Type
+	int64Type
+	uint64Type
+	float32Type
+	float64Type
+	errorType
+	objectType
+	lazyLoggerType
+	noopType
+)
+
+// Field instances are constructed via LogBool, LogString, and so on.
+// Tracing implementations may then handle them via the Field.Marshal
+// method.
+//
+// "heavily influenced by" (i.e., partially stolen from)
+// https://github.com/uber-go/zap
+type Field struct {
+	key          string
+	fieldType    fieldType
+	numericVal   int64
+	stringVal    string
+	interfaceVal interface{}
+}
+
+// String adds a string-valued key:value pair to a Span.LogFields() record
+func String(key, val string) Field {
+	return Field{
+		key:       key,
+		fieldType: stringType,
+		stringVal: val,
+	}
+}
+
+// Bool adds a bool-valued key:value pair to a Span.LogFields() record
+func Bool(key string, val bool) Field {
+	var numericVal int64
+	if val {
+		numericVal = 1
+	}
+	return Field{
+		key:        key,
+		fieldType:  boolType,
+		numericVal: numericVal,
+	}
+}
+
+// Int adds an int-valued key:value pair to a Span.LogFields() record
+func Int(key string, val int) Field {
+	return Field{
+		key:        key,
+		fieldType:  intType,
+		numericVal: int64(val),
+	}
+}
+
+// Int32 adds an int32-valued key:value pair to a Span.LogFields() record
+func Int32(key string, val int32) Field {
+	return Field{
+		key:        key,
+		fieldType:  int32Type,
+		numericVal: int64(val),
+	}
+}
+
+// Int64 adds an int64-valued key:value pair to a Span.LogFields() record
+func Int64(key string, val int64) Field {
+	return Field{
+		key:        key,
+		fieldType:  int64Type,
+		numericVal: val,
+	}
+}
+
+// Uint32 adds a uint32-valued key:value pair to a Span.LogFields() record
+func Uint32(key string, val uint32) Field {
+	return Field{
+		key:        key,
+		fieldType:  uint32Type,
+		numericVal: int64(val),
+	}
+}
+
+// Uint64 adds a uint64-valued key:value pair to a Span.LogFields() record
+func Uint64(key string, val uint64) Field {
+	return Field{
+		key:        key,
+		fieldType:  uint64Type,
+		numericVal: int64(val),
+	}
+}
+
+// Float32 adds a float32-valued key:value pair to a Span.LogFields() record
+func Float32(key string, val float32) Field {
+	return Field{
+		key:        key,
+		fieldType:  float32Type,
+		numericVal: int64(math.Float32bits(val)),
+	}
+}
+
+// Float64 adds a float64-valued key:value pair to a Span.LogFields() record
+func Float64(key string, val float64) Field {
+	return Field{
+		key:        key,
+		fieldType:  float64Type,
+		numericVal: int64(math.Float64bits(val)),
+	}
+}
+
+// Error adds an error with the key "error" to a Span.LogFields() record
+func Error(err error) Field {
+	return Field{
+		key:          "error",
+		fieldType:    errorType,
+		interfaceVal: err,
+	}
+}
+
+// Object adds an object-valued key:value pair to a Span.LogFields() record
+func Object(key string, obj interface{}) Field {
+	return Field{
+		key:          key,
+		fieldType:    objectType,
+		interfaceVal: obj,
+	}
+}
+
+// LazyLogger allows for user-defined, late-bound logging of arbitrary data
+type LazyLogger func(fv Encoder)
+
+// Lazy adds a LazyLogger to a Span.LogFields() record; the tracing
+// implementation will call the LazyLogger function at an indefinite time in
+// the future (after Lazy() returns).
+func Lazy(ll LazyLogger) Field {
+	return Field{
+		fieldType:    lazyLoggerType,
+		interfaceVal: ll,
+	}
+}
+
+// Noop creates a no-op log field that should be ignored by the tracer.
+// It can be used to capture optional fields, for example those that should
+// only be logged in non-production environment:
+//
+//     func customerField(order *Order) log.Field {
+//          if os.Getenv("ENVIRONMENT") == "dev" {
+//              return log.String("customer", order.Customer.ID)
+//          }
+//          return log.Noop()
+//     }
+//
+//     span.LogFields(log.String("event", "purchase"), customerField(order))
+//
+func Noop() Field {
+	return Field{
+		fieldType: noopType,
+	}
+}
+
+// Encoder allows access to the contents of a Field (via a call to
+// Field.Marshal).
+//
+// Tracer implementations typically provide an implementation of Encoder;
+// OpenTracing callers typically do not need to concern themselves with it.
+type Encoder interface {
+	EmitString(key, value string)
+	EmitBool(key string, value bool)
+	EmitInt(key string, value int)
+	EmitInt32(key string, value int32)
+	EmitInt64(key string, value int64)
+	EmitUint32(key string, value uint32)
+	EmitUint64(key string, value uint64)
+	EmitFloat32(key string, value float32)
+	EmitFloat64(key string, value float64)
+	EmitObject(key string, value interface{})
+	EmitLazyLogger(value LazyLogger)
+}
+
+// Marshal passes a Field instance through to the appropriate
+// field-type-specific method of an Encoder.
+func (lf Field) Marshal(visitor Encoder) {
+	switch lf.fieldType {
+	case stringType:
+		visitor.EmitString(lf.key, lf.stringVal)
+	case boolType:
+		visitor.EmitBool(lf.key, lf.numericVal != 0)
+	case intType:
+		visitor.EmitInt(lf.key, int(lf.numericVal))
+	case int32Type:
+		visitor.EmitInt32(lf.key, int32(lf.numericVal))
+	case int64Type:
+		visitor.EmitInt64(lf.key, int64(lf.numericVal))
+	case uint32Type:
+		visitor.EmitUint32(lf.key, uint32(lf.numericVal))
+	case uint64Type:
+		visitor.EmitUint64(lf.key, uint64(lf.numericVal))
+	case float32Type:
+		visitor.EmitFloat32(lf.key, math.Float32frombits(uint32(lf.numericVal)))
+	case float64Type:
+		visitor.EmitFloat64(lf.key, math.Float64frombits(uint64(lf.numericVal)))
+	case errorType:
+		if err, ok := lf.interfaceVal.(error); ok {
+			visitor.EmitString(lf.key, err.Error())
+		} else {
+			visitor.EmitString(lf.key, "<nil>")
+		}
+	case objectType:
+		visitor.EmitObject(lf.key, lf.interfaceVal)
+	case lazyLoggerType:
+		visitor.EmitLazyLogger(lf.interfaceVal.(LazyLogger))
+	case noopType:
+		// intentionally left blank
+	}
+}
+
+// Key returns the field's key.
+func (lf Field) Key() string {
+	return lf.key
+}
+
+// Value returns the field's value as interface{}.
+func (lf Field) Value() interface{} {
+	switch lf.fieldType {
+	case stringType:
+		return lf.stringVal
+	case boolType:
+		return lf.numericVal != 0
+	case intType:
+		return int(lf.numericVal)
+	case int32Type:
+		return int32(lf.numericVal)
+	case int64Type:
+		return int64(lf.numericVal)
+	case uint32Type:
+		return uint32(lf.numericVal)
+	case uint64Type:
+		return uint64(lf.numericVal)
+	case float32Type:
+		return math.Float32frombits(uint32(lf.numericVal))
+	case float64Type:
+		return math.Float64frombits(uint64(lf.numericVal))
+	case errorType, objectType, lazyLoggerType:
+		return lf.interfaceVal
+	case noopType:
+		return nil
+	default:
+		return nil
+	}
+}
+
+// String returns a string representation of the key and value.
+func (lf Field) String() string {
+	return fmt.Sprint(lf.key, ":", lf.Value())
+}

vendor/github.com/opentracing/opentracing-go/log/util.go

@@ -0,0 +1,54 @@
+package log
+
+import "fmt"
+
+// InterleavedKVToFields converts keyValues a la Span.LogKV() to a Field slice
+// a la Span.LogFields().
+func InterleavedKVToFields(keyValues ...interface{}) ([]Field, error) {
+	if len(keyValues)%2 != 0 {
+		return nil, fmt.Errorf("non-even keyValues len: %d", len(keyValues))
+	}
+	fields := make([]Field, len(keyValues)/2)
+	for i := 0; i*2 < len(keyValues); i++ {
+		key, ok := keyValues[i*2].(string)
+		if !ok {
+			return nil, fmt.Errorf(
+				"non-string key (pair #%d): %T",
+				i, keyValues[i*2])
+		}
+		switch typedVal := keyValues[i*2+1].(type) {
+		case bool:
+			fields[i] = Bool(key, typedVal)
+		case string:
+			fields[i] = String(key, typedVal)
+		case int:
+			fields[i] = Int(key, typedVal)
+		case int8:
+			fields[i] = Int32(key, int32(typedVal))
+		case int16:
+			fields[i] = Int32(key, int32(typedVal))
+		case int32:
+			fields[i] = Int32(key, typedVal)
+		case int64:
+			fields[i] = Int64(key, typedVal)
+		case uint:
+			fields[i] = Uint64(key, uint64(typedVal))
+		case uint64:
+			fields[i] = Uint64(key, typedVal)
+		case uint8:
+			fields[i] = Uint32(key, uint32(typedVal))
+		case uint16:
+			fields[i] = Uint32(key, uint32(typedVal))
+		case uint32:
+			fields[i] = Uint32(key, typedVal)
+		case float32:
+			fields[i] = Float32(key, typedVal)
+		case float64:
+			fields[i] = Float64(key, typedVal)
+		default:
+			// When in doubt, coerce to a string
+			fields[i] = String(key, fmt.Sprint(typedVal))
+		}
+	}
+	return fields, nil
+}

vendor/github.com/opentracing/opentracing-go/noop.go

@@ -0,0 +1,64 @@
+package opentracing
+
+import "github.com/opentracing/opentracing-go/log"
+
+// A NoopTracer is a trivial, minimum overhead implementation of Tracer
+// for which all operations are no-ops.
+//
+// The primary use of this implementation is in libraries, such as RPC
+// frameworks, that make tracing an optional feature controlled by the
+// end user. A no-op implementation allows said libraries to use it
+// as the default Tracer and to write instrumentation that does
+// not need to keep checking if the tracer instance is nil.
+//
+// For the same reason, the NoopTracer is the default "global" tracer
+// (see GlobalTracer and SetGlobalTracer functions).
+//
+// WARNING: NoopTracer does not support baggage propagation.
+type NoopTracer struct{}
+
+type noopSpan struct{}
+type noopSpanContext struct{}
+
+var (
+	defaultNoopSpanContext = noopSpanContext{}
+	defaultNoopSpan        = noopSpan{}
+	defaultNoopTracer      = NoopTracer{}
+)
+
+const (
+	emptyString = ""
+)
+
+// noopSpanContext:
+func (n noopSpanContext) ForeachBaggageItem(handler func(k, v string) bool) {}
+
+// noopSpan:
+func (n noopSpan) Context() SpanContext                                  { return defaultNoopSpanContext }
+func (n noopSpan) SetBaggageItem(key, val string) Span                   { return defaultNoopSpan }
+func (n noopSpan) BaggageItem(key string) string                         { return emptyString }
+func (n noopSpan) SetTag(key string, value interface{}) Span             { return n }
+func (n noopSpan) LogFields(fields ...log.Field)                         {}
+func (n noopSpan) LogKV(keyVals ...interface{})                          {}
+func (n noopSpan) Finish()                                               {}
+func (n noopSpan) FinishWithOptions(opts FinishOptions)                  {}
+func (n noopSpan) SetOperationName(operationName string) Span            { return n }
+func (n noopSpan) Tracer() Tracer                                        { return defaultNoopTracer }
+func (n noopSpan) LogEvent(event string)                                 {}
+func (n noopSpan) LogEventWithPayload(event string, payload interface{}) {}
+func (n noopSpan) Log(data LogData)                                      {}
+
+// StartSpan belongs to the Tracer interface.
+func (n NoopTracer) StartSpan(operationName string, opts ...StartSpanOption) Span {
+	return defaultNoopSpan
+}
+
+// Inject belongs to the Tracer interface.
+func (n NoopTracer) Inject(sp SpanContext, format interface{}, carrier interface{}) error {
+	return nil
+}
+
+// Extract belongs to the Tracer interface.
+func (n NoopTracer) Extract(format interface{}, carrier interface{}) (SpanContext, error) {
+	return nil, ErrSpanContextNotFound
+}

vendor/github.com/opentracing/opentracing-go/propagation.go

@@ -0,0 +1,176 @@
+package opentracing
+
+import (
+	"errors"
+	"net/http"
+)
+
+///////////////////////////////////////////////////////////////////////////////
+// CORE PROPAGATION INTERFACES:
+///////////////////////////////////////////////////////////////////////////////
+
+var (
+	// ErrUnsupportedFormat occurs when the `format` passed to Tracer.Inject() or
+	// Tracer.Extract() is not recognized by the Tracer implementation.
+	ErrUnsupportedFormat = errors.New("opentracing: Unknown or unsupported Inject/Extract format")
+
+	// ErrSpanContextNotFound occurs when the `carrier` passed to
+	// Tracer.Extract() is valid and uncorrupted but has insufficient
+	// information to extract a SpanContext.
+	ErrSpanContextNotFound = errors.New("opentracing: SpanContext not found in Extract carrier")
+
+	// ErrInvalidSpanContext errors occur when Tracer.Inject() is asked to
+	// operate on a SpanContext which it is not prepared to handle (for
+	// example, since it was created by a different tracer implementation).
+	ErrInvalidSpanContext = errors.New("opentracing: SpanContext type incompatible with tracer")
+
+	// ErrInvalidCarrier errors occur when Tracer.Inject() or Tracer.Extract()
+	// implementations expect a different type of `carrier` than they are
+	// given.
+	ErrInvalidCarrier = errors.New("opentracing: Invalid Inject/Extract carrier")
+
+	// ErrSpanContextCorrupted occurs when the `carrier` passed to
+	// Tracer.Extract() is of the expected type but is corrupted.
+	ErrSpanContextCorrupted = errors.New("opentracing: SpanContext data corrupted in Extract carrier")
+)
+
+///////////////////////////////////////////////////////////////////////////////
+// BUILTIN PROPAGATION FORMATS:
+///////////////////////////////////////////////////////////////////////////////
+
+// BuiltinFormat is used to demarcate the values within package `opentracing`
+// that are intended for use with the Tracer.Inject() and Tracer.Extract()
+// methods.
+type BuiltinFormat byte
+
+const (
+	// Binary represents SpanContexts as opaque binary data.
+	//
+	// For Tracer.Inject(): the carrier must be an `io.Writer`.
+	//
+	// For Tracer.Extract(): the carrier must be an `io.Reader`.
+	Binary BuiltinFormat = iota
+
+	// TextMap represents SpanContexts as key:value string pairs.
+	//
+	// Unlike HTTPHeaders, the TextMap format does not restrict the key or
+	// value character sets in any way.
+	//
+	// For Tracer.Inject(): the carrier must be a `TextMapWriter`.
+	//
+	// For Tracer.Extract(): the carrier must be a `TextMapReader`.
+	TextMap
+
+	// HTTPHeaders represents SpanContexts as HTTP header string pairs.
+	//
+	// Unlike TextMap, the HTTPHeaders format requires that the keys and values
+	// be valid as HTTP headers as-is (i.e., character casing may be unstable
+	// and special characters are disallowed in keys, values should be
+	// URL-escaped, etc).
+	//
+	// For Tracer.Inject(): the carrier must be a `TextMapWriter`.
+	//
+	// For Tracer.Extract(): the carrier must be a `TextMapReader`.
+	//
+	// See HTTPHeadersCarrier for an implementation of both TextMapWriter
+	// and TextMapReader that defers to an http.Header instance for storage.
+	// For example, Inject():
+	//
+	//    carrier := opentracing.HTTPHeadersCarrier(httpReq.Header)
+	//    err := span.Tracer().Inject(
+	//        span.Context(), opentracing.HTTPHeaders, carrier)
+	//
+	// Or Extract():
+	//
+	//    carrier := opentracing.HTTPHeadersCarrier(httpReq.Header)
+	//    clientContext, err := tracer.Extract(
+	//        opentracing.HTTPHeaders, carrier)
+	//
+	HTTPHeaders
+)
+
+// TextMapWriter is the Inject() carrier for the TextMap builtin format. With
+// it, the caller can encode a SpanContext for propagation as entries in a map
+// of unicode strings.
+type TextMapWriter interface {
+	// Set a key:value pair to the carrier. Multiple calls to Set() for the
+	// same key leads to undefined behavior.
+	//
+	// NOTE: The backing store for the TextMapWriter may contain data unrelated
+	// to SpanContext. As such, Inject() and Extract() implementations that
+	// call the TextMapWriter and TextMapReader interfaces must agree on a
+	// prefix or other convention to distinguish their own key:value pairs.
+	Set(key, val string)
+}
+
+// TextMapReader is the Extract() carrier for the TextMap builtin format. With it,
+// the caller can decode a propagated SpanContext as entries in a map of
+// unicode strings.
+type TextMapReader interface {
+	// ForeachKey returns TextMap contents via repeated calls to the `handler`
+	// function. If any call to `handler` returns a non-nil error, ForeachKey
+	// terminates and returns that error.
+	//
+	// NOTE: The backing store for the TextMapReader may contain data unrelated
+	// to SpanContext. As such, Inject() and Extract() implementations that
+	// call the TextMapWriter and TextMapReader interfaces must agree on a
+	// prefix or other convention to distinguish their own key:value pairs.
+	//
+	// The "foreach" callback pattern reduces unnecessary copying in some cases
+	// and also allows implementations to hold locks while the map is read.
+	ForeachKey(handler func(key, val string) error) error
+}
+
+// TextMapCarrier allows the use of regular map[string]string
+// as both TextMapWriter and TextMapReader.
+type TextMapCarrier map[string]string
+
+// ForeachKey conforms to the TextMapReader interface.
+func (c TextMapCarrier) ForeachKey(handler func(key, val string) error) error {
+	for k, v := range c {
+		if err := handler(k, v); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Set implements Set() of opentracing.TextMapWriter
+func (c TextMapCarrier) Set(key, val string) {
+	c[key] = val
+}
+
+// HTTPHeadersCarrier satisfies both TextMapWriter and TextMapReader.
+//
+// Example usage for server side:
+//
+//     carrier := opentracing.HTTPHeadersCarrier(httpReq.Header)
+//     clientContext, err := tracer.Extract(opentracing.HTTPHeaders, carrier)
+//
+// Example usage for client side:
+//
+//     carrier := opentracing.HTTPHeadersCarrier(httpReq.Header)
+//     err := tracer.Inject(
+//         span.Context(),
+//         opentracing.HTTPHeaders,
+//         carrier)
+//
+type HTTPHeadersCarrier http.Header
+
+// Set conforms to the TextMapWriter interface.
+func (c HTTPHeadersCarrier) Set(key, val string) {
+	h := http.Header(c)
+	h.Add(key, val)
+}
+
+// ForeachKey conforms to the TextMapReader interface.
+func (c HTTPHeadersCarrier) ForeachKey(handler func(key, val string) error) error {
+	for k, vals := range c {
+		for _, v := range vals {
+			if err := handler(k, v); err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}

vendor/github.com/opentracing/opentracing-go/span.go

@@ -0,0 +1,185 @@
+package opentracing
+
+import (
+	"time"
+
+	"github.com/opentracing/opentracing-go/log"
+)
+
+// SpanContext represents Span state that must propagate to descendant Spans and across process
+// boundaries (e.g., a <trace_id, span_id, sampled> tuple).
+type SpanContext interface {
+	// ForeachBaggageItem grants access to all baggage items stored in the
+	// SpanContext.
+	// The handler function will be called for each baggage key/value pair.
+	// The ordering of items is not guaranteed.
+	//
+	// The bool return value indicates if the handler wants to continue iterating
+	// through the rest of the baggage items; for example if the handler is trying to
+	// find some baggage item by pattern matching the name, it can return false
+	// as soon as the item is found to stop further iterations.
+	ForeachBaggageItem(handler func(k, v string) bool)
+}
+
+// Span represents an active, un-finished span in the OpenTracing system.
+//
+// Spans are created by the Tracer interface.
+type Span interface {
+	// Sets the end timestamp and finalizes Span state.
+	//
+	// With the exception of calls to Context() (which are always allowed),
+	// Finish() must be the last call made to any span instance, and to do
+	// otherwise leads to undefined behavior.
+	Finish()
+	// FinishWithOptions is like Finish() but with explicit control over
+	// timestamps and log data.
+	FinishWithOptions(opts FinishOptions)
+
+	// Context() yields the SpanContext for this Span. Note that the return
+	// value of Context() is still valid after a call to Span.Finish(), as is
+	// a call to Span.Context() after a call to Span.Finish().
+	Context() SpanContext
+
+	// Sets or changes the operation name.
+	SetOperationName(operationName string) Span
+
+	// Adds a tag to the span.
+	//
+	// If there is a pre-existing tag set for `key`, it is overwritten.
+	//
+	// Tag values can be numeric types, strings, or bools. The behavior of
+	// other tag value types is undefined at the OpenTracing level. If a
+	// tracing system does not know how to handle a particular value type, it
+	// may ignore the tag, but shall not panic.
+	SetTag(key string, value interface{}) Span
+
+	// LogFields is an efficient and type-checked way to record key:value
+	// logging data about a Span, though the programming interface is a little
+	// more verbose than LogKV(). Here's an example:
+	//
+	//    span.LogFields(
+	//        log.String("event", "soft error"),
+	//        log.String("type", "cache timeout"),
+	//        log.Int("waited.millis", 1500))
+	//
+	// Also see Span.FinishWithOptions() and FinishOptions.BulkLogData.
+	LogFields(fields ...log.Field)
+
+	// LogKV is a concise, readable way to record key:value logging data about
+	// a Span, though unfortunately this also makes it less efficient and less
+	// type-safe than LogFields(). Here's an example:
+	//
+	//    span.LogKV(
+	//        "event", "soft error",
+	//        "type", "cache timeout",
+	//        "waited.millis", 1500)
+	//
+	// For LogKV (as opposed to LogFields()), the parameters must appear as
+	// key-value pairs, like
+	//
+	//    span.LogKV(key1, val1, key2, val2, key3, val3, ...)
+	//
+	// The keys must all be strings. The values may be strings, numeric types,
+	// bools, Go error instances, or arbitrary structs.
+	//
+	// (Note to implementors: consider the log.InterleavedKVToFields() helper)
+	LogKV(alternatingKeyValues ...interface{})
+
+	// SetBaggageItem sets a key:value pair on this Span and its SpanContext
+	// that also propagates to descendants of this Span.
+	//
+	// SetBaggageItem() enables powerful functionality given a full-stack
+	// opentracing integration (e.g., arbitrary application data from a mobile
+	// app can make it, transparently, all the way into the depths of a storage
+	// system), and with it some powerful costs: use this feature with care.
+	//
+	// IMPORTANT NOTE #1: SetBaggageItem() will only propagate baggage items to
+	// *future* causal descendants of the associated Span.
+	//
+	// IMPORTANT NOTE #2: Use this thoughtfully and with care. Every key and
+	// value is copied into every local *and remote* child of the associated
+	// Span, and that can add up to a lot of network and cpu overhead.
+	//
+	// Returns a reference to this Span for chaining.
+	SetBaggageItem(restrictedKey, value string) Span
+
+	// Gets the value for a baggage item given its key. Returns the empty string
+	// if the value isn't found in this Span.
+	BaggageItem(restrictedKey string) string
+
+	// Provides access to the Tracer that created this Span.
+	Tracer() Tracer
+
+	// Deprecated: use LogFields or LogKV
+	LogEvent(event string)
+	// Deprecated: use LogFields or LogKV
+	LogEventWithPayload(event string, payload interface{})
+	// Deprecated: use LogFields or LogKV
+	Log(data LogData)
+}
+
+// LogRecord is data associated with a single Span log. Every LogRecord
+// instance must specify at least one Field.
+type LogRecord struct {
+	Timestamp time.Time
+	Fields    []log.Field
+}
+
+// FinishOptions allows Span.FinishWithOptions callers to override the finish
+// timestamp and provide log data via a bulk interface.
+type FinishOptions struct {
+	// FinishTime overrides the Span's finish time, or implicitly becomes
+	// time.Now() if FinishTime.IsZero().
+	//
+	// FinishTime must resolve to a timestamp that's >= the Span's StartTime
+	// (per StartSpanOptions).
+	FinishTime time.Time
+
+	// LogRecords allows the caller to specify the contents of many LogFields()
+	// calls with a single slice. May be nil.
+	//
+	// None of the LogRecord.Timestamp values may be .IsZero() (i.e., they must
+	// be set explicitly). Also, they must be >= the Span's start timestamp and
+	// <= the FinishTime (or time.Now() if FinishTime.IsZero()). Otherwise the
+	// behavior of FinishWithOptions() is undefined.
+	//
+	// If specified, the caller hands off ownership of LogRecords at
+	// FinishWithOptions() invocation time.
+	//
+	// If specified, the (deprecated) BulkLogData must be nil or empty.
+	LogRecords []LogRecord
+
+	// BulkLogData is DEPRECATED.
+	BulkLogData []LogData
+}
+
+// LogData is DEPRECATED
+type LogData struct {
+	Timestamp time.Time
+	Event     string
+	Payload   interface{}
+}
+
+// ToLogRecord converts a deprecated LogData to a non-deprecated LogRecord
+func (ld *LogData) ToLogRecord() LogRecord {
+	var literalTimestamp time.Time
+	if ld.Timestamp.IsZero() {
+		literalTimestamp = time.Now()
+	} else {
+		literalTimestamp = ld.Timestamp
+	}
+	rval := LogRecord{
+		Timestamp: literalTimestamp,
+	}
+	if ld.Payload == nil {
+		rval.Fields = []log.Field{
+			log.String("event", ld.Event),
+		}
+	} else {
+		rval.Fields = []log.Field{
+			log.String("event", ld.Event),
+			log.Object("payload", ld.Payload),
+		}
+	}
+	return rval
+}

vendor/github.com/opentracing/opentracing-go/tracer.go

@@ -0,0 +1,305 @@
+package opentracing
+
+import "time"
+
+// Tracer is a simple, thin interface for Span creation and SpanContext
+// propagation.
+type Tracer interface {
+
+	// Create, start, and return a new Span with the given `operationName` and
+	// incorporate the given StartSpanOption `opts`. (Note that `opts` borrows
+	// from the "functional options" pattern, per
+	// http://dave.cheney.net/2014/10/17/functional-options-for-friendly-apis)
+	//
+	// A Span with no SpanReference options (e.g., opentracing.ChildOf() or
+	// opentracing.FollowsFrom()) becomes the root of its own trace.
+	//
+	// Examples:
+	//
+	//     var tracer opentracing.Tracer = ...
+	//
+	//     // The root-span case:
+	//     sp := tracer.StartSpan("GetFeed")
+	//
+	//     // The vanilla child span case:
+	//     sp := tracer.StartSpan(
+	//         "GetFeed",
+	//         opentracing.ChildOf(parentSpan.Context()))
+	//
+	//     // All the bells and whistles:
+	//     sp := tracer.StartSpan(
+	//         "GetFeed",
+	//         opentracing.ChildOf(parentSpan.Context()),
+	//         opentracing.Tag{"user_agent", loggedReq.UserAgent},
+	//         opentracing.StartTime(loggedReq.Timestamp),
+	//     )
+	//
+	StartSpan(operationName string, opts ...StartSpanOption) Span
+
+	// Inject() takes the `sm` SpanContext instance and injects it for
+	// propagation within `carrier`. The actual type of `carrier` depends on
+	// the value of `format`.
+	//
+	// OpenTracing defines a common set of `format` values (see BuiltinFormat),
+	// and each has an expected carrier type.
+	//
+	// Other packages may declare their own `format` values, much like the keys
+	// used by `context.Context` (see
+	// https://godoc.org/golang.org/x/net/context#WithValue).
+	//
+	// Example usage (sans error handling):
+	//
+	//     carrier := opentracing.HTTPHeadersCarrier(httpReq.Header)
+	//     err := tracer.Inject(
+	//         span.Context(),
+	//         opentracing.HTTPHeaders,
+	//         carrier)
+	//
+	// NOTE: All opentracing.Tracer implementations MUST support all
+	// BuiltinFormats.
+	//
+	// Implementations may return opentracing.ErrUnsupportedFormat if `format`
+	// is not supported by (or not known by) the implementation.
+	//
+	// Implementations may return opentracing.ErrInvalidCarrier or any other
+	// implementation-specific error if the format is supported but injection
+	// fails anyway.
+	//
+	// See Tracer.Extract().
+	Inject(sm SpanContext, format interface{}, carrier interface{}) error
+
+	// Extract() returns a SpanContext instance given `format` and `carrier`.
+	//
+	// OpenTracing defines a common set of `format` values (see BuiltinFormat),
+	// and each has an expected carrier type.
+	//
+	// Other packages may declare their own `format` values, much like the keys
+	// used by `context.Context` (see
+	// https://godoc.org/golang.org/x/net/context#WithValue).
+	//
+	// Example usage (with StartSpan):
+	//
+	//
+	//     carrier := opentracing.HTTPHeadersCarrier(httpReq.Header)
+	//     clientContext, err := tracer.Extract(opentracing.HTTPHeaders, carrier)
+	//
+	//     // ... assuming the ultimate goal here is to resume the trace with a
+	//     // server-side Span:
+	//     var serverSpan opentracing.Span
+	//     if err == nil {
+	//         span = tracer.StartSpan(
+	//             rpcMethodName, ext.RPCServerOption(clientContext))
+	//     } else {
+	//         span = tracer.StartSpan(rpcMethodName)
+	//     }
+	//
+	//
+	// NOTE: All opentracing.Tracer implementations MUST support all
+	// BuiltinFormats.
+	//
+	// Return values:
+	//  - A successful Extract returns a SpanContext instance and a nil error
+	//  - If there was simply no SpanContext to extract in `carrier`, Extract()
+	//    returns (nil, opentracing.ErrSpanContextNotFound)
+	//  - If `format` is unsupported or unrecognized, Extract() returns (nil,
+	//    opentracing.ErrUnsupportedFormat)
+	//  - If there are more fundamental problems with the `carrier` object,
+	//    Extract() may return opentracing.ErrInvalidCarrier,
+	//    opentracing.ErrSpanContextCorrupted, or implementation-specific
+	//    errors.
+	//
+	// See Tracer.Inject().
+	Extract(format interface{}, carrier interface{}) (SpanContext, error)
+}
+
+// StartSpanOptions allows Tracer.StartSpan() callers and implementors a
+// mechanism to override the start timestamp, specify Span References, and make
+// a single Tag or multiple Tags available at Span start time.
+//
+// StartSpan() callers should look at the StartSpanOption interface and
+// implementations available in this package.
+//
+// Tracer implementations can convert a slice of `StartSpanOption` instances
+// into a `StartSpanOptions` struct like so:
+//
+//     func StartSpan(opName string, opts ...opentracing.StartSpanOption) {
+//         sso := opentracing.StartSpanOptions{}
+//         for _, o := range opts {
+//             o.Apply(&sso)
+//         }
+//         ...
+//     }
+//
+type StartSpanOptions struct {
+	// Zero or more causal references to other Spans (via their SpanContext).
+	// If empty, start a "root" Span (i.e., start a new trace).
+	References []SpanReference
+
+	// StartTime overrides the Span's start time, or implicitly becomes
+	// time.Now() if StartTime.IsZero().
+	StartTime time.Time
+
+	// Tags may have zero or more entries; the restrictions on map values are
+	// identical to those for Span.SetTag(). May be nil.
+	//
+	// If specified, the caller hands off ownership of Tags at
+	// StartSpan() invocation time.
+	Tags map[string]interface{}
+}
+
+// StartSpanOption instances (zero or more) may be passed to Tracer.StartSpan.
+//
+// StartSpanOption borrows from the "functional options" pattern, per
+// http://dave.cheney.net/2014/10/17/functional-options-for-friendly-apis
+type StartSpanOption interface {
+	Apply(*StartSpanOptions)
+}
+
+// SpanReferenceType is an enum type describing different categories of
+// relationships between two Spans. If Span-2 refers to Span-1, the
+// SpanReferenceType describes Span-1 from Span-2's perspective. For example,
+// ChildOfRef means that Span-1 created Span-2.
+//
+// NOTE: Span-1 and Span-2 do *not* necessarily depend on each other for
+// completion; e.g., Span-2 may be part of a background job enqueued by Span-1,
+// or Span-2 may be sitting in a distributed queue behind Span-1.
+type SpanReferenceType int
+
+const (
+	// ChildOfRef refers to a parent Span that caused *and* somehow depends
+	// upon the new child Span. Often (but not always), the parent Span cannot
+	// finish until the child Span does.
+	//
+	// An timing diagram for a ChildOfRef that's blocked on the new Span:
+	//
+	//     [-Parent Span---------]
+	//          [-Child Span----]
+	//
+	// See http://opentracing.io/spec/
+	//
+	// See opentracing.ChildOf()
+	ChildOfRef SpanReferenceType = iota
+
+	// FollowsFromRef refers to a parent Span that does not depend in any way
+	// on the result of the new child Span. For instance, one might use
+	// FollowsFromRefs to describe pipeline stages separated by queues,
+	// or a fire-and-forget cache insert at the tail end of a web request.
+	//
+	// A FollowsFromRef Span is part of the same logical trace as the new Span:
+	// i.e., the new Span is somehow caused by the work of its FollowsFromRef.
+	//
+	// All of the following could be valid timing diagrams for children that
+	// "FollowFrom" a parent.
+	//
+	//     [-Parent Span-]  [-Child Span-]
+	//
+	//
+	//     [-Parent Span--]
+	//      [-Child Span-]
+	//
+	//
+	//     [-Parent Span-]
+	//                 [-Child Span-]
+	//
+	// See http://opentracing.io/spec/
+	//
+	// See opentracing.FollowsFrom()
+	FollowsFromRef
+)
+
+// SpanReference is a StartSpanOption that pairs a SpanReferenceType and a
+// referenced SpanContext. See the SpanReferenceType documentation for
+// supported relationships.  If SpanReference is created with
+// ReferencedContext==nil, it has no effect. Thus it allows for a more concise
+// syntax for starting spans:
+//
+//     sc, _ := tracer.Extract(someFormat, someCarrier)
+//     span := tracer.StartSpan("operation", opentracing.ChildOf(sc))
+//
+// The `ChildOf(sc)` option above will not panic if sc == nil, it will just
+// not add the parent span reference to the options.
+type SpanReference struct {
+	Type              SpanReferenceType
+	ReferencedContext SpanContext
+}
+
+// Apply satisfies the StartSpanOption interface.
+func (r SpanReference) Apply(o *StartSpanOptions) {
+	if r.ReferencedContext != nil {
+		o.References = append(o.References, r)
+	}
+}
+
+// ChildOf returns a StartSpanOption pointing to a dependent parent span.
+// If sc == nil, the option has no effect.
+//
+// See ChildOfRef, SpanReference
+func ChildOf(sc SpanContext) SpanReference {
+	return SpanReference{
+		Type:              ChildOfRef,
+		ReferencedContext: sc,
+	}
+}
+
+// FollowsFrom returns a StartSpanOption pointing to a parent Span that caused
+// the child Span but does not directly depend on its result in any way.
+// If sc == nil, the option has no effect.
+//
+// See FollowsFromRef, SpanReference
+func FollowsFrom(sc SpanContext) SpanReference {
+	return SpanReference{
+		Type:              FollowsFromRef,
+		ReferencedContext: sc,
+	}
+}
+
+// StartTime is a StartSpanOption that sets an explicit start timestamp for the
+// new Span.
+type StartTime time.Time
+
+// Apply satisfies the StartSpanOption interface.
+func (t StartTime) Apply(o *StartSpanOptions) {
+	o.StartTime = time.Time(t)
+}
+
+// Tags are a generic map from an arbitrary string key to an opaque value type.
+// The underlying tracing system is responsible for interpreting and
+// serializing the values.
+type Tags map[string]interface{}
+
+// Apply satisfies the StartSpanOption interface.
+func (t Tags) Apply(o *StartSpanOptions) {
+	if o.Tags == nil {
+		o.Tags = make(map[string]interface{})
+	}
+	for k, v := range t {
+		o.Tags[k] = v
+	}
+}
+
+// Tag may be passed as a StartSpanOption to add a tag to new spans,
+// or its Set method may be used to apply the tag to an existing Span,
+// for example:
+//
+// tracer.StartSpan("opName", Tag{"Key", value})
+//
+//   or
+//
+// Tag{"key", value}.Set(span)
+type Tag struct {
+	Key   string
+	Value interface{}
+}
+
+// Apply satisfies the StartSpanOption interface.
+func (t Tag) Apply(o *StartSpanOptions) {
+	if o.Tags == nil {
+		o.Tags = make(map[string]interface{})
+	}
+	o.Tags[t.Key] = t.Value
+}
+
+// Set applies the tag to an existing Span.
+func (t Tag) Set(s Span) {
+	s.SetTag(t.Key, t.Value)
+}