diff --git a/vendor/github.com/uber/jaeger-client-go/tracer.go b/vendor/github.com/uber/jaeger-client-go/tracer.go
new file mode 100644
index 0000000..9a627be
--- /dev/null
+++ b/vendor/github.com/uber/jaeger-client-go/tracer.go
@@ -0,0 +1,493 @@
+// Copyright (c) 2017-2018 Uber Technologies, Inc.
+//
+// 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.
+
+package jaeger
+
+import (
+	"fmt"
+	"io"
+	"math/rand"
+	"os"
+	"reflect"
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/opentracing/opentracing-go"
+	"github.com/opentracing/opentracing-go/ext"
+
+	"github.com/uber/jaeger-client-go/internal/baggage"
+	"github.com/uber/jaeger-client-go/internal/throttler"
+	"github.com/uber/jaeger-client-go/log"
+	"github.com/uber/jaeger-client-go/utils"
+)
+
+// Tracer implements opentracing.Tracer.
+type Tracer struct {
+	serviceName string
+	hostIPv4    uint32 // this is for zipkin endpoint conversion
+
+	sampler  SamplerV2
+	reporter Reporter
+	metrics  Metrics
+	logger   log.DebugLogger
+
+	timeNow      func() time.Time
+	randomNumber func() uint64
+
+	options struct {
+		gen128Bit                   bool // whether to generate 128bit trace IDs
+		zipkinSharedRPCSpan         bool
+		highTraceIDGenerator        func() uint64 // custom high trace ID generator
+		maxTagValueLength           int
+		noDebugFlagOnForcedSampling bool
+		maxLogsPerSpan              int
+		// more options to come
+	}
+	// allocator of Span objects
+	spanAllocator SpanAllocator
+
+	injectors  map[interface{}]Injector
+	extractors map[interface{}]Extractor
+
+	observer compositeObserver
+
+	tags    []Tag
+	process Process
+
+	baggageRestrictionManager baggage.RestrictionManager
+	baggageSetter             *baggageSetter
+
+	debugThrottler throttler.Throttler
+}
+
+// NewTracer creates Tracer implementation that reports tracing to Jaeger.
+// The returned io.Closer can be used in shutdown hooks to ensure that the internal
+// queue of the Reporter is drained and all buffered spans are submitted to collectors.
+// TODO (breaking change) return *Tracer only, without closer.
+func NewTracer(
+	serviceName string,
+	sampler Sampler,
+	reporter Reporter,
+	options ...TracerOption,
+) (opentracing.Tracer, io.Closer) {
+	t := &Tracer{
+		serviceName:   serviceName,
+		sampler:       samplerV1toV2(sampler),
+		reporter:      reporter,
+		injectors:     make(map[interface{}]Injector),
+		extractors:    make(map[interface{}]Extractor),
+		metrics:       *NewNullMetrics(),
+		spanAllocator: simpleSpanAllocator{},
+	}
+
+	for _, option := range options {
+		option(t)
+	}
+
+	// register default injectors/extractors unless they are already provided via options
+	textPropagator := NewTextMapPropagator(getDefaultHeadersConfig(), t.metrics)
+	t.addCodec(opentracing.TextMap, textPropagator, textPropagator)
+
+	httpHeaderPropagator := NewHTTPHeaderPropagator(getDefaultHeadersConfig(), t.metrics)
+	t.addCodec(opentracing.HTTPHeaders, httpHeaderPropagator, httpHeaderPropagator)
+
+	binaryPropagator := NewBinaryPropagator(t)
+	t.addCodec(opentracing.Binary, binaryPropagator, binaryPropagator)
+
+	// TODO remove after TChannel supports OpenTracing
+	interopPropagator := &jaegerTraceContextPropagator{tracer: t}
+	t.addCodec(SpanContextFormat, interopPropagator, interopPropagator)
+
+	zipkinPropagator := &zipkinPropagator{tracer: t}
+	t.addCodec(ZipkinSpanFormat, zipkinPropagator, zipkinPropagator)
+
+	if t.baggageRestrictionManager != nil {
+		t.baggageSetter = newBaggageSetter(t.baggageRestrictionManager, &t.metrics)
+	} else {
+		t.baggageSetter = newBaggageSetter(baggage.NewDefaultRestrictionManager(0), &t.metrics)
+	}
+	if t.debugThrottler == nil {
+		t.debugThrottler = throttler.DefaultThrottler{}
+	}
+
+	if t.randomNumber == nil {
+		seedGenerator := utils.NewRand(time.Now().UnixNano())
+		pool := sync.Pool{
+			New: func() interface{} {
+				return rand.NewSource(seedGenerator.Int63())
+			},
+		}
+
+		t.randomNumber = func() uint64 {
+			generator := pool.Get().(rand.Source)
+			number := uint64(generator.Int63())
+			pool.Put(generator)
+			return number
+		}
+	}
+	if t.timeNow == nil {
+		t.timeNow = time.Now
+	}
+	if t.logger == nil {
+		t.logger = log.NullLogger
+	}
+	// Set tracer-level tags
+	t.tags = append(t.tags, Tag{key: JaegerClientVersionTagKey, value: JaegerClientVersion})
+	if hostname, err := os.Hostname(); err == nil {
+		t.tags = append(t.tags, Tag{key: TracerHostnameTagKey, value: hostname})
+	}
+	if ipval, ok := t.getTag(TracerIPTagKey); ok {
+		ipv4, err := utils.ParseIPToUint32(ipval.(string))
+		if err != nil {
+			t.hostIPv4 = 0
+			t.logger.Error("Unable to convert the externally provided ip to uint32: " + err.Error())
+		} else {
+			t.hostIPv4 = ipv4
+		}
+	} else if ip, err := utils.HostIP(); err == nil {
+		t.tags = append(t.tags, Tag{key: TracerIPTagKey, value: ip.String()})
+		t.hostIPv4 = utils.PackIPAsUint32(ip)
+	} else {
+		t.logger.Error("Unable to determine this host's IP address: " + err.Error())
+	}
+
+	if t.options.gen128Bit {
+		if t.options.highTraceIDGenerator == nil {
+			t.options.highTraceIDGenerator = t.randomNumber
+		}
+	} else if t.options.highTraceIDGenerator != nil {
+		t.logger.Error("Overriding high trace ID generator but not generating " +
+			"128 bit trace IDs, consider enabling the \"Gen128Bit\" option")
+	}
+	if t.options.maxTagValueLength == 0 {
+		t.options.maxTagValueLength = DefaultMaxTagValueLength
+	}
+	t.process = Process{
+		Service: serviceName,
+		UUID:    strconv.FormatUint(t.randomNumber(), 16),
+		Tags:    t.tags,
+	}
+	if throttler, ok := t.debugThrottler.(ProcessSetter); ok {
+		throttler.SetProcess(t.process)
+	}
+
+	return t, t
+}
+
+// addCodec adds registers injector and extractor for given propagation format if not already defined.
+func (t *Tracer) addCodec(format interface{}, injector Injector, extractor Extractor) {
+	if _, ok := t.injectors[format]; !ok {
+		t.injectors[format] = injector
+	}
+	if _, ok := t.extractors[format]; !ok {
+		t.extractors[format] = extractor
+	}
+}
+
+// StartSpan implements StartSpan() method of opentracing.Tracer.
+func (t *Tracer) StartSpan(
+	operationName string,
+	options ...opentracing.StartSpanOption,
+) opentracing.Span {
+	sso := opentracing.StartSpanOptions{}
+	for _, o := range options {
+		o.Apply(&sso)
+	}
+	return t.startSpanWithOptions(operationName, sso)
+}
+
+func (t *Tracer) startSpanWithOptions(
+	operationName string,
+	options opentracing.StartSpanOptions,
+) opentracing.Span {
+	if options.StartTime.IsZero() {
+		options.StartTime = t.timeNow()
+	}
+
+	// Predicate whether the given span context is an empty reference
+	// or may be used as parent / debug ID / baggage items source
+	isEmptyReference := func(ctx SpanContext) bool {
+		return !ctx.IsValid() && !ctx.isDebugIDContainerOnly() && len(ctx.baggage) == 0
+	}
+
+	var references []Reference
+	var parent SpanContext
+	var hasParent bool // need this because `parent` is a value, not reference
+	var ctx SpanContext
+	var isSelfRef bool
+	for _, ref := range options.References {
+		ctxRef, ok := ref.ReferencedContext.(SpanContext)
+		if !ok {
+			t.logger.Error(fmt.Sprintf(
+				"Reference contains invalid type of SpanReference: %s",
+				reflect.ValueOf(ref.ReferencedContext)))
+			continue
+		}
+		if isEmptyReference(ctxRef) {
+			continue
+		}
+
+		if ref.Type == selfRefType {
+			isSelfRef = true
+			ctx = ctxRef
+			continue
+		}
+
+		if ctxRef.IsValid() {
+			// we don't want empty context that contains only debug-id or baggage
+			references = append(references, Reference{Type: ref.Type, Context: ctxRef})
+		}
+
+		if !hasParent {
+			parent = ctxRef
+			hasParent = ref.Type == opentracing.ChildOfRef
+		}
+	}
+	if !hasParent && !isEmptyReference(parent) {
+		// If ChildOfRef wasn't found but a FollowFromRef exists, use the context from
+		// the FollowFromRef as the parent
+		hasParent = true
+	}
+
+	rpcServer := false
+	if v, ok := options.Tags[ext.SpanKindRPCServer.Key]; ok {
+		rpcServer = (v == ext.SpanKindRPCServerEnum || v == string(ext.SpanKindRPCServerEnum))
+	}
+
+	var internalTags []Tag
+	newTrace := false
+	if !isSelfRef {
+		if !hasParent || !parent.IsValid() {
+			newTrace = true
+			ctx.traceID.Low = t.randomID()
+			if t.options.gen128Bit {
+				ctx.traceID.High = t.options.highTraceIDGenerator()
+			}
+			ctx.spanID = SpanID(ctx.traceID.Low)
+			ctx.parentID = 0
+			ctx.samplingState = &samplingState{
+				localRootSpan: ctx.spanID,
+			}
+			if hasParent && parent.isDebugIDContainerOnly() && t.isDebugAllowed(operationName) {
+				ctx.samplingState.setDebugAndSampled()
+				internalTags = append(internalTags, Tag{key: JaegerDebugHeader, value: parent.debugID})
+			}
+		} else {
+			ctx.traceID = parent.traceID
+			if rpcServer && t.options.zipkinSharedRPCSpan {
+				// Support Zipkin's one-span-per-RPC model
+				ctx.spanID = parent.spanID
+				ctx.parentID = parent.parentID
+			} else {
+				ctx.spanID = SpanID(t.randomID())
+				ctx.parentID = parent.spanID
+			}
+			ctx.samplingState = parent.samplingState
+			if parent.remote {
+				ctx.samplingState.setFinal()
+				ctx.samplingState.localRootSpan = ctx.spanID
+			}
+		}
+		if hasParent {
+			// copy baggage items
+			if l := len(parent.baggage); l > 0 {
+				ctx.baggage = make(map[string]string, len(parent.baggage))
+				for k, v := range parent.baggage {
+					ctx.baggage[k] = v
+				}
+			}
+		}
+	}
+
+	sp := t.newSpan()
+	sp.context = ctx
+	sp.tracer = t
+	sp.operationName = operationName
+	sp.startTime = options.StartTime
+	sp.duration = 0
+	sp.references = references
+	sp.firstInProcess = rpcServer || sp.context.parentID == 0
+
+	if !sp.context.isSamplingFinalized() {
+		decision := t.sampler.OnCreateSpan(sp)
+		sp.applySamplingDecision(decision, false)
+	}
+	sp.observer = t.observer.OnStartSpan(sp, operationName, options)
+
+	if tagsTotalLength := len(options.Tags) + len(internalTags); tagsTotalLength > 0 {
+		if sp.tags == nil || cap(sp.tags) < tagsTotalLength {
+			sp.tags = make([]Tag, 0, tagsTotalLength)
+		}
+		sp.tags = append(sp.tags, internalTags...)
+		for k, v := range options.Tags {
+			sp.setTagInternal(k, v, false)
+		}
+	}
+	t.emitNewSpanMetrics(sp, newTrace)
+	return sp
+}
+
+// Inject implements Inject() method of opentracing.Tracer
+func (t *Tracer) Inject(ctx opentracing.SpanContext, format interface{}, carrier interface{}) error {
+	c, ok := ctx.(SpanContext)
+	if !ok {
+		return opentracing.ErrInvalidSpanContext
+	}
+	if injector, ok := t.injectors[format]; ok {
+		return injector.Inject(c, carrier)
+	}
+	return opentracing.ErrUnsupportedFormat
+}
+
+// Extract implements Extract() method of opentracing.Tracer
+func (t *Tracer) Extract(
+	format interface{},
+	carrier interface{},
+) (opentracing.SpanContext, error) {
+	if extractor, ok := t.extractors[format]; ok {
+		spanCtx, err := extractor.Extract(carrier)
+		if err != nil {
+			return nil, err // ensure returned spanCtx is nil
+		}
+		spanCtx.remote = true
+		return spanCtx, nil
+	}
+	return nil, opentracing.ErrUnsupportedFormat
+}
+
+// Close releases all resources used by the Tracer and flushes any remaining buffered spans.
+func (t *Tracer) Close() error {
+	t.logger.Debugf("closing tracer")
+	t.reporter.Close()
+	t.sampler.Close()
+	if mgr, ok := t.baggageRestrictionManager.(io.Closer); ok {
+		_ = mgr.Close()
+	}
+	if throttler, ok := t.debugThrottler.(io.Closer); ok {
+		_ = throttler.Close()
+	}
+	return nil
+}
+
+// Tags returns a slice of tracer-level tags.
+func (t *Tracer) Tags() []opentracing.Tag {
+	tags := make([]opentracing.Tag, len(t.tags))
+	for i, tag := range t.tags {
+		tags[i] = opentracing.Tag{Key: tag.key, Value: tag.value}
+	}
+	return tags
+}
+
+// getTag returns the value of specific tag, if not exists, return nil.
+// TODO only used by tests, move there.
+func (t *Tracer) getTag(key string) (interface{}, bool) {
+	for _, tag := range t.tags {
+		if tag.key == key {
+			return tag.value, true
+		}
+	}
+	return nil, false
+}
+
+// newSpan returns an instance of a clean Span object.
+// If options.PoolSpans is true, the spans are retrieved from an object pool.
+func (t *Tracer) newSpan() *Span {
+	return t.spanAllocator.Get()
+}
+
+// emitNewSpanMetrics generates metrics on the number of started spans and traces.
+// newTrace param: we cannot simply check for parentID==0 because in Zipkin model the
+// server-side RPC span has the exact same trace/span/parent IDs as the
+// calling client-side span, but obviously the server side span is
+// no longer a root span of the trace.
+func (t *Tracer) emitNewSpanMetrics(sp *Span, newTrace bool) {
+	if !sp.context.isSamplingFinalized() {
+		t.metrics.SpansStartedDelayedSampling.Inc(1)
+		if newTrace {
+			t.metrics.TracesStartedDelayedSampling.Inc(1)
+		}
+		// joining a trace is not possible, because sampling decision inherited from upstream is final
+	} else if sp.context.IsSampled() {
+		t.metrics.SpansStartedSampled.Inc(1)
+		if newTrace {
+			t.metrics.TracesStartedSampled.Inc(1)
+		} else if sp.firstInProcess {
+			t.metrics.TracesJoinedSampled.Inc(1)
+		}
+	} else {
+		t.metrics.SpansStartedNotSampled.Inc(1)
+		if newTrace {
+			t.metrics.TracesStartedNotSampled.Inc(1)
+		} else if sp.firstInProcess {
+			t.metrics.TracesJoinedNotSampled.Inc(1)
+		}
+	}
+}
+
+func (t *Tracer) reportSpan(sp *Span) {
+	ctx := sp.SpanContext()
+
+	if !ctx.isSamplingFinalized() {
+		t.metrics.SpansFinishedDelayedSampling.Inc(1)
+	} else if ctx.IsSampled() {
+		t.metrics.SpansFinishedSampled.Inc(1)
+	} else {
+		t.metrics.SpansFinishedNotSampled.Inc(1)
+	}
+
+	// Note: if the reporter is processing Span asynchronously then it needs to Retain() the span,
+	// and then Release() it when no longer needed.
+	// Otherwise, the span may be reused for another trace and its data may be overwritten.
+	if ctx.IsSampled() {
+		t.reporter.Report(sp)
+	}
+
+	sp.Release()
+}
+
+// randomID generates a random trace/span ID, using tracer.random() generator.
+// It never returns 0.
+func (t *Tracer) randomID() uint64 {
+	val := t.randomNumber()
+	for val == 0 {
+		val = t.randomNumber()
+	}
+	return val
+}
+
+// (NB) span must hold the lock before making this call
+func (t *Tracer) setBaggage(sp *Span, key, value string) {
+	t.baggageSetter.setBaggage(sp, key, value)
+}
+
+// (NB) span must hold the lock before making this call
+func (t *Tracer) isDebugAllowed(operation string) bool {
+	return t.debugThrottler.IsAllowed(operation)
+}
+
+// Sampler returns the sampler given to the tracer at creation.
+func (t *Tracer) Sampler() SamplerV2 {
+	return t.sampler
+}
+
+// SelfRef creates an opentracing compliant SpanReference from a jaeger
+// SpanContext. This is a factory function in order to encapsulate jaeger specific
+// types.
+func SelfRef(ctx SpanContext) opentracing.SpanReference {
+	return opentracing.SpanReference{
+		Type:              selfRefType,
+		ReferencedContext: ctx,
+	}
+}