Opentracing support

vendor/github.com/uber/jaeger-client-go/rpcmetrics/observer.go

@@ -0,0 +1,177 @@
+// Copyright (c) 2017 Uber Technologies, Inc.
+//
+// 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.
+
+package rpcmetrics
+
+import (
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/opentracing/opentracing-go"
+	"github.com/opentracing/opentracing-go/ext"
+	"github.com/uber/jaeger-lib/metrics"
+
+	jaeger "github.com/uber/jaeger-client-go"
+)
+
+const defaultMaxNumberOfEndpoints = 200
+
+// Observer is an observer that can emit RPC metrics.
+type Observer struct {
+	metricsByEndpoint *MetricsByEndpoint
+}
+
+// NewObserver creates a new observer that can emit RPC metrics.
+func NewObserver(metricsFactory metrics.Factory, normalizer NameNormalizer) *Observer {
+	return &Observer{
+		metricsByEndpoint: newMetricsByEndpoint(
+			metricsFactory,
+			normalizer,
+			defaultMaxNumberOfEndpoints,
+		),
+	}
+}
+
+// OnStartSpan creates a new Observer for the span.
+func (o *Observer) OnStartSpan(
+	operationName string,
+	options opentracing.StartSpanOptions,
+) jaeger.SpanObserver {
+	return NewSpanObserver(o.metricsByEndpoint, operationName, options)
+}
+
+// SpanKind identifies the span as inboud, outbound, or internal
+type SpanKind int
+
+const (
+	// Local span kind
+	Local SpanKind = iota
+	// Inbound span kind
+	Inbound
+	// Outbound span kind
+	Outbound
+)
+
+// SpanObserver collects RPC metrics
+type SpanObserver struct {
+	metricsByEndpoint *MetricsByEndpoint
+	operationName     string
+	startTime         time.Time
+	mux               sync.Mutex
+	kind              SpanKind
+	httpStatusCode    uint16
+	err               bool
+}
+
+// NewSpanObserver creates a new SpanObserver that can emit RPC metrics.
+func NewSpanObserver(
+	metricsByEndpoint *MetricsByEndpoint,
+	operationName string,
+	options opentracing.StartSpanOptions,
+) *SpanObserver {
+	so := &SpanObserver{
+		metricsByEndpoint: metricsByEndpoint,
+		operationName:     operationName,
+		startTime:         options.StartTime,
+	}
+	for k, v := range options.Tags {
+		so.handleTagInLock(k, v)
+	}
+	return so
+}
+
+// handleTags watches for special tags
+// - SpanKind
+// - HttpStatusCode
+// - Error
+func (so *SpanObserver) handleTagInLock(key string, value interface{}) {
+	if key == string(ext.SpanKind) {
+		if v, ok := value.(ext.SpanKindEnum); ok {
+			value = string(v)
+		}
+		if v, ok := value.(string); ok {
+			if v == string(ext.SpanKindRPCClientEnum) {
+				so.kind = Outbound
+			} else if v == string(ext.SpanKindRPCServerEnum) {
+				so.kind = Inbound
+			}
+		}
+		return
+	}
+	if key == string(ext.HTTPStatusCode) {
+		if v, ok := value.(uint16); ok {
+			so.httpStatusCode = v
+		} else if v, ok := value.(int); ok {
+			so.httpStatusCode = uint16(v)
+		} else if v, ok := value.(string); ok {
+			if vv, err := strconv.Atoi(v); err == nil {
+				so.httpStatusCode = uint16(vv)
+			}
+		}
+		return
+	}
+	if key == string(ext.Error) {
+		if v, ok := value.(bool); ok {
+			so.err = v
+		} else if v, ok := value.(string); ok {
+			if vv, err := strconv.ParseBool(v); err == nil {
+				so.err = vv
+			}
+		}
+		return
+	}
+}
+
+// OnFinish emits the RPC metrics. It only has an effect when operation name
+// is not blank, and the span kind is an RPC server.
+func (so *SpanObserver) OnFinish(options opentracing.FinishOptions) {
+	so.mux.Lock()
+	defer so.mux.Unlock()
+
+	if so.operationName == "" || so.kind != Inbound {
+		return
+	}
+
+	mets := so.metricsByEndpoint.get(so.operationName)
+	latency := options.FinishTime.Sub(so.startTime)
+	if so.err {
+		mets.RequestCountFailures.Inc(1)
+		mets.RequestLatencyFailures.Record(latency)
+	} else {
+		mets.RequestCountSuccess.Inc(1)
+		mets.RequestLatencySuccess.Record(latency)
+	}
+	mets.recordHTTPStatusCode(so.httpStatusCode)
+}
+
+// OnSetOperationName records new operation name.
+func (so *SpanObserver) OnSetOperationName(operationName string) {
+	so.mux.Lock()
+	so.operationName = operationName
+	so.mux.Unlock()
+}
+
+// OnSetTag implements SpanObserver
+func (so *SpanObserver) OnSetTag(key string, value interface{}) {
+	so.mux.Lock()
+	so.handleTagInLock(key, value)
+	so.mux.Unlock()
+}