Opentracing support

vendor/github.com/uber/jaeger-client-go/contrib_observer.go

@@ -0,0 +1,62 @@
+// 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 jaeger
+
+import (
+	opentracing "github.com/opentracing/opentracing-go"
+)
+
+// ContribObserver can be registered with the Tracer to receive notifications
+// about new Spans. Modelled after github.com/opentracing-contrib/go-observer.
+type ContribObserver interface {
+	// Create and return a span observer. Called when a span starts.
+	// If the Observer is not interested in the given span, it must return (nil, false).
+	// E.g :
+	//     func StartSpan(opName string, opts ...opentracing.StartSpanOption) {
+	//         var sp opentracing.Span
+	//         sso := opentracing.StartSpanOptions{}
+	//         if spanObserver, ok := Observer.OnStartSpan(span, opName, sso); ok {
+	//             // we have a valid SpanObserver
+	//         }
+	//         ...
+	//     }
+	OnStartSpan(sp opentracing.Span, operationName string, options opentracing.StartSpanOptions) (ContribSpanObserver, bool)
+}
+
+// ContribSpanObserver is created by the Observer and receives notifications
+// about other Span events. This interface is meant to match
+// github.com/opentracing-contrib/go-observer, via duck typing, without
+// directly importing the go-observer package.
+type ContribSpanObserver interface {
+	OnSetOperationName(operationName string)
+	OnSetTag(key string, value interface{})
+	OnFinish(options opentracing.FinishOptions)
+}
+
+// wrapper observer for the old observers (see observer.go)
+type oldObserver struct {
+	obs Observer
+}
+
+func (o *oldObserver) OnStartSpan(sp opentracing.Span, operationName string, options opentracing.StartSpanOptions) (ContribSpanObserver, bool) {
+	spanObserver := o.obs.OnStartSpan(operationName, options)
+	return spanObserver, spanObserver != nil
+}