adds basic traces using open traces

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

@@ -0,0 +1,83 @@
+// 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 (
+	"github.com/opentracing/opentracing-go/log"
+
+	"github.com/uber/jaeger-client-go/internal/baggage"
+)
+
+// baggageSetter is an actor that can set a baggage value on a Span given certain
+// restrictions (eg. maxValueLength).
+type baggageSetter struct {
+	restrictionManager baggage.RestrictionManager
+	metrics            *Metrics
+}
+
+func newBaggageSetter(restrictionManager baggage.RestrictionManager, metrics *Metrics) *baggageSetter {
+	return &baggageSetter{
+		restrictionManager: restrictionManager,
+		metrics:            metrics,
+	}
+}
+
+// (NB) span should hold the lock before making this call
+func (s *baggageSetter) setBaggage(span *Span, key, value string) {
+	var truncated bool
+	var prevItem string
+	restriction := s.restrictionManager.GetRestriction(key)
+	if !restriction.KeyAllowed() {
+		s.logFields(span, key, value, prevItem, truncated, restriction.KeyAllowed())
+		s.metrics.BaggageUpdateFailure.Inc(1)
+		return
+	}
+	if len(value) > restriction.MaxValueLength() {
+		truncated = true
+		value = value[:restriction.MaxValueLength()]
+		s.metrics.BaggageTruncate.Inc(1)
+	}
+	prevItem = span.context.baggage[key]
+	s.logFields(span, key, value, prevItem, truncated, restriction.KeyAllowed())
+	span.context = span.context.WithBaggageItem(key, value)
+	s.metrics.BaggageUpdateSuccess.Inc(1)
+}
+
+func (s *baggageSetter) logFields(span *Span, key, value, prevItem string, truncated, valid bool) {
+	if !span.context.IsSampled() {
+		return
+	}
+	fields := []log.Field{
+		log.String("event", "baggage"),
+		log.String("key", key),
+		log.String("value", value),
+	}
+	if prevItem != "" {
+		fields = append(fields, log.String("override", "true"))
+	}
+	if truncated {
+		fields = append(fields, log.String("truncated", "true"))
+	}
+	if !valid {
+		fields = append(fields, log.String("invalid", "true"))
+	}
+	span.logFieldsNoLocking(fields...)
+}