Update tracing dependencies

vendor/github.com/uber/jaeger-lib/metrics/keys.go

@@ -0,0 +1,35 @@
+// Copyright (c) 2017 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 metrics
+
+import (
+	"sort"
+)
+
+// GetKey converts name+tags into a single string of the form
+// "name|tag1=value1|...|tagN=valueN", where tag names are
+// sorted alphabetically.
+func GetKey(name string, tags map[string]string, tagsSep string, tagKVSep string) string {
+	keys := make([]string, 0, len(tags))
+	for k := range tags {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+	key := name
+	for _, k := range keys {
+		key = key + tagsSep + k + tagKVSep + tags[k]
+	}
+	return key
+}