Add ocagent exporter

ocagent allows users to send traces out of VK to a "standard"  external forwarder
(standard as in this is a format/protocol defined in the opencensus project).

This allows uers to implement metrics for whatever backend they want
without having to add it into VK directly.

vendor/contrib.go.opencensus.io/exporter/ocagent/nodeinfo.go

@@ -0,0 +1,41 @@
+// Copyright 2018, OpenCensus Authors
+//
+// 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 ocagent
+
+import (
+	"os"
+
+	commonpb "github.com/census-instrumentation/opencensus-proto/gen-go/agent/common/v1"
+	"go.opencensus.io"
+)
+
+func createNodeInfo(nodeName string) *commonpb.Node {
+	return &commonpb.Node{
+		Identifier: &commonpb.ProcessIdentifier{
+			HostName:       os.Getenv("HOSTNAME"),
+			Pid:            uint32(os.Getpid()),
+			StartTimestamp: timeToTimestamp(startTime),
+		},
+		LibraryInfo: &commonpb.LibraryInfo{
+			Language:           commonpb.LibraryInfo_GO_LANG,
+			ExporterVersion:    Version,
+			CoreLibraryVersion: opencensus.Version(),
+		},
+		ServiceInfo: &commonpb.ServiceInfo{
+			Name: nodeName,
+		},
+		Attributes: make(map[string]string),
+	}
+}