feat(analytics): adding google analytics for ZFSPV

Whenever a volume is provisioned and de-provisioned we will send a google event with mainly following details :
1.    pvName (will shown as app title in google analytics)
2.    size of the volume
3.    event type : volume-provision, volume-deprovision
4.    storage type zfs-localpv
5.    replicacount as 1
6.    ClientId as default namespace uuid

Apart from this, we send the event once in 24 hr, which will have some info like number of nodes, node type, kubernetes version etc.

This metric is cotrolled by OPENEBS_IO_ENABLE_ANALYTICS env. We can set it to false if we don't want to send the metrics.

Signed-off-by: Pawan <pawan@mayadata.io>

pkg/usage/const.go

@@ -0,0 +1,49 @@
+/*
+Copyright 2020 The OpenEBS 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 usage
+
+const (
+	// GAclientID is the unique code of OpenEBS project in Google Analytics
+	GAclientID string = "UA-127388617-1"
+
+	// supported events categories
+
+	// Install event is sent on pod starts
+	InstallEvent string = "install"
+	// Ping event is sent periodically
+	Ping string = "zfs-ping"
+	// VolumeProvision event is sent when a volume is created
+	VolumeProvision string = "volume-provision"
+	//VolumeDeprovision event is sent when a volume is deleted
+	VolumeDeprovision string = "volume-deprovision"
+	AppName           string = "OpenEBS"
+
+	// Event labels
+	RunningStatus      string = "running"
+	EventLabelNode     string = "nodes"
+	EventLabelCapacity string = "capacity"
+
+	// Event action
+	Replica             string = "replica:"
+	DefaultReplicaCount string = "replica:1"
+
+	// Event application name constant for volume event
+	DefaultCASType string = "zfs-localpv"
+
+	// LocalPVReplicaCount is the constant used by usage to represent
+	// replication factor in LocalPV
+	LocalPVReplicaCount string = "1"
+)