generateGlobalCpuReport: average CPU usage for each host

packages/xo-server-usage-report/package.json

@@ -35,6 +35,7 @@
     "babel-preset-stage-0": "^6.3.13",
     "clarify": "^1.0.5",
     "dependency-check": "^2.5.1",
+    "lodash.foreach": "^4.0.0",
     "mocha": "^2.3.4",
     "must": "^0.13.1",
     "nyc": "^5.2.0",

packages/xo-server-usage-report/src/index.js

@@ -1,3 +1,5 @@
+import forEach from 'lodash.foreach'
+
 export const configurationSchema = {
   type: 'object',
 
@@ -23,7 +25,7 @@ function computeMean (values) {
   let sum = 0
 
   for (let i = 0; i < values.length; i++) {
-    sum += values[i]
+    sum += values[i] || 0
   }
 
   return sum / values.length
@@ -119,6 +121,19 @@ class UsageReportPlugin {
     }))
 // =============================================================================
     // STATS min, max, mean
+    this._unsets.push(this._xo.api.addMethod('generateGlobalCpuReport', async ({ machines, granularity }) => {
+      machines = machines.split(',')
+      const hostMean = {}
+      for (let machine of machines) {
+        const machineStats = await this_._xo.getXapiHostStats(this_._xo.getObject(machine), granularity)
+        const cpusMean = []
+        forEach(machineStats.stats.cpus, (cpu) => {
+          cpusMean.push(computeMean(cpu))
+        })
+        hostMean[machine] = computeMean(cpusMean)
+      }
+      return hostMean
+    }))
 
     // Cpus
     this._unsets.push(this._xo.api.addMethod('generateCpuReport', async ({ machine, granularity }) => {