fix pm2 env var evaluation, stop timer

lib/processAgent.js

@@ -10,6 +10,8 @@
 'use strict'
 const { Agent, Config } = require('spm-agent')
 const pidUsageTree = require('pidusage-tree')
+const pm2Enabled = /^true/i.test(process.env.PM2)
+
 const addMetrics = function (agent, pidToCheck) {
   const timestamp = new Date()
   pidUsageTree(pidToCheck, function (err, results) {
@@ -36,7 +38,6 @@ const addMetrics = function (agent, pidToCheck) {
       }
     }
     agent.addMetrics(masterProcessMetric)
-
     const childProcesses = processes.filter(proc => proc.pid !== pidToCheck)
     if (childProcesses && childProcesses.length) {
       childProcesses.forEach((proc, counter) => {
@@ -86,37 +87,37 @@ function getDefaultProcessMetrics (agent) {
   if (process.send !== undefined) {
     return // child process, not collecting stats
   }
-
   addMetrics(agent, process.pid)
 }
+
 function getPm2Metrics (agent) {
   if (process.send === undefined) {
     return // master pm2 process, not collecting stats
   }
-
   addMetrics(agent, process.ppid)
 }
 
 function getProcessStats () {
   return {
     start: function (agent) {
-      const timerId = setInterval(function () {
-        if (
-          Boolean(process.env.PM2) === true
-        ) {
+      this.timerId = setInterval(function () {
+        if (pm2Enabled) {
           getPm2Metrics(agent)
-          return
+        } else {
+          getDefaultProcessMetrics(agent)
         }
-        getDefaultProcessMetrics(agent)
       }, Config.collectionInterval)
-      if (timerId.unref) {
-        timerId.unref()
+      if (this.timerId.unref) {
+        this.timerId.unref()
       }
     },
-    stop: function () { }
+    stop: function () {
+      clearInterval(this.timerId)
+    }
   }
 }
 
 module.exports = function () {
-  return new Agent(getProcessStats())
+  const a = getProcessStats()
+  return new Agent(a)
 }