resolve comments from review

README.md

@@ -74,27 +74,72 @@ testAgent.on('process.memory', console.log)
 ## Metric Tags
 
 The agent is able to use environment variables as metrics tags. 
-Define a list of environment variables to be used as metric tags:  
+Define a list of environment variables to be used as metric tags.
+
+Let's assume this is the enviroment of the monitored application: 
+
+```
+> env
+TERM_PROGRAM=Apple_Terminal
+TERM=xterm-256color
+SHELL=/bin/bash
+TMPDIR=/var/folders/v6/bh2q1xsn27g4d2g54z2ylv100000gn/T/
+TERM_PROGRAM_VERSION=404.1
+TERM_SESSION_ID=F12E0DBD-BF40-466D-85EC-08E89EDC3440
+USER=stefan
+PWD=/Users/stefan
+HOME=/Users/stefan
+LOGNAME=stefan
+LC_CTYPE=UTF-8
+DISPLAY=/private/tmp/com.apple.launchd.J60ybGpban/org.macosforge.xquartz:0
+_=/usr/bin/env
+```
+
+You want to see later the performance metrics aggregated or filtered for specific user. 
+In this case the agent should collect the user name as tag. You can find the user name in the process environment variable `USER`. 
+Let's also assume the workingdirectory of the application `PWD` is another relevant identifier for your monitored application. 
+
+To configure the agent collecting USER and PWD as tags you can specify a commaseparated list of environment variables for the the agent configuration: 
 
 ```
 # add the values of env. variables USER, PWD as tags to metrics
 export MONITORING_TAGS_FROM_ENV="USER, PWD"
 ```
 
+The generated metrics include then the environment variable name and its value as tags. The result in Influx Line Protocol (ILP) format, produced by the agent for metric called `swap`: 
+
+```
+swap, USER=stefan,PWD=/Users/stefan out=0i,in=0i 1576765680000000000
+```
+
 Define static tags in `key:value` format 
 
 ```
-export MONITORING_TAGS_FROM_ENV="organisation:sematext, service=api"
+export MONITORING_TAGS_FROM_ENV="organisation:sematext, service:api"
 
 ```
 
+The result in in ILP format: 
+
+```
+swap, organisation=sematext,service=api out=0i,in=0i 1576765680000000000
+```
+
+
 Both types of tags can be mixed: 
 
 ```
 export MONITORING_TAGS_FROM_ENV="organisation:sematext, service:api, USER, PWD"
 
 ```
 
+The result in in ILP format: 
+
+```
+swap, organisation=sematext,service=api,USER=stefan,PWD=/Users/stefan,os.host=imac.local out=0i,in=0i 1576765680000000000
+```
+
+
 The config file entry `influx.tagsFromEnv` in `.spmagenrc` works as well: 
 
 ```

lib/agent.js

@@ -188,19 +188,18 @@ function Agent (plugin) {
     },
     /**
      * Stops the plugin - timers could be pushed to plugins 'timers' Array, if timers exists it tries to clearInterval(timerId)
-     * if no timers are defined it tries to call stop method of the plugin
+     * and tries to call the stop() method of the agent-plugin
      */
     stop: function () {
       if (this.plugin.timers) {
         this.plugin.timers.forEach(function (tid) {
           clearInterval(tid)
         })
+      }
+      if (this.plugin.stop) {
+        this.plugin.stop()
       } else {
-        if (this.plugin.stop) {
-          this.plugin.stop()
-        } else {
-          logger.warn('could not stop agent')
-        }
+        logger.warn('Plugin ' + plugin.name + ' has no stop() function')
       }
     }
   }

test/test.js

@@ -71,7 +71,7 @@ describe('SPM for NodeJS tests', function () {
       config.logger.console = true
       config.logger.level = 'debug'
       var SpmAgent = require('../lib/index.js')
-      process.env.MONITORING_TAGS_FROM_ENV = 'USER,PWD,cutomer_id=123'
+      process.env.MONITORING_TAGS_FROM_ENV = 'USER,PWD,customer_id:123'
       var client = new SpmAgent()
       var testAgent = client.createAgent(new SpmAgent.Agent({
         start: function (agent) {