Add ability to define a custom service name when installing as a Windows service (#4753)

cmd/telegraf/telegraf.go

@@ -55,6 +55,7 @@ var fUsage = flag.String("usage", "",
 	"print usage for a plugin, ie, 'telegraf --usage mysql'")
 var fService = flag.String("service", "",
 	"operate on the service (windows only)")
+var fServiceName = flag.String("service-name", "telegraf", "service name (windows only)")
 var fRunAsConsole = flag.Bool("console", false, "run as console application (windows only)")
 
 var (
@@ -327,7 +328,7 @@ func main() {
 
 	if runtime.GOOS == "windows" && !(*fRunAsConsole) {
 		svcConfig := &service.Config{
-			Name:        "telegraf",
+			Name:        *fServiceName,
 			DisplayName: "Telegraf Data Collector Service",
 			Description: "Collects data using a series of plugins and publishes it to" +
 				"another series of plugins.",

docs/WINDOWS_SERVICE.md

@@ -46,6 +46,16 @@ Telegraf can manage its own service through the --service flag:
 | `telegraf.exe --service start`     | Start the telegraf service    |
 | `telegraf.exe --service stop`      | Stop the telegraf service     |
 
+## Install multiple services
+
+You can install multiple telegraf instances with --service-name flag:
+
+```
+   > C:\"Program Files"\Telegraf\telegraf.exe --service install --service-name telegraf-1
+   > C:\"Program Files"\Telegraf\telegraf.exe --service install --service-name telegraf-2
+   > C:\"Program Files"\Telegraf\telegraf.exe --service uninstall --service-name telegraf-1
+```
+
 Troubleshooting  common error #1067
 
 When installing as service in Windows, always double check to specify full path of the config file, otherwise windows service will fail to start

internal/usage_windows.go

@@ -33,6 +33,7 @@ The commands & flags are:
 
   --console                      run as console application (windows only)
   --service <service>            operate on the service (windows only)
+  --service-name                 service name (windows only)
 
 Examples:
 
@@ -59,4 +60,7 @@ Examples:
 
   # install telegraf service
   telegraf --service install --config "C:\Program Files\Telegraf\telegraf.conf"
+
+  # install telegraf service with custom name
+  telegraf --service install --service-name=my-telegraf
 `