Add -config-directory argument to Windows service

Fixes https://github.com/influxdata/telegraf/issues/1797

CHANGELOG.md

@@ -11,6 +11,7 @@
 
 - [#2077](https://github.com/influxdata/telegraf/issues/2077): SQL Server Input - Arithmetic overflow error converting numeric to data type int.
 - [#2262](https://github.com/influxdata/telegraf/issues/2262): Flush jitter can inhibit metric collection.
+- [#1797](https://github.com/influxdata/telegraf/issues/1797): Windows service does not support config directory.
 
 ## v1.2 [2017-01-00]
 

cmd/telegraf/telegraf.go

@@ -313,7 +313,10 @@ func main() {
 			DisplayName: "Telegraf Data Collector Service",
 			Description: "Collects data using a series of plugins and publishes it to" +
 				"another series of plugins.",
-			Arguments: []string{"-config", "C:\\Program Files\\Telegraf\\telegraf.conf"},
+			Arguments: []string{
+			    "-config", "C:\\Program Files\\Telegraf\\telegraf.conf",
+			    "-config-directory", "C:\\Program Files\\Telegraf\\telegraf.d",
+			},
 		}
 
 		prg := &program{}

docs/WINDOWS_SERVICE.md

@@ -4,8 +4,8 @@ Telegraf natively supports running as a Windows Service. Outlined below is are
 the general steps to set it up.
 
 1. Obtain the telegraf windows distribution
-2. Create the directory `C:\Program Files\Telegraf` (if you install in a different
-   location simply specify the `-config` parameter with the desired location)
+2. Create the directories `C:\Program Files\Telegraf` and `C:\Program Files\Telegraf\telegraf.d`
+   (if you install in a different location simply specify the `-config` and `-config-directory` parameters with the desired location)
 3. Place the telegraf.exe and the telegraf.conf config file into `C:\Program Files\Telegraf`
 4. To install the service into the Windows Service Manager, run the following in PowerShell as an administrator (If necessary, you can wrap any spaces in the file paths in double quotes ""):
 
@@ -17,7 +17,7 @@ the general steps to set it up.
 6. To check that it works, run:
 
    ```
-   > C:\"Program Files"\Telegraf\telegraf.exe --config C:\"Program Files"\Telegraf\telegraf.conf --test
+   > C:\"Program Files"\Telegraf\telegraf.exe --config C:\"Program Files"\Telegraf\telegraf.conf --config-directory C:\"Program Files"\Telegraf\telegraf.d --test
    ```
 
 7. To start collecting data, run: