Add docs for new windows static install option

Signed-off-by: erikbaranowski <[email protected]>

docs/sources/static/set-up/install/install-agent-on-windows.md

@@ -30,7 +30,11 @@ To do a standard graphical install of Grafana Agent on Windows, perform the foll
 1. Double-click on `grafana-agent-installer.exe` to install Grafana Agent.
 
    Grafana Agent is installed into the default directory `C:\Program Files\Grafana Agent`.
-   The [windows_exporter integration](/docs/agent/latest/static/configuration/integrations/windows-exporter-config) can be enabled with all default windows_exporter options.
+
+   The following options are available:
+
+   - The [windows_exporter integration][windows_exporter_config] can be enabled with all default windows_exporter options. 
+   - The [-config.expand-env][flags] command line flag can be enabled.
 
 ## Silent install
 
@@ -78,6 +82,24 @@ If you are using `remote_write` you must enable Windows Exporter and set the glo
 
    If you are using Powershell, make sure you use triple quotes `"""http://example.com"""` around the URL parameter.
 
+## Silent install with `-config.expand_env`
+
+It is possible to enable [-config.expand-env][flags] during a silent install.
+
+1. Navigate to the [latest release](https://github.com/grafana/agent/releases) on GitHub.
+
+1. Scroll down to the **Assets** section.
+
+1. Download the file called `grafana-agent-installer.exe.zip`.
+
+1. Unzip the downloaded file.
+
+1. Run the following command in PowerShell or Command Prompt:
+
+   ```shell
+   PATH_TO_INSTALLER/grafana-agent-installer.exe /S /ExpandEnv true
+   ```
+
 ## Verify the installation
 
 1. Make sure you can access `http://localhost:12345/-/healthy` and `http://localhost:12345/agent/api/v1/metrics/targets`.
@@ -146,6 +168,8 @@ Refer to [windows_events](/docs/loki/latest/clients/promtail/configuration/#wind
 - [Configure Grafana Agent][configure]
 
 {{% docs/reference %}}
+[flags]: "/docs/agent/ -> /docs/agent/<AGENT_VERSION>/static/configuration/flags"
+[windows_exporter_config]: "/docs/agent/ -> /docs/agent/<AGENT_VERSION>/static/configuration/integrations/windows-exporter-config"
 [start]: "/docs/agent/ -> /docs/agent/<AGENT_VERSION>/static/set-up/start-agent"
 [start]: "/docs/grafana-cloud/ -> ../start-agent"
 [configure]: "/docs/agent/ -> /docs/agent/<AGENT_VERSION>/static/configuration/create-config-file"

packaging/grafana-agent/windows/install_script.nsis

@@ -24,19 +24,19 @@ outFile "${OUT}"
 LicenseData LICENSE
 
 # Everything must be global Vars
+Var EnableOptionsDialog
+Var PassedInParameters
 Var EnableExporterCheck
 Var EnableExporterValue
-Var EnableExporterDialog
-Var ExpandEnvCheck
-Var ExpandEnvValue
-Var PassedInParameters
 Var Url
 Var Username
 Var Password
+Var ExpandEnvCheck
+Var ExpandEnvValue
 
 Page license
 Page directory
-Page custom enableWindowsExporter enableWindowsExporterLeave
+Page custom enableOptions enableOptionsLeave
 Page instfiles
 
 # Annoyingly macros need to be defined before use
@@ -60,21 +60,21 @@ Section "install"
     ThisIsSilent:
         ${GetParameters} $PassedInParameters
         ${GetOptions} $PassedInParameters "/EnableExporter" $EnableExporterValue
-        ${GetOptions} $PassedInParameters "/ExpandEnv" $ExpandEnvValue
         ${GetOptions} $PassedInParameters "/Url" $Url
         ${GetOptions} $PassedInParameters "/Username" $Username
         ${GetOptions} $PassedInParameters "/Password" $Password
+        ${GetOptions} $PassedInParameters "/ExpandEnv" $ExpandEnvValue
         Call Install
         Return
     RunInstaller:
         Call Install
 SectionEnd
 
-Function enableWindowsExporter
+Function enableOptions
     nsDialogs::Create 1018
-    Pop $EnableExporterDialog
+    Pop $EnableOptionsDialog
 
-    ${If} $EnableExporterDialog == error
+    ${If} $EnableOptionsDialog == error
         Abort
     ${EndIf}
 
@@ -93,7 +93,7 @@ Function enableWindowsExporter
     nsDialogs::Show
 FunctionEnd
 
-Function enableWindowsExporterLeave
+Function enableOptionsLeave
     ${NSD_GetState} $EnableExporterCheck $EnableExporterValue
     ${If} $EnableExporterValue == ${BST_CHECKED}
         StrCpy $EnableExporterValue "true"