Add docs for using custom config providers

docs/v3/app_model/custom_config.md

@@ -0,0 +1,129 @@
+---
+id: app_model_custom_config
+title: Custom config
+---
+This page describes how to create and configure a custom configuration provider. If you are happy with the standard config providers described in the [Instance applications](/v3/app_model/instancing_apps.md) page then you don't need to read this page.
+
+### IOptions and Ini Files
+The default Microsoft implementation of config comes via the `Microsoft.Extensions.Options.IOptions` interface that can be configured at application startup and then injected into subsequent classes.
+
+If you would perfer to use ini files for your config instead of yaml files you can use a [ini file config provider](https://docs.microsoft.com/en-us/dotnet/api/microsoft.extensions.configuration.ini.iniconfigurationprovider?view=dotnet-plat-ext-6.0) (or any other IConfigurationProvider).
+
+### How the default config is configured
+Within `program.cs` the `HostBuilder` startup instructs the framework to use the default NetDaemon configuration defined inside the core NetDaemon app:
+
+```csharp
+try
+{
+    await Host.CreateDefaultBuilder(args)
+        .UseDefaultNetDaemonLogging()   
+        .UseNetDaemonAppSettings()// <-----
+        .UseNetDaemon()
+        .Build()
+        .RunAsync();
+    /// ...
+}
+```
+
+This configuration builder uses the default [config source](https://docs.microsoft.com/en-us/dotnet/api/microsoft.extensions.hosting.host.createdefaultbuilder?view=dotnet-plat-ext-6.0#microsoft-extensions-hosting-host-createdefaultbuilder(system-string())) as well as a yaml file source custom to netdaemon, as described in the [Instance applications](v2/app_model/instancing_apps.md) page.
+
+To modify the config behaviour we can create our own config provider  within `program.cs` (note that an in-depth description of host builders is beyond the scope of this article, but you can find more information on the [Microsoft web site](https://docs.microsoft.com/en-us/aspnet/core/fundamentals/host/generic-host?view=aspnetcore-6.0))
+
+### Step 1 - Change program.cs to add the ini file config provider
+
+Go to `program.cs` and remove or comment out the call to `UseNetDaemonAppSettings()` and add the configuration provider and the netdaemon config objects so that it now looks like this:
+
+```csharp
+try
+{
+    await Host.CreateDefaultBuilder(args)
+        .UseDefaultNetDaemonLogging()   
+        //.UseNetDaemonAppSettings()// <-----
+        .ConfigureAppConfiguration((context, config) => config.AddIniFile("appsettings.ini", true, true))// <-----
+        .ConfigureServices((context, services) =>// <-----
+            services.ConfigureNetDaemonServices(context.Configuration)// <-----
+        )// <-----
+        .UseNetDaemon()
+        .Build()
+        .RunAsync();
+    /// ...
+}
+```
+Note that there may already be a ConfigurServices call in your `program.cs`. If one exists simply add this call inside the configure services (keeping what you have as well).
+
+
+### Step 2 - Create a appSettings.ini file
+
+You now need to create a ini file. In the previous step we set it up as `appsettings.ini` as such we should make a new file named `appsettings.ini` next to your `program.cs`. In this file you can put any custom config you want and it will be available in the app through dependancy injection with IOptions.
+
+Here is a exampe `appsettings.ini`:
+```ini
+MyConfigValue=My Super Awesome value
+```
+### Step 3 - Include appsettings.ini in build output
+
+In your `.csproj` file add the following to tell dotnet build to copy the file from the project into the output directory so that it exists at runtime.
+
+```xml
+<ItemGroup>
+    <None Update="$(MSBuildProjectDir)appsettings.ini">
+        <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+</ItemGroup>
+```
+
+### Step 4 - Create our config class
+
+Just like with the the original yaml config we need to make a class that will be used for us to access our values. This class can be placed anywhere as long as it is accessible from your program.cs file. 
+
+```csharp
+public class ConfigExample
+{
+  public string MyConfigValue { get; set; }
+}
+```
+
+### Step 5 - Register your config class
+
+Now that we created the class we will use to access the configuration we need to tell the app to register it. Back in our `program.cs` file we will add a line in the configure services.
+
+```csharp
+try
+{
+    await Host.CreateDefaultBuilder(args)
+        .UseDefaultNetDaemonLogging()   
+        //.UseNetDaemonAppSettings()
+        .ConfigureAppConfiguration((context, config) => config.AddIniFile("appsettings.ini", true, true))
+        .ConfigureServices((context, services) =>
+            services.ConfigureNetDaemonServices(context.Configuration)
+                    .Configure<ConfigExample>(context.Configuration)// <-----
+        )
+        .UseNetDaemon()
+        .Build()
+        .RunAsync();
+    /// ...
+}
+```
+
+### Step 6 - Use the config
+
+Inside the constructor of any class you want dependency injected (service, app, ect.) add a parameter for `IOptions<ConfigExample>`. Now we can use our config however we please.
+
+```csharp
+[NetDaemonApp]
+public class MyFancyApp
+{
+
+  public MyFancyApp(IOptions<ConfigExample> config, ILogger<MyFancyApp> logger)
+  {
+    logger.LogInformation($"My config value is {config.MyConfigValue}");
+  }
+}
+```
+
+This Fancy App simply reads the config we set up and writes it to the configured logger(s). When run it would log "My config value is My Super Awesome Value"
+
+### Additional options / other config providers
+
+You are free to add your own custom ConfigProviders or any system that implements the `Microsoft.Extensions.Configuration.IConfigurationProvider` interface.
+

sidebars.js

@@ -102,6 +102,7 @@ module.exports = {
           'v3/app_model/app_model_instancing',
           'v3/app_model/app_model_advanced_config',
           'v3/app_model/app_model_custom_logging',
+          'v3/app_model/app_model_custom_config',
           'v3/app_model/app_model_moving_from_v2',
         ],
       },