Fix IConfiguration adapter

README.md

@@ -312,8 +312,9 @@ The `dependencyResolver.Props<MySingletonDiActor>()` call will leverage the `Act
 ## IConfiguration To HOCON Adapter
 
 The `AddHocon` extension method can convert `Microsoft.Extensions.Configuration` `IConfiguration` into HOCON `Config` instance and adds it to the ActorSystem being configured.
-* All variable name are automatically converted to lower case.
-* All "." (period) in the `IConfiguration` key will be treated as a HOCON object key separator
+* Unlike `IConfiguration`, all HOCON key names are **case sensitive**.
+* **Unless enclosed inside double quotes**, all "." (period) in the `IConfiguration` key will be treated as a HOCON object key separator
+* `IConfiguration` **does not support object composition**, if you declare the same key multiple times inside multiple configuration providers (JSON/environment variables/etc), **only the last one declared will take effect**.
 * For environment variable configuration provider:
    * "__" (double underline) will be converted to "." (period).
    * "_" (single underline) will be converted to "-" (dash).
@@ -340,16 +341,33 @@ __Example:__
     }
   }    
 }
- ```
+```
 
 Environment variables:
 
 ```powershell
-AKKA__ACTOR__TELEMETRY__ENABLED=true
+AKKA__ACTOR__TELEMETRY__ENABLE=true
 AKKA__CLUSTER__SEED_NODES__0=akka.tcp//mySystem@localhost:4055
 AKKA__CLUSTER__SEED_NODES__1=akka.tcp//mySystem@localhost:4056
 AKKA__CLUSTER__SEED_NODE_TIMEOUT=00:00:05
- ```
+```
+
+Note the integer parseable key inside the seed-nodes configuration, seed-nodes will be parsed as an array. These environment variables will be parsed as HOCON settings:
+
+```hocon
+akka {
+  actor {
+    telemetry.enabled: on
+  }
+  cluster {
+    seed-nodes: [ 
+      "akka.tcp//mySystem@localhost:4055",
+      "akka.tcp//mySystem@localhost:4056" 
+    ]
+    seed-node-timeout: 5s
+  }
+}
+```
 
 Example code:
 
@@ -392,6 +410,96 @@ var host = new HostBuilder()
     });
 ```
 
+### Special Characters And Case Sensitivity
+
+This advanced usage of the `IConfiguration` adapter is solely used for edge cases where HOCON key capitalization needs to be preserved, such as declaring serialization binding. Note that when you're using this feature, none of the keys are normalized, you will have to write all of your keys in a HOCON compatible way.
+
+`appsettings.json`:
+
+```json
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning"
+    }
+  },
+  "AllowedHosts": "*",
+  "akka": {
+    "\"Key.With.Dots\"": "Key Value",
+    "cluster": {
+      "roles": [ "front-end", "back-end" ],
+      "min-nr-of-members": 3,
+      "log-info": true
+    }
+  }    
+}
+```
+
+Note that "Key.With.Dots" needs to be inside escaped double quotes, this is a HOCON requirement that preserves the "." (period) inside HOCON property names.
+
+Environment variables:
+
+```powershell
+PS C:/> [Environment]::SetEnvironmentVariable('akka__actor__telemetry__enabled', 'true')
+PS C:/> [Environment]::SetEnvironmentVariable('akka__actor__serialization_bindings__"System.Object"', 'hyperion')
+PS C:/> [Environment]::SetEnvironmentVariable('akka__cluster__seed_nodes__0', 'akka.tcp//mySystem@localhost:4055')
+PS C:/> [Environment]::SetEnvironmentVariable('akka__cluster__seed_nodes__1', 'akka.tcp//mySystem@localhost:4056')
+PS C:/> [Environment]::SetEnvironmentVariable('akka__cluster__seed_node_timeout', '00:00:05')
+```
+
+Note that:
+1. All of the environment variable names are in lower case, except "System.Object" where it needs to preserve name capitalization.
+2. To set serialization binding via environment variable, you have to use "." (period) instead of "__" (double underscore), this might be problematic for some shell scripts and there is no way of getting around this.
+
+Example code:
+
+```csharp
+/*
+Both appsettings.json and environment variables are combined
+into HOCON configuration:
+
+akka {
+  "Key.With.Dots": Key Value
+  actor {
+    telemetry.enabled: on
+    serialization-bindings {
+      "System.Object" = hyperion
+    }
+  }
+  cluster {
+    roles: [ "front-end", "back-end" ]
+    seed-nodes: [ 
+      "akka.tcp//mySystem@localhost:4055",
+      "akka.tcp//mySystem@localhost:4056" 
+    ]
+    min-nr-of-members: 3
+    seed-node-timeout: 5s
+    log-info: true
+  }
+}
+*/
+var host = new HostBuilder()
+    .ConfigureHostConfiguration(builder =>
+    {
+        // Setup IConfiguration to load from appsettings.json and
+        // environment variables
+        builder
+            .AddJsonFile("appsettings.json")
+            .AddEnvironmentVariables();
+    })
+    .ConfigureServices((context, services) =>
+    {
+        services.AddAkka("mySystem", (builder, provider) =>
+            {
+                // convert IConfiguration to HOCON
+                var akkaConfig = context.Configuration.GetSection("akka");
+                // Note the last method argument is set to false
+                builder.AddHocon(akkaConfig, HoconAddMode.Prepend, false); 
+            });
+    });
+```
+
 [Back to top](#akkahosting)
 
 <a id="microsoftextensionslogging-integration"></a>

src/Akka.Hosting.API.Tests/verify/CoreApiSpec.ApproveCore.verified.txt

@@ -66,7 +66,7 @@ namespace Akka.Hosting
         public static Microsoft.Extensions.DependencyInjection.IServiceCollection AddAkka<T>(this Microsoft.Extensions.DependencyInjection.IServiceCollection services, string actorSystemName, System.Action<Akka.Hosting.AkkaConfigurationBuilder, System.IServiceProvider> builder)
             where T : Akka.Hosting.AkkaHostedService { }
         public static Akka.Hosting.AkkaConfigurationBuilder AddHocon(this Akka.Hosting.AkkaConfigurationBuilder builder, Akka.Configuration.Config hocon, Akka.Hosting.HoconAddMode addMode) { }
-        public static Akka.Hosting.AkkaConfigurationBuilder AddHocon(this Akka.Hosting.AkkaConfigurationBuilder builder, Microsoft.Extensions.Configuration.IConfiguration configuration, Akka.Hosting.HoconAddMode addMode) { }
+        public static Akka.Hosting.AkkaConfigurationBuilder AddHocon(this Akka.Hosting.AkkaConfigurationBuilder builder, Microsoft.Extensions.Configuration.IConfiguration configuration, Akka.Hosting.HoconAddMode addMode, bool normalizeKeys = true) { }
         public static Akka.Hosting.AkkaConfigurationBuilder AddHoconFile(this Akka.Hosting.AkkaConfigurationBuilder builder, string hoconFilePath, Akka.Hosting.HoconAddMode addMode) { }
         public static Akka.Hosting.AkkaConfigurationBuilder AddSetup(this Akka.Hosting.AkkaConfigurationBuilder builder, Akka.Actor.Setup.Setup setup) { }
         public static Akka.Hosting.AkkaConfigurationBuilder WithActorAskTimeout(this Akka.Hosting.AkkaConfigurationBuilder builder, System.TimeSpan timeout) { }
@@ -187,7 +187,7 @@ namespace Akka.Hosting.Configuration
 {
     public static class ConfigurationHoconAdapter
     {
-        public static Akka.Configuration.Config ToHocon(this Microsoft.Extensions.Configuration.IConfiguration config) { }
+        public static Akka.Configuration.Config ToHocon(this Microsoft.Extensions.Configuration.IConfiguration config, bool normalizeKeys = true) { }
     }
 }
 namespace Akka.Hosting.Coordination