(#2) Call OnReload only if there is changed data

Author: colinangusmackay

src/Example/Example.csproj

@@ -14,6 +14,7 @@
     <ItemGroup>
       <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="6.0.0" />
       <PackageReference Include="Microsoft.Extensions.Hosting" Version="6.0.0" />
+      <PackageReference Include="Microsoft.FeatureManagement" Version="2.4.0" />
       <PackageReference Include="Stravaig.Configuration.Diagnostics.Logging" Version="1.0.4" />
     </ItemGroup>
 

src/Example/Program.cs

@@ -1,10 +1,9 @@
-// See https://aka.ms/new-console-template for more information
-
-using Example;
+using Example;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
+using Microsoft.FeatureManagement;
 using Stravaig.Configuration.SqlServer;
 
 await Host.CreateDefaultBuilder(args)
@@ -27,5 +26,6 @@ await Host.CreateDefaultBuilder(args)
         services.AddTransient<IHostedService, TheHostedService>();
         services.AddSingleton(configRoot);
         services.Configure<MyFeatureConfiguration>(configRoot.GetSection("MyConfiguration"));
+        services.AddFeatureManagement(configRoot.GetSection("FeatureManager"));
     })
     .RunConsoleAsync();

src/Example/TheHostedService.cs

@@ -7,6 +7,7 @@
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
+using Microsoft.FeatureManagement;
 using Stravaig.Configuration.Diagnostics.Logging;
 using Timer = System.Timers.Timer;
 
@@ -17,26 +18,29 @@ public class TheHostedService : IHostedService, IDisposable
 {
     private readonly ILogger<TheHostedService> _logger;
     private readonly IConfigurationRoot _configRoot;
+    private readonly IFeatureManager _featureManager;
     private readonly IOptionsMonitor<MyFeatureConfiguration> _featureValues;
     private readonly Timer _timer;
 
     public TheHostedService(
         ILogger<TheHostedService> logger,
         IConfigurationRoot configRoot,
+        IFeatureManager featureManager,
         IOptionsMonitor<MyFeatureConfiguration> featureValues)
     {
         _logger = logger;
         _configRoot = configRoot;
+        _featureManager = featureManager;
         _featureValues = featureValues;
         _timer = new Timer(10000);
         _timer.Elapsed += TimerOnElapsed;
         featureValues.OnChange((v, s) =>
         {
-            Console.WriteLine($"Change detected. {s}");
+            Console.WriteLine($"[{DateTime.Now:HH:mm:ss}] Change Detected. {s}");
         });
     }
 
-    private void TimerOnElapsed(object? sender, ElapsedEventArgs e)
+    private async void TimerOnElapsed(object? sender, ElapsedEventArgs e)
     {
         var jsonOptions = new JsonSerializerOptions()
         {
@@ -48,6 +52,11 @@ private void TimerOnElapsed(object? sender, ElapsedEventArgs e)
             "At {Time} the object looks like:\n{Json}",
             e.SignalTime,
             json);
+        await foreach (string feature in _featureManager.GetFeatureNamesAsync())
+        {
+            var state = await _featureManager.IsEnabledAsync(feature);
+            _logger.LogInformation("{Feature} : {State}", feature, state);
+        }
         _logger.LogConfigurationValuesAsInformation(_configRoot.GetSection("MyConfiguration"));
     }
 

src/Example/appsettings.json

@@ -7,6 +7,10 @@
             "ConnectionString": "*** Found in User Secrets ***"
         }
     },
+    "FeatureManager": {
+        "FeatureA": true,
+        "FeatureB": {}
+    },
     "MyConfiguration": {
         "SomeNumber": 123,
         "SomeString": "A value from appsettings",

src/Stravaig.Configuration.SqlServer/SqlServerConfigurationProvider.cs

@@ -36,8 +36,27 @@ public override void Load()
 
     internal void Reload()
     {
+        // Get existing data
+        var oldData = Data;
         Load();
-        OnReload();
+
+        if (DataDifferent(oldData, Data))
+            OnReload();
+    }
+
+    private bool DataDifferent(IDictionary<string, string> oldData, IDictionary<string, string> newData)
+    {
+        if (oldData.Count != newData.Count)
+            return true;
+        foreach (var oldKey in oldData.Keys)
+        {
+            if (!newData.ContainsKey(oldKey))
+                return true;
+            if (oldData[oldKey] != newData[oldKey])
+                return true;
+        }
+
+        return false;
     }
 
     public override string ToString()

src/Stravaig.Configuration.SqlServer/SqlServerConfigurationWatcher.cs

@@ -19,7 +19,7 @@ private void TimerOnElapsed(object? sender, ElapsedEventArgs e)
     {
         try
         {
-            Console.WriteLine("Timer elapsed");
+            Console.WriteLine($"[{DateTime.Now:HH:mm:ss}] Polling the database.");
             _provider.Reload();
         }
         catch (Exception ex)