Merge pull request #17 from Stravaig-Projects/#11/logging

#11: Add logging

Author: colinangusmackay

README.md

@@ -54,7 +54,40 @@ builder.AddSqlServer(opts =>
 });
 ```
 
+### Adding logging
 
+The configuration provider is set up too early in the pipeline to be able to accept logging from the start. However you can attach a logger after it has been set up. The configuration provider will also hold on to any log messages and replay them once a logger it attached. It works like this:
+
+* When calling `AddSqlServer` on the configuration builder. Make sure you call `ExpectLogger()`. This sets up the replay mechanism.
+* Then set up your loggers. The SqlServerConfigurationProvider logs from Debug up.
+* By the time you get to configure services, you should be able to get a `ILoggerFactory`. There is an extension method, `AttachLoggerToSqlServerProvider` on `IConfigurationRoot` that will attach the logger.
+
+```csharp
+await Host.CreateDefaultBuilder(args)
+    .ConfigureAppConfiguration(builder =>
+    {
+        builder.AddSqlServer(opts =>
+        {
+            opts.FromExistingConfiguration()
+                .ExpectLogger();
+        });
+    })
+    .ConfigureLogging(builder =>
+    {
+        builder.AddConsole();
+        builder.AddDebug();
+        builder.SetMinimumLevel(LogLevel.Debug);
+    })
+    .ConfigureServices((ctx, services) =>
+    {
+        // Attach the logger to the SQL Server Configuration Provider
+        IConfigurationRoot configRoot = (IConfigurationRoot) ctx.Configuration;
+        configRoot.AttachLoggerToSqlServerProvider(services.BuildServiceProvider().GetService<ILoggerFactory>());
+    })
+
+```
+
+CAUTION: If you call `ExpectLogger` and never attach a logger, it will just hold on to the log messages for the lifetime of the application in memory.
 
 ## Contributing / Getting Started
 

release-notes/wip-release-notes.md

@@ -4,20 +4,9 @@
 
 Date: ???
 
-### Bugs
-
 ### Features
 
-### Miscellaneous
-
-### Dependent Packages
-
-- .NET 5.0
-  - No changes
-- .NET Core 3.1
-  - No changes
-- General
-  - No changes
+- #11: Add logging
 
 ---
 

src/Example/Program.cs

@@ -12,17 +12,20 @@ await Host.CreateDefaultBuilder(args)
         builder.AddUserSecrets<Program>();
         builder.AddSqlServer(opts =>
         {
-            opts.FromExistingConfiguration();
+            opts.FromExistingConfiguration()
+                .ExpectLogger();
         });
     })
     .ConfigureLogging(builder =>
     {
         builder.AddConsole();
         builder.AddDebug();
+        builder.SetMinimumLevel(LogLevel.Debug);
     })
     .ConfigureServices((ctx, services) =>
     {
         IConfigurationRoot configRoot = (IConfigurationRoot) ctx.Configuration;
+        configRoot.AttachLoggerToSqlServerProvider(services.BuildServiceProvider().GetService<ILoggerFactory>());
         services.AddTransient<IHostedService, TheHostedService>();
         services.AddSingleton(configRoot);
         services.Configure<MyFeatureConfiguration>(configRoot.GetSection("MyConfiguration"));

src/Example/TheHostedService.cs

@@ -36,7 +36,7 @@ public TheHostedService(
         _timer.Elapsed += TimerOnElapsed;
         featureValues.OnChange((_, s) =>
         {
-            Console.WriteLine($"[{DateTime.Now:HH:mm:ss}] Change Detected. {s}");
+            _logger.LogInformation($"Change Detected. {s}", s);
         });
     }
 
@@ -47,7 +47,7 @@ private async void TimerOnElapsed(object? sender, ElapsedEventArgs e)
             WriteIndented = true,
         };
         string json = JsonSerializer.Serialize(_featureValues.CurrentValue, jsonOptions);
-        Console.Clear();
+        Console.WriteLine(Environment.NewLine);
         _logger.LogInformation(
             "At {Time} the object looks like:\n{Json}",
             e.SignalTime,

src/Stravaig.Configuration.SqlServer.Tests/FakeDataLoader.cs

@@ -1,13 +1,15 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 
 namespace Stravaig.Configuration.SqlServer.Tests;
 
 public class FakeDataLoader : IDataLoader
 {
     public KeyValuePair<string, string>[] FakeData { get; set; } = Array.Empty<KeyValuePair<string, string>>();
-    public IEnumerable<KeyValuePair<string, string>> RetrieveData(SqlServerConfigurationSource source)
+    
+    public IDictionary<string, string> RetrieveData(SqlServerConfigurationSource source)
     {
-        return FakeData;
+        return FakeData.ToDictionary(k => k.Key, v => v.Value);
     }
 }

src/Stravaig.Configuration.SqlServer.sln.DotSettings

@@ -1,3 +1,4 @@
-<wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+<wpf:ResourceDictionary xml:space="preserve" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:ss="urn:shemas-jetbrains-com:settings-storage-xaml" xmlns:wpf="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+	<s:Boolean x:Key="/Default/UserDictionary/Words/=Materialise/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Nulling/@EntryIndexedValue">True</s:Boolean>
 	<s:Boolean x:Key="/Default/UserDictionary/Words/=Stravaig/@EntryIndexedValue">True</s:Boolean></wpf:ResourceDictionary>

src/Stravaig.Configuration.SqlServer/ConfigurationRootExtensions.cs

@@ -0,0 +1,23 @@
+using System.Linq;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Logging.Abstractions;
+
+namespace Stravaig.Configuration.SqlServer;
+
+public static class ConfigurationRootExtensions
+{
+    public static IConfigurationRoot AttachLoggerToSqlServerProvider(this IConfigurationRoot configRoot, ILoggerFactory? loggerFactory)
+    {
+        loggerFactory ??= NullLoggerFactory.Instance;
+
+        var providers = configRoot.Providers
+            .OfType<SqlServerConfigurationProvider>();
+        foreach (var provider in providers)
+        {
+            provider.AttachLogger(loggerFactory);
+        }
+
+        return configRoot;
+    }
+}

src/Stravaig.Configuration.SqlServer/DataLoader.cs

@@ -3,29 +3,33 @@
 
 namespace Stravaig.Configuration.SqlServer;
 
-public interface IDataLoader
-{
-    IEnumerable<KeyValuePair<string, string>> RetrieveData(SqlServerConfigurationSource source);
-}
 public class DataLoader : IDataLoader
 {
     private const string RetrieveSqlTemplate = "SELECT [ConfigKey], [ConfigValue] FROM [{0}].[{1}]";
     private const int KeyColumnPosition = 0;
     private const int ValueColumnPosition = 1;
 
-    public IEnumerable<KeyValuePair<string, string>> RetrieveData(SqlServerConfigurationSource source)
+    public IDictionary<string, string> RetrieveData(SqlServerConfigurationSource source)
     {
         var sql = RetrieveSql(source.SchemaName, source.TableName);
         using SqlConnection connection = new SqlConnection(source.ConnectionString);
         connection.Open();
         var cmd = new SqlCommand(sql, connection);
         using var reader = cmd.ExecuteReader();
+        return MaterialiseData(reader);
+    }
+
+    private static IDictionary<string, string> MaterialiseData(SqlDataReader reader)
+    {
+        Dictionary<string, string> results = new ();
         while (reader.Read())
         {
             var key = reader.GetString(KeyColumnPosition);
             var value = reader.GetString(ValueColumnPosition);
-            yield return new KeyValuePair<string, string>(key, value);
+            results.Add(key,value);
         }
+
+        return results;
     }
 
     private string RetrieveSql(string schemaName, string tableName) =>

src/Stravaig.Configuration.SqlServer/IDataLoader.cs

@@ -0,0 +1,8 @@
+using System.Collections.Generic;
+
+namespace Stravaig.Configuration.SqlServer;
+
+public interface IDataLoader
+{
+    IDictionary<string, string> RetrieveData(SqlServerConfigurationSource source);
+}

src/Stravaig.Configuration.SqlServer/ISqlServerConfigurationWatcher.cs

@@ -1,6 +1,9 @@
+using Microsoft.Extensions.Logging;
+
 namespace Stravaig.Configuration.SqlServer;
 
 public interface ISqlServerConfigurationWatcher
 {
     void EnsureStarted();
+    void AttachLogger(ILogger logger);
 }