added history

Author: Erwinvandervalk

src/Config.SqlStreamStore.Tests/ConfigRepositoryTests.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using SqlStreamStore;
@@ -7,10 +8,11 @@
 namespace Config.SqlStreamStore.Tests
 {
 
-    // Optimistic concurrency checks
+    // Max number of versions
     // Can roll back to a version
-    // wait until sql is available
-    // configure stream name
+    // List versions
+    // Hooks for encryption / decryption
+    // 
 
     public class ConfigRepositoryTests
     {
@@ -109,10 +111,11 @@ Task<IConfigurationSettings> StartModification(string value)
                 return _streamStoreConfigRepository.Modify(
                     changeSettings: async (currentSettings, ct) =>
                     {
-                        if (++count == 2)
+                        if (Interlocked.Increment(ref count) == 2)
                         {
                             waitUntilBothStarted.SetResult(true);
                         }
+
                         await delayWriting.Task;
                         return currentSettings.WithModifiedSettings(("setting1", value));
                     },
@@ -142,6 +145,31 @@ Task<IConfigurationSettings> StartModification(string value)
             Assert.True(errorHandlerInvoked);
         }
 
+        [Fact]
+        public async Task Can_get_history()
+        {
+            // write 100 modifications, 0 .. 99
+            for (int i = 0; i < 100; i++)
+            {
+                await _streamStoreConfigRepository.Modify(CancellationToken.None, 
+                    ("setting", i.ToString()),
+                    ("othersetting", "constant")
+                    );
+            }
+
+            var history = await _streamStoreConfigRepository.GetSettingsHistory(CancellationToken.None);
+
+            Assert.Equal(Constants.DefaultMaxCount, history.Count);
+
+            // Check first and last entry
+            Assert.Equal("90", history.First()["setting"]); 
+            Assert.Equal("constant", history.First()["othersetting"]); 
+            Assert.Equal(90, history.First().Version);
+            Assert.Equal("99", history.Last()["setting"]);
+            Assert.Equal(99, history.Last().Version);
+            Assert.Equal("constant", history.Last()["othersetting"]);
+        }
+
         private static ModifiedConfigurationSettings BuildNewSettings()
         {
             var settings = new ModifiedConfigurationSettings(

src/Config.SqlStreamStore/ConfigRepository.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -17,6 +18,9 @@ public interface IStreamStoreConfigRepository
         IDisposable SubscribeToChanges(int version, 
             StreamStoreConfigRepository.OnSettingsChanged onSettingsChanged,
             CancellationToken ct);
+
+        Task<int?> GetMaxCount(CancellationToken ct);
+        Task SetMaxCount(int maxCount, CancellationToken ct);
     }
 
     public class StreamStoreConfigRepository : IStreamStoreConfigRepository
@@ -67,6 +71,21 @@ public async Task<IConfigurationSettings> Modify(CancellationToken ct,
             return await WriteChanges(modified, ct);
         }
 
+        public async Task<IReadOnlyList<IConfigurationSettings>> GetSettingsHistory(CancellationToken ct)
+        {
+            var maxCount = await GetMaxCount(ct) ?? Constants.DefaultMaxCount;
+            var stream = await _streamStore.ReadStreamBackwards(_streamId, StreamVersion.End, maxCount, true, ct);
+
+            var result = new List<IConfigurationSettings> ();
+            foreach (var message in stream.Messages.OrderBy(x => x.StreamVersion))
+            {
+                var setting = await BuildConfigurationSettingsFromMessage(message, ct);
+                result.Add(setting);
+            }
+
+            return result;
+        }
+
         public async Task<IConfigurationSettings> Modify(
             Func<IConfigurationSettings, CancellationToken, Task<ModifiedConfigurationSettings>> changeSettings, 
             ErrorHandler errorHandler,
@@ -92,9 +111,25 @@ public async Task<IConfigurationSettings> Modify(
             throw new InvalidOperationException("Failed to write configuration settings");
         }
 
+        public async Task<int?> GetMaxCount(CancellationToken ct)
+        {
+            var metaData = await _streamStore.GetStreamMetadata(_streamId, ct);
+            return metaData?.MaxCount;
+        }
+
+        public async Task SetMaxCount(int maxCount, CancellationToken ct)
+        {
+            await _streamStore.SetStreamMetadata(_streamId, maxCount: maxCount, cancellationToken: ct);
+        }
 
         public async Task<IConfigurationSettings> WriteChanges(ModifiedConfigurationSettings settings, CancellationToken ct)
         {
+            if (await GetMaxCount(ct) == null)
+            {
+                // Ensure default value is set
+                await SetMaxCount(Constants.DefaultMaxCount, CancellationToken.None);
+            }
+
             var changes = settings.GetChanges();
 
             if (changes == null)

src/Config.SqlStreamStore/Constants.cs

@@ -4,5 +4,6 @@ public static class Constants
     {
         public const string DefaultStreamName = "Config.SqlStreamStore";
         public const string ConfigChangedMessageName = "Config.SqlStreamStore.ConfigChanged";
+        public const int DefaultMaxCount = 10;
     }
 }

src/Config.SqlStreamStore/StreamStoreConfigurationSource.cs

@@ -16,13 +16,14 @@ public class StreamStoreConfigurationSource : IConfigurationSource
 
         private readonly BuildStreamStoreFromConfig _buildStreamStoreFromConfig;
 
+        public string StreamId { get; set; } = Constants.DefaultStreamName;
+
         public bool SubscribeToChanges { get; set; }
 
         public ErrorHandler ErrorHandler { get; set; }
 
         private readonly BuildConfigRepository _getConfigRepository;
 
-
         public StreamStoreConfigurationSource(BuildStreamStoreFromConfig buildStreamStoreFromConfig)
         {
             _buildStreamStoreFromConfig = buildStreamStoreFromConfig;
@@ -44,10 +45,9 @@ public StreamStoreConfigurationSource(string connectionStringKey, BuildStreamSto
             });
         }
 
-        public StreamStoreConfigurationSource(Func<IStreamStore> getStreamStore) :
-            this(() => new StreamStoreConfigRepository(getStreamStore()))
+        public StreamStoreConfigurationSource(Func<IStreamStore> getStreamStore)
         {
-            
+            _getConfigRepository = () => BuildRepository(getStreamStore());
         }
 
         public StreamStoreConfigurationSource(BuildConfigRepository getConfigRepository)
@@ -71,11 +71,18 @@ public IConfigurationProvider Build(IConfigurationBuilder builder)
                 }
             }
 
-            var repo = new StreamStoreConfigRepository(_buildStreamStoreFromConfig(innerBuilder.Build()));
+            var streamStore = _buildStreamStoreFromConfig(innerBuilder.Build());
+            var streamStoreConfigRepository = BuildRepository(streamStore);
 
-            return new StreamStoreConfigurationProvider(this, repo);
-        
+            return new StreamStoreConfigurationProvider(this, streamStoreConfigRepository);
         }
 
+        private StreamStoreConfigRepository BuildRepository(IStreamStore streamStore)
+        {
+            var repo = new StreamStoreConfigRepository(
+                streamStore: streamStore,
+                streamId: StreamId);
+            return repo;
+        }
     }
 }