Adds abstraction around boot time checks for database availability (#19848)

* Adds abstraction around boot time checks for database availability.

* Addressed issues raised in code review.

Author: AndyButland

src/Umbraco.Infrastructure/DependencyInjection/UmbracoBuilder.CoreServices.cs

@@ -90,6 +90,9 @@ public static IUmbracoBuilder AddCoreInitialServices(this IUmbracoBuilder builde
         builder.AddNotificationAsyncHandler<RuntimeUnattendedUpgradeNotification, UnattendedUpgrader>();
         builder.AddNotificationAsyncHandler<RuntimePremigrationsUpgradeNotification, PremigrationUpgrader>();
 
+        // Database availability check.
+        builder.Services.AddUnique<IDatabaseAvailabilityCheck, DefaultDatabaseAvailabilityCheck>();
+
         // Add runtime mode validation
         builder.Services.AddSingleton<IRuntimeModeValidationService, RuntimeModeValidationService>();
         builder.RuntimeModeValidators()

src/Umbraco.Infrastructure/Persistence/DefaultDatabaseAvailabilityCheck.cs

@@ -0,0 +1,52 @@
+using Microsoft.Extensions.Logging;
+
+namespace Umbraco.Cms.Infrastructure.Persistence;
+
+/// <summary>
+/// Checks if a configured database is available on boot using the default method of 5 attempts with a 1 second delay between each one.
+/// </summary>
+internal class DefaultDatabaseAvailabilityCheck : IDatabaseAvailabilityCheck
+{
+    private const int NumberOfAttempts = 5;
+    private const int DefaultAttemptDelayMilliseconds = 1000;
+
+    private readonly ILogger<DefaultDatabaseAvailabilityCheck> _logger;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="DefaultDatabaseAvailabilityCheck"/> class.
+    /// </summary>
+    /// <param name="logger"></param>
+    public DefaultDatabaseAvailabilityCheck(ILogger<DefaultDatabaseAvailabilityCheck> logger) => _logger = logger;
+
+    /// <summary>
+    /// Gets or sets the number of milliseconds to delay between attempts.
+    /// </summary>
+    /// <remarks>
+    /// Exposed for testing purposes, hence settable only internally.
+    /// </remarks>
+    public int AttemptDelayMilliseconds { get; internal set; } = DefaultAttemptDelayMilliseconds;
+
+    /// <inheritdoc/>
+    public bool IsDatabaseAvailable(IUmbracoDatabaseFactory databaseFactory)
+    {
+        bool canConnect;
+        for (var i = 0; ;)
+        {
+            canConnect = databaseFactory.CanConnect;
+            if (canConnect || ++i == NumberOfAttempts)
+            {
+                break;
+            }
+
+            if (_logger.IsEnabled(LogLevel.Debug))
+            {
+                _logger.LogDebug("Could not immediately connect to database, trying again.");
+            }
+
+            // Wait for the configured time before trying again.
+            Thread.Sleep(AttemptDelayMilliseconds);
+        }
+
+        return canConnect;
+    }
+}

src/Umbraco.Infrastructure/Persistence/IDatabaseAvailabilityCheck.cs

@@ -0,0 +1,16 @@
+namespace Umbraco.Cms.Infrastructure.Persistence;
+
+/// <summary>
+/// Checks if a configured database is available on boot.
+/// </summary>
+public interface IDatabaseAvailabilityCheck
+{
+    /// <summary>
+    /// Checks if the database is available for Umbraco to boot.
+    /// </summary>
+    /// <param name="databaseFactory">The <see cref="IUmbracoDatabaseFactory"/>.</param>
+    /// <returns>
+    /// A value indicating whether the database is available.
+    /// </returns>
+    bool IsDatabaseAvailable(IUmbracoDatabaseFactory databaseFactory);
+}

src/Umbraco.Infrastructure/Runtime/RuntimeState.cs

@@ -31,6 +31,7 @@ public class RuntimeState : IRuntimeState
     private readonly IConflictingRouteService _conflictingRouteService = null!;
     private readonly IEnumerable<IDatabaseProviderMetadata> _databaseProviderMetadata = null!;
     private readonly IRuntimeModeValidationService _runtimeModeValidationService = null!;
+    private readonly IDatabaseAvailabilityCheck _databaseAvailabilityCheck = null!;
 
     /// <summary>
     /// The initial <see cref="RuntimeState"/>
@@ -46,6 +47,7 @@ private RuntimeState()
     /// <summary>
     /// Initializes a new instance of the <see cref="RuntimeState" /> class.
     /// </summary>
+    [Obsolete("Please use the constructor taking all parameters. Scheduled for removal in Umbraco 18.")]
     public RuntimeState(
        IOptions<GlobalSettings> globalSettings,
        IOptions<UnattendedSettings> unattendedSettings,
@@ -56,6 +58,34 @@ public RuntimeState(
        IConflictingRouteService conflictingRouteService,
        IEnumerable<IDatabaseProviderMetadata> databaseProviderMetadata,
        IRuntimeModeValidationService runtimeModeValidationService)
+       : this(
+             globalSettings,
+             unattendedSettings,
+             umbracoVersion,
+             databaseFactory,
+             logger,
+             packageMigrationState,
+             conflictingRouteService,
+             databaseProviderMetadata,
+             runtimeModeValidationService,
+             StaticServiceProvider.Instance.GetRequiredService<IDatabaseAvailabilityCheck>())
+    {
+    }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="RuntimeState" /> class.
+    /// </summary>
+    public RuntimeState(
+       IOptions<GlobalSettings> globalSettings,
+       IOptions<UnattendedSettings> unattendedSettings,
+       IUmbracoVersion umbracoVersion,
+       IUmbracoDatabaseFactory databaseFactory,
+       ILogger<RuntimeState> logger,
+       PendingPackageMigrations packageMigrationState,
+       IConflictingRouteService conflictingRouteService,
+       IEnumerable<IDatabaseProviderMetadata> databaseProviderMetadata,
+       IRuntimeModeValidationService runtimeModeValidationService,
+       IDatabaseAvailabilityCheck databaseAvailabilityCheck)
     {
         _globalSettings = globalSettings;
         _unattendedSettings = unattendedSettings;
@@ -66,6 +96,7 @@ public RuntimeState(
         _conflictingRouteService = conflictingRouteService;
         _databaseProviderMetadata = databaseProviderMetadata;
         _runtimeModeValidationService = runtimeModeValidationService;
+        _databaseAvailabilityCheck = databaseAvailabilityCheck;
     }
 
     /// <inheritdoc />
@@ -242,7 +273,7 @@ private UmbracoDatabaseState GetUmbracoDatabaseState(IUmbracoDatabaseFactory dat
     {
         try
         {
-            if (!TryDbConnect(databaseFactory))
+            if (_databaseAvailabilityCheck.IsDatabaseAvailable(databaseFactory) is false)
             {
                 return UmbracoDatabaseState.CannotConnect;
             }
@@ -305,27 +336,4 @@ private bool DoesUmbracoRequireUpgrade(IReadOnlyDictionary<string, string?>? key
         }
         return CurrentMigrationState != FinalMigrationState;
     }
-
-    private bool TryDbConnect(IUmbracoDatabaseFactory databaseFactory)
-    {
-        // anything other than install wants a database - see if we can connect
-        // (since this is an already existing database, assume localdb is ready)
-        bool canConnect;
-        var tries = 5;
-        for (var i = 0; ;)
-        {
-            canConnect = databaseFactory.CanConnect;
-            if (canConnect || ++i == tries)
-            {
-                break;
-            }
-            if (_logger.IsEnabled(Microsoft.Extensions.Logging.LogLevel.Debug))
-            {
-                _logger.LogDebug("Could not immediately connect to database, trying again.");
-            }
-            Thread.Sleep(1000);
-        }
-
-        return canConnect;
-    }
 }

tests/Umbraco.Tests.UnitTests/Umbraco.Infrastructure/Persistence/DefaultDatabaseAvailabilityCheckTests.cs

@@ -0,0 +1,71 @@
+using Microsoft.Extensions.Logging.Abstractions;
+using Moq;
+using NUnit.Framework;
+using Umbraco.Cms.Core.Install.Models;
+using Umbraco.Cms.Infrastructure.Persistence;
+using Umbraco.Cms.Persistence.SqlServer.Services;
+
+namespace Umbraco.Cms.Tests.UnitTests.Umbraco.Infrastructure.Persistence;
+
+[TestFixture]
+public class DefaultDatabaseAvailabilityCheckTests
+{
+    [Test]
+    public void IsDatabaseAvailable_WithDatabaseUnavailable_ReturnsFalse()
+    {
+        var mockDatabaseFactory = new Mock<IUmbracoDatabaseFactory>();
+        mockDatabaseFactory
+            .Setup(x => x.CanConnect)
+            .Returns(false);
+
+        var sut = CreateDefaultDatabaseAvailabilityCheck();
+        var result = sut.IsDatabaseAvailable(mockDatabaseFactory.Object);
+        Assert.IsFalse(result);
+    }
+
+    [Test]
+    public void IsDatabaseAvailable_WithDatabaseImmediatelyAvailable_ReturnsTrue()
+    {
+        var mockDatabaseFactory = new Mock<IUmbracoDatabaseFactory>();
+        mockDatabaseFactory
+            .Setup(x => x.CanConnect)
+            .Returns(true);
+
+        var sut = CreateDefaultDatabaseAvailabilityCheck();
+        var result = sut.IsDatabaseAvailable(mockDatabaseFactory.Object);
+        Assert.IsTrue(result);
+    }
+
+    [TestCase(5, true)]
+    [TestCase(6, false)]
+    public void IsDatabaseAvailable_WithDatabaseImmediatelyAvailableAfterMultipleAttempts_ReturnsExpectedResult(int attemptsUntilConnection, bool expectedResult)
+    {
+        if (attemptsUntilConnection < 1)
+        {
+            throw new ArgumentException($"{nameof(attemptsUntilConnection)} must be greater than or equal to 1.", nameof(attemptsUntilConnection));
+        }
+
+        var attemptResults = new Queue<bool>();
+        for (var i = 0; i < attemptsUntilConnection - 1; i++)
+        {
+            attemptResults.Enqueue(false);
+        }
+
+        attemptResults.Enqueue(true);
+
+        var mockDatabaseFactory = new Mock<IUmbracoDatabaseFactory>();
+        mockDatabaseFactory
+            .Setup(x => x.CanConnect)
+            .Returns(attemptResults.Dequeue);
+
+        var sut = CreateDefaultDatabaseAvailabilityCheck();
+        var result = sut.IsDatabaseAvailable(mockDatabaseFactory.Object);
+        Assert.AreEqual(expectedResult, result);
+    }
+
+    private static DefaultDatabaseAvailabilityCheck CreateDefaultDatabaseAvailabilityCheck()
+        => new(new NullLogger<DefaultDatabaseAvailabilityCheck>())
+        {
+            AttemptDelayMilliseconds = 1 // Set to 1 ms for faster tests.
+        };
+}