Better cancellation for migration. (#418)

* Better cancellation for migration.

src/Squidex.Infrastructure/Migrations/Migrator.cs

@@ -7,6 +7,7 @@
 
 using System;
 using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using Squidex.Infrastructure.Log;
 
@@ -32,7 +33,7 @@ namespace Squidex.Infrastructure.Migrations
             this.log = log;
         }
 
-        public async Task MigrateAsync()
+        public async Task MigrateAsync(CancellationToken ct = default)
         {
             var version = 0;
 
@@ -49,7 +50,7 @@ namespace Squidex.Infrastructure.Migrations
 
                 version = await migrationStatus.GetVersionAsync();
 
-                while (true)
+                while (!ct.IsCancellationRequested)
                 {
                     var (newVersion, migrations) = migrationPath.GetNext(version);
 

src/Squidex.Infrastructure/Orleans/GrainBootstrap.cs

@@ -28,6 +28,7 @@ namespace Squidex.Infrastructure.Orleans
         {
             for (var i = 1; i <= NumTries; i++)
             {
+                ct.ThrowIfCancellationRequested();
                 try
                 {
                     var grain = grainFactory.GetGrain<T>(SingleGrain.Id);

src/Squidex/Config/Startup/MigratorHost.cs

@@ -25,7 +25,7 @@ namespace Squidex.Config.Startup
 
         protected override Task StartAsync(ISemanticLog log, CancellationToken ct)
         {
-            return migrator.MigrateAsync();
+            return migrator.MigrateAsync(ct);
         }
     }
 }

tests/Squidex.Infrastructure.Tests/Migrations/MigratorTests.cs

@@ -108,7 +108,7 @@ namespace Squidex.Infrastructure.Migrations
 
             A.CallTo(() => migrator_1_2.UpdateAsync()).Throws(new ArgumentException());
 
-            await Assert.ThrowsAsync<MigrationFailedException>(sut.MigrateAsync);
+            await Assert.ThrowsAsync<MigrationFailedException>(() => sut.MigrateAsync());
 
             A.CallTo(() => migrator_0_1.UpdateAsync()).MustHaveHappened();
             A.CallTo(() => migrator_1_2.UpdateAsync()).MustHaveHappened();
@@ -147,7 +147,7 @@ namespace Squidex.Infrastructure.Migrations
 
             var sut = new Migrator(new InMemoryStatus(), path, log) { LockWaitMs = 2 };
 
-            await Task.WhenAll(Enumerable.Repeat(0, 10).Select(x => Task.Run(sut.MigrateAsync)));
+            await Task.WhenAll(Enumerable.Repeat(0, 10).Select(x => Task.Run(() => sut.MigrateAsync())));
 
             A.CallTo(() => migrator_0_1.UpdateAsync())
                 .MustHaveHappened(1, Times.Exactly);