Ensure change token is reset

src/Microsoft.Extensions.Logging.Console/ConsoleLoggerProvider.cs

@@ -47,20 +47,29 @@ public ConsoleLoggerProvider(IConsoleLoggerSettings settings)
 
         private void OnConfigurationReload(object state)
         {
-            // The settings object needs to change here, because the old one is probably holding on
-            // to an old change token.
-            _settings = _settings.Reload();
+            try
+            {
+                // The settings object needs to change here, because the old one is probably holding on
+                // to an old change token.
+                _settings = _settings.Reload();
 
-            foreach (var logger in _loggers.Values)
+                foreach (var logger in _loggers.Values)
+                {
+                    logger.Filter = GetFilter(logger.Name, _settings);
+                    logger.IncludeScopes = _settings.IncludeScopes;
+                }
+            }
+            catch (Exception ex)
             {
-                logger.Filter = GetFilter(logger.Name, _settings);
-                logger.IncludeScopes = _settings.IncludeScopes;
+                System.Console.WriteLine($"Error while loading configuration changes.{Environment.NewLine}{ex}");
             }
-
-            // The token will change each time it reloads, so we need to register again.
-            if (_settings?.ChangeToken != null)
+            finally
             {
-                _settings.ChangeToken.RegisterChangeCallback(OnConfigurationReload, null);
+                // The token will change each time it reloads, so we need to register again.
+                if (_settings?.ChangeToken != null)
+                {
+                    _settings.ChangeToken.RegisterChangeCallback(OnConfigurationReload, null);
+                }
             }
         }
 

test/Microsoft.Extensions.Logging.Test/ConsoleLoggerTest.cs

@@ -695,7 +695,7 @@ public void ConsoleLogger_ReloadSettings_CanChangeLogLevel()
                 Cancel = new CancellationTokenSource(),
                 Switches =
                 {
-                    ["Test"] = LogLevel.Information,
+                    ["Test"] = "Information",
                 }
             };
 
@@ -705,7 +705,7 @@ public void ConsoleLogger_ReloadSettings_CanChangeLogLevel()
             var logger = loggerFactory.CreateLogger("Test");
             Assert.False(logger.IsEnabled(LogLevel.Trace));
 
-            settings.Switches["Test"] = LogLevel.Trace;
+            settings.Switches["Test"] = "Trace";
 
             var cancellationTokenSource = settings.Cancel;
             settings.Cancel = new CancellationTokenSource();
@@ -726,7 +726,7 @@ public void ConsoleLogger_ReloadSettings_CanReloadMultipleTimes()
                 Cancel = new CancellationTokenSource(),
                 Switches =
                 {
-                    ["Test"] = LogLevel.Information,
+                    ["Test"] = "Information",
                 }
             };
 
@@ -739,7 +739,7 @@ public void ConsoleLogger_ReloadSettings_CanReloadMultipleTimes()
             // Act & Assert
             for (var i = 0; i < 10; i++)
             {
-                settings.Switches["Test"] = i % 2 == 0 ? LogLevel.Information : LogLevel.Trace;
+                settings.Switches["Test"] = i % 2 == 0 ? "Information" : "Trace";
 
                 var cancellationTokenSource = settings.Cancel;
                 settings.Cancel = new CancellationTokenSource();
@@ -750,6 +750,49 @@ public void ConsoleLogger_ReloadSettings_CanReloadMultipleTimes()
             }
         }
 
+        [Fact]
+        public void ConsoleLogger_ReloadSettings_CanRecoverAfterFailedReload()
+        {
+            // Arrange
+            var settings = new MockConsoleLoggerSettings()
+            {
+                Cancel = new CancellationTokenSource(),
+                Switches =
+                {
+                    ["Test"] = "Information",
+                }
+            };
+
+            var loggerFactory = new LoggerFactory();
+            loggerFactory.AddConsole(settings);
+            loggerFactory.AddDebug();
+
+            var logger = loggerFactory.CreateLogger("Test");
+
+            // Act & Assert
+            Assert.True(logger.IsEnabled(LogLevel.Information));
+
+            settings.Switches["Test"] = "InvalidLevel";
+
+            // Trigger reload
+            var cancellationTokenSource = settings.Cancel;
+            settings.Cancel = new CancellationTokenSource();
+
+            cancellationTokenSource.Cancel();
+
+            Assert.False(logger.IsEnabled(LogLevel.Trace));
+
+            settings.Switches["Test"] = "Trace";
+
+            // Trigger reload
+            cancellationTokenSource = settings.Cancel;
+            settings.Cancel = new CancellationTokenSource();
+
+            cancellationTokenSource.Cancel();
+
+            Assert.True(logger.IsEnabled(LogLevel.Trace));
+        }
+
         [Fact]
         public void WriteCore_NullMessageWithException()
         {
@@ -868,7 +911,7 @@ private class MockConsoleLoggerSettings : IConsoleLoggerSettings
 
             public IChangeToken ChangeToken => new CancellationChangeToken(Cancel.Token);
 
-            public IDictionary<string, LogLevel> Switches { get; } = new Dictionary<string, LogLevel>();
+            public IDictionary<string, string> Switches { get; } = new Dictionary<string, string>();
 
             public bool IncludeScopes { get; set; }
 
@@ -879,7 +922,12 @@ public IConsoleLoggerSettings Reload()
 
             public bool TryGetSwitch(string name, out LogLevel level)
             {
-                return Switches.TryGetValue(name, out level);
+                if (Enum.TryParse(Switches[name], out level))
+                {
+                    return true;
+                }
+
+                throw new Exception("Failed to parse LogLevel");
             }
         }