feat: add tokenStyles dictionary parameter

Author: GerkinDev

README.md

@@ -35,3 +35,5 @@ Example:
 ```
 <<color: red;>>{Level}<<_>>: {Message}
 ```
+
+You can also define styles for tokens via the `tokenStyles` dictionary.

src/Serilog.Sinks.BrowserConsole/LoggerConfigurationBrowserConsoleExtensions.cs

@@ -27,19 +27,20 @@ namespace Serilog;
 public static class LoggerConfigurationBrowserConsoleExtensions
 {
     const string SerilogToken =
-        "%cserilog{_}color:white;background:#8c7574;border-radius:3px;padding:1px 2px;font-weight:600;";
-            
-    const string DefaultConsoleOutputTemplate = SerilogToken + "{Message}{NewLine}{Exception}";
-        
+        "<<color:white;background:#8c7574;border-radius:3px;padding:1px 2px;font-weight:600;>>serilog<<_>>";
+
+    const string DefaultConsoleOutputTemplate = SerilogToken + "[{Timestamp:HH:mm:ss} {Level:u3}] {Message:lj}{NewLine}{Exception}";
+
     /// <summary>
     /// Writes log events to the browser console.
     /// </summary>
     /// <param name="sinkConfiguration">Logger sink configuration.</param>
     /// <param name="restrictedToMinimumLevel">The minimum level for
     /// events passed through the sink. Ignored when <paramref name="levelSwitch"/> is specified.</param>
     /// <param name="outputTemplate">A message template describing the format used to write to the sink.
-    /// The default is <code>"[{Timestamp:HH:mm:ss} {Level:u3}] {Message:lj}{NewLine}{Exception}"</code>.</param>
+    /// The default is <code>"(serilog) [{Timestamp:HH:mm:ss} {Level:u3}] {Message:lj}{NewLine}{Exception}"</code>.</param>
     /// <param name="formatProvider">Supplies culture-specific formatting information, or null.</param>
+    /// <param name="tokenStyles">A dictionary of styles to apply to tokens. See <a href="https://developer.mozilla.org/en-US/docs/Web/API/console#styling_console_output">MDN about console styling</a></param>
     /// <param name="levelSwitch">A switch allowing the pass-through minimum level
     /// to be changed at runtime.</param>
     /// <param name="jsRuntime">An instance of <see cref="IJSRuntime"/> to interact with the browser.</param>
@@ -49,11 +50,12 @@ public static LoggerConfiguration BrowserConsole(
         LogEventLevel restrictedToMinimumLevel = LevelAlias.Minimum,
         string outputTemplate = DefaultConsoleOutputTemplate,
         IFormatProvider? formatProvider = null,
+        IReadOnlyDictionary<string, string>? tokenStyles = null,
         LoggingLevelSwitch? levelSwitch = null,
         IJSRuntime? jsRuntime = null)
     {
         ArgumentNullException.ThrowIfNull(sinkConfiguration);
-        var formatter = new OutputTemplateRenderer(outputTemplate, formatProvider); 
+        var formatter = new OutputTemplateRenderer(outputTemplate, formatProvider, tokenStyles); 
         return sinkConfiguration.Sink(new BrowserConsoleSink(jsRuntime, formatter), restrictedToMinimumLevel, levelSwitch);
     }
 }

src/Serilog.Sinks.BrowserConsole/Sinks/BrowserConsole/Output/OutputTemplateRenderer.cs

@@ -1,37 +1,56 @@
 using Serilog.Events;
 using Serilog.Formatting.Display;
 using Serilog.Parsing;
+using System;
 
 namespace Serilog.Sinks.BrowserConsole.Output;
 
 class OutputTemplateRenderer
 {
     readonly OutputTemplateTokenRenderer[] _renderers;
+    private readonly IFormatProvider? _formatProvider;
+    private readonly IReadOnlyDictionary<string, string>? _tokenStyles;
+    private readonly MessageTemplate _template;
 
-    public OutputTemplateRenderer(string outputTemplate, IFormatProvider? formatProvider)
+    public OutputTemplateRenderer(string outputTemplate, IFormatProvider? formatProvider, IReadOnlyDictionary<string, string>? tokenStyles = default)
     {
         ArgumentNullException.ThrowIfNull(outputTemplate);
-        var template = new MessageTemplateParser().Parse(outputTemplate);
-            
-        _renderers = template.Tokens
-            .Select(token => token switch
+        _formatProvider = formatProvider;
+        _tokenStyles = tokenStyles;
+        _template = new MessageTemplateParser().Parse(outputTemplate);
+
+        _renderers = _template.Tokens
+            .SelectMany(token => token switch
             {
-                TextToken tt => new TextTokenRenderer(tt.Text),
-                PropertyToken pt => pt.PropertyName switch
-                {
-                    OutputProperties.LevelPropertyName => new LevelTokenRenderer(pt) as OutputTemplateTokenRenderer,
-                    OutputProperties.NewLinePropertyName => new NewLineTokenRenderer(pt.Alignment),
-                    OutputProperties.ExceptionPropertyName => new ExceptionTokenRenderer(),
-                    OutputProperties.MessagePropertyName => new MessageTemplateOutputTokenRenderer(),
-                    OutputProperties.TimestampPropertyName => new TimestampTokenRenderer(pt, formatProvider),
-                    OutputProperties.PropertiesPropertyName => new PropertiesTokenRenderer(pt, template),
-                    _ => new EventPropertyTokenRenderer(pt, formatProvider)
-                },
+                TextToken tt => [new TextTokenRenderer(tt.Text)],
+                PropertyToken pt => WrapStyle(pt),
                 _ => throw new InvalidOperationException()
             })
             .ToArray();
     }
 
+    private OutputTemplateTokenRenderer[] WrapStyle(PropertyToken token)
+    {
+        OutputTemplateTokenRenderer renderer = token.PropertyName switch
+        {
+            OutputProperties.LevelPropertyName => new LevelTokenRenderer(token),
+            OutputProperties.NewLinePropertyName => new NewLineTokenRenderer(token.Alignment),
+            OutputProperties.ExceptionPropertyName => new ExceptionTokenRenderer(),
+            OutputProperties.MessagePropertyName => new MessageTemplateOutputTokenRenderer(),
+            OutputProperties.TimestampPropertyName => new TimestampTokenRenderer(token, _formatProvider),
+            OutputProperties.PropertiesPropertyName => new PropertiesTokenRenderer(token, _template),
+            _ => new EventPropertyTokenRenderer(token, _formatProvider)
+        };
+        if (_tokenStyles?.TryGetValue(token.PropertyName, out var style) ?? false)
+        {
+            return [new StyleTokenRenderer(style), renderer, StyleTokenRenderer.Reset];
+        }
+        else
+        {
+            return [renderer];
+        }
+    }
+
     public object?[] Format(LogEvent logEvent)
     {
         ArgumentNullException.ThrowIfNull(logEvent);

src/Serilog.Sinks.BrowserConsole/Sinks/BrowserConsole/Output/StyleTokenRenderer.cs

@@ -0,0 +1,34 @@
+// Copyright 2017 Serilog Contributors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+using Serilog.Events;
+
+namespace Serilog.Sinks.BrowserConsole.Output;
+
+class StyleTokenRenderer : OutputTemplateTokenRenderer
+{
+    public static readonly StyleTokenRenderer Reset = new("");
+
+    private readonly string _style;
+
+    public StyleTokenRenderer(string style)
+    {
+        _style = style;
+    }
+
+    public override void Render(LogEvent logEvent, TokenEmitter emitToken)
+    {
+        emitToken.Style(_style);
+    }
+}

test/Serilog.Sinks.BrowserConsole.Tests/FormatterTests.cs

@@ -3,6 +3,7 @@
 using Serilog.Parsing;
 using Serilog.Sinks.BrowserConsole.Output;
 using System;
+using System.Collections.Generic;
 using Xunit;
 
 namespace Serilog.Sinks.BrowserConsole.Tests
@@ -104,5 +105,21 @@ public void EscapePercentFromMessages()
             var args = formatter.Format(new LogEvent(DateTimeOffset.Now, LogEventLevel.Verbose, null, new MessageTemplateParser().Parse(MESSAGE), Array.Empty<LogEventProperty>()));
             Assert.Equal([$"%cA first%c %% sign %c{MESSAGE.Replace($"%", "%%")}%c", STYLE1, "", STYLE2, ""], args);
         }
+
+        [Fact]
+        public void SupportsTokenStyling()
+        {
+            var MESSAGE = $"Test";
+            var LEVEL = LogEventLevel.Verbose;
+            var NOW = DateTimeOffset.Now;
+            var formatter = new OutputTemplateRenderer($"{{{OutputProperties.LevelPropertyName}}}@{{{OutputProperties.TimestampPropertyName}:HH:mm}}: {{{OutputProperties.MessagePropertyName}}}", default, new Dictionary<string, string>
+            {
+                {OutputProperties.LevelPropertyName, STYLE1 },
+                {OutputProperties.TimestampPropertyName, STYLE2 },
+                {OutputProperties.MessagePropertyName, STYLE3 }
+            });
+            var args = formatter.Format(new LogEvent(NOW, LEVEL, null, new MessageTemplateParser().Parse(MESSAGE), Array.Empty<LogEventProperty>()));
+            Assert.Equal([$"%c%s%c@%c%s%c: %c{MESSAGE}%c", STYLE1, LEVEL.ToString(), "", STYLE2, NOW.ToString("HH:mm"), "", STYLE3, ""], args);
+        }
     }
 }