ColoredConsole target

Writes log messages to the console with customizable coloring.

Platforms Supported: Limited (Not available for NetStandard1.3)

There is also the simple Console-Target without any overhead from coloring.

Configuration Syntax

<targets>
  <target xsi:type="ColoredConsole"
          name="String"
          encoding="Encoding"
          layout="Layout"
          header="Layout"
          footer="Layout"
          useDefaultRowHighlightingRules="Boolean"
          stderr="Boolean"
          enableAnsiOutput="Boolean"
          detectConsoleAvailable="Boolean"
          detectOutputRedirected="Boolean">
    <highlight-row condition="Condition" backgroundColor="Enum" foregroundColor="Enum"/><!-- repeated -->
    <highlight-word text="String" condition="Condition" backgroundColor="Enum" foregroundColor="Enum"
                    ignoreCase="Boolean" regex="String" wholeWords="Boolean" compileRegex="Boolean"/><!-- repeated -->
  </target>
</targets>

Read more about using the Configuration File.

Parameters

General Options

• name - Name of the target.

• encoding - File encoding name like "utf-8", "ascii" or "utf-16". See Encoding class on MSDN. Defaults to Encoding.Default.

  Introduced with NLog 4.0

Layout Options

• layout - Text to be rendered. Layout Required. Default: ${longdate}|${level:uppercase=true}|${logger}|${message}
• header - Header. Layout
• footer - Footer. Layout

Output Options

• StdErr - Indicates whether the error stream (stderr) should be used instead of the output stream (stdout). Boolean Default: False

  Before NLog v5.0 the property was named errorStream.

• detectConsoleAvailable - Indicates whether the console target should disable itself when no console detected. Boolean Default: false

  Introduced in NLog 4.3.10 with default: true, then NLog 4.4 changed default to false.

• detectOutputRedirected - Indicates whether the console target should disable coloring when it detects that Console.IsOutputRedirected = true (Skip coloring when pipe to file)

  Introduced in NLog 4.6.7

• enableAnsiOutput - Enables output using ANSI Color Codes. Needed for e.g. Visual Studio Code. Boolean Default: false

  Introduced in NLog 4.6

• autoFlush - Performs explicit flush after every console write. Useful if having redirected to custom console-stream that doesn't has autoflush enabled. Boolean. Default = False.

  Introduced in NLog 4.6.3

Highlighting Rules

• useDefaultRowHighlightingRules - Indicates whether to use default row highlighting rules. Boolean Default: True The default rules are using these Colors :

Condition	Foreground Color	Background Color
level == LogLevel.Fatal	Red	NoChange
level == LogLevel.Error	Yellow	NoChange
level == LogLevel.Warn	Magenta	NoChange
level == LogLevel.Info	White	NoChange
level == LogLevel.Debug	Gray	NoChange
level == LogLevel.Trace	DarkGray	NoChange

• rowHighlightingRules - The row highlighting rules. Collection
  Each collection item is represented by <highlight-row /> element with the following attributes:

  • backgroundColor - Background color. Color Enum Default: NoChange
  • foregroundColor - Foreground color. Color Enum Default: NoChange
  • condition - Condition that must be met in order to set the specified foreground and background color. Condition Required.

• wordHighlightingRules - The word highlighting rules. Collection
  Each collection item is represented by <highlight-word /> element with the following attributes:

  • backgroundColor - Background color. Color Enum Default: NoChange
  • foregroundColor - Foreground color. Color Enum Default: NoChange
  • text - Text to be matched. You must specify either text or regex.
  • regex - Regular expression to be matched. You must specify either text or regex.
  • ignoreCase - Indicates whether to ignore case when comparing texts. Boolean Default: false
  • wholeWords - Indicates whether to match whole words only. Boolean Default: false
  • compileRegex - Introduced in NLog 4.3. Compiles the Regex. If false, the regex cache is used. Setting this to true can improve performance, but costs memory. Default: false
  • condition - Introduced in NLog 4.7.1. Condition that must be met before scanning for words to highlight. Condition.

Colors

Color Enum	Description	HEX Code	ANSI Foreground	ANSI Background
NoChange	Don't change the color
Black	Black Color	#000000	\x1B[30m	\x1B[40m
Blue	Blue Color	#0000FF	\x1B[94m	\x1B[104m
Cyan	Cyan Color	#00FFFF	\x1B[96m	\x1B[106m
DarkBlue	Dark Blue Color	#000080	\x1B[34m	\x1B[44m
DarkCyan	Dark Cyan Color	#008080	\x1B[36m	\x1B[46m
DarkGray	Dark Gray Color	#808080	\x1B[90m	\x1B[100m
DarkGreen	Dark Green Color	#008000	\x1B[32m	\x1B[42m
DarkMagenta	Dark Magenta Color	#800080	\x1B[35m	\x1B[45m
DarkRed	Dark Red Color	#800000	\x1B[31m	\x1B[41m
DarkYellow	Dark Yellow Color	#808000	\x1B[33m	\x1B[43m
Gray	Gray Color	#C0C0C0	\x1B[37m	\x1B[47m
Green	Green Color	#00FF00	\x1B[92m	\x1B[102m
Magenta	Magenta Color	#FF00FF	\x1B[95m	\x1B[105m
Red	Red Color	#FF0000	\x1B[91m	\x1B[101m
White	White Color	#FFFFFF	\x1b[97m	\x1B[107m
Yellow	Yellow Color	#FFFF00	\x1B[93m	\x1B[103m

Programmatic example

var consoleTarget = new ColoredConsoleTarget();

var highlightRule = new ConsoleRowHighlightingRule();
highlightRule.Condition = ConditionParser.ParseExpression("level == LogLevel.Info");
highlightRule.ForegroundColor = ConsoleOutputColor.Green;
consoleTarget.RowHighlightingRules.Add(highlightRule);

Microsoft Extension Logging AddConsole

The NLog Layout of the ColoredConsole-Target can be configured to match the output of the default MEL AddConsole().

See also NLog Console and AddConsole

Visual Studio Output window

The Visual Studio "Output Window" is bit tricky with colors. It is not a real console window - it just displays the console output from the application.

You could get colors by prefixing the message in your config (Ex. Layout="${level:format=FulleName}: ${message}")

• "Error: " - for errors - red
• "Warning: " - for warnings - orange

See Stackoverflow

Or use The Visual Studio extension VSColorOutput (VS2015-2019). Then you could also use the regular Console target.

Missing colors for dotnet watch run

When running application using dotnet watch run then one might experience that console colors are missing.

This can be fixed by changing launchSettings.json and removing the entry launchBrowser and the colors should return.

See also: https://github.com/dotnet/aspnetcore/issues/25317