Formatter

AddCustomLogging attaches this formatter to the console sink it adds, unless includeConsoleSink is false. The formatter is internal to the package, so application code never constructs it; write normal Serilog message templates and the console output comes back colored.

Usage

Program.cs

using AlmightyShogun.Serilog;
using Microsoft.Extensions.DependencyInjection;

builder.Services.AddCustomLogging(builder.Configuration);

ImportWorker.cs

using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;

public sealed class ImportWorker(
    ILogger<ImportWorker> logger
) : BackgroundService
{
    protected override Task ExecuteAsync(CancellationToken stoppingToken)
    {
        logger.LogInformation(
            "Imported {Count} rows for {Tenant:|bg} in {Elapsed:N1|y} ms",
            4218,
            "contoso",
            92.47
        );

        logger.LogWarning("Retrying after {Failures:|br} failures", 3);

        return Task.CompletedTask;
    }
}

Output format

Each line starts with a timestamp and a three-letter, upper-case level, colored by severity, followed by the rendered message template:

[13:45:02 INF] Imported 4218 rows in 92.5 ms

An exception is written on the following line in dark gray.

Level colors

Color	Level
White	Verbose
White	Debug
Green	Information
Yellow	Warning
Red	Error
Bright red	Fatal

Default property colors

A property with no color code is colored by the type of its value:

Color	Value
White	string
Cyan	Any numeric type, including byte, short, int, long, their unsigned forms, nint, nuint, Half, float, double, and decimal
Magenta	bool
Dark gray	null
White	Anything else

Template syntax

A color is applied by putting a shorthand code after a | in the property's format section:

Template	Result
{Value}	Default color for the value's type.
{Value:|r}	Red, no format applied.
{Value:N2|r}	Formatted with N2, then colored red.
{Value:N2}	Formatted with N2, default color.

Colors

Code	Color
r	Red
g	Green
b	Blue
c	Cyan
y	Yellow
m	Magenta
br	Bright red
bg	Bright green
bb	Bright blue
bc	Bright cyan
by	Bright yellow
bm	Bright magenta

Codes are matched case-insensitively. An unrecognized code renders white rather than failing.

When colors are suppressed

ANSI escape codes are omitted when the output is redirected, or when the NO_COLOR environment variable is set. This keeps escape sequences out of a log file or a piped stream, where they would otherwise appear as literal bytes.

Detection runs once per process. Pass enableColors to AddCustomLogging to override it, for example on a CI system that renders ANSI but reports its output as redirected.