Logf (FSharp.Logf)

Logf Module

Namespace: Fable.FSharp
Assembly: Fable.FSharp.Logf.dll

Printf style formatting for ILogger objects, with optional structured logging support.

All functions in this module support format specifiers implemented by FSharp.Core printf functions. Named parameters for structured loggers are specified in curly braces immediately after the format specifier. For example, the format string "Hello, %s{user}!" would give the string argument "user" in a structured logger. Parameter name specifiers are simply ignored by non-structured loggers.

Example

let greet logger person (miles: float) =
    logf logger LogLevel.Information "Hello, %s{user}! You walked %.1f{distance} miles today." person miles
greet logger "Jim" 1.7

Output when using console logging: "Hello, Jim! You walked 1.7 miles today."

Output when using Serilog JSON file logging: {"@t":"2022-01-01T03:44:57.8532799Z","@mt":"Hello, {user}! You walked {distance} miles today.","user":"Jim","distance":"1.7"}

Functions and values

Function or value	Description
`elogf logger logLevel exn format` Full Usage: `elogf logger logLevel exn format` Parameters: logger : `ILogger` - The logger to output to. logLevel : `LogLevel` - The LogLevel to use. exn : `Exception` - The exception to include in the message. format : `Format<'T, unit, string, unit>` - The input formatter. Returns: `'T` The return type and arguments of the formatter.	Formatted error printing to an ILogger at the specified LogLevel. logger : `ILogger` The logger to output to. logLevel : `LogLevel` The LogLevel to use. exn : `Exception` The exception to include in the message. format : `Format<'T, unit, string, unit>` The input formatter. Returns: `'T` The return type and arguments of the formatter.
`elogfc logger exn format` Full Usage: `elogfc logger exn format` Parameters: logger : `ILogger` - The logger to output to. exn : `Exception` format : `Format<'T, unit, string, unit>` - The input formatter. Returns: `'T` The return type and arguments of the formatter.	Formatted error printing to an ILogger at Critical level. logger : `ILogger` The logger to output to. exn : `Exception` format : `Format<'T, unit, string, unit>` The input formatter. Returns: `'T` The return type and arguments of the formatter.
`elogfe logger exn format` Full Usage: `elogfe logger exn format` Parameters: logger : `ILogger` - The logger to output to. exn : `Exception` format : `Format<'T, unit, string, unit>` - The input formatter. Returns: `'T` The return type and arguments of the formatter.	Formatted error printing to an ILogger at Error level. logger : `ILogger` The logger to output to. exn : `Exception` format : `Format<'T, unit, string, unit>` The input formatter. Returns: `'T` The return type and arguments of the formatter.
`elogfw logger exn format` Full Usage: `elogfw logger exn format` Parameters: logger : `ILogger` - The logger to output to. exn : `Exception` format : `Format<'T, unit, string, unit>` - The input formatter. Returns: `'T` The return type and arguments of the formatter.	Formatted error printing to an ILogger at Warning level. logger : `ILogger` The logger to output to. exn : `Exception` format : `Format<'T, unit, string, unit>` The input formatter. Returns: `'T` The return type and arguments of the formatter.
`logf logger logLevel format` Full Usage: `logf logger logLevel format` Parameters: logger : `ILogger` - The logger to output to. logLevel : `LogLevel` - The LogLevel to use. format : `Format<'T, unit, string, unit>` - The input formatter. Returns: `'T` The return type and arguments of the formatter.	Formatted printing to an ILogger at the specified LogLevel. logger : `ILogger` The logger to output to. logLevel : `LogLevel` The LogLevel to use. format : `Format<'T, unit, string, unit>` The input formatter. Returns: `'T` The return type and arguments of the formatter.
`logfc logger format` Full Usage: `logfc logger format` Parameters: logger : `ILogger` - The logger to output to. format : `Format<'T, unit, string, unit>` - The input formatter. Returns: `'T` The return type and arguments of the formatter.	Formatted printing to an ILogger at Critical level. logger : `ILogger` The logger to output to. format : `Format<'T, unit, string, unit>` The input formatter. Returns: `'T` The return type and arguments of the formatter.
`logfd logger format` Full Usage: `logfd logger format` Parameters: logger : `ILogger` - The logger to output to. format : `Format<'T, unit, string, unit>` - The input formatter. Returns: `'T` The return type and arguments of the formatter.	Formatted printing to an ILogger at Debug level. logger : `ILogger` The logger to output to. format : `Format<'T, unit, string, unit>` The input formatter. Returns: `'T` The return type and arguments of the formatter.
`logfe logger format` Full Usage: `logfe logger format` Parameters: logger : `ILogger` - The logger to output to. format : `Format<'T, unit, string, unit>` - The input formatter. Returns: `'T` The return type and arguments of the formatter.	Formatted printing to an ILogger at Error level. logger : `ILogger` The logger to output to. format : `Format<'T, unit, string, unit>` The input formatter. Returns: `'T` The return type and arguments of the formatter.
`logfi logger format` Full Usage: `logfi logger format` Parameters: logger : `ILogger` - The logger to output to. format : `Format<'T, unit, string, unit>` - The input formatter. Returns: `'T` The return type and arguments of the formatter.	Formatted printing to an ILogger at Information level. logger : `ILogger` The logger to output to. format : `Format<'T, unit, string, unit>` The input formatter. Returns: `'T` The return type and arguments of the formatter.
`logft logger format` Full Usage: `logft logger format` Parameters: logger : `ILogger` - The logger to output to. format : `Format<'T, unit, string, unit>` - The input formatter. Returns: `'T` The return type and arguments of the formatter.	Formatted printing to an ILogger at Trace level. logger : `ILogger` The logger to output to. format : `Format<'T, unit, string, unit>` The input formatter. Returns: `'T` The return type and arguments of the formatter.
`logfw logger format` Full Usage: `logfw logger format` Parameters: logger : `ILogger` - The logger to output to. format : `Format<'T, unit, string, unit>` - The input formatter. Returns: `'T` The return type and arguments of the formatter.	Formatted printing to an ILogger at Warning level. logger : `ILogger` The logger to output to. format : `Format<'T, unit, string, unit>` The input formatter. Returns: `'T` The return type and arguments of the formatter.