LoggerPro for Delphi

The Modern, Async, Pluggable Logging Framework for Delphi

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Why Developers Love LoggerPro

LoggerPro is the most complete and battle-tested logging framework for Delphi. Used in thousands of production applications worldwide, it provides everything you need for professional-grade logging.

Key Features

• Async by Design - Non-blocking logging with zero impact on application performance
• 20+ Built-in Appenders - File, Console, HTTP, Syslog, ElasticSearch, Database, Email, and many more
• Cross-Platform - Windows, Linux, macOS, Android, iOS - write once, log everywhere
• Thread-Safe - Built from the ground up for multi-threaded applications
• Fluent Builder API - Clean, readable, Serilog-style configuration
• Structured Logging - First-class support for key-value context in log messages
• Production Ready - Stable, maintained, and continuously improved since 2010

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Quick Taste

uses
  LoggerPro.GlobalLogger;

begin
  Log.Info('Application started');
  Log.Debug('Processing item %d', [42], 'WORKER');
  Log.Error('Connection failed', 'DATABASE');
end.

One line of uses, and you're logging to rotating files. It's that simple.

Builder API (v2.0)

Log := LoggerProBuilder
  .WithDefaultTag('MYAPP')
  .WriteToFile
    .WithLogsFolder('logs')
    .Done
  .WriteToConsole.Done
  .WriteToHTTP
    .WithURL('https://logs.example.com/api')
    .Done
  .Build;

Structured Context Logging

Log.Info('Order completed', 'ORDERS', [
  LogParam.I('order_id', 12345),
  LogParam.S('customer', 'John Doe'),
  LogParam.F('total', 299.99)
]);

Disabling Logging at Runtime

Option 1: Set Minimum Level (Simple)

// Disable Debug and Info, keep Warnings and above
Log := LoggerProBuilder
  .WithMinimumLevel(TLogType.Warning)
  .WriteToFile.Done
  .Build;

// Change at runtime
(Log as TCustomLogWriter).MinimumLevel := TLogType.Fatal; // Disable almost everything

Option 2: Filtering Provider (Advanced)

uses LoggerPro.Proxy;

var
  lAppender: ILogAppender;
  lEnabled: Boolean;

lEnabled := True;

lAppender := TLoggerProFileAppender.Create(5, 1000);

// Wrap with runtime filter
lAppender := TLoggerProFilter.Build(
  lAppender,
  function(const aLogItem: TLogItem): Boolean
  begin
    Result := lEnabled; // Toggle at runtime
  end);

Log := BuildLogWriter([lAppender]);

// Later: disable all logging
lEnabled := False;

UDP Syslog Appender

Send logs to remote syslog servers (RFC 5424):

Log := LoggerProBuilder
  .WriteToUDPSyslog
    .WithHost('syslog.example.com')
    .WithPort(514)
    .WithApplication('MyApp')
    .WithUseLocalTime(True)  // Use local time instead of UTC
    .Done
  .Build;

ElasticSearch with Authentication

Send logs to ElasticSearch with authentication support:

// Basic Authentication
Log := LoggerProBuilder
  .WriteToElasticSearch
    .WithURL('https://elastic.example.com:9200/logs/_doc')
    .WithBasicAuth('username', 'password')
    .Done
  .Build;

// API Key Authentication
Log := LoggerProBuilder
  .WriteToElasticSearch
    .WithHost('https://elastic.example.com')
    .WithPort(9200)
    .WithIndex('app-logs')
    .WithAPIKey('your-api-key-here')
    .Done
  .Build;

// Bearer Token Authentication
Log := LoggerProBuilder
  .WriteToElasticSearch
    .WithURL('https://elastic.example.com:9200/logs/_doc')
    .WithBearerToken('your-jwt-token')
    .Done
  .Build;

Getting Current Log File Name

Get the active log file name from file appenders (useful for uploading, emailing, etc.):

uses LoggerPro.FileAppender;

var
  lAppender: TLoggerProSimpleFileAppender;
  lFileName: string;
begin
  lAppender := TLoggerProSimpleFileAppender.Create;
  Log := BuildLogWriter([lAppender]);

  Log.Info('Message');

  // Get current log file name
  lFileName := lAppender.GetCurrentLogFileName;
  WriteLn('Logging to: ', lFileName);

  // Now you can upload it, email it, etc.
  UploadLogFile(lFileName);
end;

For TLoggerProFileAppender (separate files per tag):

var
  lAppender: TLoggerProFileAppender;
  lFileName: string;
  lAllFiles: TArray<string>;
begin
  lAppender := TLoggerProFileAppender.Create;

  // Get file for specific tag
  lFileName := lAppender.GetCurrentLogFileName('ORDERS');

  // Get all current log files
  lAllFiles := lAppender.GetAllCurrentLogFileNames;
end;

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Full Documentation

For complete documentation, tutorials, advanced examples, and best practices:

https://www.danieleteti.it/loggerpro/

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Installation

Manual

Add the LoggerPro source folder to your Delphi Library Path.

Delphinus

Search for "LoggerPro" in the Delphinus package manager.

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Supported Platforms

Platform	Status
Windows (32/64-bit)	Full Support
Linux	Full Support
macOS	Full Support
Android	Full Support
iOS	Full Support

Delphi Version Requirements

LoggerPro Version	Minimum Delphi Version	Notes
2.0.x (current)	Delphi 10.3 Rio	Full compatibility from 10.3+
1.x (legacy)	Delphi 10 Seattle+	Legacy support

Tested on: Delphi 13 Florence, 12 Athens, 11 Alexandria, 10.4 Sydney, 10.3 Rio

Note: LoggerPro 2.0 is fully compatible with Delphi 10.3 Rio and later versions.

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Sample Projects

The samples/ folder contains 25+ working examples covering every appender and use case. The best way to learn LoggerPro is by exploring these samples.

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License

Apache License 2.0 - Use it freely in personal and commercial projects.

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Author

Daniele Teti

• Blog: danieleteti.it
• LoggerPro Docs: danieleteti.it/loggerpro
• Twitter/X: @danieleteti

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LoggerPro - Professional Logging for Professional Delphi Developers