LogRotator

Below is the extract from the README.MD that provides more specific technical info. For background context, however, this tool was originally created with intent to be used with One Identity’s Active Roles product. When enabled, that application creates exceptionally large text files very quickly. This tool is an attempt to help mitigate that problem. Active Roles happens to have a registry key that toggles the enabled/disabled state of logging. The intent is to disable logging for a moment (thereby releasing the file system lock on the file that would prevent it from being moved), move/rename the file, then immediately re-enable logging and allowing the application to create a brand new log.

There is nothing herein that requires Active Roles or any other One Identity product- if you find it useful for other purposes, I would be thrilled.

Note that I don’t have much history with bona fide software development, and none whatsoever with releasing freeware online, so please be kind!

https://madriamservices.com/download/logrotator-1-0-6-win-x64-zip/

README.MD

A C# command-line tool that rotates log files with timestamp-based renaming, compression, and automatic cleanup based on configurable size limits. Rotation only occurs when the log file exceeds a configurable threshold size.

Features

  • Conditional Rotation: Only rotates log files when they exceed a configurable size threshold
  • Timestamp-based Renaming: Renames rotated files with a customizable date/time format
  • Compression: Supports ZIP and GZIP compression formats
  • Automatic Cleanup: Deletes oldest archived files when total archive size exceeds a limit
  • Registry Toggle Support: Optionally toggle registry keys to disable logging/file locks before rotation
  • Configurable: All parameters can be specified via command-line arguments or JSON config file

Usage

Basic Usage

LogRotator --log-file "C:\Logs\app.log" --rotation-threshold "10MB"

Full Example

# Rotate only if log exceeds 10MB, keep archives under 500MB total, use ZIP compression
LogRotator --log-file "C:\Logs\app.log" --rotation-threshold "10MB" --size-limit "500MB" --compression zip

Command-Line Arguments

Required Arguments

  • --log-file, -f <path>: Path to the log file to rotate
  • --rotation-threshold, -t <size>: Minimum size before rotation occurs (e.g., “10MB”, “100MB”). Rotation only happens if the log file exceeds this size.

Optional Arguments

  • --size-limit, -s <size>: Maximum total size for archived logs (e.g., “500MB”, “1GB”). When exceeded, oldest archived files are deleted.
  • --archive-dir, -d <path>: Directory for archived logs (default: same directory as log file)
  • --compression, -c <format>: Compression format: zip or gzip (default: zip)
  • --date-format, -df <format>: Date format pattern for timestamp in archived filenames (default: yyyy-MM-dd_HH-mm-ss)
  • --registry-key, -rk <path>: Registry key path to toggle before rotation (e.g., HKEY_LOCAL_MACHINE\SOFTWARE\MyApp\Settings). Used to disable logging/file locks.
  • --registry-value-name, -rvn <name>: Registry value name to modify (default: empty string for default value)
  • --registry-disable-value, -rdv <val>: Value to set when disabling logging (e.g., 0, false, Disabled). Required if --registry-key is specified.
  • --registry-delay, -rd <ms>: Delay in milliseconds after setting registry value before attempting file move (default: 2000)
  • --help, -h: Show help message

Size Formats

Size values can be specified with the following units:

  • B – Bytes
  • KB – Kilobytes (1024 bytes)
  • MB – Megabytes (1024 * 1024 bytes)
  • GB – Gigabytes (1024 * 1024 * 1024 bytes)

Examples: 10MB, 1GB, 500KB, 1024B

Date Format

The date format uses standard .NET DateTime format strings. Examples:

  • yyyy-MM-dd_HH-mm-ss (default) – Produces: 2024-01-15_14-30-45
  • yyyyMMdd_HHmmss – Produces: 20240115_143045
  • yyyy-MM-dd – Produces: 2024-01-15

How It Works

  1. Size Check: The tool first checks if the log file exists and if its size exceeds the rotation threshold.
  • If the file is below the threshold, the tool exits successfully without performing any rotation.
  1. Registry Toggle (if configured): Before attempting to move the log file:
  • Reads the current registry value from the specified key
  • Sets the registry value to the disable value (to stop logging/release file locks)
  • Waits for the configured delay period to allow the logging service to release the file lock
  1. Rotation: If the threshold is met:
  • The current log file is renamed with a timestamp: {original-name}_{timestamp}.{ext}
  1. Registry Restore (if configured): After rotation (or if rotation fails):
  • Restores the original registry value to re-enable logging
  1. Compression: The renamed file is compressed using the specified format (ZIP or GZIP), and the uncompressed file is deleted.
  2. Cleanup: If a size limit is configured:
  • The tool calculates the total size of all archived log files
  • If the total exceeds the limit, it sorts files by modification time (oldest first)
  • Oldest files are deleted until the total size is below the limit

Examples

Example 1: Basic Rotation

LogRotator -f "app.log" -t "50MB"

This will rotate app.log only if it exceeds 50MB. Archived files will be stored in the same directory.

Example 2: With Archive Size Limit

LogRotator -f "C:\Logs\app.log" -t "10MB" -s "500MB" -d "C:\Logs\Archive"

This will:

  • Rotate app.log when it exceeds 10MB
  • Store archives in C:\Logs\Archive
  • Delete oldest archives when total archive size exceeds 500MB

Example 3: Custom Date Format and GZIP Compression

LogRotator -f "app.log" -t "100MB" -c gzip -df "yyyyMMdd_HHmmss"

This will:

  • Rotate when file exceeds 100MB
  • Use GZIP compression
  • Use date format yyyyMMdd_HHmmss for archived filenames

Example 4: With Registry Toggle

LogRotator -f "app.log" -t "10MB" --registry-key "HKEY_LOCAL_MACHINE\SOFTWARE\MyApp\Logging" --registry-value-name "Enabled" --registry-disable-value "0" --registry-delay 3000

This will:

  • Rotate when file exceeds 10MB
  • Before rotation, set the registry value HKEY_LOCAL_MACHINE\SOFTWARE\MyApp\Logging\Enabled to 0 to disable logging
  • Wait 3 seconds for the logging service to release the file lock
  • Attempt to rotate the log file
  • Restore the original registry value after rotation (or if rotation fails)

Exit Codes

  • 0: Success (rotation completed or not needed)
  • 1: Error (file not found, invalid arguments, etc.)

Error Handling

The tool includes comprehensive error handling:

  • Validates file paths and permissions
  • Handles file locks gracefully
  • Provides clear error messages
  • Validates all command-line arguments
  • Continues operation even if compression fails (with warning)
  • If registry toggle fails, the rotation operation fails immediately
  • Registry value is always restored in a finally block, even if rotation fails

Notes

  • The tool will create the archive directory if it doesn’t exist
  • If compression fails, the uncompressed archived file is retained
  • The tool only processes archived files that match the naming pattern (contain an underscore, indicating a timestamp)
  • File operations are performed synchronously to ensure data integrity
  • Registry toggle functionality requires administrator privileges for HKEY_LOCAL_MACHINE keys
  • The registry delay allows time for the logging service to release file locks before attempting rotation
  • Registry values support DWORD (integers), String, and Boolean types (booleans are stored as DWORD: 0 or 1)

License

This software is provided as freeware. See LICENCE.txt for full license terms and warranty disclaimers.

Summary:

  • Free to use for personal or commercial purposes
  • Modification, reverse engineering, and redistribution are prohibited
  • Provided “AS IS” without warranty