> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ditto.live/llms.txt
> Use this file to discover all available pages before exploring further.

# SDK Logging

> Learn how to configure and use the logging system in the Ditto SDK for monitoring and debugging your applications.

<Callout icon="circle-info" color="#3B82F6" iconType="regular">
  This content is for SDK V4. For the latest version, see the [V5 documentation](/sdk/latest).
</Callout>

Ditto provides comprehensive logging capabilities to help you monitor, debug, and optimize your applications. The SDK includes a sophisticated logging system with automatic rotation, compression, and configurable retention policies.

## Logging Rotation in Ditto

### Core System

Ditto uses a custom `ditto-rotating-file` crate that provides thread-safe rotating file writers with automatic compression.

### Rotation Triggers

Files rotate based on two criteria:

* **Size limit**: Default 1MB uncompressed (configurable 1MB-1GB)
* **Age limit**: Default 24 hours (configurable 1+ hours)

### File Management

* **Naming**: `ditto-logs-YYYY-MM-DD-HH-MM-SS.microseconds.log`
* **Compression**: Automatic gzip compression when rotated (`.log` → `.log.gz`)
* **Retention**: Default 15 files maximum (configurable 3-64 files)

## Configuration Parameters

| Parameter                             | Default | Range      | Description               |
| ------------------------------------- | ------- | ---------- | ------------------------- |
| `rotating_log_file_max_size_mb`       | 1MB     | 1MB-1GB    | Size trigger for rotation |
| `rotating_log_file_max_age_h`         | 24      | 1+ hours   | Age trigger for rotation  |
| `rotating_log_file_max_files_on_disk` | 15      | 3-64 files | Maximum files to retain   |

## Key Features

* **Multi-threaded compression** in background
* **Automatic cleanup** of oldest files when limit exceeded
* **Runtime reconfiguration** without restart
* **Export functionality** for diagnostics
* **Crash recovery** - compresses leftover uncompressed files on startup

## Integration

* Uses `tracing-subscriber` with JSON formatting
* Always logs at **DEBUG level** to disk (independent of console level)
* Filtered to prevent recursive logging from the rotation system itself

## Disk Usage

The system maintains approximately **\~15MB disk usage** by default (15 × 1MB compressed files) and handles rotation completely automatically with robust error recovery.

## Related Documentation

* For debugging specific issues, see [Troubleshooting](/sdk/v4/deployment/troubleshooting)
* For remote log collection, see [Device Observability](/sdk/v4/deployment/device-observability-and-ditto-logs/)