Customizations Example

This example demonstrates all of Logly's advanced customization features.

Features Shown

1. Global Root Path - Configure all logs to be stored in a single directory
2. Format Structure - Customize message prefixes, suffixes, and field separators
3. Color Customization - Define custom ANSI colors for each log level
4. Diagnostics Logging - Emit system diagnostics with structured data
5. Highlighters & Alerts - Configure pattern matching for special handling
6. Combined Configuration - Use all features together

Running the Example

zig build run-customizations

Code Structure

The example is organized into 6 demonstrations:

1. Global Root Path Configuration

var config = logly.Config.default();
config.logs_root_path = "./logs";

_ = try logger.addSink(logly.SinkConfig.file("application.log"));
_ = try logger.addSink(logly.SinkConfig.file("errors.log"));

This automatically creates the ./logs directory and stores both log files there.

Output:

./logs/
├── application.log
└── errors.log

2. Format Structure Customization

config.format_structure = .{
    .message_prefix = ">>> ",
    .message_suffix = " <<<",
    .field_separator = " :: ",
    .enable_nesting = true,
};

Customizes how messages appear in the output.

3. Color Customization Per Level

config.level_colors = .{
    .info_color = "\x1b[36m",      // Cyan
    .warning_color = "\x1b[35m",   // Magenta
    .error_color = "\x1b[31m",     // Red
};

Each log level can have a unique color scheme.

4. Diagnostics Custom Path

config.diagnostics_output_path = "./diagnostics/system_info.log";
config.logs_root_path = "./logs";
config.emit_system_diagnostics_on_init = true;

System information is logged with structured fields available for custom formats.

5. Highlighter Patterns and Alerts

config.highlighters = .{
    .enabled = true,
    .alert_on_match = true,
    .alert_min_severity = .warning,
    .log_matches = true,
};

Matches patterns in log messages and triggers alerts.

6. Combined Customizations

All features work together seamlessly:

var config_combined = logly.Config.default();
config_combined.logs_root_path = "./logs";
config_combined.diagnostics_output_path = "./logs/diagnostics.log";
config_combined.emit_system_diagnostics_on_init = true;

config_combined.format_structure = .{
    .message_prefix = "[APP] ",
    .field_separator = " | ",
    .enable_nesting = true,
};

config_combined.level_colors = .{
    .info_color = "\x1b[34m",
    .warning_color = "\x1b[33m",
    .error_color = "\x1b[31m",
};

config_combined.highlighters = .{
    .enabled = true,
    .alert_on_match = true,
    .log_matches = true,
};

const logger = try logly.Logger.initWithConfig(allocator, config_combined);

Expected Output

When you run the example, you'll see:

1. Section headers for each customization feature
2. Formatted log messages with custom prefixes, suffixes, and colors
3. Diagnostics information including OS, CPU, and memory details
4. File creation confirmation

Example console output:

=== Logly Customizations Example ===

1. Global Root Path Configuration
   Setting logs to be stored in './logs' directory

[2025-12-08 16:36:10.574] [INFO] Application started - logs stored in ./logs directory
[2025-12-08 16:36:10.575] [WARNING] This warning is saved to ./logs/application.log

2. Format Structure Customization
   Customizing log message format with prefix, suffix, and separators

>>> Message with custom format prefix and suffix <<<

3. Color Customization Per Level
   Setting custom colors for each log level

[2025-12-08 16:36:10.575] [INFO] Custom cyan info message
[2025-12-08 16:36:10.575] [WARNING] Custom magenta warning

Generated Files

The example creates the following directory structure:

./logs/
├── application.log      # From example 1
├── errors.log           # From example 1
└── combined.log         # From example 6

./diagnostics/
└── system_info.log      # From example 4 (if configured)

Each file contains the formatted log entries with custom colors (in ANSI format).

Customization Options Reference

Feature	Config Field	Purpose
Root Path	logs_root_path	Set directory for all file sinks
Format	format_structure	Customize message structure
Colors	level_colors	Per-level ANSI color codes
Diagnostics Path	diagnostics_output_path	Custom diagnostics file location
Highlighters	highlighters	Pattern matching & alerts

Use Cases

Development:

config.logs_root_path = "./dev_logs";
config.format_structure.message_prefix = "[DEV] ";
config.highlighters.enabled = true;

Production:

config.logs_root_path = "/var/log/myapp";
config.level_colors.critical_color = "\x1b[1;31m";
config.diagnostics_output_path = "/var/log/myapp/system.log";

Testing:

config.logs_root_path = "./test_output";
config.highlighters.log_matches = true;
config.emit_system_diagnostics_on_init = true;

Learning Resources

• Guide: See docs/guide/customizations.md for detailed usage
• API Reference: See docs/api/customizations.md for complete API docs
• Full Example: Check examples/customizations.zig for the complete source code