BitLogger

BitLogger is a structured logging library for MoonBit projects.

• Mooncake package page
• Chinese README

Overview

BitLogger gives you consistent levels, targets, structured fields, configurable text output, native file logging, and an async logging layer.

Quick Start

let logger = build_logger(
  text_console(
    min_level=Level::Info,
    target="demo",
    text_formatter=TextFormatterConfig::new(show_timestamp=false, separator=" | "),
  ),
)

logger.info("starting", fields=[field("port", "8080")])
ignore(logger.flush())

Start with console(...), json_console(...), text_console(...), or file(...), then add with_queue(...) or with_file_rotation(...) only when needed.

Use Logger::new(...) when you want to assemble custom sink graphs directly.

Support Status

• Current local verification covers native, js, wasm, and wasm-gc for the main src package and src-async
• llvm is still treated as experimental in the current release context and was not locally re-verified in the current environment
• The source packages still declare wasm support alongside native, llvm, js, and wasm-gc; see target-verification.md for the current release-facing verification boundary
• File output is a native capability; check native_files_supported() in cross-target code
• src-async is available, while examples/async_basic is still shipped as a native entry example

Main Features

• Structured logs with levels, targets, messages, and fields
• Multiple outputs: console, JSON console, text console, and file
• Custom text formatting with templates, style tags, and color control
• Config-based builders: build_logger(...) and build_async_logger(...)
• Composition helpers: queue, filter, patch, fanout, split, callback
• Separate async package under src-async

Examples

• examples/console_basic/: minimal console and JSON console example
• examples/text_formatter/: text formatting and template example
• examples/style_tags/: style tags and colored output example
• examples/config_build/: config-based build example
• examples/presets/: common preset combinations
• examples/file_rotation/: native file logging and rotation example
• examples/async_basic/: async logging example

Documentation

• API index: canonical API reference, organized as one public API per file
• src package README: package-level usage notes and target reminders
• docs/changes/: versioned release notes and publish-facing change summaries
• docs/dev/: developer reference material kept in the repository, intentionally excluded from the public static docs site

Common entry points: text_console(...), file(...), with_queue(...), build_logger(...), build_async_logger(...)