@faremeter/logs

A configurable logging abstraction with pluggable backends.

Installation

pnpm install @faremeter/logs

Features

• Unified logging interface across all packages
• Pluggable backends (console, logtape)
• Hierarchical logger naming
• Runtime backend swapping

API Reference

Functions

• shouldLog
• ConsoleBackend.debug
• configureApp
• getLogger

shouldLog

| Function | Type | | ----------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | shouldLog | (level: "trace" or "debug" or "info" or "warning" or "error" or "fatal", configuredLevel: "trace" or "debug" or "info" or "warning" or "error" or "fatal") => boolean |

ConsoleBackend.debug

| Function | Type | | ---------------------- | ----------------------------------------------------------- | | ConsoleBackend.debug | (message: string, context?: Context or undefined) => void |

configureApp

Initializes the global logging system.

Call this once at application startup to configure the log level and backend. If no backend is specified, logtape is used when available, otherwise falls back to console output.

| Function | Type | | -------------- | -------------------------------------------- | | configureApp | (args?: ConfigureAppArgs) => Promise<void> |

Parameters:

• args: - Configuration options for level and backend.

Examples:

await configureApp({ level: "debug" });

getLogger

Creates a logger for a specific subsystem.

The returned logger automatically adapts if the backend changes after creation (e.g., when {@link configureApp} is called later).

| Function | Type | | ----------- | --------------------------------------------------- | | getLogger | (subsystem: readonly string[]) => Promise<Logger> |

Parameters:

• subsystem: - Hierarchical category path for the logger.

Returns:

A logger instance scoped to the subsystem.

Examples:

const logger = await getLogger(["faremeter", "client"]);
logger.info("Client initialized", { version: "1.0.0" });

Constants

• LogLevels

LogLevels

| Constant | Type | | ----------- | ------------------------------------------------------------------ | | LogLevels | readonly ["trace", "debug", "info", "warning", "error", "fatal"] |

Interfaces

• Logger
• LoggingBackend
• ConfigureAppArgs

Logger

| Property | Type | Description | | -------- | ---- | ----------- |

LoggingBackend

Backend implementation for the logging system.

Backends handle log output destinations (console, file, external service) and can be swapped at runtime via {@link configureApp}.

| Property | Type | Description | | -------- | ---- | ----------- |

ConfigureAppArgs

Configuration options for initializing the logging system.

| Property | Type | Description | | --------- | ------------------------------------------------------------------------------ | ------------------------------------------------------------- | | level | "trace" or "debug" or "info" or "warning" or "error" or "fatal" or undefined | Minimum log level to emit. Defaults to "info". | | backend | LoggingBackend<BaseConfigArgs> or undefined | Backend implementation to use. Auto-detected if not provided. |

Types

• LogLevel
• Context
• LogArgs
• BaseConfigArgs

LogLevel

| Type | Type | | ---------- | ---------------------------- | | LogLevel | (typeof LogLevels)[number] |

Context

| Type | Type | | --------- | ------------------------- | | Context | Record<string, unknown> |

LogArgs

| Type | Type | | --------- | -------------------------------------- | | LogArgs | [message: string, context?: Context] |

BaseConfigArgs

| Type | Type | | ---------------- | --------------------- | | BaseConfigArgs | { level: LogLevel } |

Related Packages

• @faremeter/middleware - Server middleware
• @faremeter/facilitator - Facilitator server

License

LGPL-3.0-only