// Structured logging with configurable levels and context
export enum LogLevel {
ERROR = 'error',
WARN = 'warn',
INFO = 'info',
DEBUG = 'debug'
}
export interface LogEntry {
timestamp: string
level: LogLevel
message: string
context?: Record<string, unknown>
error?: {
name: string
message: string
stack?: string
}
}
export interface LoggerConfig {
minLevel: LogLevel
includeStackTraces: boolean
prettyPrint: boolean
enableDebug?: boolean
}
const LOG_LEVEL_PRIORITY: Record<LogLevel, number> = {
[LogLevel.ERROR]: 0,
[LogLevel.WARN]: 1,
[LogLevel.INFO]: 2,
[LogLevel.DEBUG]: 3
}
export class Logger {
private config: LoggerConfig
constructor(config: Partial<LoggerConfig> = {}) {
const minLevel =
config.enableDebug === true ? LogLevel.DEBUG : (config.minLevel ?? LogLevel.INFO)
this.config = {
minLevel,
includeStackTraces: config.includeStackTraces ?? true,
prettyPrint: config.prettyPrint ?? false,
enableDebug: config.enableDebug
}
}
error(message: string, context?: Record<string, unknown>, error?: Error): void {
this.log(LogLevel.ERROR, message, context, error)
}
warn(message: string, context?: Record<string, unknown>, error?: Error): void {
this.log(LogLevel.WARN, message, context, error)
}
info(message: string, context?: Record<string, unknown>): void {
this.log(LogLevel.INFO, message, context)
}
debug(message: string, context?: Record<string, unknown>, error?: Error): void {
this.log(LogLevel.DEBUG, message, context, error)
}
private log(
level: LogLevel,
message: string,
context?: Record<string, unknown>,
error?: Error
): void {
if (LOG_LEVEL_PRIORITY[level] > LOG_LEVEL_PRIORITY[this.config.minLevel]) {
return
}
const entry: LogEntry = {
timestamp: new Date().toISOString(),
level,
message
}
if (context && Object.keys(context).length > 0) {
entry.context = context
}
if (error) {
entry.error = {
name: error.name,
message: error.message
}
if (this.config.includeStackTraces && error.stack) {
entry.error.stack = error.stack
}
}
const output = this.config.prettyPrint ? JSON.stringify(entry, null, 2) : JSON.stringify(entry)
// biome-ignore lint/suspicious/noConsole: Logger intentionally outputs to stderr
console.error(output)
}
setConfig(config: Partial<LoggerConfig>): void {
this.config = {
...this.config,
...config
}
}
getConfig(): LoggerConfig {
return { ...this.config }
}
}
export const defaultLogger = new Logger()
export const log = {
error: (message: string, context?: Record<string, unknown>, error?: Error) =>
defaultLogger.error(message, context, error),
warn: (message: string, context?: Record<string, unknown>, error?: Error) =>
defaultLogger.warn(message, context, error),
info: (message: string, context?: Record<string, unknown>) =>
defaultLogger.info(message, context),
debug: (message: string, context?: Record<string, unknown>, error?: Error) =>
defaultLogger.debug(message, context, error)
}
