autotel
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Write Once, Observe Anywhere
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TypeScript
export { Logger as PinoLogger } from 'pino';
/**
* Zero-dependency structured logger for autotel
*
* This logger provides:
* - Structured JSON logging (production) or pretty print (development)
* - Auto trace context injection (traceId, spanId, correlationId)
* - Dynamic log level control (per-request via OTel context)
* - Level support (debug, info, warn, error, none)
* - Zero additional dependencies (uses @opentelemetry/api, already a dep)
*
* Uses Pino-compatible signature supporting both patterns:
* - `log.info('simple message')` - string-only
* - `log.info({ userId: '123' }, 'message')` - object first with optional message
*
* Used as the default fallback when users don't provide Pino/Bunyan.
* Can also be used directly: import { createBuiltinLogger } from 'autotel/logger'
*
* @example
* ```typescript
* import { createBuiltinLogger, runWithLogLevel } from 'autotel/logger';
*
* const log = createBuiltinLogger('my-service');
*
* // Simple message (no metadata)
* log.info('Server started');
*
* // With metadata (Pino-style: object first, message second)
* log.info({ userId: '123' }, 'User created');
* // Output: {"level":"info","service":"my-service","msg":"User created","userId":"123","traceId":"..."}
*
* // Dynamic log level per-request
* runWithLogLevel('debug', () => {
* log.debug('This will log even if default level is "info"');
* });
* ```
*/
type BuiltinLogLevel = 'debug' | 'info' | 'warn' | 'error' | 'none';
/**
* Get the active log level from context (if set)
* Falls back to undefined if no log level is set in context
*/
declare function getActiveLogLevel(): BuiltinLogLevel | undefined;
/**
* Run a function with a specific log level
* The log level is stored in OpenTelemetry context and applies to all logger calls within the callback
*
* @example
* ```typescript
* // Enable debug logging for a specific request
* runWithLogLevel('debug', () => {
* log.debug('This will be logged');
* processRequest();
* });
*
* // Disable logging temporarily
* runWithLogLevel('none', () => {
* log.info('This will NOT be logged');
* });
* ```
*/
declare function runWithLogLevel<T>(level: BuiltinLogLevel, callback: () => T): T;
/**
* Helper to get trace context (useful for BYOL - Bring Your Own Logger)
*
* @example
* ```typescript
* import bunyan from 'bunyan';
* import { getTraceContext } from 'autotel/logger';
*
* const bunyanLogger = bunyan.createLogger({ name: 'myapp' });
* const ctx = getTraceContext();
* bunyanLogger.info({ ...ctx, email: 'test@example.com' }, 'Creating user');
* ```
*/
declare function getTraceContext(): {
traceId: string;
spanId: string;
correlationId: string;
} | null;
interface BuiltinLoggerOptions {
/** Minimum log level. Default: 'info' */
level?: BuiltinLogLevel;
/** Pretty print for development. Default: false (JSON output) */
pretty?: boolean;
}
/**
* Create a lightweight structured logger
*
* @param service - Service name for logging
* @param options - Optional configuration
*
* @example
* ```typescript
* const log = createBuiltinLogger('user-service');
*
* log.info('Creating user', { email: 'test@example.com' });
* // Output: {"level":"info","service":"user-service","msg":"Creating user",
* // "email":"test@example.com","traceId":"...","spanId":"..."}
*
* // Dynamic log level control per-request
* runWithLogLevel('debug', () => {
* log.debug('This will be logged even if logger was created with level: "info"');
* });
* ```
*/
declare function createBuiltinLogger(service: string, options?: BuiltinLoggerOptions): Logger;
/**
* Pino-like factory function for creating an autotel logger
*
* @example
* ```typescript
* import { autotelLogger } from 'autotel/logger';
*
* const log = autotelLogger();
*
* // Simple message
* log.info('Server started');
*
* // With metadata (Pino-style: object first, message second)
* log.info({ userId: '123' }, 'User created');
*
* // With options
* const devLog = autotelLogger({ service: 'my-app', level: 'debug', pretty: true });
* ```
*/
declare function autotelLogger(options?: {
service?: string;
level?: BuiltinLogLevel;
pretty?: boolean;
}): Logger;
/**
* Logger types and utilities for autotel
*
* **Zero-Config Option:** Don't provide a logger to `init()` and autotel uses
* a built-in structured JSON logger with automatic trace context injection.
*
* **BYOL (Bring Your Own Logger):** Pass Pino or Bunyan to `init()` for
* automatic instrumentation with trace context and OTLP log export.
*
* ## Logger Signature
*
* Autotel v2.10+ uses **Pino's signature**: `logger.info({ metadata }, 'message')`.
*
* ### Backward Compatibility
*
* The built-in logger auto-detects legacy Winston-style calls and swaps arguments:
* ```typescript
* // Legacy (auto-detected and handled)
* logger.info('User created', { userId: '123' });
* // → Internally treated as: logger.info({ userId: '123' }, 'User created')
* // → Logs warning in development, works silently in production
* ```
*
* ### Recommended Usage
*
* ```typescript
* // ✅ Pino-style (preferred)
* logger.info({ userId: '123' }, 'User created');
*
* // ✅ Simple message (no metadata)
* logger.info('Server started');
* ```
*
* **Note:** If you BYOL (bring your own logger), it must use Pino signature.
* Winston and other `(message, meta)` loggers are NOT compatible.
* For Winston, use `@opentelemetry/instrumentation-winston` instead.
*
* @example Zero-config (uses built-in logger)
* ```typescript
* import { init } from 'autotel';
*
* init({ service: 'my-app' });
* // Internal logs: {"level":"info","service":"my-app","msg":"...","traceId":"..."}
* ```
*
* @example Using built-in logger directly
* ```typescript
* import { createBuiltinLogger, runWithLogLevel } from 'autotel/logger';
*
* const log = createBuiltinLogger('my-service');
*
* // Simple message (no metadata)
* log.info('Server started');
*
* // With metadata (Pino-style: object first, message second)
* log.info({ userId: '123' }, 'User created');
* // Output: {"level":"info","service":"my-service","msg":"User created","userId":"123","traceId":"..."}
*
* // Dynamic log level per-request
* runWithLogLevel('debug', () => {
* log.debug('Debug info for this request only');
* });
* ```
*
* @example Using Pino (recommended for production, auto-instrumented)
* ```typescript
* import pino from 'pino'; // npm install pino
* import { init } from 'autotel';
*
* const logger = pino({ level: 'info' });
* init({ service: 'my-app', logger });
*
* // Logs automatically include traceId/spanId and export via OTLP!
* logger.info({ userId: '123' }, 'User created');
* ```
*
* @example Using Bunyan (auto-instrumented, same signature as Pino)
* ```typescript
* import bunyan from 'bunyan'; // npm install bunyan @opentelemetry/instrumentation-bunyan
* import { init } from 'autotel';
* import { BunyanInstrumentation } from '@opentelemetry/instrumentation-bunyan';
*
* const logger = bunyan.createLogger({ name: 'my-app' });
* init({
* service: 'my-app',
* logger,
* instrumentations: [new BunyanInstrumentation()]
* });
* ```
*
* @example Custom logger (MUST use Pino-compatible signature)
* ```typescript
* // ⚠️ Your custom logger MUST accept (object, message?) signature
* const logger = {
* info: (extra, msg) => console.log(msg || '', extra),
* warn: (extra, msg) => console.warn(msg || '', extra),
* error: (extra, msg) => console.error(msg || '', extra),
* debug: (extra, msg) => console.debug(msg || '', extra),
* };
* init({ service: 'my-app', logger });
* ```
*
* @example BYOL helper: inject trace context into any logger
* ```typescript
* import bunyan from 'bunyan';
* import { getTraceContext } from 'autotel/logger';
*
* const bunyanLogger = bunyan.createLogger({ name: 'myapp' });
* const ctx = getTraceContext();
* bunyanLogger.info({ ...ctx, userId: '123' }, 'Creating user');
* ```
*/
/**
* Log level constants
*/
declare const LOG_LEVEL: {
readonly DEBUG: "debug";
readonly INFO: "info";
readonly WARN: "warn";
readonly ERROR: "error";
};
type LogLevel = (typeof LOG_LEVEL)[keyof typeof LOG_LEVEL];
/**
* Logger configuration (for reference - not needed with BYOL approach)
*/
interface LoggerConfig {
service: string;
level?: LogLevel;
pretty?: boolean;
redact?: string[] | false;
}
/**
* Pino-compatible log function signature
*
* Matches Pino's actual LogFn type which supports:
* - `(msg: string)` - simple string message
* - `(obj: object, msg?: string)` - object first with optional message
*
* @example
* ```typescript
* logger.info('User logged in');
* logger.info({ userId: '123' }, 'User created');
* logger.error({ err: error }, 'Operation failed');
* ```
*/
interface LogFn {
(msg: string): void;
(obj: Record<string, unknown>, msg?: string): void;
}
/**
* Simple logger interface - Pino/Bunyan-compatible
*
* Uses Pino's LogFn signature which supports both:
* - `logger.info('message')` - simple string message
* - `logger.info({ extra }, 'message')` - object first with optional message
*
* This is compatible with Pino, Bunyan, and any logger following this pattern.
*
* @example Using Pino (just works!)
* ```typescript
* import pino from 'pino';
* const logger = pino({ level: 'info' });
* init({ service: 'my-app', logger });
* ```
*
* @example Direct usage
* ```typescript
* logger.info('Simple message');
* logger.info({ userId: '123' }, 'User created');
* logger.error({ err: error }, 'Operation failed');
* ```
*/
interface Logger {
info: LogFn;
warn: LogFn;
error: LogFn;
debug: LogFn;
}
/**
* Alias for Logger interface (backwards compatibility)
* @deprecated Use Logger instead
*/
type ILogger = Logger;
interface LoggedOperationOptions {
/** Operation name for tracing (e.g., 'user.createUser') */
operationName: string;
}
/**
* TS5+ Standard Decorator for logging and tracing operations
* Uses TC39 Stage 3 decorator syntax
*
* This is the traditional per-method decorator approach.
* For zero-boilerplate solution, see @Instrumented class decorator.
*
* @example
* // Simple usage (Pino-style: object first, message second)
* class OrderService {
* constructor(private readonly deps: { log: Logger }) {}
*
* @LoggedOperation('order.create')
* async createOrder(data: CreateOrderData) {
* // ✅ Correct Pino-style logging
* this.deps.log.info({ orderId: data.id }, 'Creating order');
* }
* }
*
* // Advanced usage (future-proof for options)
* @LoggedOperation({ operationName: 'order.create' })
* async createOrder(data: CreateOrderData) { }
*/
declare function LoggedOperation(operationNameOrOptions: string | LoggedOperationOptions): <This, Args extends unknown[], Return>(originalMethod: (this: This, ...args: Args) => Promise<Return>, context: ClassMethodDecoratorContext<This, (this: This, ...args: Args) => Promise<Return>>) => (this: This, ...args: Args) => Promise<Return>;
export { type BuiltinLogLevel, type BuiltinLoggerOptions, type ILogger, LOG_LEVEL, type LogFn, type LogLevel, LoggedOperation, type LoggedOperationOptions, type Logger, type LoggerConfig, autotelLogger, createBuiltinLogger, getActiveLogLevel, getTraceContext, runWithLogLevel };