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      • ctx.logger

      A logging wrapper based on pino, providing high-performance structured JSON logs. It is recommended to use ctx.logger instead of console for easier log collection and analysis.

      Scenarios

      ctx.logger can be used in all RunJS scenarios for debugging, error tracking, performance analysis, etc.

      Type Definition

      logger: pino.Logger;

      ctx.logger is an instance of engine.logger.child({ module: 'flow-engine' }), which is a pino child logger with a module context.

      Log Levels

      pino supports the following levels (from highest to lowest):

      LevelMethodDescription
      fatalctx.logger.fatal()Fatal error, usually leading to process exit
      errorctx.logger.error()Error, indicating a failed request or operation
      warnctx.logger.warn()Warning, indicating potential risks or abnormal situations
      infoctx.logger.info()General runtime information
      debugctx.logger.debug()Debugging information, used during development
      tracectx.logger.trace()Detailed trace, used for deep diagnostics

      The recommended format is level(msg, meta): the message comes first, followed by an optional metadata object.

      ctx.logger.info('Block loading complete');
ctx.logger.info('Operation successful', { recordId: 456 });
ctx.logger.warn('Performance warning', { duration: 5000 });
ctx.logger.error('Operation failed', { userId: 123, action: 'create' });
ctx.logger.error('Request failed', { err });

      pino also supports level(meta, msg) (object first) or level({ msg, ...meta }) (single object), which can be used as needed.

      Examples

      Basic Usage

      ctx.logger.info('Block loading complete');
ctx.logger.warn('Request failed, using cache', { err });
ctx.logger.debug('Saving...', { recordId: ctx.record?.id });

      Creating a Child Logger with child()

      // Create a child logger with context for the current logic
const log = ctx.logger.child({ scope: 'myBlock' });
log.info('Executing step 1');
log.debug('Executing step 2', { step: 2 });

      Relationship with console

      It is recommended to use ctx.logger directly to obtain structured JSON logs. If you are accustomed to using console, the mappings are: console.log → ctx.logger.info, console.error → ctx.logger.error, console.warn → ctx.logger.warn.

      Log Format

      pino outputs structured JSON, where each log entry contains:

      • level: Log level (numeric)
      • time: Timestamp (milliseconds)
      • msg: Log message
      • module: Fixed as flow-engine
      • Other custom fields (passed via objects)

      Notes

      • Logs are structured JSON, making them easy to collect, search, and analyze.
      • Child loggers created via child() also follow the level(msg, meta) recommendation.
      • Some runtime environments (such as Workflows) may use different log output methods.
      • pino — The underlying logging library