#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):

#Recommended Usage

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.

#Related

• pino — The underlying logging library