createLogger() — fastify Function Reference

Architecture documentation for the createLogger() function in logger-factory.js from the fastify codebase.

Function javascript CoreKernel InstanceFactory calls 1

Entity Profile

CoreKernel→ InstanceFactory→ createLogger() — fastify Function Reference

Dependency Diagram

graph TD
  56538483_b07d_ce58_e660_069d1d5aa7d1["createLogger()"]
  70c4c824_7f74_0fe8_3d46_0407aa0eeae5["logger-factory.js"]
  56538483_b07d_ce58_e660_069d1d5aa7d1 -->|defined in| 70c4c824_7f74_0fe8_3d46_0407aa0eeae5
  95ccc80e_6854_d1b9_83d9_4d37bdbc7396["validateLogger()"]
  56538483_b07d_ce58_e660_069d1d5aa7d1 -->|calls| 95ccc80e_6854_d1b9_83d9_4d37bdbc7396
  style 56538483_b07d_ce58_e660_069d1d5aa7d1 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

lib/logger-factory.js lines 75–123

function createLogger (options) {
  if (options.logger && options.loggerInstance) {
    throw new FST_ERR_LOG_LOGGER_AND_LOGGER_INSTANCE_PROVIDED()
  }

  if (!options.loggerInstance && !options.logger) {
    const nullLogger = require('abstract-logging')
    const logger = nullLogger
    logger.child = () => logger
    return { logger, hasLogger: false }
  }

  const { createPinoLogger, serializers } = require('./logger-pino.js')

  // check if the logger instance has all required properties
  if (validateLogger(options.loggerInstance)) {
    const logger = createPinoLogger({
      logger: options.loggerInstance,
      serializers: Object.assign({}, serializers, options.loggerInstance.serializers)
    })
    return { logger, hasLogger: true }
  }

  // if a logger instance is passed to logger, throw an exception
  if (validateLogger(options.logger)) {
    throw FST_ERR_LOG_INVALID_LOGGER_CONFIG()
  }

  if (options.loggerInstance) {
    throw FST_ERR_LOG_INVALID_LOGGER_INSTANCE()
  }

  const localLoggerOptions = {}
  if (Object.prototype.toString.call(options.logger) === '[object Object]') {
    Reflect.ownKeys(options.logger).forEach(prop => {
      Object.defineProperty(localLoggerOptions, prop, {
        value: options.logger[prop],
        writable: true,
        enumerable: true,
        configurable: true
      })
    })
  }
  localLoggerOptions.level = localLoggerOptions.level || 'info'
  localLoggerOptions.serializers = Object.assign({}, serializers, localLoggerOptions.serializers)
  options.logger = localLoggerOptions
  const logger = createPinoLogger(options.logger)
  return { logger, hasLogger: true }
}