Debugging

Lucid emits the db:query event when debugging is enabled globally or for an individual query.

You can enable debugging globally by setting the debug flag to true inside the config/database.ts file.

{
  client: 'pg',
  connection: {},
  debug: true, // 👈
}

You can enable debugging for an individual query using the debug method on the query builder.

Database
  .query()
  .select('*')
  .debug(true) // 👈

Database
  .insertQuery()
  .debug(true) // 👈
  .insert({})

Database
  .rawQuery('select * from users')
  .debug(true) // 👈

Listening to the Event

Once you have enabled debugging, you can listen for the db:query event using the Event module.

import Event from '@ioc:Adonis/Core/Event'

Event.on('db:query', function ({ sql, bindings }) {
  console.log(sql, bindings)
})

Pretty print queries

You can use the Database.prettyPrint method as the event listener to pretty-print the queries on the console.

import Event from '@ioc:Adonis/Core/Event'
import Database from '@ioc:Adonis/Lucid/Database'

Event.on('db:query', Database.prettyPrint)

Debugging in production

Pretty printing queries add additional overhead to the process and can impact the performance of your application. Hence, we recommend using the Logger to log the database queries during production.

Following is a complete example of switching the event listener based upon the application environment.

import Event from '@ioc:Adonis/Core/Event'
import Database from '@ioc:Adonis/Lucid/Database'

import Logger from '@ioc:Adonis/Core/Logger'
import Application from '@ioc:Adonis/Core/Application'

Event.on('db:query', (query) => {
  if (Application.inProduction) {
    Logger.debug(query)    
  } else {
    Database.prettyPrint(query)
  }
})

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