Firebase logger - Get your (mobile) app logs remotely

This library allows you to log data from a web or mobile app to a Firebase Realtime Database, to be able to debug and monitor remotely.

Compatibility:

Firebase version	@firebase-logger version
<9	1.x.x
>=9	>=2.x.x

✨ Features

• Save logs to a Firebase Realtime Database
• Logs locally in development mode and remotely in production mode
• Remote and reactive triggerable log level to prevent logs' flooding
• Supports firebase and ReactNative firebase SDKs
• Save logs to a user-specific path, to easily find user's logs

🗒️ Table of contents

• Firebase logger - Get your (mobile) app logs remotely
  • Features
  • Get started
    • Firebase SDK
      • Install the package
      • Prepare Firebase
      • Initialize the logger
      • It's ready, log messages
    • ReactNative SDK
  • API
    • init
    • log
  • Samples

Get started

Depending on the SDK you want to use, read the Firebase SDK section or the ReactNative SDK section below.

Firebase SDK

Please note that Javascript SDK can also be used with ReactNative.

Install the package

npm i @firebase-logger/core @firebase-logger/web or yarn add @firebase-logger/core @firebase-logger/web

Prepare Firebase

If you already have a Firebase setup in your project, you can skip this part.

1. Create a Firebase project
2. Create the database with open rules (you can replace them later on with the example rules in the code samples)
3. Add an app to your project (get help here)
4. Get the config and initialize Firebase in your code:

import firebase from "firebase/app";

if (!firebase.apps.length) {
  firebase.initializeApp(FIREBASE_CONFIG);
}

5. Finally, don't forget to create the logger in database that will contain the log level, for instance, add this to the database:

{
  "loggers": {
    "production": {
      "level": "ERROR"
    }
  }
}

Initialize the logger

import logger from "@firebase-logger/web";

logger.init(process.env.NODE_ENV === 'production');

It will initialize the logger that will log remotely only in production mode, under the logs/main path, using the loggers/main You can re-initialize the logger as soon as the user is authenticated to prevent logging everything in the anonymous path, but in the user-specific path. Learn more in the code samples

It's ready, log messages

It can be used like the standard console object.

import logger from '@firebase-logger/web'

logger.debug('Hello world');
logger.info('Hello world', 42);
logger.warn({ title: 'Hello', subtitle: 'World' });
logger.error(error);
logger.critical('Something bad happened');

ReactNative SDK

🚧 This part is currently in development

API

init

Parameter	Required	Default value	Usage
shouldLogRemotely	No	true	Logs to Firebase only if set to true, otherwise, uses the standard console methods like console.error
getUserId	No	async () => 'anonymous'	A function that returns a promise containing the user identifier as a string or a number
databaseLoggerPathOrNull	No	'loggers/main'	The database path to the logger data. Note that this is where the log level is defined (see the sample data)
databaseLogsCollectionOrNull	false	'logs/main'	The database path to the logs. It gets created automatically when logging

log

You can use the following methods to log information:

Method	Logs when log level is
debug	DEBUG
info	DEBUG, INFO
warn	DEBUG, INFO, WARN
error	DEBUG, INFO, WARN, ERROR
critical	DEBUG, INFO, WARN, ERROR, CRITICAL

All these methods accept as many arguments as you want to provide them.

Samples

Logger initialization with userId

const onUserAuthenticated = () => {
  logger.init(
    process.env.NODE_ENV === 'production',
    () => AsyncStorage.getItem('@myApp/userEMail'), // can return a promise
    'loggers/production',
    'logs/production'
  );
}

Example database rules

{
  "rules": {
    "loggers": {
      ".read": true,
      ".write": false
    },
    "logs-dev": {
      ".read": false,
      ".write": true
    },
    "logs-staging": {
      ".read": false,
      ".write": true
    },
    "logs-prod": {
      ".read": false,
      ".write": true
    }
  }
}

Example loggers sample

{
  "loggers": {
    "dev": {
      "level": "WARN"
    },
    "staging": {
      "level": "CRITICAL"
    },
    "prod": {
      "level": "CRITICAL"
    }
  }
}