molindo-node-logger

A Node.js logger that integrates well with the Molindo infrastructure.

Features

Pretty prints messages in development mode.
Prints JSON messages in production mode.
Errors are printed to stderr, while all other levels are printed to stdout.
In development only infos, warnings and errors are printed, while in production all levels are printed.
If the process encounters an error, it will log it to the console before shutting down. unhandledRejection errors thrown from promises are logged as well.
Offers an express integration that logs HTTP requests, including the operationName in the case of GraphQL requests. Confidential headers like cookie or authorization are masked.
Uses the levels and level values from logback: ERROR (40000), WARN (30000), INFO (20000), DEBUG (10000), TRACE (5000).

Usage

import Logger from 'molindo-node-logger';

const logger = new Logger({ service: 'pizza-shop' });
logger.trace('Making a salami pizza …');
logger.debug('Adding salami …');
logger.info('Putting it in the oven …');
logger.warn("Don't forget to get it out in time …");
logger.error('Oh no, the pizza is burned!');

In production, printed JSON will look like this (except that it's not pretty printed):

{
  "service": "pizza-shop",
  "@timestamp": "2017-10-19T08:26:13.168Z",
  "level": "INFO",
  "level_value": 20000,
  "message": "Pizza is ready!"
}

Express integration

If you're running an express server, you can register the logger middleware to log HTTP requests. GraphQL requests get automatically detected and attached as meta.graphql, with properties operationName and the respective variables.

import express from 'express';
import Logger, { createLoggerMiddleware } from 'molindo-node-logger';

const server = express();

const logger = new Logger({ service: 'pizza-shop' });
server.use(createLoggerMiddleware({ logger }));

The size of meta.graphql.variables can sometimes grow too large to log effectively. To manage this, the createLoggerMiddleware() function provides a configurable parameter: maxGraphQLVariablesLength.

Configuration of `maxGraphQLVariablesLength`

Set maxGraphQLVariablesLength (default: 512), to set the maximum size of the meta.graphql.variables payload to be logged.
Set maxGraphQLVariablesLength to 0 to completely turn off logging for meta.graphql.variables.
Set maxGraphQLVariablesLength to -1 to include the complete meta.graphql.variables payload without size restrictions.