Zenvia Logger for Node.js

A wrapper for Winston Logging Node.js library that formats the output on STDOUT as Logstash JSON format. Since version 1.5.0 it is possible to use log tracking. Zenvia Logger uses the cls-trace to perform the tracking

Installation

npm install @zenvia/logger

Environment Variables

The following environment variables can be used for increase the log information:

• APP_NAME: value to filled the "application" field in the output JSON. If empty, the name attribute on package.json will be used instead.
• NODE_ENV: value to filled the "environment" field in the output JSON.
• HOST or HOSTNAME: value to filled the "host" field in the output JSON.
• LOGGING_LEVEL: set the level of messages that the logger should log. Default to DEBUG.
• LOGGING_FORMATTER_DISABLED (version 1.1.0 and above): When true, the output logging will not be formatted to JSON. Useful during development time. Default to false.
• LOGGING_FRAMEWORK_MIDDLEWARE (version 1.5.0 and above): Value that defines which middleware will be used. It is possible to choose between the middlewares: EXPRESS, FASTIFY, HAPI and KOA. If empty, the middleware default is EXPRESS.
• LOGGING_TRACE_HEADER (version 1.5.0 and above): Value indicating the header name that must be obtained from the traceId value in the request. Default is X-TraceId.

Basic Usage (Express users)

// ES6 or Typescript
import express from 'express';
import logger, { traceMiddleware } from '@zenvia/logger';

const app = express();
app.use(traceMiddleware);

logger.info('some message');

Basic Usage (FASTIFY users)

// ES6 or Typescript
import fastify from 'fastify'
import logger, { traceMiddleware } from '@zenvia/logger';

fastify.register(traceMiddleware);

logger.info('some message');

Basic Usage (KOA users)

// ES6 or Typescript
import Koa from 'koa';
import logger, { traceMiddleware } from '@zenvia/logger';

const app = new Koa();
app.use(traceMiddleware);

logger.info('some message');

Basic Usage (HAPI users)

// ES6 or Typescript
import Koa from 'koa';
import logger, { traceMiddleware } from '@zenvia/logger';

const init = async () => {
  const server = Hapi.server({
    port: 3000,
    host: 'localhost'
  });

  await server.register({
    plugin: traceMiddleware
  });
}

logger.info('some message');

Output:

{
  "@timestamp": "2018-06-05T18:20:42.345Z",
  "@version": 1,
  "application": "application-name",
  "message": "some message",
  "level": "INFO",
  "traceID": "123e4567-e32b-12d3-a432-626614174888"
}

Available logging levels

The log levels are as follows.

• fatal
• error
• warn
• info
• debug

For backward compatibility purposes, "verbose" and "silly" levels will behave the same as "debug" level.

Adding extra key/value fields

logger.debug('Some text message', { keyA: 'value A', keyB: 'value B' });

Output:

{
  "keyA": "value A",
  "keyB": "value B",
  "@timestamp": "2018-06-05T22:04:42.039Z",
  "@version": 1,
  "application": "application-name",
  "message": "Some text message",
  "level": "DEBUG"
}

Logging errors

logger.error('Ops!', new Error('Something goes wrong'));

Output:

{
  "message": "Ops!: Something goes wrong",
  "@timestamp": "2018-06-05T22:14:09.683Z",
  "@version": 1,
  "application": "application-name",
  "level": "ERROR",
  "stack_trace": "Error: Something goes wrong\n    at repl:1:34\n    at Script.runInThisContext (vm.js:91:20)\n    at REPLServer.defaultEval (repl.js:317:29)\n    at bound (domain.js:396:14)\n    at REPLServer.runBound [as eval] (domain.js:409:12)\n    at REPLServer.onLine (repl.js:615:10)\n    at REPLServer.emit (events.js:187:15)\n    at REPLServer.EventEmitter.emit (domain.js:442:20)\n    at REPLServer.Interface._onLine (readline.js:290:10)\n    at REPLServer.Interface._line (readline.js:638:8)"
}

Due to limitations of winston lib, when a text, an error and extra key/value fields are logged at once, the output message field will contain the text message, the error message and the full stack trace as shown.

logger.fatal('Ops!', { new Error('Something goes wrong'), { keyA: 'value A', keyB: 'value B' } });

Output:

{
  "keyA": "value A",
  "keyB": "value B",
  "@timestamp": "2018-06-05T22:09:22.750Z",
  "@version": 1,
  "application": "application-name",
  "message": "Ops! Error: Something goes wrong\n    at repl:1:34\n    at Script.runInThisContext (vm.js:91:20)\n    at REPLServer.defaultEval (repl.js:317:29)\n    at bound (domain.js:396:14)\n    at REPLServer.runBound [as eval] (domain.js:409:12)\n    at REPLServer.onLine (repl.js:615:10)\n    at REPLServer.emit (events.js:187:15)\n    at REPLServer.EventEmitter.emit (domain.js:442:20)\n    at REPLServer.Interface._onLine (readline.js:290:10)\n    at REPLServer.Interface._line (readline.js:638:8)",
  "level": "FATAL"
}

Using trace logs

From version 1.5.0 it is possible to track logs. To do traceability, the cls-rTrace package is used. To use it, just add the middleware in the framework you are using. In this way it is possible to propagate the traceId received in a request to the logs throughout your project. If no traceId is passed in the request, Zenvia Logger generates a random traceId for the request being processed.

Request example sending traceId:

curl 'http://localhost/your-application' \
--header 'X-TraceId: dbcdd40e-10cd-40a7-b912-1b0a17483d67' \

Log

logger.info('message with traceID');

Log Output

{
  "@timestamp": "2018-06-05T18:20:42.345Z",
  "@version": 1,
  "application": "application-name",
  "message": "message with traceID",
  "level": "INFO",
  "traceID": "dbcdd40e-10cd-40a7-b912-1b0a17483d67'"
}

Request example without sending traceId:

curl 'http://localhost/your-application'

Log

logger.info('message without traceID');

Log Output

{
  "@timestamp": "2018-06-05T18:20:42.345Z",
  "@version": 1,
  "application": "application-name",
  "message": "message with traceID",
  "level": "INFO",
  "traceID": "912c029c-c38f-49e7-9968-e575c5108178'"
}

License

MIT