fh-logger

fh-logger

Enables a simple way of configuring and creating Bunyan loggers, configured with request serializers, including clustering information.

Install

npm install fh-logger

Usage

JavaScript object configuration

var fh_logger = require('fh-logger');
var logger = fh_logger.createLogger({name: 'first'});

This will produce a Bunyan logger that will have a request serializer, and will log to process.stdout.

String configuration

You can pass in a JSON string containing your logger configuration. This is useful if you define your logger configuration externally to your code, for example in a .json file:

{
  "name": "testing",
  "streams": [{
    "type": "file",
    "stream": "file",
    "path": "/path/to/testing.log",
    "level": "info"
  }, {
    "type": "stream",
    "src": true,
    "level": "trace",
    "stream": "process.stdout"
  }, {
    "type": "raw",
    "src": true,
    "level": "trace"
  }]
}

Create the logger passing in the string configuration read from the above file:

var fh_logger = require("fh-logger");
var logger = fh_logger.createLogger(stringConfig);

Testing

To run all the tests:

grunt mochaTest

Request Id logging

fh-loggger also exports express-compatible middleware to generate unique requestId and automatically include it in logging methods.

var fh_logger = require('fh-logger');

// must be called to setup the middleware
var logger = fh_logger.createLogger({
  name: 'first',
  requestIdHeader: 'X-SOME-HTTP-HEADER'
});
app.use(logger.requestIdMiddleware);
app.get('/', function(req, res) {
  console.log(req.requestId); // uuid
  console.log(logger.requestId); // uuid
  logger.info('some message'); // -> {msg: 'some message', requestId: 'some-uuid'}
  logger.info(logger.requestIdHeader) // -> {msg: 'X-SOME-HTTP-HEADER', requestId: 'some-uuid'}
})

By default it utilizes the 'X-FH-REQUEST-ID' header, this can be overridden by the configuration passed to createLogger as shown above

ensureRequestId

For logging inside callbacks that are supposed to display the requestId but for some reason do not, utilize the exported ensureRequestId({Function}):

logger.ensureRequestId(function asyncOperation(err, data){
  logger.error(err); // -> {req.reqId: 'some-uuid'}
});

For more information refer to the continuation-local-storage module docs