beaver-logger

beaver-logger
------------

[![npm version][version-badge]][package]

[version-badge]: https://img.shields.io/npm/v/beaver-logger.svg?style=flat-square
[package]: https://www.npmjs.com/package/beaver-logger

Front-end logger, which will:

- Buffer your front-end logs and periodically send them to the server side
- Automatically flush logs for any errors or warnings

This is a great tool to use if you want to do logging on the client side in the same way you do on the server, without worrying about sending off a million beacons. You can quickly get an idea of what's going on on your client, including error cases, page transitions, or anything else you care to log!

Overview
---------

Setup

``javascript
var $logger = beaver.Logger({
url: '/my/logger/url'
});
`

Basic logging

$3

Queues a log. Options are debug, info, warn, error.

For example:

$logger.error('something_went_wrong', { error: err.toString() })

$3

Call this to attach general tracking information to the current page. This is useful if the data is not associated with a specific event, and will be sent to the server the next time the logs are flushed.

Advanced

$3

Attach a method which is called and will attach general information to the logging payload whenever the logs are flushed

`javascript
$logger.addMetaBuilder(function() {
return {
current_page: getMyCurrentPage()
};
});
`

$3

Attach a method which is called and will attach values to each individual log's payload whenever the logs are flushed

`javascript
$logger.addPayloadBuilder(function() {
return {
performance_ts: window.performance.now()
};
});
`

$3

Attach a method which is called and will attach values to each individual log's tracking whenever the logs are flushed

`javascript
$logger.addTrackingBuilder(function() {
return {
pageLoadTime: getPageLoadTime()
};
});
`

$3

Attach a method which is called and will attach values to each individual log requests' headers whenever the logs are flushed

`javascript
$logger.addHeaderBuilder(function() {
return {
'x-csrf-token': getCSRFToken()
};
});
`

$3

Flushes the logs to the server side. Recommended you don't call this manually, as it will happen automatically after a configured interval.


Installing
----------

- Install via npm

npm install --save beaver-logger

- Include in your project

`html

`

or

`javascript
let $logger = require('beaver-logger');
`


Configuration
-------------

Full configuration options:

`javascript
var $logger = beaver.Logger({

// Url to send logs to
url: '/my/logger/url',

// Prefix to prepend to all events
prefix: 'myapp',

// Log level to display in the browser console
logLevel: beaver.LOG_LEVEL.WARN,

// Interval to flush logs to server
flushInterval: 60 * 1000,

// Use sendBeacon if supported rather than XHR to send logs; defaults to false
enableSendBeacon: true,
});
`

Server Side
-----------

beaver-logger includes a small node endpoint which will automatically accept the logs sent from the client side. You can mount this really easily:

`javascript
let beaverLogger = require('beaver-logger/server');

myapp.use(beaverLogger.expressEndpoint({

// URI to recieve logs at
uri: '/api/log',

// Custom logger (optional, by default logs to console)
logger: myLogger,

// Enable cross-origin requests to your logging endpoint
enableCors: false
}))
`

Or if you're using kraken, you can add this in your config.json as a middleware:

`json
"beaver-logger": {
"priority": 106,
"module": {
"name": "beaver-logger/server",
"method": "expressEndpoint",
"arguments": [
{
"uri": "/api/log",
"logger": "require:my-custom-logger-module"
}
]
}
}
`

Custom backend logger
---------------------

Setting up a custom logger is really easy, if you need to transmit these logs to some backend logging service rather than just logging them to your server console:

`javascript
module.exports = {

log: function(req, level, event, payload) {

logSocket.send(JSON.stringify({
level: level,
event: event,
payload: payload
}));
}
}
``

Data Flow
---------

!Flow