@krakenjs/beaver-logger

beaver-logger

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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.

$3

Queues a counter metric, helper wrapping logger.metric

`
logger.metricCounter({
namespace: "pp.team.product.feature",
event: "button_click",
dimensions: {
type: "paypal"
}
})
`

#### Using a namespace prefix

`
const logger = new Logger({...options, metricNamespacePrefix: "company.team.app"})

logger.metricCounter({
namespace: "product.feature",
event: "button_click",
})

// creates metric with namespace of
// company.team.app.product.feature
`

$3

Queues a gauge metric, helper wrapping logger.metric

`
logger.metricGauge({
namespace: "pp.team.product.feature",
event: "request_latency",
value: 100,
dimensions: {
method: "GET"
}
})
`

#### Using a namespace prefix

`
const logger = new Logger({...options, metricNamespacePrefix: "company.team.app"})

logger.metricGauge({
namespace: "product.feature",
event: "request_latency",
value: 100
})

// creates metric with namespace of
// company.team.app.product.feature
`

$3

Queues a metric. We suggest using the metricCount or metricGauge interface for better type safety and clearer intention in your code.

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 metric's dimensions whenever the logs are flushed

`javascript
$logger.addMetricDimensionBuilder(() => ({
token_used: true,
type: "user_id_token",
}));
`

$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

`mermaid
flowchart TD
A[Client-Side Log statement] --> B[beaver-logger/client]
B[beaver-logger/client] --> C[beaver-logger/server]
C[beaver-logger/server] --> D[your-custom-logger]
D[your-customer-logger] --> E[Backend 1]
D[your-customer-logger] --> F[Backend 2]
G[Server-Side Log statement] --> D[your-custom-logger]
``