BunyanCWLogger

This library is used as a helper to bunyan and bunyan-cloudwatch to work together in an AWS Lambda environment.

Motivation

I write a lot of lambdas that require some form of customized logging to CloudWatch. I really liked bunyan-cloudwatch library but having to copy-paste code from project to project got annoying.

I wrote this tiny utility library that makes it very simply to configure your bunyan.

If you write a lot of lambdas and want to aggrigate their output into custom log groups on CloudWatch based on various attributes this library will help you make logging easy.

Usage

Attributes

Library permits you to specify the following attributes:

• logGroup - name of the log group you want to create (required)
• streamName - name of the stream you want this log to go to (required)
• arn - ARN of the lambda that wants to send data to CloudWatch (required)

Logging Information

The logs will be sent in the JSON format and will have the following content default:

• name - lambda name (from ARN)
• hostname - lambda qualifier (from ARN)
• node_env - node environment setting
• level - logging level The level is set based on environment. INFO in prod, DEBUG everywhere else.

Sample Logs:

{"name":"fnName","hostname":"dev","node_env":"dev","pid":1,"level":30,"data":{"hello":"world", 
"msg": "Sample log message", "src": { "file": "/var/task/resources/index.js", "line": 30 }, "v": 0}

Example

exports.handler = (event, context, callback) => {
    const BunyanCWLogger = require('bunyancwlogger');
    new BunyanCWLogger('group', 'stream', context.invokedFunctionArn).build();
     const logger = BunyanCWLogger.getInstance();
 
     logger.info({hello: 'world'}, 'Thest message');
     callback();
}