health

Health

Health is a resource status monitoring library.

This is handy when you want to monitor the status of multiple resources using a simple configuration file. For example, if your application requires a web service and a MongoDB database to be available, Health module can monitor those resources and return status ok/fail against each resource along with the response time.

It also supports result caching via ttl attribe of each resource, which is handy when you want to monitor multiple resources at a different interval or to reduce the load on certain resources.

Installation

npm install -g health 

Usage

// use default formatter
var health = new (require('health'))(
  setup: [ { name: 'google', uri: 'http://google.com' } ]
);

// use built-in formatter (html, text, or xml)
var health = new (require('health'))(
  setup: [ { name: 'google', uri: 'http://google.com' } ],
  formatter: 'html'
);

// use custom formatter function
var health = new (require('health'))(
  setup: [ { name: 'google', uri: 'http://google.com' } ],
  formatter: function (results) {
    return results.join('|');
  }
);

// check resources
health.check(function (err, result) {
});

From command-line:

health -f html -s health.json check

Configuration

Health setup is just a simple JSON:

[
  { "name": "google", "uri", "http://google.com", "statusCodes": [ 200 ] },
  { "name": "gmail", "uri", "https://mail.google.com", "timeout": "1000" },
  { "name": "mongodb", "uri": "mongodb://somehost:27017", "timeout": 200, "ttl": 30000 }
]

Attribute	Type	Description	Protocol	Usage	Default	Example
uri	string	Resource URI to check	All	Mandatory		mongodb://somehost:27017
name	string	Resource name	All	Optional		someapp
ttl	number	Cache time to live in milliseconds	All	Optional		30000
lenient	boolean	Replace fail or error with warning	All	Optional	false	true, false
group	string	Resource group name, status is set to warning when there's at least one group member having success/warning status, group members status is set to fail/error only when none of the group members has success/warning status	All	Optional		databases, apps, datacenter1
timeout	number	Request/connect timeout in milliseconds	http, https, mongodb	Optional		500
statusCodes	array	An array of acceptable response HTTP status codes, any match means status OK	http, https	Optional		[ 200, '3xx', 409 ]
texts	array	An array of all texts that must exist in response body, any of them does not exist means status FAIL	http, https	Optional		[ 'foo', 'bar' ]