pac-health-check

Check

Install

$ npm install pac-health-check

Usage

Health Check by Cron Job

var healthCheck = require('pac-health-check');
 
/* Sample configuration */
 const configuration = {
    cron: '* */5 * * * *',
    max_retry: 2,
    services: {
        api: [{
            name: 'localhost 304',
            url: 'http://localhost:' + port + '/304',
            method: 'GET',
            expectedStatusCode: "200|202|304"
        }, {
            name: 'localhost 200',
            url: 'http://localhost:' + port + '/200',
            method: 'GET',
            expectedStatusCode: 200
        }],
        mssql: [{
            user: "username",
            password: "password",
            server: "server",
            port: 123,
            database: "database",
            connectionTimeout: 2000
        }],
        cas: [{
            seeds: "seed ip",
            keyspace: "key space",
            username: "username",
            password: "password"
        }],
        zkp: [{
            connectionString: "<host>:<port>/<root>"
        }],
        kaf: [{
            connectionString: "<host>:<port>/<root>/<kafka root>"
        }]
    }
};
 
//Init job
var job = healthCheck.initJob(configuration)
 
// Wait 5000ms to let the job run
setTimeout(function () {
    var result = healthCheck.reportJob();
    console.log(JSON.stringify(result));
    //Stop the job
    job.stop();
}, 5000)
 

Healch Check on Demand

healthCheck.reportOnDemand(configuration)

It is recommended to set a ttl configuration.ttl (in seconds).
If ttl is set, healthCheck will leverage local cache.

var healthCheck = require('pac-health-check');
 
//Sample configuration
var configuration = {
    ttl: 600,
    services: {
        api: [{
            name: 'httpstat.us 202',
            url: 'http://httpstat.us/202',
            method: 'GET',
            expectedStatusCode: "200|204",
            noncritical: true
        }, {
            name: 'httpstat.us 200',
            url: 'https://httpstat.us/200',
            method: 'GET',
            expectedStatusCode: 200
        }
        ]
    }
};
 
healthCheck.reportOnDemand(configuration)
    .then(function (result) {
        console.log(JSON.stringify(result));
    })
    .catch(function (error) {
        console.log(error);
    });

Health Check Offline

var healthCheck = require('pac-health-check');
healthCheck.offline();

Once offline method is called:

• Both cron job and on demand request will stop perform actual health check. And health check cannont be resumed.
• Health check status is DOWN, previous report is still accessible. (on demand request caching subjects to ttl)

Specification

Common Configuration Object

RCO	Multitude	Property	Type	Description
C	0-1	cron	String	For health check by cron job flavor. Cron expression to run health check job(will run on init).
C	0-1	ttl	Number	For healch check on demand flavor. The time to live as number in seconds for local health check report cache. 0 = unlimited
O	0-1	max_retry	Number	Max retry to determine the application status is DOWN (critical dependency is DOWN). Default is 3.
R	1	services	Object	services config for running actaul health check.
R	1-N	→{service}	Array of Object	Health Check for Supported Services
C	0-1	→→noncritical	Boolean	If this service is critical. Optional, default is undefined/false.

Supported Services:

• api: Api Service
• mssql: Microsoft SQL Server Service
• cas: Cassandra Service
• zkp: Zookeeper Service
• kaf: kafka Service

Common Application Report Object

Property	Type	Description
status	String	Value is UP, DOWN, DEGRADED. Check Overall Status section for detail.
max_retry	Number	From max_retry property in configuration, Default is 3.
services	Object	Health check report in detail for each service in configuration.
→ {service}[index].status	String	Value is UP, DOWN. Check each service section of detail.
→ {service}[index].noncritical	Boolean	From configuration services.{service}[index].noncritical property

Overall Status

• status is UP, When services.{service}[index].status is UP in all services.

• status is DOWN, When any non noncritical servise services.{service}[index].status is DOWN.

• status is DEGRADED, only if any noncritical servise services.{service}[index].status is DOWN.

Service api

Configuration

RCO	Multitude	Property	Type	Description
R	1	name	String	Name of the API
R	1	url	String	Url for health check
R	1	method	String	Http method, only support GET for now.
O	1	services.api[index].expectedStatusCode	Number/String	Optional, accpet: Number(e.g.200); RegEx String(e.g."202|204"). Default value is "^[1-3][0-9]{2}$".

Report

Property	Type	Description
services.api[index].name	String	From configuration
services.api[index].url	String	From configuration
services.api[index]. method	String	From configuration
services.api[index].status	String	Check Api Status
services.api[index].expectedStatusCode	String	From configuration.
services.api[index].currentStatusCode	Number	Actaul http status from response.

Api Status

• report.api[index].status is UP by default.

• report.api[index].status is DOWN, when health check result actualStatusCode is not matching expectedStatusCode.

Service mssql

Configuration

RCO	Multitude	Property	Type	Description
R	1	server	String	Mssql Server hostname or IP
R	1	port	Number	Mssql Server port
R	1	database	String	Mssql database
C	1	user	String	Mssql username
C	1	password	String	Mssql password
O	1	connectionTimeout	Number	Optional, in miliseconds, default is 15000

Report

Property	Type	Description
services.mssql[index].server	String	From configuration
services.mssql[index].database	String	From configuration
services.mssql[index].status	String	Value is UP by default, DOWN when cannot connect to MsSql.

Service cas

Configuration

RCO	Multitude	Property	Type	Description
R	1	seeds	String	Cassandra seeds
R	1	keyspace	Number	Cassandra keyspace
C	1	username	String	username
C	1	password	String	password

Report

Property	Type	Description
services.cas[index].seeds	String	From configuration
services.cas[index].keyspace	String	From configuration
services.cas[index].status	String	Value is UP by default, DOWN when cannot connect to Cassandra.

Service zkp

Configuration

RCO	Multitude	Property	Type	Description
R	1	connectionString	String	Zookeeper connection string. E.g. <host>:<port>/<root>

Report

Property	Type	Description
services.zkp[index].connectionString	String	From configuration
services.zkp[index].status	String	Value is UP by default, DOWN when cannot connect to Zookeeper.

Service kaf

Configuration

RCO	Multitude	Property	Type	Description
R	1	connectionString	String	Kafka connection string. E.g. <host>:<port>/<root>/<kafka root>

Report

Property	Type	Description
services.kaf[index].connectionString	String	From configuration
services.kaf[index].status	String	Value is UP by default, DOWN when cannot connect to Kafka.

Sample Report

Heath Check

{
    "status": "UP",
    "max_retry": 3,
    "api": [{
        "name": "localhost 304",
        "url": "http://localhost:9999/304",
        "method": "GET",
        "expectedStatusCode": "200|202|304",
        "currentStatusCode": 304,
        "noncritical": true,
        "status": "UP"
    }, {
        "name": "localhost 200",
        "url": "http://localhost:9999/200",
        "method": "GET",
        "expectedStatusCode": 200,
        "currentStatusCode": 200,
        "status": "UP"
    }],
    "mssql": [{
        "server": "10.1.1.1",
        "database": "Access",
        "status": "UP"
    }],
    "cas": [{
        "seeds": "10.1.1.2",
        "keyspace": "dev_def",
        "status": "UP"
    }],
    "zkp": [{
        "connectionString": "10.1.1.3:2181/dev",
        "status": "UP"
    }],
    "kaf": [{
        "connectionString": "10.1.1.4:2181/dev/kafka",
        "status": "UP"
    }]
}

Heath Check Offline

{
    "status": "DOWN",
    "max_retry": 2,
    "api": [{
        "name": "localhost 202",
        "url": "http://localhost:9999/202",
        "method": "GET",
        "expectedStatusCode": 202,
        "currentStatusCode": 202,
        "status": "UP"
    }, {
        "name": "localhost 202 2",
        "url": "http://localhost:9999/202",
        "method": "GET",
        "expectedStatusCode": 202,
        "currentStatusCode": 202,
        "status": "UP"
    }],
    "mssql": [{
        "server": "10.231.22.213",
        "database": "Access",
        "status": "UP"
    }, {
        "server": "10.231.22.212",
        "database": "Access",
        "status": "UP"
    }],
    "cas": [{
        "seeds": "10.231.23.40",
        "keyspace": "dev_def",
        "status": "UP"
    }, {
        "seeds": "10.231.23.41",
        "keyspace": "dev_def",
        "status": "UP"
    }],
    "zkp": [{
        "connectionString": "dev-usw-r1-def-h1:2181/dev",
        "status": "UP"
    }, {
        "connectionString": "dev-usw-r2-def-h2:2181/dev",
        "status": "UP"
    }],
    "kaf": [{
        "connectionString": "dev-usw-r1-def-h1:2181/dev/kafka",
        "status": "UP"
    }, {
        "connectionString": "dev-usw-r2-def-h2:2181/dev/kafka",
        "status": "UP"
    }],
    "offline": true
}

Test

Test Coverage

File	% Stmts	% Branch	% Funcs	% Lines	Uncovered Line #s
All files	100	97.41	100	100
src	100	95	100	100
→ consts.js	100	100	100	100
→ healthcheck.js	100	94.44	100	100	66,96,99
src/component	100	100	100	100
→ api.js	100	100	100	100
→ cas.js	100	100	100	100
→ kaf.js	100	100	100	100
→ mssql.js	100	100	100	100
→ zkp.js	100	100	100	100