Check several different TCP/IP services for availability? - node.js

Question

Let's say I have a list of hostnames and ports, not all of which are HTTP related.
var config = {
"checks": [
{
"name": "NPM",
"hostname": "npmjs.com",
"port": 80
},
{
"name": "AWS",
"hostname": "aws.amazon.com",
"port": 443
},
{
"name": "RabbitMQ",
"hostname": "merry-butterfly.rmq.cloudamqp.com",
"port": 5671
}
]
}
What is an effective way to test that each of these services can be reached? My first thoughts were to use a typical telnet-like approach, I did this:
var telnet = require('telnet-client')
config.checks.forEach(function(check) {
var connection = new telnet()
var params = {
host: check.hostname,
port: check.port,
negotiationMandatory: false
}
connection.on('connect', function() {
connection.send('GET /', {
ors: '\r\n',
waitfor: '\n'
}, function(err, data) {
console.log(err, data);
connection.end()
})
})
connection.connect(params)
results.push(result);
});
The above seems to work, but I'm actually not sure what data to send to each individual services to get back a response that suggests the service is "reachable", I don't need to auth or do any operations with the service, just check that it can be reached. Additionally it raises an exception if the DNS is unreachable:
Error: getaddrinfo ENOTFOUND merry-butterfly.rmq.cloudamqp.com/api merry-butterfly.rmq.cloudamqp.com/api:443
What would be the appropriate way to handle the errors, and async test each of the entries in the list of "checks"?

Answer 1

Ping the host.
https://www.npmjs.com/package/ping
For example:
var ping = require('ping');
var hosts = ['192.168.1.1', 'google.com', 'yahoo.com'];
hosts.forEach(function(host){
ping.sys.probe(host, function(isAlive){
var msg = isAlive ? 'host ' + host + ' is alive' : 'host ' + host + ' is dead';
console.log(msg);
});
});