Best practice for developing Node.js applications

Using environment variables

If a Node.js application accesses a resource, such as a TCP/IP port or URI or database, it is recommended to externalize the configuration of that resource using an environment variable. This allows different values to be specified when the application is deployed in development, test, and production environments.

PORT=8080

var httpPort = process.env.PORT

Graceful termination

When a CICS BUNDLE containing a Node.js application is DISABLED, CICS sends the signal SIGTERM to the Node.js process. This gives the Node.js application an opportunity to terminate gracefully. For example, by no longer accepting new connections, stopping persistent connections, completing outstanding requests, and finally closing files and connection to databases, and exiting. The application should terminate within the period specified by option NODEJSAPP_DISABLE_TIMEOUT.

Here's an example of handling the SIGTERM signal and closing an HTTP server:

var http = require('http');
var httpPort = process.env.PORT;
var process = require('process');

//create a server object
var server = http.createServer(
    function (request, response) {
        response.write('Hello World! PID:' + process.pid); //write a response to the client
        response.end(); //end the response
    }
);

process.on('SIGTERM',
    function () {
      server.close(
            function () {
                console.log('Received SIGTERM at ' + (new Date()));
            }
        );
    }
);

console.log("Started hello.js at " + (new Date()));
server.listen(httpPort);