Networking: Changing the Hostname in Linux

 When you are planning and configuring your server farm, one of the most common task will probably be changing your server names to fit your organization's naming convention.  In this post we are going to change one of our Linux hostname with the hostnamectl command.  Here are the steps to change your Linux hostname.

1.  Open a terminal session on the host that you want to change the hostname, then type the command hostnamectl the hostname information will be displayed, as you can see the hostname is currently localhost.localdomain

2.  Let's see we want to change the name of the server to dc.acmebanking.com because this is the server for our company ACME Banking Inc.  and we want this server to be the domain controller hence the letters dc. to label it as the domain controller.  Some people like to be creative and use movie characters or attractions as the server names.  It's a matter of preference, but I like to look at a server name and know exactly what it's for.  But it's really up to you.

3. Now what you want to do is type in the following command, to change the hostname

hostnamectl set-hostname 'dc.acmebanking.com'

4. Type hostnamectl again to verify that the hostname has been changed

Azure In Depth Pt 3: Create a Windows Server 2016 Virtual Machine

Now that we have our virtual network and subnet setup in Azure, the next thing we want to do is create a Windows Server virtual machine.  A virtual machine is a great way to learn Azure because it's a fixed cost.  You can try different things without paying anything extra, also most of the promotional deals that Microsoft gives you should be more than enough to cover your costs for the virtual machine.

The following steps is how you would create a Windows 2016 Server in the Azure Portal:

1. Log into Azure Portal, and mouse over "Virtual Machines", click on "Create"

Azure In Depth Pt. 2: Create A Virtual Network And Subnet

In the previous blog post we created a "Resource Group", in this post we are going to create a "Virtual Network" in that resource group so that we have more control over four Azure network settings.  Azure actually creates a virtual network for us automatically, but we want to have more control over our Azure infrastructure.

The following is how you would create a "Virtual Network" in Azure.

1. Search for "Virtual Network" and click on "Virtual Network", mouse over and click on "Create"

Azure In Depth Pt. 1: Create a Resource Group

The first thing you want to create after you have an Azure account is to create a "Resource Group"  as "Resource Group" as the name implies is an Azure Resource Group, groups all of your resources in a single group so that it's easily managed.

The following steps is how you would create a "Resource Group" in the Azure Portal.

1. Log into Azure portal, and click on "Resource Group" or "More Services" depending on your UI

AngularJS SPA: Show Bank Accounts With $scope and Controller

In our last post we created our business entities, in this post we are going to use our business objects to display information to the users.  I this post we are going to show the accounts to the users.  In the previous posts we have been setting up the environment the plumbing sort of speak.  Starting now we are going to build the application.  The first thing we want to do is counter-intuitive, we are going to take the database out of the equation and start using mock data to get so that we can see how our application will run.

In our previous post we created some user stories.  In this post we are going to work on one of the stories:

• As a user I should be able to view my accounts. (2 pts)

It's a simple process, but we know exactly what we have to do with user stories.  It's a different mindset than the traditional requirements.  The typical requirement that you are used to seeing is

1.1.1 System shall allow the user to view his/her accounts

It's basically saying the same thing, but the first one the user stories is in plain English and it's a lot easier to comprehend.  You can take it to the business user, the web designer, or the web developer and it's easily understood.  That's the benefit of Agile development. 

First let's take the Iffe out of the account.js file so that it's easier to work with and then we want to make changes to the bankController.js file

Here is how the account.js file should now look like.

function Account(balance, type) {
    this.balance = balance;
    this.type = type;
}

Account.prototype.deposit = function (d) {

    this.balance = this.balance + d;
    return this.balance;
}

Account.prototype.withdrawal = function (w) {
    this.balance = this.balance - w;
    return this.balance;
}


function inherits(baseClass, childClass) {
    childClass.prototype = Object.create(baseClass.prototype);
}

function Premium(balance, type) {
    this.balance = balance + (balance * .05);
    this.type = type;
}


inherits(Account, Premium);

Premium.prototype.transfer = function (from, to, amount) {
    from.balance -= amount;
    to.balance += amount;
    from.rebalance();
    to.rebalance();
}

Premium.prototype.deposit = function (d) {
    this.balance = this.balance + d;
    this.balance = this.balance + (this.balance * .05);
    return this.balance;

}
Premium.prototype.rebalance = function () {
    this.balance += this.balance * .05;
}

Here is the code we change in the bankController.js file

(function () {
    'use strict';

    angular.module('bankController', [])
        .controller('bankController', ["$scope", function ($scope) {
            $scope.accounts = [new Account(1000, 'Checking'), new Account(10000, 'Saving'), new Premium(100000, 'Premium Checking')];
            console.log($scope.accounts);
        }]);

})();

AngularJS SPA: Agile Development With User Stories

In our previous post we created some mockups, now we are going to create some user stories so that we can started development with some idea of what should be included in the application.  This is just a quick planning session.

We'll pretend like we are running a Sprint, we can think of this as a very loose Sprint planning.

Sprint 1 User Stories;

• As a user I should be able to view my accounts. (2 pts)
• As a user I should be view my user profile. (1 pt)
• As a user I should be able to view my account details. (2 pts)
• As a user I should be able to view my past transactions. (1 pt)
• As a user I should be able to view my upcoming transactions ( 1 pt)
• As a user I should be able to search my transactions (2 pts)

AngularJS SPA: ACME Bank Mockups

In the previous post we created the JavaScript business objects in our AngularJS application.  While that's great and all we should we really take a step back create some rough mockups of our banking application so that we will know what we will be building.

First let's mock up the home page:























On our home page we have a profile section were we can access our account/profile. Then we have the ACME bank logo/branding, and finally the accounts that we have in the bank.

The next mock-up is the the Accounts Details page, when we click on one of the accounts:





























As you can see from the mock-up it's pretty straightforward.  You have an identification of the account, then a display of upcoming  transactions, and past transactions.  There's also a search box for searching of transactions.

Finally we have the Money Transfer screen which enables the users to transfer money into and out of the account.  It just has the basic information, where the money is coming from, where it's going to, the transfer date, the amount and the transfer button.




















As you can see the mock-up is pretty simple and easy to change.  Actually it's just pen and paper.  I am a big fan of low-fidelity design.  Meaning simple and low effort.  We can change it anytime.

Previous: AngularJS SPA: Building The Bank Application JavaScript Objects (Business Entities)

Hour 18 Asp.Net Core: Create A Web API For NorthwindCafe With Postman

In the last few posts we have been working with our models and retrieving the data natively in the application, but most of the project you will work with in real life will probably have you call some kind of api with an endpoint.  In this post we are going to substitute the products call what we made with an api.

Here are steps to create our first Api:

1. First we want to set up our application to use postman to test out our api. To do that right-click on the project and click on "Properties", in Properties screen click on "Debug" and uncheck "Launch browser" and make a note of the port number of the App URL.  We will make the api calls with postman initially to make sure that our api works.  Postman has become pretty popular with api development because it allows us to make api calls and see the results.  You can get postman here

https://www.getpostman.com/downloads/ I would get the desktop version because it's more robust.





















2. Now we are ready to create a ProductController to be our api controller, Asp.NET Core has the api control built-in so we don't have to do anything special for a controller to be a web api controller. So create a file call ProductController in the Controllers folder.  The ProductController should have the following code

using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;
using NorthwindCafe.Web.Data;
using System;

namespace NorthwindCafe.Web.Controllers
{
    [Route("api/[Controller]")]
    public class ProductController : Controller
    {
        private readonly  IProductRepository _repository;
        private readonly  ILogger _logger;

        public ProductController(IProductRepository repository, ILogger logger)
        {
            _repository = repository;
            _logger = logger;
        }

        [HttpGet]
        public IActionResult Get()
        {
            try
            {
                return Ok(_repository.GetProducts());
            }
            catch (Exception ex)
            {
                _logger.LogError($"Get products failed {ex}");
                return BadRequest("Get products failed");
            }
        }
    }
}

The code above is pretty straightforward.  You have the define private variables _repository and _logger for the repository to hold the injected objects in the constructor. Then you define a method call Get with the decorator [HttpGet] to handle get requests.  The Get() method returns the list of products and retruns Ok = 200 status code if everything is ok and returns a 400 error status code if there's an exception.  The other important thing is the [Route("api/[Controller]")] decorator.  This is what you typed into the browser.  So for this route you would type http://localhost:50051/api/product into Postman.

3. So now we are ready to test our code in Postman, first we need to run our code, press CRTL+F5
Then select "GET" method on Postman call, type in the URL localhost:50051/api/product and you will see the list of products returned in Json, usually the resource in this product should be pluralize, but I forgot the s.  So the URLs should be localhost:<port>/api/products but since it's just development we can let it slide.  However, if you work with other people you might want to pluralize it.

SQL Server : Add a Data Connection To A SQL Server Database In Visual Studio 2013

The "Server Explorer" tool in Visual Studio 2013 is a good tool at your disposal if want to interact with the database in GUI environment.  To create a new data connection to the database in the "Server Explorer" perform the following actions:

1. Click on "Server Explorer" tab in the left hand side, then click on "Add Connection"

SQL Server : Attaching A Database File to SQL Server 2012

There are times when you are handed over an .mdf file and are tasked to create a new database out of it.  There's no log just an .mdf file.  The easiest way to create a new database is to use the query editor in SQL Management Studio type the following into the Sql Query window

CREATE DATABASE Northwind
 ON (name= 'Northwind',
 filename = 'C:\Northwind.mdf')
FOR ATTACH_REBUILD_LOG;

The query above will create a new database for you call "Northwind", all you have to do is specify the location of the .mdf file and the "FOR ATTACH_REBUILD_LOG" will rebuild the log for you. You might run into a "Access denied" error but it's a permissions issue. Make sure the user that is running the query has permission to the file.