<h2>Table of Contents</h2>



<ul><li>Introduction<ul><li>What is AWS Copilot CLI?</li><li>What application are we deploying?</li></ul></li></ul>



<ul><li>Deployment<ul><li>Step 1 &#8211; Download &amp; Configure AWS Copilot</li><li>Step 2 &#8211; Download some code to deploy</li><li>Step 3 &#8211; Set up our app</li><li>Step 4 &#8211; Answer a few questions</li><li>Step 5 &#8211; Deploy your service</li><li>Step 6 &#8211; Clean up</li></ul></li></ul>



<h2>What is AWS Copilot CLI?</h2>



<h2>What application are we deploying?</h2>

Deploy your docker containers to ECS the easy way

How to deploy a Docker containers to AWC ECS with Copilot CLI

<h2>PostgreSQL CREATE TABLE Syntax</h2>



A relational database consists of multiple related tables. A table consists of rows and columns. Tables allow you to store structured data like customers, products, employees, etc.



To create a new table, you use the <code>CREATE TABLE</code> statement. The following illustrates the basic syntax of the <code>CREATE TABLE</code> statement:


<pre class="wp-block-code" aria-describedby="shcb-language-1" data-shcb-language-name="SQL (Structured Query Language)" data-shcb-language-slug="sql"><link rel='stylesheet' id='syntax-highlighting-code-block-css' href='https://cms.arontolentino.com/wp-content/plugins/syntax-highlighting-code-block/vendor/scrivo/highlight-php/styles/qtcreator_dark.css?ver=1.3.1' media='all' /><style>.wp-block-code {
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</style><div><code class="hljs language-sql shcb-wrap-lines">CREATE TABLE [IF NOT EXISTS] table_name (
 column1 datatype(length) column_contraint,
 column2 datatype(length) column_contraint,
 column3 datatype(length) column_contraint,
 table_constraints
);</code></div>Code language: SQL (Structured Query Language) (sql)</pre>


<h2>PostgreSQL Column Constraints</h2>



PostgreSQL includes the following column constraints:



<ul><li><a href="https://www.postgresqltutorial.com/postgresql-not-null-constraint/">NOT NULL&nbsp;</a>– ensures that values in a column cannot be <code>NULL</code>.</li><li><a href="https://www.postgresqltutorial.com/postgresql-unique-constraint/">UNIQUE</a> – ensures the values in a column unique across the rows within the same table.</li><li><a href="https://www.postgresqltutorial.com/postgresql-primary-key/">PRIMARY KEY</a> – a primary key column uniquely identify rows in a table. A table can have one and only one primary key. The primary key constraint allows you to define the primary key of a table.</li><li><a href="https://www.postgresqltutorial.com/postgresql-check-constraint/">CHECK</a> – a <code>CHECK</code> constraint ensures the data must satisfy a boolean expression.</li><li><a href="https://www.postgresqltutorial.com/postgresql-foreign-key/">FOREIGN KEY</a> – ensures values in a column or a group of columns from a table exists in a column or group of columns in another table. Unlike the primary key, a table can have many foreign keys.</li></ul>



Table constraints are similar to column constraints except that they are applied to more than one column.



<h2>PostgreSQL CREATE TABLE Examples</h2>



We will create a new table called <code>accounts</code> that has the following columns:



<ul><li>user_id – primary key</li><li>username – unique and not null</li><li>password – not null</li><li>email – unique and not null</li><li>created_on – not null</li><li>last_login – null</li></ul>



The following statement creates the <code>accounts</code> table:


<pre class="wp-block-code" aria-describedby="shcb-language-2" data-shcb-language-name="SQL (Structured Query Language)" data-shcb-language-slug="sql"><div><code class="hljs language-sql shcb-wrap-lines">CREATE TABLE accounts (
 user_id serial PRIMARY KEY,
 username VARCHAR ( 50 ) UNIQUE NOT NULL,
 password VARCHAR ( 50 ) NOT NULL,
 email VARCHAR ( 255 ) UNIQUE NOT NULL,
 created_on TIMESTAMP NOT NULL,
 last_login TIMESTAMP 
);</code></div>Code language: SQL (Structured Query Language) (sql)</pre>


<figure class="wp-block-image"><img src="https://sp.postgresqltutorial.com/wp-content/uploads/2020/07/PostgreSQL-Create-Table-accounts-example.png" alt="PostgreSQL Create Table - accounts example" class="wp-image-5174"/></figure>



The following statement creates the&nbsp;&nbsp;<code>roles</code> table that consists of two columns: <code>role_id</code> and <code>role_name</code>:


<pre class="wp-block-code" aria-describedby="shcb-language-3" data-shcb-language-name="SQL (Structured Query Language)" data-shcb-language-slug="sql"><div><code class="hljs language-sql shcb-wrap-lines">CREATE TABLE roles(
 role_id serial PRIMARY KEY,
 role_name VARCHAR (255) UNIQUE NOT NULL
);</code></div>Code language: SQL (Structured Query Language) (sql)</pre>


<figure class="wp-block-image"><img src="https://sp.postgresqltutorial.com/wp-content/uploads/2020/07/PostgreSQL-Create-Table-roles-example.png" alt="PostgreSQL Create Table - roles example" class="wp-image-5175"/></figure>



The following statement creates the <code>account_roles</code> table that has three columns: <code>user_id</code>, <code>role_id</code> and <code>grant_date</code>.


<pre class="wp-block-code" aria-describedby="shcb-language-4" data-shcb-language-name="SQL (Structured Query Language)" data-shcb-language-slug="sql"><div><code class="hljs language-sql">CREATE TABLE account_roles (
 user_id INT NOT NULL,
 role_id INT NOT NULL,
 grant_date TIMESTAMP,
 PRIMARY KEY (user_id, role_id),
 FOREIGN KEY (role_id)
 REFERENCES roles (role_id),
 FOREIGN KEY (user_id)
 REFERENCES accounts (user_id)
);</code></div>Code language: SQL (Structured Query Language) (sql)</pre>


<figure class="wp-block-image"><img src="https://sp.postgresqltutorial.com/wp-content/uploads/2020/07/PostgreSQL-Create-Table-account_roles-example.png" alt="PostgreSQL Create Table - account_roles example" class="wp-image-5176"/></figure>



The primary key of the <code>account_roles</code>&nbsp;table consists of two columns: <code>user_id&nbsp;</code>and <code>role_id</code>, therefore, we have to define the primary key constraint as a table constraint.


<pre class="wp-block-code" aria-describedby="shcb-language-5" data-shcb-language-name="SQL (Structured Query Language)" data-shcb-language-slug="sql"><div><code class="hljs language-sql">PRIMARY KEY (user_id, role_id)</code></div>Code language: SQL (Structured Query Language) (sql)</pre>


Because the <code>user_id</code> column references to the <code>user_id</code> column in the <code>accounts</code> table, we need to define a <a href="https://www.postgresqltutorial.com/postgresql-foreign-key/">foreign key constraint</a> for the <code>user_id</code>column:


<pre class="wp-block-code" aria-describedby="shcb-language-6" data-shcb-language-name="SQL (Structured Query Language)" data-shcb-language-slug="sql"><div><code class="hljs language-sql">FOREIGN KEY (user_id)
REFERENCES accounts (user_id)</code></div>Code language: SQL (Structured Query Language) (sql)</pre>


The <code>role_id</code> column references the <code>role_id</code> column in the <code>roles</code> table, we also need to define a foreign key constraint for the <code>role_id</code> column.


<pre class="wp-block-code" aria-describedby="shcb-language-7" data-shcb-language-name="SQL (Structured Query Language)" data-shcb-language-slug="sql"><div><code class="hljs language-sql">FOREIGN KEY (role_id)
REFERENCES roles (role_id)</code></div>Code language: SQL (Structured Query Language) (sql)</pre>


The following shows the relationship between the <code>accounts</code>, <code>roles</code>, and <code>account_roles</code> tables:



<figure class="wp-block-image"><img src="https://sp.postgresqltutorial.com/wp-content/uploads/2020/07/PostgreSQL-Create-Table-example.png" alt="PostgreSQL Create Table example" class="wp-image-5177"/></figure>



<h2>Summary</h2>



<ul><li>Use the <code>CREATE TABLE</code> statement to create a new table.</li><li>Use the <code>IF NOT EXISTS</code> option to create the new table only if it does not exist.</li><li>Apply the primary key, foreign key, not null, unique, and check constraints to columns of a table.</li></ul>

PostgreSQL – Create Table

oday I had the need to check if an object was empty.



Since in JavaScript objects are compared by reference, we can’t do a simple comparison like this:


<pre class="wp-block-code" aria-describedby="shcb-language-8" data-shcb-language-name="JavaScript" data-shcb-language-slug="javascript"><div><code class="hljs language-javascript">const obj = {}

if (obj === {}) {
 //no
}
</code></div>Code language: JavaScript (javascript)</pre>


The solution is to pass the object to the built-in method <code>Object.keys()</code> and to check if the object constructor is <code>Object</code>:


<pre class="wp-block-code" aria-describedby="shcb-language-9" data-shcb-language-name="JavaScript" data-shcb-language-slug="javascript"><div><code class="hljs language-javascript">const obj = {}

Object.keys(obj).length === 0 &amp;&amp; obj.constructor === Object
</code></div>Code language: JavaScript (javascript)</pre>


It’s important to add the second check, to avoid false positives.

A quick guide to the mkdir command, used to create folders

How to test for an empty object in JavaScript

You create folders using the <code>mkdir</code> command:


<pre><div><code class="hljs">mkdir fruits</code></div></pre>


You can create multiple folders with one command:


<pre><div><code class="hljs">mkdir dogs cars</code></div></pre>


You can also create multiple nested folders by adding the <code>-p</code> option:


<pre><div><code class="hljs">mkdir -p fruits/apples</code></div></pre>


Options in UNIX commands commonly take this form. You add them right after the command name, and they change how the command behaves. You can often combine multiple options, too.



You can find which options a command supports by typing <code>man &lt;commandname&gt;</code>. Try now with <code>man mkdir</code> for example (press the <code>q</code> key to esc the man page). Man pages are the amazing built-in help for UNIX.

The mkdir command

In this post I want to guide you through the process of setting up your first Linux Virtual Private Server (VPS) on DigitalOcean.



DigitalOcean is one of the most famous VPS services.



DigitalOcean has a 1-click installation process for the most famous applictions and operating systems, it provides a global network of data centers and CDN locations. It’s also very reliable and with a 5$/m starting point it’s also convenient.



I consider DigitalOcean to be one of the most affordable and easy to use solutions, and I use it for various services.



<h2 id="step-1-create-a-digitalocean-account">Step 1: Create a DigitalOcean account</h2>



You can <a href="https://m.do.co/c/bd0657b4877c">use this affiliate link</a> to get a $100 credit you can use for the next 60 days.



<blockquote class="wp-block-quote">Disclaimer: this is an affiliate link. When you use this link to sign up, you will get a $100 credit and I will get $25 in DigitalOcean credits.</blockquote>



I don’t suggest DigitalOcean just because they have an affiliate program, obviously. It’s the opposite: since I use it a lot, if I can lower my bill I take advantage of this opportunity.



Once you are on the website:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.11.59.png" alt=""/></figure>



Fill the registration form and you’ll quickly be up and running. You can also sign up with Google or GitHub.



You need to confirm your email:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.22.10-redacted%20(1).png" alt=""/></figure>



Then you will need to enter the billing information that will be needed when you finish your $100 free credits:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.22.40.png" alt=""/></figure>



<h2 id="step-2-create-a-project">Step 2: Create a project</h2>



Once you’re signed up, you are now able to create a new project:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.15.51-redacted%20(1).png" alt=""/></figure>



Enter a name and a description for the project:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.26.18.png" alt=""/></figure>



Once you click “Create Project”, the project is now added to you list of projects, and the Project Dashboard appears:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.26.34.png" alt=""/></figure>



This is the control center for anything you want to do with this project.



First, there is a big blue button with the Get Started with a Droplet text.



What is a Droplet? A DigitalOcean Droplet is a virtual machine, a VPS. The thing we want to create. Everything on DigitalOcean revolves around Droplets.



From this interface we can also initialize a managed database, create a space (a place to store files) and create a load balancer to distribute traffic between multiple droplets.



But let’s keep things simple. We just want to create a droplet.



<h2 id="create-a-droplet">Create a droplet</h2>



Click the Get Started with a Droplet button in the project dashboard.



This will show you a page with lots of options:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.31.52.png" alt=""/></figure>



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.31.58.png" alt=""/></figure>



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.32.05-redacted.png" alt=""/></figure>



Let’s start from the top.



The first choice is Choose an image. Here we can choose between several Linux distributions (Ubuntu, Fedora, Debian and CentOS) and FreeBSD, another UNIX OS.



For each of those, we can choose a specific version:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.33.19.png" alt=""/></figure>



Along with Distributions, we also have other categories. Marketplace in particular lets us install a server preconfigured with an application like WordPress, Ghost, a LAMP server or any of the 150+ applications with a single click. This is a really handy way to quickly get up and running with any project.



Snapshots, Backups and Custom images let you create a server from a pre-existing server you had.



Now that you know everything you can do here, let’s pick Ubuntu LTS from the Distributions panel.



In Choose a plan you can choose between the Standard plan (which is the one we’ll use), or a more performant CPU-Optimized or Memory-Optimized server. This implies the server will cost more.



Speaking of cost, now we have a table where we can choose the size of the server (and the cost):



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.43.56.png" alt=""/></figure>



Don’t be tricked: click the left arrow to reveal the cheaper plans:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.44.19.png" alt=""/></figure>



A $5/m plan can go a long way, before you ever need to upgrade. Start with that. Also note that billing is per hour, so if you use a server for 10 minutes, you’re still being billed 1 hour.



Next we can choose to add block storage to have persistent data storage (not needed now) and you can choose a data center region:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.48.49.png" alt=""/></figure>



Which should you choose?



The one nearest to your visitors. I almost always choose New York as it’s in the middle between Europe and the rest of the US.



We have other options next, which you can ignore, then we have Authentication:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.51.13.png" alt=""/></figure>



Choose Password to keep things simpler, but for real servers I recommend using SSH keys authentication (which is more complicated to setup, but more secure).



Type a password you’re going to use for the <code>root</code> user, the Linux system administrator.



Then fill a username that’s meaningful to you:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.53.32.png" alt=""/></figure>



Finally, click the Create Droplet button:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.54.24.png" alt=""/></figure>



And DigitalOcean will start the droplet creation process:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.54.38.png" alt=""/></figure>



Once it ends, it will show you the public server IP address:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.55.37.png" alt=""/></figure>



Click the name to show the droplet dashboard:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.55.57.png" alt=""/></figure>



From here you have full control of anything. You can turn it on, turn it off, resize it, and much more.



Remember that turning off a droplet does not stop DigitalOcean billing: you must destroy it, so it does not take any space at all.



<h2 id="access-the-droplet-as-root">Access the Droplet as root</h2>



From the Droplet, you can now access the droplet by clicking the Access menu, and the Launch Console button:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.59.39.png" alt=""/></figure>



This will open a login window inside the browser, which lets you login to the server. Enter <code>root</code> as the user name, and the password you set previously:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.58.46.png" alt=""/></figure>



You should then be able to login to the server:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2016.59.01.png" alt=""/></figure>



The console in the browser is not ideal. It’s much better to use your operating system terminal.



Let me access the server using the macOS Terminal app. I write the command <code>ssh root@&lt;IP ADDRESS&gt;</code>:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2017.02.27.png" alt=""/></figure>



I immediately get a warning that tells me I’ve never connected to this server before. I accept with “yes”:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2017.01.40.png" alt=""/></figure>



Now the server asks me the password:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2017.01.50.png" alt=""/></figure>



and I’m logged into it:



<figure class="wp-block-image"><img src="https://flaviocopes.com/digitalocean-create-vps/Screen%20Shot%202020-06-11%20at%2017.02.06.png" alt=""/></figure>

A complete guide from zero to having a DigitalOcean VPS

How to create your first VPS on DigitalOcean

I’ve been asked how to change the HTTP port of an app built using Next.js, when you are running it locally. By default the port is <code>3000</code>, but that’s a commonly used port and perhaps you have another service running on it.



How can you change it?



The answer is in the <code>package.json</code> file stored in the Next.js app main folder.



By default the file content is this:


<pre class="wp-block-code" aria-describedby="shcb-language-10" data-shcb-language-name="JSON / JSON with Comments" data-shcb-language-slug="json"><div><code class="hljs language-json">{
 "name": "learn-starter",
 "version": "0.1.0",
 "private": true,
 "scripts": {
 "dev": "next dev",
 "build": "next build",
 "start": "next start"
 },
 "dependencies": {
 "next": "9.3.5",
 "react": "16.13.1",
 "react-dom": "16.13.1"
 }
}</code></div>Code language: JSON / JSON with Comments (json)</pre>


The thing you need to change is the <code>scripts</code> part.



Change:


<pre class="wp-block-code" aria-describedby="shcb-language-11" data-shcb-language-name="JavaScript" data-shcb-language-slug="javascript"><div><code class="hljs language-javascript">"dev": "next dev",</code></div>Code language: JavaScript (javascript)</pre>


to


<pre class="wp-block-code" aria-describedby="shcb-language-12" data-shcb-language-name="JavaScript" data-shcb-language-slug="javascript"><div><code class="hljs language-javascript">"dev": "next dev -p 3001"</code></div>Code language: JavaScript (javascript)</pre>


to start Next.js on port <code>3001</code> instead of <code>3000</code>.



Now when you run <code>npm run dev</code>, the command used to start the development server locally, you will see it start on port <code>3001</code>:



<figure class="wp-block-image size-large"><img loading="lazy" width="1024" height="864" src="https://cms.arontolentino.com/wp-content/uploads/2020/08/Screen-Shot-2020-08-20-at-14.44.52-1024x864.png" alt="" class="wp-image-80" srcset="https://cms.arontolentino.com/wp-content/uploads/2020/08/Screen-Shot-2020-08-20-at-14.44.52-1024x864.png 1024w, https://cms.arontolentino.com/wp-content/uploads/2020/08/Screen-Shot-2020-08-20-at-14.44.52-300x253.png 300w, https://cms.arontolentino.com/wp-content/uploads/2020/08/Screen-Shot-2020-08-20-at-14.44.52-768x648.png 768w, https://cms.arontolentino.com/wp-content/uploads/2020/08/Screen-Shot-2020-08-20-at-14.44.52-1536x1296.png 1536w, https://cms.arontolentino.com/wp-content/uploads/2020/08/Screen-Shot-2020-08-20-at-14.44.52-1200x1013.png 1200w, https://cms.arontolentino.com/wp-content/uploads/2020/08/Screen-Shot-2020-08-20-at-14.44.52-1980x1671.png 1980w, https://cms.arontolentino.com/wp-content/uploads/2020/08/Screen-Shot-2020-08-20-at-14.44.52.png 2010w" sizes="(max-width: 1024px) 100vw, 1024px" /></figure>

Learn how to change the port that Next.js runs on in development mode

How to change a Next.js app port

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Aron Tolentino