DEV Community: Santosh Venkatraman 🖖

Configure nginx to host multiple subdomains

Santosh Venkatraman 🖖 — Sun, 17 Feb 2019 02:36:40 +0000

This post has been cross-posted from my blog

Configuring nginx for subdomains in the same machine was confusing for me. So I am writing this tutorial primarily for (self)reference but people can find it useful. Without much ado, let's get started.

For those of you who don't know what nginx is exactly, head over to this freeCodeCamp article as a starting point.

I assume you're on a linux machine and you know what nginx means.

First and foremost, install nginx -

sudo apt-get install nginx

Second head over to /etc/nginx/sites-available/default by opening it on vim/nano. You would come across something like this -

##
# You should look at the following URL's in order to grasp a solid understanding
# of Nginx configuration files in order to fully unleash the power of Nginx.
# https://www.nginx.com/resources/wiki/start/
# https://www.nginx.com/resources/wiki/start/topics/tutorials/config_pitfalls/
# https://wiki.debian.org/Nginx/DirectoryStructure
#
# In most cases, administrators will remove this file from sites-enabled/ and
# leave it as reference inside of sites-available where it will continue to be
# updated by the nginx packaging team.
#
# This file will automatically load configuration files provided by other
# applications, such as Drupal or Wordpress. These applications will be made
# available underneath a path with that package name, such as /drupal8.
#
# Please see /usr/share/doc/nginx-doc/examples/ for more detailed examples.
##

# Default server configuration
#
server {
    listen 80 default_server;
    listen [::]:80 default_server;

    # SSL configuration
    #
    # listen 443 ssl default_server;
    # listen [::]:443 ssl default_server;
    #
    # Note: You should disable gzip for SSL traffic.
    # See: https://bugs.debian.org/773332
    #
    # Read up on ssl_ciphers to ensure a secure configuration.
    # See: https://bugs.debian.org/765782
    #
    # Self signed certs generated by the ssl-cert package
    # Don't use them in a production server!
    #
    # include snippets/snakeoil.conf;

    root /var/www/html;

    # Add index.php to the list if you are using PHP
    index index.html index.htm index.nginx-debian.html;

    server_name _;

    location / {
        # First attempt to serve request as file, then
        # as directory, then fall back to displaying a 404.
        try_files $uri $uri/ =404;
    }

    # pass PHP scripts to FastCGI server
    #
    #location ~ \.php$ {
    #   include snippets/fastcgi-php.conf;
    #
    #   # With php-fpm (or other unix sockets):
    #   fastcgi_pass unix:/var/run/php/php7.0-fpm.sock;
    #   # With php-cgi (or other tcp sockets):
    #   fastcgi_pass 127.0.0.1:9000;
    #}

    # deny access to .htaccess files, if Apache's document root
    # concurs with nginx's one
    #
    #location ~ /\.ht {
    #   deny all;
    #}
}


# Virtual Host configuration for example.com
#
# You can move that to a different file under sites-available/ and symlink that
# to sites-enabled/ to enable it.
#
#server {
#   listen 80;
#   listen [::]:80;
#
#   server_name example.com;
#
#   root /var/www/example.com;
#   index index.html;
#
#   location / {
#       try_files $uri $uri/ =404;
#   }.
#}

From the above you can gather the following points -

server {} - that tells nginx that "Hey this is how I think you should configure the server"
listen 80 - translates to "Listen to port 80, which is the default port for web clients"
root /var/www/html; - nginx understands that HTML file/files from that location can be served
index index.html index.htm index.nginx-debian.html; - this indicates that these kind of files should be served in a decreasing order of priority (left to right).
server_name _; - this conveys that _ is the server name. Assuming our domain to be example.com, the server name would be example.com. That's because when a request is received for example.com, nginx should whether to process it or not.
location / {} - this means that all requests must be handled by this server config. There is an option to handle specific requests as well. For example, requests starting with /server_1 can load server_1.html and all other requests can load default.html.

Next obvious question is - how do I configure subdomains?

It's not that complicated. It involves 7 steps -

Copy the default configuration and rename it as subdomain1.example.com.

cp /etc/nginx/sites-available/default /etc/nginx/sites-available/subdomain1.example.com

Note: You don't necessarily have to name the file subdomain1.example.com. It's easier if you follow a convention that makes it easy for everybody involved.

Open it and remove the term default_server besides listen 80 and the line below it. This is crucial.
Change the server_name as subdomain1.example.com & change the HTML root that's being used
Then link that file to a file in nginx's sites-enabled directory. This is for nginx to understand that configuration subdomain1.example.com is enabled in the configuration.

sudo ln -s /etc/nginx/sites-available/subdomain1.example.com /etc/nginx/sites-enabled/subdomain1.example.com

Write a HTML file inside /var/www/html for subdomain1.example.com
Restart the nginx server
If you're using a DNS provider like Cloudflare, add the box's IP to it with an A record subdomain1.example.com. If not, then add the box's IP and subdomain1.example.com to /etc/hosts.
Load subdomain1.example.com on the browser to check how it loads. If everything is fine, you will see the HTML that you wrote for this subdomain.

Extend the same approach for any other domain or subdomain that you require.

Looking back at 2018

Santosh Venkatraman 🖖 — Mon, 31 Dec 2018 17:43:59 +0000

Yelo and welcome to yet another episode in the "looking back at" series. This time it's 2018 and boy does it look positive. Last year, backstreet dogs inaugurated the new year. 2k18 began with a piss drunk gentleman hanging off a parapet wall. He was shouting "Happy New Year" while his friends were begging him not to drop dead.

Notable things -

Moved to a new house

This year saw me leaving my old house and moving into a new house with one of my closest college friends, Kate. For the uninitiated, he's a Marathi guy.
Got closer to the family

Familial struggles became a general topic of discussion. Also group-calling the sister's kid.
Started getting fitter

My close friend Achyuth and I are in the process of going back to college first-year/freshman sizes. 95 => 81.5.
Started cooking

In order to achieve my continuous goal of becoming fitter, I had to start cooking on my own. And man do I love cooking. I hate doing the dishes, tho (gotten used to it).
Got my head dunked in water on stage in a serious play

As part of Creashakthi Bangalore's 2nd production, this serious play 'The Undertrials' was a whole new experience. For those who don't know, Creashakthi is a Chennai based theater group. I got to work with new people from different backgrounds (college kid, marketing manager, nano-chip designer, lawyer-turned-actor, and a full-time actor). Dushyanth (founder of Creashakthi) liked my performance and got head dunked in water on stage & beaten to a pulp. I guess I could check off two things of my bucket list.
Highly recommend Hemingwayapp and Grammarly for content writing
Fell in love with Twitter's mobile site, it's tweet thread & bookmarks features
Discovered a beautiful platform called dev.to through Twitter
Marketing is hard, especially in the B2C space

Last year I was enthusiastic about building Footyfollowr. My main pitch point was sOmE tEcHy ThInG tHaT aDdS nO tAnGiBlE vAlUe To A nOrMaL uSeR. Yes, I am a fan of Spongebob memes. TODO - Have to read more about marketing.
Code review is easy if done in smaller chunks

In the last couple of years, I have felt that reviewing code is easy if done in smaller chunks or commits if you will. When you look at the large diff(erence) after you've reviewed the smaller ones, you will get the big picture. This is not an intuition alone. I have implemented it with my mentor and it works.
"Any fool can write code that a computer can understand. Good programmers write code that humans can understand."

That was quoted by Martin Fowler, in "Refactoring: Improving the Design of Existing Code". A solo developer in a team full of developers becomes that 'fool'. Incoherent documentation, broken setup scripts, improper dependency versioning, etc is a common theme. It could be worse - single line readme and unmaintainable hacky "legacy" codebase that some poor soul has to inherit. It takes a toll on the other employees (mental) and the company (financial) to inherit and maintain such codebases with large technical debt.
Email communication is underrated
Built a type-checker in Python
Built a hackernews app using Google's Flutter SDK
Wrote a Spongebob mocking meme text converter in Typescript

It converts "Spongebob mocking meme" into "sPoNgEbOb MoCkInG mEmE".
Started learning golang
Built a Twitter thread extractor
Fixing performance bottleneck

This particular performance bottleneck came to be because of the architecture. An infinite horizontal content view became slow via notifications. Had to figure out how, how much, and why using analytics (fun aspect).
Got my feet wet in native Android development by building a custom notification layout

Had to build a custom notification layout (with image, icon, ability to share, etc) for an app I am building. Coming from the background of React Native, paying the abstraction tax was hard. The native world is different.
Stay away from unethical peeps coz they will pull you down eventually

TODO -

Lots
of
things

2019 has a lot in store and I am looking forward to this Christian concept of New Year (thanks Yeshua).

(This post originally appeared on blog.onstash.me)

Type-checking in Python

Santosh Venkatraman 🖖 — Wed, 06 Jun 2018 00:59:14 +0000

Type checking function arguments is a common sanity check for function arguments in Python.

What do you mean "type-checking function arguments"?

Let's say you have a function add that takes in two arguments a and b. There is an implicit understanding that a and b must be either integer (type int) or float (type float).

def add(a, b):
    return a + b

add(1, 2) gives the output 3 which is what we intended the function for.
But add([2], [3]) seems to be returning [2, 3], a concatenated list.
Also add((2,), (3,)) seems to be returning (2, 3), a concatenated tuple.

To operate only on int and float arguments, we can add type or isinstance checks. Check out this StackOverflow post for understanding the difference between type and isinstance checks.

valid_add_types = (int, float)
def add(a, b):
    if isinstance(a, valid_add_types) and isinstance(b, valid_add_types):
        return a + b
    return None

add(1, 2) gives the output 3 which is what we intended the function for.
add([2], [3]) and add((2,), (3,)) return None because they're are neither integers nor floats.

Pros:

It can help you, the developer, understand what types of arguments a function needs at a glance
Useful for existing and new developers
Bug-fixes and feature additions are less painful

Cons:

It is manageable for small codebases
Manual type checking makes large codebases convoluted

In the course of discussing how to improve the Developer Experience (DX) of a Python developer, my mentor, Sriram, and I came with up with an idea of a type checking decorator for type checking function arguments.

Introducing typy_checker, an easy-to-use library for type-checking your functions without losing your sanity over it.

Here is how we could use typy_checker in our example.

from typy_checker import type_checker

valid_add_types = (int, float)
@type_checker(a=valid_add_types, b=valid_add_types)
def add(a, b):
    return a + b

Calling add([2], [3]) will result in the following error -

SystemError: add(): Invalid type for variable 'a'. Expected int / float but got list.

Using typy_checker results in a cleaner codebase, from my experience. I have used it in two codebases and they are running in production at the moment.