Serving Apps Locally with Nginx and Pretty Domains

2013-03-04 ·

This post describes how to configure Nginx to serve application locally with pretty domains such as yourappname.dev/ without using over-engineered solutions, like pow, trying to shield the user from the complexity with extra, unnecessary abstraction layers.

The instructions are OSX specific, but they can be easily adjusted to *nix systems.

Nginx

Let's start by making sure there is no Apache process running. On OSX, we can use the following command to turn it off:

sudo launchctl unload -w /System/Library/LaunchDaemons/org.apache.httpd.plist

Nginx can be installed in various ways, I'll use homebrew:

brew install nginx

Running Nginx on port 80 (or any port below 1024) requires sudo command, otherwise the launch agent will fail. For ports above 1024, we can just symlink the launch script as follows:

ln -sfv /usr/local/opt/nginx/*.plist ~/Library/LaunchAgents
launchctl load -w ~/Library/LaunchAgents/homebrew.mxcl.nginx.plist

For default HTTP port, we need to change listen value from 8080 to 80 in /usr/local/etc/nginx.conf . We can also slightly adjust server_name, so both app/ and localhost/ resolve to 127.0.0.1.

server {
     …
     listen 80;
     server_name app localhost;
     …
}

For ports below 1024 we cannot symlink the launch script. It must be copied to system's /Library/LaunchAgents.

sudo cp /usr/local/opt/nginx/homebrew.mxcl.nginx.plist /Library/LaunchAgents

In homebrew.mxcl.nginx.plist, we have to change UserName to root. For convenience, we can also change Label to nginx, which will allow us to write:

launchctl start nginx

instead of:

launchctl stop homebrew.mxcl.nginx

Local DNS

Next step is setting up a local DNS. As it is not possible to use wildcards in the /etc/hosts file, we cannot specify something like:

127.0.0.1      *.dev.

To get around this problem, we will install a DNS proxy, called DNSMasq:

brew install dnsmasq

The configuration is stored in dnsmasq.conf under /usr/local/etc/.

touch /usr/local/etc/dnsmasq.conf

Inside we put the following line:

address=/.dev/127.0.0.1

It says that all *.dev sites should be redirected to the local IP, i.e. 127.0.0.1.

Similar to Nginx process, dnsmasq must be run by root.

sudo cp -fv /usr/local/opt/dnsmasq/*.plist /Library/LaunchDaemons
sudo launchctl load /Library/LaunchDaemons/homebrew.mxcl.dnsmasq.plist

Then, we must configure OSX to use our local system as first DNS server. Go to System Preferences and then Network. For DNS configuration put the loopback IP (i.e. 127.0.0.1) as first followed by usual DNS IP addresses:

127.0.0.1
8.8.8.8
8.8.4.4

Now, if we try to ping some any address ending in .dev, it should return 127.0.0.1.

$ ping example.dev
PING example.dev (127.0.0.1): 56 data bytes

Note: On Linux it is possible to automatically prefix DNS server list with 127.0.0.1. It may be useful if you have to use DNS servers provided by DHCP and/or you change your network often (e.g. home, office). I haven't found similar solution for OSX.

Virtual Hosts

For virtual hosts configurations, we will follow the convention of two directories: sites-enabled and sites-available, under /usr/local/etc/nginx.

cd /usr/local/etc/nginx
mkdir sites-available
mkdir sites-enabled

We must slightly adjust nginx.conf by adding the following line within http section:

 include sites-enabled/*.dev;

Configuration with Backend

We are ready to specify per-app configuration. Let's take a look at the configuration file template.

upstream NAME {
    server 127.0.0.1:3000;
}

server {
    listen 80;
    server_name NAME.dev;
    root PATH_TO_PUBLIC

    try_files $uri/index.html $uri.html $uri @app;

    location @app {
      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
      proxy_set_header Host $http_host;
      proxy_redirect off;

      proxy_pass http://NAME;
    }
}

To make it work, we need to adjust it at least in two places i.e. NAME and PATH_TO_PUBLIC. NAME can be anything, I put there application's name. PATH_TO_PUBLIC specifies where assets are, e.g. for Rails it is the path to public folder, for Pyramid, the path to static folder, etc.

The configuration file can be placed in sites-available, and then, it must be linked to sites-enabled, e.g.

ln -s /usr/local/etc/nginx/sites-available/anapp.dev \
  /usr/local/etc/nginx/sites-enabled/anapp.dev

Once linked, we have to restart Nginx process. On OSX, it can be done in the following way:

sudo launchctl stop nginx
sudo launchctl start nginx

Configuration without Backend

An additional, configuration file is not necessary for client-side only applications. We can set up a dynamic application dispatch by using a default server directive, located in /usr/local/etc/nginx/nginx.conf. Nginx will look for directories in defined base path that match the name from requested domain, e.g. appname.dev will match a directory named appname inside /Users/zaiste/dev from the example below:

server {
        listen       80;
        server_name  app localhost .dev;

        set $basepath "/Users/zaiste/dev";

        set $domain $host;
        if ($domain ~ "^(.*)\.dev$") {
            set $domain $1;
        }
        set $rootpath "${domain}";
        if (-d $basepath/$domain/public) {
            set $rootpath "${domain}/public";
        }
        if (-f $basepath/$domain/index.html) {
            set $rootpath $domain;
        }

        root $basepath/$rootpath;

        # redirect server error pages to the static page /50x.html
        error_page   500 502 503 504  /50x.html;
        location = /50x.html {
            root   html;
        }
    }

For now on, we can just create a new directory under /Users/zaiste/dev with a HTML file, and it will be automatically picked up by Nginx.

Summary

General solutions are just great: we build it from proven components and they are aimed for wider compatibility. Conventions are also great, but not when they try to simplify what's already simple. Using Nginx for serving applications locally is easy to set up and use. Moreover, the proposed solution is language/technology agnostic, it can be used for Rails, Pyramid, AngularJS or any other web technology.

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