ProcessWire in Yaws

YAWS (Yet Another Webserver) is a HTTP 1.0/1.1 webserver which is completely written in Erlang. YAWS has been noted well suited for dynamic-content web applications in many cases.

Most developers who are moving from other web development environments to Erlang and Yaws will have used other web servers such as Nginx or Apache. The Erlang Yaws web server performs the same basic tasks, but the details of performing common actions are often different.

Erlang is not only a language, but also a runtime system and something that looks a lot like an application server. As such, Erlang and Yaws (or other web servers) will fill the same role as Apache/PHP/MySQL and other components all in one system.

The major differences between Erlang/Yaws and Apache/PHP have a lot to do with how Erlang tends to set things up. Erlang assumes that systems will be clustered, and processes in Erlang are somewhat different from those used in many other systems.

If you’ve used Apache with mod_php, you may remember that each request is handled by a process or thread (depending on how things are set up). The classic Common Gateway Interface (CGI) would start a new process for every request. These threads and processes are constructions of the OS and are relatively heavyweight objects. In Erlang the processes are owned not by the OS, but by the language runtime.

Because Yaws uses Erlang's lightweight threading system, it performs well under high concurrency. A load test conducted in 2002 comparing Yaws and Apache found that with the hardware tested, Apache failed at 4,000 concurrent connections, while Yaws continued functioning with over 80,000 concurrent connections.

Erlang was built for low latency binary data streaming in telecom systems. It was designed with extreme manageability, scalability and concurrent processing in mind. Using Erlang for the Web you unlock the full power of telecom systems for web-scale, asynchronuous, non-blocking, sharded, event-driven, message-passing, noSQL, reliable, highly-available, high-performance, secure, qualative, real-time, clusterable applications.

Erlang

The recommended way is using a package manager with a pre built erlang installation. Is recommended Erlang 22 or newer.

You can also follow the instructions at the Erlang installation guide.

Once you have Erlang installed, you must install YAWS.

Follow futher instructions at https://github.com/erlyaws/yaws/

Port fowarding

If you need to forward port 80 to 8080 on the firewall:

iptables -A PREROUTING -t nat -p tcp --dport 80 -j REDIRECT --to-port 8080

Bragful

If you want to execute your PHP code inside Erlang, you can also use Bragful to interpret PHP code.

Note

.htaccess files are know as appmods in yaws. The provided file at yaws/appmods/processwire.erl is just a minimal mod_rewrite. It does not includes all the security considerations of the official .htaccess file. Feel free to send a Pull Request to have a proper appmod for ProcessWire.

Why?

Mixing Erlang and PHP is a powerful combination. PHP has a vast web development ecosystem and Erlang has more than 30 years of production ready concurrency solutions that scale well.

Makefile

make install: Downloads ProcessWire to www directory, copies php.ini and build Dockerfile.
make up: Uses docker-compose to start services.
make bash: Enters YAWS container to a shell.

Some Useful Docker Commands

docker-compose up -d : Starts the containers
docker ps: Show the running containers
docker kill <container id>: Kills a container
docker network prune: Reset the network
docker container prune: Resets the stopped containers

Server

The default address is localhost:8080.

YAWS Config

The yaws directory contains configuration files for YAWS.

yaws.conf: The main configuration file for the server. Used for the entry point yaws -i --conf /usr/local/etc/yaws/yaws.conf.
conf.d/processwire.conf: Site configuration for the www directory that holds ProcessWire.
appmods/processwire.erl: Contains the rewrite rules (similar to .htaccess files). Needs to be compiled using (generates processwire.beam).

erlc processwire.erl

References

Credits

Made with ♥ by Ninjas.cl.

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