Running webtoolkit application as nginx FastCGI on CentOS 6.x

Wt (pronounced as witty) is a powerful C++ library for developing web applications. Witty-based apps can be integrated as FastCGI with nginx and other web servers. This guide is about the integration of witty w/ nginx on CentOS 6.x OS.

On this how to, we'll be using the simplest witty example: hello

I assumed you already had installed a CentOS 6.x minimal x86_64.

The Steps

1. Login as a sudoer user.
2. Append EPEL repository by creating the file /etc/yum.repos.d/epel.repo with the following content:

[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
#baseurl=http://download.fedoraproject.org/pub/epel/6/$basearch
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearch
failovermethod=priority
enabled=1
gpgcheck=0

3. Install required packages: nginx, witty and CentOS development kit:

$ sudo yum install nginx 
$ sudo yum install wt
$ sudo yum install fcgi
$ sudo yum install spawn-fcgi
$ sudo yum install wt-devel wt-examples      # Only for development env
$ sudo yum groupinstall "Development Tools"  # Only for development env
$ sudo yum install nano                      # Only for development env

4. Go to Wt's examples directory and edit the CMakeLists.txt archive:

$ cd /usr/lib64/Wt/examples/hello
$ sudo nano CMakeLists.txt

and replace

WT_ADD_EXAMPLE(hello.wt hello.C)

by:

ADD_EXECUTABLE(hello.wt hello.C)
TARGET_LINK_LIBRARIES(hello.wt ${EXAMPLES_CONNECTOR})

5. Run CMake specifying FastCGI support & copy resulting binary to nginx document root:

$ sudo rm -rf target
$ sudo mkdir -p target
$ cd target
$ sudo cmake ../ -DEXAMPLES_CONNECTOR=wtfcgi -DCONNECTOR_FCGI=yes -DCONNECTOR_HTTP=no 
$ sudo make
$ sudo cp -a hello.wt /usr/share/nginx/html/

6. Create a new archive /etc/sysconfig/spawn-fcgi-hello.wt with the following content:

FCGI_SOCKET=/var/run/hello.wt.socket
FCGI_PROGRAM=/usr/share/nginx/html/hello.wt
FCGI_USER=nginx
FCGI_GROUP=nginx
FCGI_EXTRA_OPTIONS="-M 0700"
OPTIONS="-u $FCGI_USER -g $FCGI_GROUP -s $FCGI_SOCKET -S $FCGI_EXTRA_OPTIONS -F 1 -P /var/run/hello.wt.socket.pid -- $FCGI_PROGRAM"

7. Allow nginx to write at /var/spool/wt/run/:

$ sudo chgrp nginx /var/spool/wt/run/
$ sudo chmod g+w /var/spool/wt/run/

8. Launch hello app via spawn-fcgi:

$ source /etc/sysconfig/spawn-fcgi-hello.wt
$ spawn-fcgi $OPTIONS

now the FastCGI is running and waiting.
9. Create a new file /etc/nginx/conf.d/wt.conf w/ the following content:

server {
    listen  9091;
    server_name  _;

    # by default relative to /usr/share/nginx/html
    location / {
      access_log /var/log/nginx/nginx-fastcgi-access.log;
      gzip off;

      # the full path /usr/share/nginx/html/hello.wt
      if ($uri !~ "^/hello.wt/$") {
        fastcgi_pass unix:/var/run/hello.wt.socket;
      }
      include /etc/nginx/fastcgi_params;
      fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
    }
}

10. Restart nginx:

$ service ngnix restart

11. Visit http://HOST:9091 and enjoy it!

The NGINX's RAM-only Jail. Adding nginx to RAM-only diskless Linux box

Without any doubt, nginx is one of the best ever created HTTP servers, it solves the C10K problem with an elegant event-drive architecture. Many big sites around the WWW use it: Wikipedia, Hyves, etc.

This is a how to prepare your rambox to run nginx smoothly. It makes sense only after the preparation of the RAM-only PXE boot in my previous post. This post isn't about any kind of nginx optimization stuff beside of its compilation in a single binary rock. At the end of this guide, you will be running the nginx very much like in a jail.

Run these steps BEFORE the step "Change ownership to everything" at RAM-only PXE boot in my previous post.

1. Download latest stable version nginx and upack it.

$ pushd /tmp/wrk
$ ngx=nginx-1.2.1.tar.gz
$ cache $ngx http://nginx.org/download/$ngx
$ tar -xvzf /tmp/cache/$ngx -C .
$ mv $ngx nginx

2. Add options depending on the features that you want to support. Beside of the default options I only add static compilation options:

$ pushd nginx
$ ./configure --with-ld-opt="-static -static-libgcc" \
  --with-cc-opt="-static -static-libgcc"

make it (jN means N threads devoted to compilation and linking):


$ make -j2

ensure that it's not a dynamic executable:


$ ldd objs/nginx
 not a dynamic executable
$ popd

3. Copy the nginx executable to rambox's /sbin :

   $ popd 
   $ pushd sbin
   $ chmod +w .
   $ cp ../../nginx/objs/nginx .
   $ chmod -w .
   $ popd
   

4. Create /usr/local/nginx directories:

$ mkdir -p -m 0755 usr/local/nginx/{conf,logs}

5. Copy some needed libs:

$ chmod +w lib
$ cp /lib64/{ld-2.12.so,ld-linux-x86-64.so.2} lib/
$ cp /lib64/{libc-2.12.so,libc.so.6} lib/
$ cp /lib64/{libnsl-2.12.so,libnsl.so.1} lib/
$ cp /lib64/{libnss_compat-2.12.so,libnss_compat.so.2} lib/
$ chmod -w lib

6. Copy mime conf file:

$ cp ../nginx/conf/mime.types usr/local/nginx/conf/

7. Create the nginx.conf file with some basic settings:

$ dd of=usr/local/nginx/conf/nginx.conf << EOT
# user and group to run nginx
user www www;

# numbers of dedicated CPUs
worker_processes 1;

# pid archive
pid /var/run/nginx.pid;

events {
    # max connections in WAIT 
    worker_connections  128;
  
    # accept & enqueue NEW connections, put them in WAIT
    multi_accept        on;
}

http {
        include       mime.types;
        default_type  application/octet-stream;

        server {
                listen 80;

                autoindex on;
 
                location / {
                        root /var/www;
                        index  index.php index.html index.htm;
                }
        }
}
EOT

8. Resume the rambox creation process and once it gets started run:

$ nginx

Enjoy it by browsing at http://HOSTADDRESS

Post install steps

Daemonize nginx by running it at /init script!