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!