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mysql-proxy: error while loading shared libraries: libmysql-proxy.so.0 or libmysql-chassis.so

Shahid — Fri, 01 Jan 2010 08:06:32 +0000

Getting the below errors:

$ ./agent/sbin/mysql-proxy -V
mysql-proxy: error while loading shared libraries: libmysql-chassis.so.0: cannot open shared object file: No such file or directory
mysql-proxy: error while loading shared libraries: libmysql-proxy.so.0: cannot open shared object file: No such file or directory

The error occurred because the mysql-proxy can’t find the library files needed for it. So copy the needed files to necessary directory.

 $ sudo cp /usr/local/lib/libmysql-* /usr/lib/i486-linux-gnu/
 $ mysql-proxy -V
  mysql-proxy 0.7.2
  glib2: 2.20.1
  libevent: 1.3e
  lua: Lua 5.1.4
    LUA_PATH: /usr/local/lib/mysql-proxy/lua/?.lua
    LUA_CPATH: /usr/local/lib/mysql-proxy/lua/?.so
  == plugins ==
  admin: 0.7.0
  proxy: 0.7.0

URL Redirecting (301,302) in Varnish

Shahid — Wed, 22 Oct 2008 17:37:04 +0000

There is no straight forward method for 301/302 URL redirection as we did with rewrite rule. But there are some situations where we need to redirect a URL on a host to some URL on different host. In this situation we need to use 301/302 redirection. There are two ways we can implement this.

First method is to use set req.http.host and set req.url in the vcl.conf file. Using these two methods we perform normal redirection. Using these method we will redirect the url to some other URL on the same host. For example say the URL http://example.com/error500.php will be redirect to the URL http://example.com/redirect.php. We specify 301/302 redirection to the URL http://foo.com/index.php in the redirect.php file using header method.

In the sub vcl_recv method use the following code.

sub vcl_recv {
   if (req.http.host ~ "example.com") {
      if (req.url ~ "error500.php") {
         set req.http.host = "example.com";
         set req.url = "/redirect.php";
      }
   }
}

In the redirect.php file use the following method.

Second method is to use vcl_error error method. In this error method we can specify HTML tags, so using meta tags we can implement redirection. This option is available with the latest version of varnish.

In the sub vcl_recv method use the following code.

sub vcl_recv {
   if (req.http.host ~ "example.com") {
      if (req.url ~ "error500.php")
         error;
      }
   }
}
sub vcl_error {
        set obj.http.Content-Type = "text/html; charset=utf-8";
        if (req.http.host ~ "example.com") {
                if (req.url ~ "error500.php") {
                        synthetic {"
                                
                                
                                
                                        
                                                
                                        
                                
                        "};
                }
        }
        deliver;
}

How to Log or mail Errors in PHP Code

Shahid — Tue, 09 Sep 2008 17:21:26 +0000

There are a number of things that can go wrong in code and they bound to through errors, even if you’ve tested them hundreds of times. PHP provides some error handling methods such as error_reporting(), set_error_handler(), error_log(), restore_error_handler() for handling errors in the PHP code.

error_reporting – Sets which PHP errors are reported.

int error_reporting ([ int $level] )

error_reporting() level constants

error_log – Sends an error message to the web server’s error log, a TCP port or to a file.

bool error_log ( string $message  [, int $message_type  [, string $destination  [, string $extra_headers ]]] )

Parameters

$message – The error message that should be logged.

$message_type – Says where the error should go. The possible message types are as follows:

$extra_headers – The extra headers. It’s used when the message_type parameter is set to 1. This message type uses the same internal function as mail() does.

restore_error_handler – Restores the previous error handler function

bool restore_error_handler ( void )

set_error_handler – Sets a user-defined error handler function

mixed set_error_handler ( callback $error_handler  [, int $error_types] )

Example: