C:

         char buf[1024]
         strcpy(buf, user_data)

Python:

         buf = user_data[:1024]
         if len(user_data) > 1024: security_hole(user_data[1024:])

actually, the translation is not difficult, so long as you implement security_hole() properly.

(c) Twisted Quotes

Python syslog as it should be

First, the code:

from logging.handlers import SysLogHandler, SYSLOG_UDP_PORT
from logging import Handler
import socket

class UdpSysLogHandler(SysLogHandler):
    def createLock(self): pass
    def acquire(self): pass
    def release(self): pass
   
    def __init__(self, address=('127.0.0.1', SYSLOG_UDP_PORT), facility=SysLogHandler.LOG_USER):
        Handler.__init__(self)
        assert type(address) == tuple
        self.address = address
        self.facility = facility
        self.socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        self.formatter = None

    def emit(self, record):
        msg = self.format(record)
        msg = self.log_format_string % (
            self.encodePriority(self.facility,
                                self.mapPriority(record.levelname)),
            msg)
        try:
            self.socket.sendto(msg, self.address)
        except (KeyboardInterrupt, SystemExit):
            raise
        except:
            self.handleError(record)

    def close(self):
        Handler.close(self)
        self.socket.close()

How it is different from standard SysLogHandler in Python logging package?

First, a lock is eliminated. This lock is taken (in original version) for each logging operation. And IO is performed inside the lock, which is very bad.

    def createLock(self): pass
    def acquire(self): pass
    def release(self): pass

Second, there is no support for logging through UNIX domain socket (/dev/log). This has slightly simplified the emit method.

One might say that UNIX domain sockets should be faster that actual networking UDP sockets, because they dont involve all the networking stack. In practice, however, I noticed that UNIX domain sockets perform much worser. I dont know why. If someone has a clue, please, let me know.

How to save $60 a month with 20 lines of code

We use Amazon AWS S3 service to store users pictures. There is huge amount of small pictures.

As the traffic at out WEB service increased, the cost for serving the pictures from the S3 increased also. Last month we had about 250 GB of traffic for pictures and this was around $60.

While we could move all the pictures to a separate static server this would imply some downtime and complexity in further migrations of our servers. And also reduce reliability.

I modified few lines in Nginx configuration to make it work as a proxy to Amazon S3:

   location @s3 {
       internal;
       proxy_pass           http://your-bucket-name.s3.amazonaws.com;
       proxy_store          on;
       proxy_store_access   user:rw  group:rw  all:r;
       proxy_temp_path      /var/static_data/tmp;
       root                 /var/static_data;
   }

   location ~* \.(jpg|jpeg|gif|png|ico|css|bmp|js|swf|mp3)$ {
       access_log           off;
       error_log            /var/log/nginx/static_cache_miss.log;
       expires              max;
       root                 /var/static_data;
       error_page           404 = @s3;
   }

Now the traffic for S3 has reduced from ~10 GB a day to less than 400 MB.