Simone 'Wiz' Tellini - SysAdmin

Who's linking to your site?

nospam@example.com (Simone) — Fri, 20 Jun 2008 14:57:28 -0700

If you're using LogMiner to analyse your Apache/IIS logs, here's an easy recipe to be notified of sites that send visitors your way.

First, let's define a Pg/PLSQL function to extract the new referrers:

CREATE TYPE new_referrer AS (
site_id int8,
site_name text,
referrer text,
hits int
);

CREATE OR REPLACE FUNCTION get_new_referrers()
RETURNS SETOF new_referrer AS $body$
DECLARE
rec new_referrer;
lastRef int8;
BEGIN

SELECT INTO lastRef CAST( value AS int8 )
FROM catalog
WHERE name = 'LastReferrer';

IF lastRef IS NULL THEN
INSERT INTO catalog ( name, value ) VALUES ( 'LastReferrer', 0 );
lastRef := 0;
END IF;

FOR rec IN
EXECUTE 'SELECT s.id AS site_id, s.name AS site_name, r.referrer, tmp.hits ' ||
'FROM ( ' ||
' SELECT site, referrer, COUNT(*) AS hits ' ||
' FROM accesses ' ||
' WHERE referrer > ' || lastRef ||
' GROUP BY site, referrer ' ||
') tmp ' ||
'JOIN sites s ON s.id = tmp.site ' ||
'JOIN referrers r ON tmp.referrer = r.id ' ||
'WHERE r.extern = true ' ||
'ORDER BY s.name, tmp.hits DESC, r.referrer'
LOOP

RETURN NEXT rec;

END LOOP;

UPDATE catalog
SET value = ( SELECT MAX( id ) FROM referrers )
WHERE name = 'LastReferrer';

RETURN;
END;
$body$ LANGUAGE plpgsql;

Then, a little PHP script to run the query and format the results:

#!/usr/local/bin/php
<?php

$lines = array();
$lastSite = '';

// quickest and dirtiest way to execute a query in PHP ;-)
exec ( "echo 'SELECT r.* " .
"FROM get_new_referrers() r " .
"LEFT JOIN search_engines se ON ( r.referrer ~* se.pattern AND r.referrer ~* se.query_pattern )" .
"WHERE se.id IS NULL' | /usr/local/pgsql/bin/psql -U logminer -At logminer",
$lines );

foreach( $lines as $line ) {

$parts = explode( '|', $line, 4 );

if( $lastSite != $parts[ 0 ] ) {

printf( "\n\n\n\n" .
"-------------------------------------------------------\n" .
"Referrers for %s\n" .
"-------------------------------------------------------\n\n",
$parts[ 1 ] );

$lastSite = $parts[ 0 ];
}

printf( "[%d] %s\n\n", $parts[ 3 ], $parts[ 2 ] );
}
?>

The query above grabs the referrers for every site available in the DB, filtering requests coming from known search engines to reduce the level of "noise".

This script is finally invoked by the cron job that processes the logs:

referrers_report.php | mail -s 'New referrers report' email@example.com

lm_sensors config for Asus T3-P5945GCX (P5L13L motherboard)

nospam@example.com (Simone) — Sat, 08 Mar 2008 11:24:00 -0800

I've just installed the latest Mandriva 2008.1 RC on this fine Asus barebone.

Everything went fine, except that the output of sensors showed too many ALARM messages for my taste... so, here's how I've modified the pre-installed sensors.conf to set some min/max values closer to reality and to hide useless lines:

# Winbond W83627EHF configuration originally contributed by Leon Moonen
# This is for an Asus P5P800, voltages for A8V-E SE.
chip "w83627ehf-*" "w83627dhg-*"

label in0 "VCore"
label in2 "AVCC"
label in3 "3VCC"
label in7 "VSB"
label in8 "VBAT"

# +12V is in1 and +5V is in6 as recommended by datasheet
compute in1 @*(1+(56/10)), @/(1+(56/10))
compute in6 @*(1+(22/10)), @/(1+(22/10))
set in1_min 12.0*0.9
set in1_max 12.0*1.1
set in6_min 5.0*0.95
set in6_max 5.0*1.05

set in4_min 1.6*0.9
set in4_max 1.6*1.05
set in9_min 1.6*0.9
set in9_max 1.6*1.05

# Set the 3.3V
set in2_min 3.3*0.95
set in2_max 3.3*1.05
set in3_min 3.3*0.95
set in3_max 3.3*1.05
set in7_min 3.3*0.95
set in7_max 3.3*1.05
set in8_min 3.3*0.95
set in8_max 3.3*1.05

# Fans
label fan2 "CPU Fan"

ignore fan1
ignore fan3
ignore fan4
ignore fan5

# Temperatures
label temp1 "Sys Temp"
label temp2 "CPU Temp"
label temp3 "AUX Temp"

set temp1_over 45
set temp1_hyst 40

Corrections are welcome.

LogMiner: purging old accesses

nospam@example.com (Simone) — Sat, 26 Jan 2008 18:53:22 -0800

I've just committed a function to easily purge old data from LogMiner's database, useful to prevent it from growing too much.

It'll appear in the next version, but since its release might still be far from now, here's the code for those who need it:

CREATE OR REPLACE FUNCTION cleanup( _site int8, _upToDate date )
RETURNS INT AS $body$
BEGIN

DELETE FROM accesses
WHERE req_time < _upToDate
AND site = _site;

ALTER TABLE accesses DROP CONSTRAINT accesses_request_fkey;
ALTER TABLE accesses DROP CONSTRAINT accesses_search_fkey;
ALTER TABLE accesses DROP CONSTRAINT accesses_referrer_fkey;

DELETE FROM requests
WHERE id NOT IN ( SELECT DISTINCT request FROM accesses );

DELETE FROM search_referrals
WHERE id NOT IN ( SELECT DISTINCT search FROM accesses );

DELETE FROM referrers
WHERE id NOT IN ( SELECT DISTINCT referrer FROM accesses );

ALTER TABLE accesses
ADD CONSTRAINT "accesses_request_fkey"
FOREIGN KEY ( request )
REFERENCES requests( id ) ON DELETE CASCADE;

ALTER TABLE accesses
ADD CONSTRAINT "accesses_search_fkey"
FOREIGN KEY ( search )
REFERENCES search_referrals( id ) ON DELETE SET NULL;

ALTER TABLE accesses
ADD CONSTRAINT "accesses_referrer_fkey"
FOREIGN KEY ( referrer )
REFERENCES referrers( id ) ON DELETE SET NULL;

RETURN 0;
END;
$body$ LANGUAGE plpgsql;

For instance, if you want to keep only the last six month of data, you can set up a cron job which runs at the first day of every month executing the command:

# supposing 1 is the id of your site
echo "SELECT * FROM cleanup( 1, CAST( date_trunc( 'month', now() ) - interval '5 months' AS date ));" | psql -U logminer logminer

Mac OS X version statistics through CFNetwork analysis

nospam@example.com (Simone) — Fri, 07 Dec 2007 12:05:00 -0800

Recently I needed to gather some statistics about the distribution of the different Mac OS X versions installed by users of a certain application.

Since the application has an update-check feature, I thought I'd use the web server logs to infer the data I was interested in. The only thing I could use was the User-Agent string sent by the application when requesting the file containing the update information.

After some digging in Darwin's build plists and a bit of googling, I came up with this list of patterns:



            OS            |                user agent pattern

--------------------------+---------------------------------------------------

 Mac OS X 10.2            | ^CFNetwork/1\.1$

 Mac OS X 10.3.2-10.3.8   | ^CFNetwork/1\.2\.1$

 Mac OS X 10.3.9          | ^CFNetwork/1\.2\.[2-6]$

 Mac OS X 10.4            | ^CFNetwork/128$

 Mac OS X 10.4.10         | ^CFNetwork/129\.21$

 Mac OS X 10.4.11         | ^CFNetwork/129\.22$

 Mac OS X 10.4.2          | ^CFNetwork/128\.2$

 Mac OS X 10.4.3          | ^CFNetwork/(129\.5|10\.4\.3)$

 Mac OS X 10.4.4          | ^CFNetwork/(129\.(9|10)|10\.4\.4)$

 Mac OS X 10.4.5          | ^CFNetwork/129\.11$

 Mac OS X 10.4.6          | ^CFNetwork/129\.13$

 Mac OS X 10.4.7          | ^CFNetwork/(129\.16|4\.0)$

 Mac OS X 10.4.8          | ^CFNetwork/129\.1(8|9)$

 Mac OS X 10.4.9          | ^CFNetwork/129\.20$

 Mac OS X 10.5            | ^CFNetwork/21[7-9]$

 Mac OS X 10.5.1          | ^CFNetwork/220$

 Mac OS X 10.5-prerelease | ^CFNetwork/1[4-9][0-9](\.[0-9])?|20[0-9]|21[0-9]$

They might not be 100% correct, but they're good enough.