Recently I’ve been getting 500 errors once in a while on my DH account. This is usually because a process is long running and the DH monitor kills it for consuming too many resources. Meh. The real cause is putting waaay to much stuff on a shared account.
So, to see what my culripts are I wrote a quick script that I’m hooking to a cron job. First I’ll see what domains are generating 500 errors, and then later I’ll try to locate the exact scripts and clean them up.
500-Error-Finder.sh
#!/bin/bash
cd /home/jmhobbs/logs
for i in *; do
if [ -d "$i" ] && [ -f "$i/http/error.log.0" ]; then
ERRS=$( grep internal_error.html $i/http/error.log.0 | wc -l )
if [ "0" != "$ERRS" ]; then
echo "# $i - $ERRS"
fi
fi
done
The output looks like this.
[pristina]$ ./500-Error-Finder.sh
# gallery.velvetcache.org - 11
[pristina]$
I’ve been tinkering with using UNIX sockets for IPC from Python and I thought I would share my most basic experiment.
This is a super simple example of client/server usage of a socket. Essentially the server is a blocking command socket that echo’s whatever is passed through it.
Listing: server.py
# -*- coding: utf-8 -*-
import socket
import os, os.path
import time
if os.path.exists( "/tmp/python_unix_sockets_example" ):
os.remove( "/tmp/python_unix_sockets_example" )
print "Opening socket..."
server = socket.socket( socket.AF_UNIX, socket.SOCK_DGRAM )
server.bind("/tmp/python_unix_sockets_example")
print "Listening..."
while True:
datagram = server.recv( 1024 )
if not datagram:
break
else:
print "-" * 20
print datagram
if "DONE" == datagram:
break
print "-" * 20
print "Shutting down..."
server.close()
os.remove( "/tmp/python_unix_sockets_example" )
print "Done"
Listing: client.py
# -*- coding: utf-8 -*-
import socket
import os, os.path
print "Connecting..."
if os.path.exists( "/tmp/python_unix_sockets_example" ):
client = socket.socket( socket.AF_UNIX, socket.SOCK_DGRAM )
client.connect( "/tmp/python_unix_sockets_example" )
print "Ready."
print "Ctrl-C to quit."
print "Sending 'DONE' shuts down the server and quits."
while True:
try:
x = raw_input( "> " )
if "" != x:
print "SEND:", x
client.send( x )
if "DONE" == x:
print "Shutting down."
break
except KeyboardInterrupt, k:
print "Shutting down."
client.close()
else:
print "Couldn't Connect!"
print "Done"
Here is the transcript of me running the client.
[email protected]:~/Desktop$ python client.py
Connecting...
Ready.
Ctrl-C to quit.
Sending 'DONE' shuts down the server and quits.
> Helo!
SEND: Helo!
> DONE
SEND: DONE
Shutting down.
Done
[email protected]:~/Desktop$
And here is the server transcript from that session.
[email protected]:~/Desktop$ python server.py
Opening socket...
Listening...
--------------------
Helo!
--------------------
DONE
--------------------
Shutting down...
Done
[email protected]:~/Desktop$
Now all you need is a protocol and you’ll be set for basic IPC.
I was working on a screen cast for a project and I could not get anything to work the way I wanted to. I didn’t have the desire to purchase software, so I sought a way to annotate it for free. I tried a half dozen free and open source video editors, with no real luck. Either they choked on the format I captured (from CamStudio) or they didn’t have a readily available inline text tool.
What I ended up using was plain old subtitles, plus the handyman’s secret weapon, mplayer/mencoder.
Here’s what I did. I fired up the video in VLC and found the points where I wanted to put my subtitle help text. Subtitle files are usually pretty straight forward. I chose the .srt format, which is plain text. You can edit by hand, or you can use a tool, I used the aptly named subtitleeditor. Which, by the way, barfed on my video file.
Here’s a snippet of the resulting .srt file:
1
00:00:00,000 --> 00:00:13,000
Welcome to the product gallery walk through.
2
00:00:13,000 --> 00:00:23,000
Adding a product: Select image.
3
00:00:23,000 --> 00:00:32,000
Insert title and description.
Next I needed to turn those “soft” subs into “hard” ones. This is where mplayer/mencoder come in. To add soft subs to a video in mplayer, you use the -sub option. Running this in mplayer first is a good way to see how it will look at tweak it according to the many options you have. I went with the defaults, it looks pretty good that way.
Lastly, I needed a good mencoder recipe to pull it all together. After lots of searching I found a great MPEG4 one here.
It’s a two pass system, and the crucial piece is in calculating the bitrate:
bitrate = 50 * 25 * width_of_video * height_of_video / 256
My bitrate was 2540600. After you get that, you just plug it into the two passes below. This includes my subtitle options.
mencoder -o /dev/null -ovc lavc -lavcopts vcodec=msmpeg4v2:vpass=1:vbitrate=2540600:mbd=2:keyint=132:vqblur=1.0:cmp=2:subcmp=2:dia=2:mv0:last_pred=3 -nosound -sub MySubTitles.srt -subfont-text-scale 3 RawScreenCast.avi
mencoder -o FinishedScreenCast.avi -ovc lavc -lavcopts vcodec=msmpeg4v2:vpass=2:vbitrate=2540600:mbd=2:keyint=132:vqblur=1.0:cmp=2:subcmp=2:dia=2:mv0:last_pred=3 -nosound -sub MySubTitles.srt -subfont-text-scale 3 RawScreenCast.avi
It takes a while but not too long. When all was said and done I had a perfect hard-subbed version and it shrank my file size from ~550MB to 7.6MB. That is a great encoding recipe.
An average frame, with hard subs.
