archlinux pacman helper

I don't always follow pacman updates output. I believe this behavior was the reason I was left with an unbootable system. Mainly because of a long time due change for /bin/systemd to be removed, /bin/init being the sole entry point for the bootloader to continue. Anyway, as for LFS (Linux From Scratch), logging things could help, so as for now I'll use :

pacman -Su | tee pacman.dash.Su.`date +%d%b%G_%H%M%S`.log

in order to be able to read useful information later on.

lennart's day : pulseaudio, systemd, initials and misconfigured system

I stumbled upon some kind of leak. /var/log/journal is eating 2GB. That explains why journalctl is sluggish as hell.

luser@x60s_GPT ~ % journalctl | awk '{print $5}' | sed 's,[^a-zA-Z\-],,g' > log
# 2 hours and 22MB later

luser@x60s_GPT ~ % sort log | uniq -c | sort -nr | head
1953078 pulseaudio
  62863 kernel
  39051 systemd
  14992 sudo
  14463 udisks-daemon
   7923 USRSBINCROND
   4015 usrsbincrond
   1601 dhcpcd
    733 systemd-logind
    704 systemd-journal

So pulseaudio is the prime suspect. A while back I used '-vvvv' for debugging purposes, but removed the vvvverbose option for at least a few weeks. It was dropping dozens of messages every 5 seconds and I can't find a way to trim the old persisted logs. I'm tempted to blindly delete them but will wait a bit before doing so.

tl;dr still looking for a way to manage, meaning trim, systemd journal disk usage a posteriori in case of log bloat.

Trivia: journal log header include LPKSHHRH. I thought it was a compression format magic number, PKZIP comes to mind, but apparently it is more of a signature.

LP KS HH RH ;)

ha, computers. I mean noobs.

debugging notes with python

- with pdb, use aliases

# Ned's .pdbrc
# Print a dictionary, sorted. %1 is the dict, %2 is the prefix for the names.
alias p_ for k in sorted(%1.keys()): print "%s%-15s= %-80.80s" % ("%2",k,repr(%1[k]))
alias pi p_ %1.__dict__ %1. .. # instance variables of %1
alias ps pi self ............. # instance variables of self.
alias pl p_ locals() local: .. # Print the locals.
alias nl n;;l ................ # Next and list.
alias sl s;;l ................ # and step and list.
alias uu u;;u ................ # up the stack
alias dd d;;d ................ # down the stack

source : http://stackoverflow.com/a/1624037

- use sys hooks to react on exception

def traceit(frame, event, arg):
   if event == "line":
        lineno = frame.f_lineno
        print "line", lineno
   return traceit

def main():
    print "In main"
    for i in range(5):
        print i, i*3
    print "Done."

sys.settrace(traceit)
main()

source : http://www.dalkescientific.com/writings/diary/archive/2005/04/20/tracing_python_code.html

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

# code snippet, to be included in 'sitecustomize.py' import sys def info(type, value, tb): if hasattr(sys, 'ps1') or not sys.stderr.isatty(): # we are in interactive mode or we don't have a tty-like # device, so we call the default hook sys.__excepthook__(type, value, tb) else: import traceback, pdb # we are NOT in interactive mode, print the exception... traceback.print_exception(type, value, tb) print # ...then start the debugger in post-mortem mode. pdb.pm() sys.excepthook = info

source : http://code.activestate.com/recipes/65287/

- simple logging 

import logging
logging.basicConfig(level=logging.DEBUG)
logging.debug('This is a debug message.')

source : http://aymanh.com/python-debugging-techniques#logging