Jochem wrote
Why not directly log to XML?

Because it doesn’t have any advantage over using dicts, is completely unreadable to most human beings, is extremely verbose, and requires specific packages/programs to be parsed?

def log(**kw):
    print >> logfile, kw

and use it like this:

log(state='failed-to-parse', strange_data=data, time=time.ctime())

if not parseData(data):
  print >> logfile, {'state' : 'failed-to-parse', 'strange-data' : data,
                     'time' : time.ctime() }

Python’s serializing code ensures that I’ll only get one record per line, regardless of what binary garbage is in the ‘data’. And processing existing logs is as easy as grep or:

for line in file('logfile'):
   rec = eval( line.rstrip() )
   if rec['state'] == 'failed-to-parse':
      lookOver( rec['strange-data'] )

Granted, there are security problems if you eval someone else’s data, but for logs you generate, this is as easy & powerful as it gets.

Jochem: grep.