tahoe-lafs/misc/make_umid

#!/usr/bin/python

"""Create a short probably-unique string for use as a umid= argument in a
Foolscap log() call, to make it easier to locate the source code that
generated the message. The main text of the log message is frequently
unhelpful for this, and python doesn't make it cheap to compile in the
filename and line number of logging calls.

Given a message-unique-ID like 'aXoWcA', make your logging call look like:

 log.msg('OMG badness', level=log.WEIRD, umid='aXoWcA')

Then later, if this message actually occurs, you can grep your source tree
for aXoWcA to locate the code that caused it.

Just stick to the convention that 'umid=' is reserved for this job. It is a
good idea to make all the logging statements that could provoke an Incident
(i.e. those at level=log.WEIRD or higher) have umid= arguments, to make it
easier to write classifier functions for the incident-gatherer.

"""

'''
The following elisp code may be useful:

 (defun insert-umid ()
   (interactive)
   (insert ", umid=\"")
   (call-process "make_umid" nil t)
   (delete-char -1)
   (insert "\"")
 )
 (global-set-key (kbd "C-\`") 'insert-umid)
'''

# '   # emacs gets confused by the odd number of single-quotes there

import os, base64, sys

def make_id():
    while True:
        m = os.urandom(4) # this gives 6-character message ids
        m = base64.b64encode(m)
        if "/" in m or "+" in m:
            continue
        m = m.replace("=", "")
        break
    return m

count = 1
if len(sys.argv) > 1:
    count = int(sys.argv[1])
for i in range(count):
    print make_id()