Crier: simple introspection for long-running Python processes

crier.py

import pprint
import os
import sys
import threading
import time
import traceback

_crier = None
def init_crier(temp_dir='/tmp'):
    "Initialzies Crier, ensuring it's only created once in the process"
    global _crier
    if _crier is None:
        _crier = Crier(threading.current_thread(), temp_dir=temp_dir)

class Crier(object):
    """
    Crier spawns a thread watching for the existence of crier request files
    in the temp directory. Upon finding a request file, Crier writes a
    traceback file to the temp directory. Traceback files include a stack trace
    and a snapshot of local variables for each thread in the process.
    """
    def __init__(self, app_thread, temp_dir='/tmp'):
        self.app_thread = app_thread
        self.watch_file = os.path.join(temp_dir, 'crier-%d' % os.getpid())
        self.traceback_file = os.path.join(temp_dir, 'dump-%d' % os.getpid())
        self.watch_thread = threading.Thread(target=self.watch_thread)
        self.watch_thread.start()

    def watch_thread(self):
        """
        Check for dump requests while the thread that initialized
        Crier is still alive
        """
        while self.app_thread.isAlive():
            if self.check_request():
                self.write_traceback()
            time.sleep(1)

    def check_request(self):
        """
        Checks the temp directory for the existence for a file named
        'crier-{pid}', where {pid} is the ID of this process.
        """
        if os.path.exists(self.watch_file):
            os.unlink(self.watch_file)
            return True
        return False

    def write_traceback(self):
        """
        Writes a traceback file to the temp directory named 'traceback-{pid},
        where {pid} is the ID of this process.
        """
        tmap = {}
        main_thread = None
        # get a map of threads by their ID so we can print their names
        # during the traceback dump
        for t in threading.enumerate():
            if t.ident:
                tmap[t.ident] = t
            else:
                main_thread = t
        out = open(self.traceback_file, 'w')
        # Loop over each thread's current frame, writing info about it
        for tid, frame in sys._current_frames().iteritems():
            thread = tmap.get(tid, main_thread)
            # no reason to write about Crier's thread.
            if thread == self.watch_thread:
                continue
            out.write('%s\n' % thread.getName())
            out.write('========================================\n')
            traceback.print_stack(frame, file=out)
            out.write('========================================\n')
            out.write('LOCAL VARIABLES:\n')
            out.write('========================================\n')
            pprint.pprint(frame.f_locals, stream=out)
            out.write('\n\n')
        out.close()

example.py

import time
from crier import init_crier

init_crier()

def main():
    i = 60
    while i:
        time.sleep(1)
        i -= 1

if __name__ == '__main__':
    main()

#########################################################
# assume example.py has a process id of 1234
#
# $> touch /tmp/crier-1234
# $> cat /tmp/dump-1234
# MainThread
# ========================================
#   File "example.py", line 88, in <module>
#     main()
#   File "example.py", line 84, in main
#     time.sleep(1)
# ========================================
# LOCAL VARIABLES:
# ========================================
# {'i': 34}
# 

Hello,

Can you tell me under what license this code is published?
Thanks!