Add SIGUSR1 traceback (made by jimbo, committed by TPG)

TracebackPrinter.py

+"""
+TracebackPrinter.py - Prints the current stack trace to a specified
+file when SIGUSR1 is received.
+---
+Author: James Arcus <jimbo@ucc.asn.au>
+Based-On: python-traceback-signal
+          <https://github.com/angelcam/python-traceback-signal>
+Author: Angelcam <dev@angelcam.com>
+"""
+
+import os
+import sys
+import traceback
+import signal
+
+def print_traceback(wfd, frame):
+    msg = "Traceback signal received.\nTraceback (most recent call last):\n"
+    msg += ''.join(traceback.format_stack(frame))
+    os.write(wfd, msg)
+
+def register_sigusr(wfd):
+    def sigusr_handler(_, frame):
+        # first param is which signal
+        print_traceback(wfd, frame)
+
+    signal.signal(signal.SIGUSR1, sigusr_handler)
+
+def traceback_init(f):
+    wfd = os.open(f, os.O_WRONLY | os.O_APPEND | os.O_CREAT, 0o600)
+    register_sigusr(wfd)

VendServer/VendServer.py

@@ -20,6 +20,7 @@ from SnackConfig import get_snack#, get_snacks
 import socket
 from posix import geteuid
 from OpenDispense import OpenDispense as Dispense
+import TracebackPrinter
 
 CREDITS="""
 This vending machine software brought to you by:
@@ -963,6 +964,7 @@ def parse_args():
 	op.add_option('-v', '--verbose', dest='verbose', action='store_true', default=False, help='spit out lots of debug output')
 	op.add_option('-q', '--quiet', dest='quiet', action='store_true', default=False, help='only report errors')
 	op.add_option('--pid-file', dest='pid_file', metavar='FILE', default='', help='store daemon\'s pid in the given file')
+        op.add_option('--traceback-file', dest='traceback_file', default='', help='destination to print tracebacks when receiving SIGUSR1')
 	options, args = op.parse_args()
 
 	if len(args) != 0:
@@ -991,7 +993,7 @@ def set_stuff_up():
 	if options.daemon: become_daemon()
 	set_up_logging(options)
 	if options.pid_file != '': create_pid_file(options.pid_file)
-
+	if options.traceback_file != '': TracebackPrinter.traceback_init(options.traceback_file)
 	return options, config_opts
 
 def clean_up_nicely(options, config_opts):
@@ -1055,7 +1057,7 @@ def do_vend_server(options, config_opts):
 			continue
 		
 #		run_forever(rfh, wfh, options, config_opts)
-		
+
 		try:
 			vserver = VendServer()
 			vserver.run_forever(rfh, wfh, options, config_opts)