Python: different run vs debug mode behavior in PyCharm

Question

Python code when you start from PyCharm without a debugger attached behaves differently than when you start with pydev.

I run the POX SDN controller in PyCharm and Mininet from a console that connects a listening socket opened by POX. When starting in debug mode, the POX process ends as soon as the Mininet simulation connects to it without any errors, while it continues to work as expected in start mode. Here is the result:

Run:

/usr/bin/python2.7 /home/wirate/pyretic/pyretic.py pyretic.sdx.main Initialize SDX SDX: {'_policy': drop, 'notify': None, 'arp_policy': [DynamicPolicy] packets FwdBucket} Creating SDX environment from the config files Adding Physical ports for A Adding virtual ports for A Adding Physical ports for C Adding virtual ports for C Adding Physical ports for B Adding virtual ports for B {u'A': {u'A': [1], u'C': [3], u'B': [2]}, u'C': {u'C': [3, 4]}, u'B': {u'B': [2]}} {u'A': {u'A': [1], u'C': [3], u'B': [2]}, u'C': {u'A': [1], u'C': [3, 4], u'B': [2]}, u'B': {u'B': [2]}} {u'A': {u'A': [1], u'C': [3], u'B': [2]}, u'C': {u'A': [1], u'C': [3, 4], u'B': [2]}, u'B': {u'A': [1], u'C': [3], u'B': [2]}} Parsing participant policies Starting VNH Assignment After new assignment Virtual Next Hop --> IP Prefix: {'VNH1': set([u'110.0.0.0/24', u'100.0.0.0/24']), 'VNH2': set([u'140.0.0.0/24', u'150.0.0.0/24'])} Virtual Next Hop --> Next Hop IP Address (Virtual): {'VNH1': '172.0.1.1', 'VNH2': '172.0.1.2', 'VNH': [IPAddress('172.0.1.0'), IPAddress('172.0.1.1'), IPAddress('172.0.1.2'), IPAddress('172.0.1.3'), IPAddress('172.0.1.4'), IPAddress('172.0.1.5'), IPAddress('172.0.1.6'), IPAddress('172.0.1.7'), IPAddress('172.0.1.8'), IPAddress('172.0.1.9'), IPAddress('172.0.1.10'), IPAddress('172.0.1.11'), IPAddress('172.0.1.12'), IPAddress('172.0.1.13'), IPAddress('172.0.1.14'), IPAddress('172.0.1.15')]} Virtual Next Hop --> Next Hop Mac Address (Virtual) {'VNH1': aa:00:00:00:00:01, 'VNH2': aa:00:00:00:00:02, 'VNH': 'aa:00:00:00:00:00'} Completed VNH Assignment POX 0.2.0 (carp) / Copyright 2011-2013 James McCauley, et al. Connected to pyretic frontend. DEBUG:core:POX 0.2.0 (carp) going up... DEBUG:core:Running on CPython (2.7.8/Oct 20 2014 15:05:19) DEBUG:core:Platform is Linux-3.16.0-24-generic-x86_64-with-Ubuntu-14.10-utopic INFO:core:POX 0.2.0 (carp) is up. DEBUG:openflow.of_01:Listening on 0.0.0.0:6633 INFO:openflow.of_01:[00-00-00-00-00-01 1] connected 

Debug:

 /usr/bin/python2.7 /home/wirate/pycharm-4.0/helpers/pydev/pydevd.py --multiproc --client 127.0.0.1 --port 49196 --file /home/wirate/pyretic/pyretic.py pyretic.sdx.main pydev debugger: process 5555 is connecting Connected to pydev debugger (build 139.574) Initialize SDX SDX: {'_policy': drop, 'notify': None, 'arp_policy': [DynamicPolicy] packets FwdBucket} Creating SDX environment from the config files Adding Physical ports for A Adding virtual ports for A Adding Physical ports for C Adding virtual ports for C Adding Physical ports for B Adding virtual ports for B {u'A': {u'A': [1], u'C': [3], u'B': [2]}, u'C': {u'C': [3, 4]}, u'B': {u'B': [2]}} {u'A': {u'A': [1], u'C': [3], u'B': [2]}, u'C': {u'A': [1], u'C': [3, 4], u'B': [2]}, u'B': {u'B': [2]}} {u'A': {u'A': [1], u'C': [3], u'B': [2]}, u'C': {u'A': [1], u'C': [3, 4], u'B': [2]}, u'B': {u'A': [1], u'C': [3], u'B': [2]}} Parsing participant policies Starting VNH Assignment After new assignment Virtual Next Hop --> IP Prefix: {'VNH1': set([u'110.0.0.0/24', u'100.0.0.0/24']), 'VNH2': set([u'140.0.0.0/24', u'150.0.0.0/24'])} Virtual Next Hop --> Next Hop IP Address (Virtual): {'VNH1': '172.0.1.1', 'VNH2': '172.0.1.2', 'VNH': [IPAddress('172.0.1.0'), IPAddress('172.0.1.1'), IPAddress('172.0.1.2'), IPAddress('172.0.1.3'), IPAddress('172.0.1.4'), IPAddress('172.0.1.5'), IPAddress('172.0.1.6'), IPAddress('172.0.1.7'), IPAddress('172.0.1.8'), IPAddress('172.0.1.9'), IPAddress('172.0.1.10'), IPAddress('172.0.1.11'), IPAddress('172.0.1.12'), IPAddress('172.0.1.13'), IPAddress('172.0.1.14'), IPAddress('172.0.1.15')]} Virtual Next Hop --> Next Hop Mac Address (Virtual) {'VNH1': aa:00:00:00:00:01, 'VNH2': aa:00:00:00:00:02, 'VNH': 'aa:00:00:00:00:00'} Completed VNH Assignment pydev debugger: process 5595 is connecting POX 0.2.0 (carp) / Copyright 2011-2013 James McCauley, et al. POX 0.2.0 (carp) / Copyright 2011-2013 James McCauley, et al. Connected to pyretic frontend. DEBUG:core:POX 0.2.0 (carp) going up... DEBUG:core:Running on CPython (2.7.8/Oct 20 2014 15:05:19) DEBUG:core:Platform is Linux-3.16.0-24-generic-x86_64-with-Ubuntu-14.10-utopic INFO:core:POX 0.2.0 (carp) is up. DEBUG:openflow.of_01:Listening on 0.0.0.0:6633 INFO:openflow.of_01:[None 1] closed INFO:openflow.of_01:[00-00-00-00-00-01 2] connected Process finished with exit code 137 

This is the code that starts the controller:

 def main(): global of_client (op, options, args, kwargs_to_pass) = parseArgs() if options.mode == 'i': options.mode = 'interpreted' elif options.mode == 'r0': options.mode = 'reactive0' elif options.mode == 'p0': options.mode = 'proactive0' elif options.mode == 'p1': options.mode = 'proactive1' try: module_name = args[0] except IndexError: print 'Module must be specified' print '' op.print_usage() sys.exit(1) try: module = import_module(module_name) except ImportError, e: print 'Must be a valid python module' print 'eg, full module name,' print ' no .py suffix,' print ' located on the system PYTHONPATH' print '' print 'Exception message for ImportError was:' print e sys.exit(1) main = module.main kwargs = { k : v for [k,v] in [ i.lstrip('--').split('=') for i in kwargs_to_pass ]} sys.setrecursionlimit(1500) #INCREASE THIS IF "maximum recursion depth exceeded" # Set up multiprocess logging. verbosity_map = { 'low' : logging.WARNING, 'normal' : logging.INFO, 'high' : logging.DEBUG, 'please-make-it-stop' : logging.DEBUG } logging_queue = Queue() # Make a logging process. def log_writer(queue, log_level): formatter = logging.Formatter('%(levelname)s:%(name)s: %(message)s') handler = logging.StreamHandler() handler.setFormatter(formatter) handler.setLevel(log_level) logger = logging.getLogger() logger.addHandler(handler) logger.setLevel(log_level) while(True): try: to_log = queue.get() except KeyboardInterrupt, e: print "\nkilling log" import sys sys.exit(0) logger.handle(to_log) log_level = verbosity_map.get(options.verbosity, logging.DEBUG) log_process = Process(target=log_writer,args=(logging_queue, log_level,)) log_process.daemon = True log_process.start() # Set default handler. logger = logging.getLogger() handler = util.QueueStreamHandler(logging_queue) logger.addHandler(handler) logger.setLevel(log_level) runtime = Runtime(Backend(),main,kwargs,options.mode,options.verbosity) if not options.frontend_only: try: output = subprocess.check_output('echo $PYTHONPATH',shell=True).strip() except: print 'Error: Unable to obtain PYTHONPATH' sys.exit(1) poxpath = None for p in output.split(':'): if re.match('.*pox/?$',p): poxpath = os.path.abspath(p) break if poxpath is None: print 'Error: pox not found in PYTHONPATH' sys.exit(1) pox_exec = os.path.join(poxpath,'pox.py') python=sys.executable # TODO(josh): pipe pox_client stdout to subprocess.PIPE or # other log file descriptor if necessary of_client = subprocess.Popen([python, pox_exec, '--verbose', 'of_client.pox_client' ], stdout=sys.stdout, stderr=subprocess.STDOUT) signal.signal(signal.SIGINT, signal_handler) signal.pause() 

Maybe I should add that I'm running PyCharm as root because privileges are required to run the controller.

Answer 1

I am not sure about your particular case. However, to debug the POX component (in Pycharm ), I use the code below:

 import sys sys.path.append('Address_to_POX_folder') from pox import boot def main(): sys.argv.append('Your_POX_Component') boot.boot() if __name__=='__main__': main() 

When I use this code to start POX in Pycharm , mininet switches to POX and the component I use ('Your_POX_Component'), and I can also debug my component (pause execution and see variable ...) without any problems.

Answer 2

My project worked in Debug and did not work in Run. This happened to me several times during the revisions. Decisions taken included:

• restart pycharm
• update
• upgrade to a new installation of PyCharm
• clearing cache
• starting a new project using only python files
• and etc.

One thing solved the problem for me.

• I went to the Run menu → "Attach to local process .."
• I chose the only available option "pydevconsole.py" (also some process identifiers coincided with the name).

The problem is resolved; It worked both at startup and during debugging.