implement utils.print_exception()

Previously we used logging.error(e) and traceback.print_exc()
to output error stack trace. The problem is, we want to
output the stack trace only when verbose > 0. The if statement
scattered around the code. So we replaced them with the new
utils.print_exception() call.

shadowsocks/asyncdns.py

@@ -25,7 +25,7 @@ import struct
 import re
 import logging
 
-from shadowsocks import common, lru_cache, eventloop
+from shadowsocks import common, lru_cache, eventloop, utils
 
 
 CACHE_SWEEP_INTERVAL = 30
@@ -221,9 +221,7 @@ def parse_response(data):
                 response.answers.append((an[1], an[2], an[3]))
             return response
     except Exception as e:
-        import traceback
-        traceback.print_exc()
-        logging.error(e)
+        utils.print_exception(e)
         return None
 
 

shadowsocks/daemon.py

@@ -23,7 +23,7 @@ import sys
 import logging
 import signal
 import time
-from shadowsocks import common
+from shadowsocks import common, utils
 
 # this module is ported from ShadowVPN daemon.c
 
@@ -58,7 +58,7 @@ def write_pid_file(pid_file, pid):
         fd = os.open(pid_file, os.O_RDWR | os.O_CREAT,
                      stat.S_IRUSR | stat.S_IWUSR)
     except OSError as e:
-        logging.error(e)
+        utils.print_exception(e)
         return -1
     flags = fcntl.fcntl(fd, fcntl.F_GETFD)
     assert flags != -1
@@ -127,7 +127,7 @@ def daemon_start(pid_file, log_file):
         freopen(log_file, 'a', sys.stdout)
         freopen(log_file, 'a', sys.stderr)
     except IOError as e:
-        logging.error(e)
+        utils.print_exception(e)
         sys.exit(1)
 
 
@@ -140,7 +140,7 @@ def daemon_stop(pid_file):
             if not buf:
                 logging.error('not running')
     except IOError as e:
-        logging.error(e)
+        utils.print_exception(e)
         if e.errno == errno.ENOENT:
             # always exit 0 if we are sure daemon is not running
             logging.error('not running')
@@ -155,7 +155,7 @@ def daemon_stop(pid_file):
                 logging.error('not running')
                 # always exit 0 if we are sure daemon is not running
                 return
-            logging.error(e)
+            utils.print_exception(e)
             sys.exit(1)
     else:
         logging.error('pid is not positive: %d', pid)

shadowsocks/eventloop.py

@@ -28,6 +28,8 @@ import errno
 import logging
 from collections import defaultdict
 
+from shadowsocks import utils
+
 
 __all__ = ['EventLoop', 'POLL_NULL', 'POLL_IN', 'POLL_OUT', 'POLL_ERR',
            'POLL_HUP', 'POLL_NVAL', 'EVENT_NAMES']
@@ -223,9 +225,7 @@ class EventLoop(object):
                 try:
                     handler(events)
                 except (OSError, IOError) as e:
-                    logging.error(e)
-                    import traceback
-                    traceback.print_exc()
+                    utils.print_exception(e)
             if self._handlers_to_remove:
                 for handler in self._handlers_to_remove:
                     self._handlers.remove(handler)

shadowsocks/local.py

@@ -65,10 +65,7 @@ def main():
         daemon.set_user(config.get('user', None))
         loop.run()
     except Exception as e:
-        logging.error(e)
-        if config['verbose']:
-            import traceback
-            traceback.print_exc()
+        utils.print_exception(e)
         sys.exit(1)
 
 if __name__ == '__main__':

shadowsocks/server.py

@@ -80,10 +80,7 @@ def main():
             daemon.set_user(config.get('user', None))
             loop.run()
         except Exception as e:
-            logging.error(e)
-            if config['verbose']:
-                import traceback
-                traceback.print_exc()
+            utils.print_exception(e)
             sys.exit(1)
 
     if int(config['workers']) > 1:

shadowsocks/tcprelay.py

@@ -203,9 +203,7 @@ class TCPRelayHandler(object):
                             errno.EWOULDBLOCK):
                 uncomplete = True
             else:
-                logging.error(e)
-                if self._config['verbose']:
-                    traceback.print_exc()
+                utils.print_exception(e)
                 self.destroy()
                 return False
         if uncomplete:
@@ -259,7 +257,7 @@ class TCPRelayHandler(object):
                     self._config['fast_open'] = False
                     self.destroy()
                 else:
-                    logging.error(e)
+                    utils.print_exception(e)
                     if self._config['verbose']:
                         traceback.print_exc()
                     self.destroy()
@@ -383,7 +381,7 @@ class TCPRelayHandler(object):
                         self._update_stream(STREAM_DOWN, WAIT_STATUS_READING)
                     return
                 except Exception as e:
-                    logging.error(e)
+                    utils.print_exception(e)
                     if self._config['verbose']:
                         traceback.print_exc()
         self.destroy()
@@ -445,7 +443,7 @@ class TCPRelayHandler(object):
         try:
             self._write_to_sock(data, self._local_sock)
         except Exception as e:
-            logging.error(e)
+            utils.print_exception(e)
             if self._config['verbose']:
                 traceback.print_exc()
             # TODO use logging when debug completed
@@ -683,7 +681,7 @@ class TCPRelay(object):
                                     errno.EWOULDBLOCK):
                         continue
                     else:
-                        logging.error(e)
+                        utils.print_exception(e)
                         if self._config['verbose']:
                             traceback.print_exc()
             else:

shadowsocks/udprelay.py

@@ -69,7 +69,7 @@ import struct
 import errno
 import random
 
-from shadowsocks import encrypt, eventloop, lru_cache, common
+from shadowsocks import encrypt, eventloop, lru_cache, common, utils
 from shadowsocks.common import parse_header, pack_addr
 
 
@@ -208,7 +208,7 @@ class UDPRelay(object):
             if err in (errno.EINPROGRESS, errno.EAGAIN):
                 pass
             else:
-                logging.error(e)
+                utils.print_exception(e)
 
     def _handle_client(self, sock):
         data, r_addr = sock.recvfrom(BUF_SIZE)

shadowsocks/utils.py

@@ -29,6 +29,8 @@ from shadowsocks import encrypt
 
 VERBOSE_LEVEL = 5
 
+verbose = 0
+
 
 def check_python():
     info = sys.version_info
@@ -43,6 +45,14 @@ def check_python():
         sys.exit(1)
 
 
+def print_exception(e):
+    global verbose
+    logging.error(e)
+    if verbose > 0:
+        import traceback
+        traceback.print_exc()
+
+
 def print_shadowsocks():
     version = ''
     try:
@@ -115,6 +125,8 @@ def check_config(config, is_local):
 
 
 def get_config(is_local):
+    global verbose
+
     logging.basicConfig(level=logging.INFO,
                         format='%(levelname)-s: %(message)s')
     if is_local:
@@ -243,6 +255,7 @@ def get_config(is_local):
         level = logging.ERROR
     else:
         level = logging.INFO
+    verbose = config['verbose']
     logging.basicConfig(level=level,
                         format='%(asctime)s %(levelname)-8s %(message)s',
                         datefmt='%Y-%m-%d %H:%M:%S')