Only enable console logging when running interactive session

By default, only a NullHandler is added to the 'scapy' logger. This
allows third party applications that use scapy as a library to control
the logging of scapy messages.

Signed-off-by: Robin Jarry <robin.jarry@6wind.com>

scapy/error.py

@@ -45,10 +45,16 @@ class ScapyFreqFilter(logging.Filter):
             self.warning_table[caller] = (tm,nb)
         return 1    
 
+try:
+    from logging import NullHandler
+except ImportError:
+    # compat for python 2.6
+    from logging import Handler
+    class NullHandler(Handler):
+        def emit(self, record):
+            pass
 log_scapy = logging.getLogger("scapy")
-console_handler = logging.StreamHandler()
-console_handler.setFormatter(logging.Formatter("%(levelname)s: %(message)s"))
-log_scapy.addHandler(console_handler)
+log_scapy.addHandler(NullHandler())
 log_runtime = logging.getLogger("scapy.runtime")          # logs at runtime
 log_runtime.addFilter(ScapyFreqFilter())
 log_interactive = logging.getLogger("scapy.interactive")  # logs in interactive functions

scapy/main.py

@@ -196,6 +196,10 @@ def interact(mydict=None,argv=None,mybanner=None,loglevel=20):
     if loglevel is not None:
         conf.logLevel=loglevel
 
+    console_handler = logging.StreamHandler()
+    console_handler.setFormatter(logging.Formatter("%(levelname)s: %(message)s"))
+    log_scapy.addHandler(console_handler)
+
     the_banner = "Welcome to Scapy (%s)"
     if mybanner is not None:
         the_banner += "\n"