Improve error handling.

Now all errors that should be reported back to the pymin client should
inherit from dispatcher.HandlerError. Any other error is reported to the
client as an internal server error and it's printed in the daemon standard
output for debugging purposes. A new line is now appended to errors
reported to the client for better consistency with OK responses.

diff --git a/dispatcher.py b/dispatcher.py
index 0284da5c499b03805babd97caec2dda8fa99c5ab..b78db93a3e0f042c273821dda82c44450aec8403 100644 (file)
--- a/dispatcher.py
+++ b/dispatcher.py
@@ -18,16 +18,17 @@ class Error(RuntimeError):
     command - is the command that raised the exception, expressed as a list of
               paths (or subcommands).
     """
+    pass
 
-    def __init__(self, command):
-        r"""Initialize the Error object.
+class HandlerError(Error):
+    r"""
+    HandlerError(command) -> HandlerError instance :: Base handlers exception.
 
-        See Error class documentation for more info.
-        """
-        self.command = command
+    All exceptions raised by the handlers should inherit from this one, so
+    dispatching errors could be separated from real programming errors (bugs).
+    """
+    pass
 
-    def __str__(self):
-        return 'Command not found: "%s"' % ' '.join(self.command)
 
 class CommandNotFoundError(Error):
     r"""
@@ -36,7 +37,16 @@ class CommandNotFoundError(Error):
     This exception is raised when the command received can't be dispatched
     because there is no handlers to process it.
     """
-    pass
+
+    def __init__(self, command):
+        r"""Initialize the Error object.
+
+        See Error class documentation for more info.
+        """
+        self.command = command
+
+    def __str__(self):
+        return 'Command not found: "%s"' % ' '.join(self.command)
 
 def handler(f):
     f._dispatcher_handler = True

diff --git a/pymindaemon.py b/pymindaemon.py
index c3fdda68674fffd65b589181f153b60d4d094d84..b7e56e4cbf4c06cd7c6736aac8df457c8b13ad27 100644 (file)
--- a/pymindaemon.py
+++ b/pymindaemon.py
@@ -65,8 +65,13 @@ class PyminDaemon(eventloop.EventLoop):
             if result is not None:
                 result = serializer.serialize(result)
             response = u'OK '
+        except dispatcher.Error, e:
+            result = unicode(e) + u'\n'
+            response = u'ERROR '
         except Exception, e:
-            result = unicode(e)
+            import traceback
+            result = u'Internal server error'
+            traceback.print_exc() # TODO logging!
             response = u'ERROR '
         if result is None:
             response += u'0'

diff --git a/services/dhcp/__init__.py b/services/dhcp/__init__.py
index 5734c2f70e1ca1c2335092582ebb05de37edfdc3..b728162c278276837a5a35771b859aa611cd9474 100644 (file)
--- a/services/dhcp/__init__.py
+++ b/services/dhcp/__init__.py
@@ -8,11 +8,17 @@ try:
 except ImportError:
     import pickle
 
-import seqtools
 try:
-    from dispatcher import handler
+    from seqtools import Sequence
 except ImportError:
-    def handler(f): return f # NOP for testing
+    # NOP for testing
+    class Sequence: pass
+try:
+    from dispatcher import handler, HandlerError
+except ImportError:
+    # NOP for testing
+    class HandlerError(RuntimeError): pass
+    def handler(f): return f
 
 __ALL__ = ('DhcpHandler',)
 
@@ -24,7 +30,7 @@ config_filename = 'dhcpd.conf'
 
 template_dir = path.join(path.dirname(__file__), 'templates')
 
-class Error(RuntimeError):
+class Error(HandlerError):
     r"""
     Error(command) -> Error instance :: Base DhcpHandler exception class.
 
@@ -99,7 +105,7 @@ class ParameterNotFoundError(ParameterError):
         self.message = 'Parameter not found: "%s"' % paramname
 
 
-class Host(seqtools.Sequence):
+class Host(Sequence):
     r"""Host(name, ip, mac) -> Host instance :: Class representing a host.
 
     name - Host name, should be a fully qualified name, but no checks are done.