BIND 10 trac2676, updated. 6667c5c3485db2ec1da350d4b90896b871e07bad [2676] Error handling in the rpc_call

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- Log -----------------------------------------------------------------
commit 6667c5c3485db2ec1da350d4b90896b871e07bad
Author: Michal 'vorner' Vaner <michal.vaner at nic.cz>
Date:   Thu Feb 14 10:54:07 2013 +0100

    [2676] Error handling in the rpc_call

commit 488d42f3ae5c7f97ef144370036b5c9b7736a9d1
Author: Michal 'vorner' Vaner <michal.vaner at nic.cz>
Date:   Thu Feb 14 10:34:16 2013 +0100

    [2676] Further tests for rpc_call
    
    An unusual case and a malformed answer.

-----------------------------------------------------------------------

Summary of changes:
 src/lib/python/isc/config/ccsession.py            |   29 +++++++++++
 src/lib/python/isc/config/tests/ccsession_test.py |   55 ++++++++++++++++++---
 2 files changed, 76 insertions(+), 8 deletions(-)

-----------------------------------------------------------------------
diff --git a/src/lib/python/isc/config/ccsession.py b/src/lib/python/isc/config/ccsession.py
index c5c8a89..529408c 100644
--- a/src/lib/python/isc/config/ccsession.py
+++ b/src/lib/python/isc/config/ccsession.py
@@ -51,6 +51,31 @@ logger = isc.log.Logger("config")
 
 class ModuleCCSessionError(Exception): pass
 
+class RPCError(ModuleCCSessionError):
+    """
+    An exception raised by rpc_call in case the remote side reports
+    an error. It can be used to distinguish remote errors from protocol errors.
+    Also, it holds the code as well as the error message.
+    """
+    def __init__(self, code, message):
+        ModuleCCSessionError.__init__(self, message)
+        self.__code = code
+
+    def code(self):
+        """
+        The code as sent over the CC.
+        """
+        return self.__code
+
+class RPCRecipientMissing(RPCError):
+    """
+    Special version of the RPCError, for cases the recipient of the call
+    isn't connected to the bus. The code is always
+    isc.cc.proto_defs.CC_REPLY_NO_RECPT.
+    """
+    def __init__(self, message):
+        RPCError.__init__(self, CC_REPLY_NO_RECPT, message)
+
 def parse_answer(msg):
     """Returns a tuple (rcode, value), where value depends on the
        command that was called. If rcode != 0, value is a string
@@ -484,6 +509,10 @@ class ModuleCCSession(ConfigData):
         # works)
         reply, rheaders = self._session.group_recvmsg(nonblock=False, seq=seq)
         code, value = parse_answer(reply)
+        if code == CC_REPLY_NO_RECPT:
+            raise RPCRecipientMissing(value)
+        elif code != 0:
+            raise RPCError(code, value)
         return value
 
 class UIModuleCCSession(MultiConfigData):
diff --git a/src/lib/python/isc/config/tests/ccsession_test.py b/src/lib/python/isc/config/tests/ccsession_test.py
index 0f772ff..cc81526 100644
--- a/src/lib/python/isc/config/tests/ccsession_test.py
+++ b/src/lib/python/isc/config/tests/ccsession_test.py
@@ -289,26 +289,65 @@ class TestModuleCCSession(unittest.TestCase):
         fake_session.close()
         mccs.__del__() # with closed fake_session
 
-    def test_rpc_call_success(self):
-        """
-        Test we can send an RPC (command) and get an answer. The answer is
-        success in this case.
-        """
+    def rpc_check(self, reply):
         fake_session = FakeModuleCCSession()
         mccs = self.create_session("spec1.spec", None, None, fake_session)
         fake_session.message_queue = [
-            ["Spec1", None, {"result": [0, {"Hello": "a"}]}, False]
+            ["Spec1", None, reply, False]
         ]
-        result = mccs.rpc_call("test", "Spec2", param1="Param 1",
-                               param2="Param 2")
+        exception = None
+        try:
+            result = mccs.rpc_call("test", "Spec2", param1="Param 1",
+                                   param2="Param 2")
+        except Exception as e:
+            # We first want to check the value sent, raise the exception
+            # afterwards. So store it for a short while.
+            exception = e
         self.assertEqual([
                 ["Spec2", "*", {"command": ["test", {
                     "param1": "Param 1",
                     "param2": "Param 2"
                 }]}, True]
             ], fake_session.message_queue)
+        if exception is not None:
+            raise exception
+        return result
+
+    def test_rpc_call_success(self):
+        """
+        Test we can send an RPC (command) and get an answer. The answer is
+        success in this case.
+        """
+        result = self.rpc_check({"result": [0, {"Hello": "a"}]})
         self.assertEqual({"Hello": "a"}, result)
 
+    def test_rpc_call_success_none(self):
+        """
+        Test the success case of RPC command, but the answer is empty
+        (eg. a "void" function on the remote side).
+        """
+        self.assertIsNone(self.rpc_check({"result": [0]}))
+
+    def test_rpc_call_malformed_answer(self):
+        """
+        Test it successfully raises ModuleCCSessionError when a malformed
+        reply is sent.
+        """
+        self.assertRaises(ModuleCCSessionError, self.rpc_check, ["Nonsense"])
+
+    def test_rpc_call_error(self):
+        """
+        Test it raises an exception when the remote side reports an error.
+        """
+        self.assertRaises(RPCError, self.rpc_check, {"result": [1, "Error"]})
+
+    def test_rpc_call_no_recpt(self):
+        """
+        Test RPC raises an error when the recipient is not there.
+        """
+        self.assertRaises(RPCRecipientMissing, self.rpc_check,
+                          {"result": [-1, "Error"]})
+
     def my_config_handler_ok(self, new_config):
         return isc.config.ccsession.create_answer(0)