THRIFT-4904: Fix python unit test errors and exception escapes

Due to the way SSL layers on top of sockets, it was possible
to complete a connection and then have the server close it.
This would happen if the client is not checking certificates
but the server is.  The TSSLSocket unit test was enhanced to
do a read and a write as well as just connecting to ensure a
more complete test.

The TSocket read() and write() calls were leaking OSError,
socker.error, and ssl.Error exceptions.  These cases are now
wrapped into a TTransportException of the appropriate type,
and the original exception is added as an argument named inner.

lib/py/src/transport/TSSLSocket.py

@@ -291,11 +291,11 @@ class TSSLSocket(TSocket.TSocket, TSSLBase):
         plain_sock = socket.socket(family, socktype)
         try:
             return self._wrap_socket(plain_sock)
-        except Exception:
+        except Exception as ex:
             plain_sock.close()
             msg = 'failed to initialize SSL'
             logger.exception(msg)
-            raise TTransportException(TTransportException.NOT_OPEN, msg)
+            raise TTransportException(type=TTransportException.NOT_OPEN, message=msg, inner=ex)
 
     def open(self):
         super(TSSLSocket, self).open()
@@ -307,7 +307,7 @@ class TSSLSocket(TSocket.TSocket, TSSLBase):
             except TTransportException:
                 raise
             except Exception as ex:
-                raise TTransportException(TTransportException.UNKNOWN, str(ex))
+                raise TTransportException(message=str(ex), inner=ex)
 
 
 class TSSLServerSocket(TSocket.TServerSocket, TSSLBase):

lib/py/src/transport/TSocket.py

@@ -94,13 +94,13 @@ class TSocket(TSocketBase):
 
     def open(self):
         if self.handle:
-            raise TTransportException(TTransportException.ALREADY_OPEN)
+            raise TTransportException(type=TTransportException.ALREADY_OPEN, message="already open")
         try:
             addrs = self._resolveAddr()
-        except socket.gaierror:
+        except socket.gaierror as gai:
             msg = 'failed to resolve sockaddr for ' + str(self._address)
             logger.exception(msg)
-            raise TTransportException(TTransportException.NOT_OPEN, msg)
+            raise TTransportException(type=TTransportException.NOT_OPEN, message=msg, inner=gai)
         for family, socktype, _, _, sockaddr in addrs:
             handle = self._do_open(family, socktype)
 
@@ -119,7 +119,7 @@ class TSocket(TSocketBase):
         msg = 'Could not connect to any of %s' % list(map(lambda a: a[4],
                                                           addrs))
         logger.error(msg)
-        raise TTransportException(TTransportException.NOT_OPEN, msg)
+        raise TTransportException(type=TTransportException.NOT_OPEN, message=msg)
 
     def read(self, sz):
         try:
@@ -134,8 +134,10 @@ class TSocket(TSocketBase):
                 self.close()
                 # Trigger the check to raise the END_OF_FILE exception below.
                 buff = ''
+            elif e.args[0] == errno.ETIMEDOUT:
+                raise TTransportException(type=TTransportException.TIMED_OUT, message="read timeout", inner=e)
             else:
-                raise
+                raise TTransportException(message="unexpected exception", inner=e)
         if len(buff) == 0:
             raise TTransportException(type=TTransportException.END_OF_FILE,
                                       message='TSocket read 0 bytes')
@@ -148,12 +150,15 @@ class TSocket(TSocketBase):
         sent = 0
         have = len(buff)
         while sent < have:
+            try:
                 plus = self.handle.send(buff)
                 if plus == 0:
                     raise TTransportException(type=TTransportException.END_OF_FILE,
                                               message='TSocket sent 0 bytes')
                 sent += plus
                 buff = buff[plus:]
+            except socket.error as e:
+                raise TTransportException(message="unexpected exception", inner=e)
 
     def flush(self):
         pass

lib/py/src/transport/TTransport.py

@@ -34,9 +34,10 @@ class TTransportException(TException):
     SIZE_LIMIT = 6
     INVALID_CLIENT_TYPE = 7
 
-    def __init__(self, type=UNKNOWN, message=None):
+    def __init__(self, type=UNKNOWN, message=None, inner=None):
         TException.__init__(self, message)
         self.type = type
+        self.inner = inner
 
 
 class TTransportBase(object):

lib/py/test/test_sslsocket.py

@@ -75,6 +75,9 @@ class ServerAcceptor(threading.Thread):
 
         try:
             self._client = self._server.accept()
+            if self._client:
+                self._client.read(5)  # hello
+                self._client.write(b"there")
         except Exception:
             logging.exception('error on server side (%s):' % self.name)
             if not self._expect_failure:
@@ -141,7 +144,8 @@ class TSSLSocketTest(unittest.TestCase):
                 client.setTimeout(20)
                 with self._assert_raises(TTransportException):
                     client.open()
-                self.assertTrue(acc.client is None)
+                    client.write(b"hello")
+                    client.read(5)  # b"there"
         finally:
             logging.disable(logging.NOTSET)
 
@@ -153,8 +157,10 @@ class TSSLSocketTest(unittest.TestCase):
 
     def _assert_connection_success(self, server, path=None, **client_args):
         with self._connectable_client(server, path=path, **client_args) as (acc, client):
-            client.open()
             try:
+                client.open()
+                client.write(b"hello")
+                self.assertEqual(client.read(5), b"there")
                 self.assertTrue(acc.client is not None)
             finally:
                 client.close()