Lint Python Flight code

cpp/src/arrow/python/flight.h

@@ -34,7 +34,6 @@ namespace flight {
 /// \brief A table of function pointers for calling from C++ into
 /// Python.
 class ARROW_PYTHON_EXPORT PyFlightServerVtable {
-
  public:
   // Must return int so Cython will propagate exceptions
   std::function<int(PyObject*, const arrow::flight::Criteria*,
@@ -75,12 +74,14 @@ class ARROW_PYTHON_EXPORT PyFlightServer : public arrow::flight::FlightServerBas
 };
 
 /// \brief A callback that obtains the next result from a Flight action.
-typedef std::function<int(PyObject*, std::unique_ptr<arrow::flight::Result>*)> PyFlightResultStreamCallback;
+typedef std::function<int(PyObject*, std::unique_ptr<arrow::flight::Result>*)>
+    PyFlightResultStreamCallback;
 
 /// \brief A ResultStream built around a Python callback.
 class ARROW_PYTHON_EXPORT PyFlightResultStream : public arrow::flight::ResultStream {
  public:
-  explicit PyFlightResultStream(PyObject* generator, PyFlightResultStreamCallback callback);
+  explicit PyFlightResultStream(PyObject* generator,
+                                PyFlightResultStreamCallback callback);
   Status Next(std::unique_ptr<arrow::flight::Result>* result) override;
 
  private:

python/examples/flight/server.py

@@ -36,12 +36,14 @@ class FlightServer(pyarrow.flight.FlightServerBase):
     def list_flights(self, criteria):
         for key, table in self.flights.items():
             if key[1] is not None:
-                descriptor = pyarrow.flight.FlightDescriptor.for_command(key[1])
+                descriptor = \
+                    pyarrow.flight.FlightDescriptor.for_command(key[1])
             else:
                 descriptor = pyarrow.flight.FlightDescriptor.for_path(*key[2])
 
             endpoints = [
-                pyarrow.flight.FlightEndpoint(repr(key), [('localhost', 5005)]),
+                pyarrow.flight.FlightEndpoint(repr(key),
+                                              [('localhost', 5005)]),
             ]
             yield pyarrow.flight.FlightInfo(table.schema,
                                             descriptor, endpoints,
@@ -52,7 +54,8 @@ class FlightServer(pyarrow.flight.FlightServerBase):
         if key in self.flights:
             table = self.flights[key]
             endpoints = [
-                pyarrow.flight.FlightEndpoint(repr(key), [('localhost', 5005)]),
+                pyarrow.flight.FlightEndpoint(repr(key),
+                                              [('localhost', 5005)]),
             ]
             return pyarrow.flight.FlightInfo(table.schema,
                                              descriptor, endpoints,
@@ -80,7 +83,8 @@ class FlightServer(pyarrow.flight.FlightServerBase):
 
     def do_action(self, action):
         if action.type == "clear":
-            raise NotImplementedError("{} is not implemented.".format(action.type))
+            raise NotImplementedError(
+                "{} is not implemented.".format(action.type))
         else:
             yield pyarrow.flight.Result(pyarrow.py_buffer(b'Shutdown!'))
 

python/pyarrow/_flight.pyx

@@ -47,7 +47,10 @@ cdef class Action:
         return pyarrow_wrap_buffer(self.action.body)
 
 
-class ActionType(collections.namedtuple('ActionType', ['type', 'description'])):
+_ActionType = collections.namedtuple('_ActionType', ['type', 'description'])
+
+
+class ActionType(_ActionType):
     """A type of action executable on a Flight service."""
 
     def make_action(self, buf):
@@ -414,18 +417,21 @@ cdef class RecordBatchStream(FlightDataStream):
         """
         cdef shared_ptr[CRecordBatchReader] reader
         if isinstance(data_source, _CRecordBatchReader):
-            stream = new CRecordBatchStream((<_CRecordBatchReader> data_source).reader)
+            reader = (<_CRecordBatchReader> data_source).reader
+            stream = new CRecordBatchStream(reader)
             self.stream.reset(stream)
         elif isinstance(data_source, lib.Table):
-            reader.reset(new TableBatchReader(deref((<Table> data_source).table)))
+            table = (<Table> data_source).table
+            reader.reset(new TableBatchReader(deref(table)))
             stream = new CRecordBatchStream(reader)
             self.stream.reset(stream)
         else:
-            raise TypeError("Expected RecordBatchReader or Table, but got: {}".format(type(data_source)))
+            raise TypeError("Expected RecordBatchReader or Table, "
+                            "but got: {}".format(type(data_source)))
 
 
 cdef int _list_flights(void* self, const CCriteria* c_criteria,
-                        unique_ptr[CFlightListing]* listing) except -1:
+                       unique_ptr[CFlightListing]* listing) except -1:
     """Callback for implementing ListFlights in Python."""
     cdef:
         vector[CFlightInfo] flights
@@ -433,14 +439,15 @@ cdef int _list_flights(void* self, const CCriteria* c_criteria,
     for info in result:
         if not isinstance(info, FlightInfo):
             raise TypeError("FlightServerBase.list_flights must return "
-                            "FlightInfo instances, but got {}".format(type(info)))
+                            "FlightInfo instances, but got {}".format(
+                                type(info)))
         flights.push_back(CFlightInfo(deref((<FlightInfo> info).info.get())))
     listing.reset(new CSimpleFlightListing(flights))
     return 0
 
 
 cdef int _get_flight_info(void* self, CFlightDescriptor c_descriptor,
-                           unique_ptr[CFlightInfo]* info) except -1:
+                          unique_ptr[CFlightInfo]* info) except -1:
     """Callback for implementing Flight servers in Python."""
     cdef:
         FlightDescriptor py_descriptor = \
@@ -449,12 +456,14 @@ cdef int _get_flight_info(void* self, CFlightDescriptor c_descriptor,
     result = (<object> self).get_flight_info(py_descriptor)
     if not isinstance(result, FlightInfo):
         raise TypeError("FlightServerBase.get_flight_info must return "
-                        "a FlightInfo instance")
+                        "a FlightInfo instance, but got {}".format(
+                            type(result)))
     info[0] = move((<FlightInfo> result).info)
     return 0
 
 
-cdef int _do_put(void* self, unique_ptr[CFlightMessageReader] reader) except -1:
+cdef int _do_put(void* self,
+                 unique_ptr[CFlightMessageReader] reader) except -1:
     """Callback for implementing Flight servers in Python."""
     cdef:
         FlightRecordBatchReader py_reader = FlightRecordBatchReader()
@@ -468,7 +477,7 @@ cdef int _do_put(void* self, unique_ptr[CFlightMessageReader] reader) except -1:
 
 
 cdef int _do_get(void* self, CTicket ticket,
-                  unique_ptr[CFlightDataStream]* stream) except -1:
+                 unique_ptr[CFlightDataStream]* stream) except -1:
     """Callback for implementing Flight servers in Python."""
     py_ticket = Ticket(ticket.ticket)
     result = (<object> self).do_get(py_ticket)
@@ -480,7 +489,7 @@ cdef int _do_get(void* self, CTicket ticket,
 
 
 cdef int _do_action_result_next(void* self,
-                                 unique_ptr[CResult]* result) except -1:
+                                unique_ptr[CResult]* result) except -1:
     """Callback for implementing Flight servers in Python."""
     try:
         action_result = next(<object> self)

python/pyarrow/flight.py

@@ -15,8 +15,15 @@
 # specific language governing permissions and limitations
 # under the License.
 
-from pyarrow._flight import (FlightClient, Action, ActionType,  # noqa
-                             FlightDescriptor, FlightEndpoint,
-                             FlightInfo, Ticket, Location,
-                             FlightServerBase, DescriptorType,
-                             RecordBatchStream, Result)
+from pyarrow._flight import (Action,  # noqa
+                             ActionType,
+                             DescriptorType,
+                             FlightClient,
+                             FlightDescriptor,
+                             FlightEndpoint,
+                             FlightInfo,
+                             FlightServerBase,
+                             Location,
+                             Ticket,
+                             RecordBatchStream,
+                             Result)

python/pyarrow/includes/libarrow_flight.pxd

@@ -147,8 +147,10 @@ cdef extern from "arrow/python/flight.h" namespace "arrow::py::flight" nogil:
         void Run(int port)
         void Shutdown()
 
-    cdef cppclass CPyFlightResultStream" arrow::py::flight::PyFlightResultStream"(CResultStream):
-        CPyFlightResultStream(object generator, function[cb_result_next] callback)
+    cdef cppclass CPyFlightResultStream\
+            " arrow::py::flight::PyFlightResultStream"(CResultStream):
+        CPyFlightResultStream(object generator,
+                              function[cb_result_next] callback)
 
     cdef CStatus CreateFlightInfo" arrow::py::flight::CreateFlightInfo"(
         shared_ptr[CSchema] schema,