Initial work on protocol objects

11 files changed, 217 insertions, 120 deletions

diff --git a/src/python/grpcio/grpc/framework/core/_end.py b/src/python/grpcio/grpc/framework/core/_end.py
index 336e9c21fd..8e07d9061e 100644
--- a/src/python/grpcio/grpc/framework/core/_end.py
+++ b/src/python/grpcio/grpc/framework/core/_end.py
@@ -168,7 +168,7 @@ class _End(End):
 
   def operate(
       self, group, method, subscription, timeout, initial_metadata=None,
-      payload=None, completion=None):
+      payload=None, completion=None, protocol_options=None):
     """See base.End.operate for specification."""
     operation_id = uuid.uuid4()
     with self._lock:
@@ -177,9 +177,9 @@ class _End(End):
       termination_action = _termination_action(
           self._lock, self._stats, operation_id, self._cycle)
       operation = _operation.invocation_operate(
-          operation_id, group, method, subscription, timeout, initial_metadata,
-          payload, completion, self._mate.accept_ticket, termination_action,
-          self._cycle.pool)
+          operation_id, group, method, subscription, timeout, protocol_options,
+          initial_metadata, payload, completion, self._mate.accept_ticket,
+          termination_action, self._cycle.pool)
       self._cycle.operations[operation_id] = operation
       return operation.context, operation.operator
 
diff --git a/src/python/grpcio/grpc/framework/core/_interfaces.py b/src/python/grpcio/grpc/framework/core/_interfaces.py
index 2a534cb7e7..7ac440722c 100644
--- a/src/python/grpcio/grpc/framework/core/_interfaces.py
+++ b/src/python/grpcio/grpc/framework/core/_interfaces.py
@@ -111,8 +111,8 @@ class TransmissionManager(object):
 
   @abc.abstractmethod
   def kick_off(
-      self, group, method, timeout, initial_metadata, payload, completion,
-      allowance):
+      self, group, method, timeout, protocol_options, initial_metadata,
+      payload, completion, allowance):
     """Transmits the values associated with operation invocation."""
     raise NotImplementedError()
 
diff --git a/src/python/grpcio/grpc/framework/core/_operation.py b/src/python/grpcio/grpc/framework/core/_operation.py
index f5679d0356..d4eacc5a3f 100644
--- a/src/python/grpcio/grpc/framework/core/_operation.py
+++ b/src/python/grpcio/grpc/framework/core/_operation.py
@@ -84,8 +84,9 @@ class _EasyOperation(_interfaces.Operation):
 
 
 def invocation_operate(
-    operation_id, group, method, subscription, timeout, initial_metadata,
-    payload, completion, ticket_sink, termination_action, pool):
+    operation_id, group, method, subscription, timeout, protocol_options,
+    initial_metadata, payload, completion, ticket_sink, termination_action,
+    pool):
   """Constructs objects necessary for front-side operation management.
 
   Args:
@@ -95,6 +96,8 @@ def invocation_operate(
     subscription: A base.Subscription describing the customer's interest in the
       results of the operation.
     timeout: A length of time in seconds to allow for the operation.
+    protocol_options: A transport-specific, application-specific, and/or
+      protocol-specific value relating to the invocation. May be None.
     initial_metadata: An initial metadata value to be sent to the other side of
       the operation. May be None if the initial metadata will be passed later or
       if there will be no initial metadata passed at all.
@@ -136,7 +139,8 @@ def invocation_operate(
     emission_manager.set_ingestion_manager(ingestion_manager)
 
     transmission_manager.kick_off(
-        group, method, timeout, initial_metadata, payload, completion, None)
+        group, method, timeout, protocol_options, initial_metadata, payload,
+        completion, None)
 
   return _EasyOperation(
       lock, termination_manager, transmission_manager, expiration_manager,
diff --git a/src/python/grpcio/grpc/framework/core/_transmission.py b/src/python/grpcio/grpc/framework/core/_transmission.py
index 8f852cfe9f..65b12c4160 100644
--- a/src/python/grpcio/grpc/framework/core/_transmission.py
+++ b/src/python/grpcio/grpc/framework/core/_transmission.py
@@ -207,18 +207,19 @@ class TransmissionManager(_interfaces.TransmissionManager):
     self._transmitting = True
 
   def kick_off(
-      self, group, method, timeout, initial_metadata, payload, completion,
-      allowance):
+      self, group, method, timeout, protocol_options, initial_metadata,
+      payload, completion, allowance):
     """See _interfaces.TransmissionManager.kickoff for specification."""
     # TODO(nathaniel): Support other subscriptions.
     subscription = links.Ticket.Subscription.FULL
     terminal_metadata, code, message, termination = _explode_completion(
         completion)
     self._remote_allowance = 1 if payload is None else 0
+    protocol = links.Protocol(links.Protocol.Kind.CALL_OPTION, protocol_options)
     ticket = links.Ticket(
         self._operation_id, 0, group, method, subscription, timeout, allowance,
         initial_metadata, payload, terminal_metadata, code, message,
-        termination, None)
+        termination, protocol)
     self._lowest_unused_sequence_number = 1
     self._transmit(ticket)
 
diff --git a/src/python/grpcio/grpc/framework/crust/_calls.py b/src/python/grpcio/grpc/framework/crust/_calls.py
index 4c6bf16f43..68db9fab8e 100644
--- a/src/python/grpcio/grpc/framework/crust/_calls.py
+++ b/src/python/grpcio/grpc/framework/crust/_calls.py
@@ -38,12 +38,14 @@ _ITERATOR_EXCEPTION_LOG_MESSAGE = 'Exception iterating over requests!'
 _EMPTY_COMPLETION = utilities.completion(None, None, None)
 
 
-def _invoke(end, group, method, timeout, initial_metadata, payload, complete):
+def _invoke(
+    end, group, method, timeout, protocol_options, initial_metadata, payload,
+    complete):
   rendezvous = _control.Rendezvous(None, None)
   operation_context, operator = end.operate(
       group, method, utilities.full_subscription(rendezvous), timeout,
-      initial_metadata=initial_metadata, payload=payload,
-      completion=_EMPTY_COMPLETION if complete else None)
+      protocol_options=protocol_options, initial_metadata=initial_metadata,
+      payload=payload, completion=_EMPTY_COMPLETION if complete else None)
   rendezvous.set_operator_and_context(operator, operation_context)
   outcome = operation_context.add_termination_callback(rendezvous.set_outcome)
   if outcome is not None:
@@ -93,36 +95,43 @@ def _event_return_stream(
 
 
 def blocking_unary_unary(
-    end, group, method, timeout, with_call, initial_metadata, payload):
+    end, group, method, timeout, with_call, protocol_options, initial_metadata,
+    payload):
   """Services in a blocking fashion a unary-unary servicer method."""
   rendezvous, unused_operation_context, unused_outcome = _invoke(
-      end, group, method, timeout, initial_metadata, payload, True)
+      end, group, method, timeout, protocol_options, initial_metadata, payload,
+      True)
   if with_call:
     return next(rendezvous), rendezvous
   else:
     return next(rendezvous)
 
 
-def future_unary_unary(end, group, method, timeout, initial_metadata, payload):
+def future_unary_unary(
+    end, group, method, timeout, protocol_options, initial_metadata, payload):
   """Services a value-in value-out servicer method by returning a Future."""
   rendezvous, unused_operation_context, unused_outcome = _invoke(
-      end, group, method, timeout, initial_metadata, payload, True)
+      end, group, method, timeout, protocol_options, initial_metadata, payload,
+      True)
   return rendezvous
 
 
-def inline_unary_stream(end, group, method, timeout, initial_metadata, payload):
+def inline_unary_stream(
+    end, group, method, timeout, protocol_options, initial_metadata, payload):
   """Services a value-in stream-out servicer method."""
   rendezvous, unused_operation_context, unused_outcome = _invoke(
-      end, group, method, timeout, initial_metadata, payload, True)
+      end, group, method, timeout, protocol_options, initial_metadata, payload,
+      True)
   return rendezvous
 
 
 def blocking_stream_unary(
-    end, group, method, timeout, with_call, initial_metadata, payload_iterator,
-    pool):
+    end, group, method, timeout, with_call, protocol_options, initial_metadata,
+    payload_iterator, pool):
   """Services in a blocking fashion a stream-in value-out servicer method."""
   rendezvous, operation_context, outcome = _invoke(
-      end, group, method, timeout, initial_metadata, None, False)
+      end, group, method, timeout, protocol_options, initial_metadata, None,
+      False)
   if outcome is None:
     def in_pool():
       for payload in payload_iterator:
@@ -141,10 +150,12 @@ def blocking_stream_unary(
 
 
 def future_stream_unary(
-    end, group, method, timeout, initial_metadata, payload_iterator, pool):
+    end, group, method, timeout, protocol_options, initial_metadata,
+    payload_iterator, pool):
   """Services a stream-in value-out servicer method by returning a Future."""
   rendezvous, operation_context, outcome = _invoke(
-      end, group, method, timeout, initial_metadata, None, False)
+      end, group, method, timeout, protocol_options, initial_metadata, None,
+      False)
   if outcome is None:
     def in_pool():
       for payload in payload_iterator:
@@ -155,10 +166,12 @@ def future_stream_unary(
 
 
 def inline_stream_stream(
-    end, group, method, timeout, initial_metadata, payload_iterator, pool):
+    end, group, method, timeout, protocol_options, initial_metadata,
+    payload_iterator, pool):
   """Services a stream-in stream-out servicer method."""
   rendezvous, operation_context, outcome = _invoke(
-      end, group, method, timeout, initial_metadata, None, False)
+      end, group, method, timeout, protocol_options, initial_metadata, None,
+      False)
   if outcome is None:
     def in_pool():
       for payload in payload_iterator:
@@ -169,36 +182,40 @@ def inline_stream_stream(
 
 
 def event_unary_unary(
-    end, group, method, timeout, initial_metadata, payload, receiver,
-    abortion_callback, pool):
+    end, group, method, timeout, protocol_options, initial_metadata, payload,
+    receiver, abortion_callback, pool):
   rendezvous, operation_context, outcome = _invoke(
-      end, group, method, timeout, initial_metadata, payload, True)
+      end, group, method, timeout, protocol_options, initial_metadata, payload,
+      True)
   return _event_return_unary(
       receiver, abortion_callback, rendezvous, operation_context, outcome, pool)
 
 
 def event_unary_stream(
-    end, group, method, timeout, initial_metadata, payload,
+    end, group, method, timeout, protocol_options, initial_metadata, payload,
     receiver, abortion_callback, pool):
   rendezvous, operation_context, outcome = _invoke(
-      end, group, method, timeout, initial_metadata, payload, True)
+      end, group, method, timeout, protocol_options, initial_metadata, payload,
+      True)
   return _event_return_stream(
       receiver, abortion_callback, rendezvous, operation_context, outcome, pool)
 
 
 def event_stream_unary(
-    end, group, method, timeout, initial_metadata, receiver, abortion_callback,
-    pool):
+    end, group, method, timeout, protocol_options, initial_metadata, receiver,
+    abortion_callback, pool):
   rendezvous, operation_context, outcome = _invoke(
-      end, group, method, timeout, initial_metadata, None, False)
+      end, group, method, timeout, protocol_options, initial_metadata, None,
+      False)
   return _event_return_unary(
       receiver, abortion_callback, rendezvous, operation_context, outcome, pool)
 
 
 def event_stream_stream(
-    end, group, method, timeout, initial_metadata, receiver, abortion_callback,
-    pool):
+    end, group, method, timeout, protocol_options, initial_metadata, receiver,
+    abortion_callback, pool):
   rendezvous, operation_context, outcome = _invoke(
-      end, group, method, timeout, initial_metadata, None, False)
+      end, group, method, timeout, protocol_options, initial_metadata, None,
+      False)
   return _event_return_stream(
       receiver, abortion_callback, rendezvous, operation_context, outcome, pool)
diff --git a/src/python/grpcio/grpc/framework/crust/_control.py b/src/python/grpcio/grpc/framework/crust/_control.py
index 7bddf46a57..e02a41d720 100644
--- a/src/python/grpcio/grpc/framework/crust/_control.py
+++ b/src/python/grpcio/grpc/framework/crust/_control.py
@@ -442,6 +442,10 @@ class Rendezvous(base.Operator, future.Future, stream.Consumer, face.Call):
         else:
           return self._termination.abortion
 
+  def protocol_context(self):
+    with self._condition:
+      raise NotImplementedError('TODO: protocol context implementation!')
+
   def initial_metadata(self):
     with self._condition:
       while True:
diff --git a/src/python/grpcio/grpc/framework/crust/_service.py b/src/python/grpcio/grpc/framework/crust/_service.py
index 6ff7249e75..f1855c2f47 100644
--- a/src/python/grpcio/grpc/framework/crust/_service.py
+++ b/src/python/grpcio/grpc/framework/crust/_service.py
@@ -52,6 +52,9 @@ class _ServicerContext(face.ServicerContext):
   def cancel(self):
     self._rendezvous.cancel()
 
+  def protocol_context(self):
+    return self._rendezvous.protocol_context()
+
   def invocation_metadata(self):
     return self._rendezvous.initial_metadata()
 
diff --git a/src/python/grpcio/grpc/framework/crust/implementations.py b/src/python/grpcio/grpc/framework/crust/implementations.py
index d38fab8ba0..4ebc4e9ae8 100644
--- a/src/python/grpcio/grpc/framework/crust/implementations.py
+++ b/src/python/grpcio/grpc/framework/crust/implementations.py
@@ -66,22 +66,23 @@ class _UnaryUnaryMultiCallable(face.UnaryUnaryMultiCallable):
     self._pool = pool
 
   def __call__(
-      self, request, timeout, metadata=None, with_call=False):
+      self, request, timeout, metadata=None, with_call=False,
+      protocol_options=None):
     return _calls.blocking_unary_unary(
         self._end, self._group, self._method, timeout, with_call,
-        metadata, request)
+        protocol_options, metadata, request)
 
-  def future(self, request, timeout, metadata=None):
+  def future(self, request, timeout, metadata=None, protocol_options=None):
     return _calls.future_unary_unary(
-        self._end, self._group, self._method, timeout, metadata,
-        request)
+        self._end, self._group, self._method, timeout, protocol_options,
+        metadata, request)
 
   def event(
       self, request, receiver, abortion_callback, timeout,
-      metadata=None):
+      metadata=None, protocol_options=None):
     return _calls.event_unary_unary(
-        self._end, self._group, self._method, timeout, metadata,
-        request, receiver, abortion_callback, self._pool)
+        self._end, self._group, self._method, timeout, protocol_options,
+        metadata, request, receiver, abortion_callback, self._pool)
 
 
 class _UnaryStreamMultiCallable(face.UnaryStreamMultiCallable):
@@ -92,17 +93,17 @@ class _UnaryStreamMultiCallable(face.UnaryStreamMultiCallable):
     self._method = method
     self._pool = pool
 
-  def __call__(self, request, timeout, metadata=None):
+  def __call__(self, request, timeout, metadata=None, protocol_options=None):
     return _calls.inline_unary_stream(
-        self._end, self._group, self._method, timeout, metadata,
-        request)
+        self._end, self._group, self._method, timeout, protocol_options,
+        metadata, request)
 
   def event(
       self, request, receiver, abortion_callback, timeout,
-      metadata=None):
+      metadata=None, protocol_options=None):
     return _calls.event_unary_stream(
-        self._end, self._group, self._method, timeout, metadata,
-        request, receiver, abortion_callback, self._pool)
+        self._end, self._group, self._method, timeout, protocol_options,
+        metadata, request, receiver, abortion_callback, self._pool)
 
 
 class _StreamUnaryMultiCallable(face.StreamUnaryMultiCallable):
@@ -115,21 +116,23 @@ class _StreamUnaryMultiCallable(face.StreamUnaryMultiCallable):
 
   def __call__(
       self, request_iterator, timeout, metadata=None,
-      with_call=False):
+      with_call=False, protocol_options=None):
     return _calls.blocking_stream_unary(
         self._end, self._group, self._method, timeout, with_call,
-        metadata, request_iterator, self._pool)
+        protocol_options, metadata, request_iterator, self._pool)
 
-  def future(self, request_iterator, timeout, metadata=None):
+  def future(
+      self, request_iterator, timeout, metadata=None, protocol_options=None):
     return _calls.future_stream_unary(
-        self._end, self._group, self._method, timeout, metadata,
-        request_iterator, self._pool)
+        self._end, self._group, self._method, timeout, protocol_options,
+        metadata, request_iterator, self._pool)
 
   def event(
-      self, receiver, abortion_callback, timeout, metadata=None):
+      self, receiver, abortion_callback, timeout, metadata=None,
+      protocol_options=None):
     return _calls.event_stream_unary(
-        self._end, self._group, self._method, timeout, metadata,
-        receiver, abortion_callback, self._pool)
+        self._end, self._group, self._method, timeout, protocol_options,
+        metadata, receiver, abortion_callback, self._pool)
 
 
 class _StreamStreamMultiCallable(face.StreamStreamMultiCallable):
@@ -140,16 +143,18 @@ class _StreamStreamMultiCallable(face.StreamStreamMultiCallable):
     self._method = method
     self._pool = pool
 
-  def __call__(self, request_iterator, timeout, metadata=None):
+  def __call__(
+      self, request_iterator, timeout, metadata=None, protocol_options=None):
     return _calls.inline_stream_stream(
-        self._end, self._group, self._method, timeout, metadata,
-        request_iterator, self._pool)
+        self._end, self._group, self._method, timeout, protocol_options,
+        metadata, request_iterator, self._pool)
 
   def event(
-      self, receiver, abortion_callback, timeout, metadata=None):
+      self, receiver, abortion_callback, timeout, metadata=None,
+      protocol_options=None):
     return _calls.event_stream_stream(
-        self._end, self._group, self._method, timeout, metadata,
-        receiver, abortion_callback, self._pool)
+        self._end, self._group, self._method, timeout, protocol_options,
+        metadata, receiver, abortion_callback, self._pool)
 
 
 class _GenericStub(face.GenericStub):
@@ -161,66 +166,70 @@ class _GenericStub(face.GenericStub):
 
   def blocking_unary_unary(
       self, group, method, request, timeout, metadata=None,
-      with_call=None):
+      with_call=None, protocol_options=None):
     return _calls.blocking_unary_unary(
-        self._end, group, method, timeout, with_call, metadata,
-        request)
+        self._end, group, method, timeout, with_call, protocol_options,
+        metadata, request)
 
   def future_unary_unary(
-      self, group, method, request, timeout, metadata=None):
+      self, group, method, request, timeout, metadata=None,
+      protocol_options=None):
     return _calls.future_unary_unary(
-        self._end, group, method, timeout, metadata, request)
+        self._end, group, method, timeout, protocol_options, metadata, request)
 
   def inline_unary_stream(
-      self, group, method, request, timeout, metadata=None):
+      self, group, method, request, timeout, metadata=None,
+      protocol_options=None):
     return _calls.inline_unary_stream(
-        self._end, group, method, timeout, metadata, request)
+        self._end, group, method, timeout, protocol_options, metadata, request)
 
   def blocking_stream_unary(
       self, group, method, request_iterator, timeout, metadata=None,
-      with_call=None):
+      with_call=None, protocol_options=None):
     return _calls.blocking_stream_unary(
-        self._end, group, method, timeout, with_call, metadata,
-        request_iterator, self._pool)
+        self._end, group, method, timeout, with_call, protocol_options,
+        metadata, request_iterator, self._pool)
 
   def future_stream_unary(
-      self, group, method, request_iterator, timeout, metadata=None):
+      self, group, method, request_iterator, timeout, metadata=None,
+      protocol_options=None):
     return _calls.future_stream_unary(
-        self._end, group, method, timeout, metadata,
+        self._end, group, method, timeout, protocol_options, metadata,
         request_iterator, self._pool)
 
   def inline_stream_stream(
-      self, group, method, request_iterator, timeout, metadata=None):
+      self, group, method, request_iterator, timeout, metadata=None,
+      protocol_options=None):
     return _calls.inline_stream_stream(
-        self._end, group, method, timeout, metadata,
+        self._end, group, method, timeout, protocol_options, metadata,
         request_iterator, self._pool)
 
   def event_unary_unary(
       self, group, method, request, receiver, abortion_callback, timeout,
-      metadata=None):
+      metadata=None, protocol_options=None):
     return _calls.event_unary_unary(
-        self._end, group, method, timeout, metadata, request,
+        self._end, group, method, timeout, protocol_options, metadata, request,
         receiver, abortion_callback, self._pool)
 
   def event_unary_stream(
       self, group, method, request, receiver, abortion_callback, timeout,
-      metadata=None):
+      metadata=None, protocol_options=None):
     return _calls.event_unary_stream(
-        self._end, group, method, timeout, metadata, request,
+        self._end, group, method, timeout, protocol_options, metadata, request,
         receiver, abortion_callback, self._pool)
 
   def event_stream_unary(
       self, group, method, receiver, abortion_callback, timeout,
-      metadata=None):
+      metadata=None, protocol_options=None):
     return _calls.event_stream_unary(
-        self._end, group, method, timeout, metadata, receiver,
+        self._end, group, method, timeout, protocol_options, metadata, receiver,
         abortion_callback, self._pool)
 
   def event_stream_stream(
       self, group, method, receiver, abortion_callback, timeout,
-      metadata=None):
+      metadata=None, protocol_options=None):
     return _calls.event_stream_stream(
-        self._end, group, method, timeout, metadata, receiver,
+        self._end, group, method, timeout, protocol_options, metadata, receiver,
         abortion_callback, self._pool)
 
   def unary_unary(self, group, method):
diff --git a/src/python/grpcio/grpc/framework/interfaces/base/base.py b/src/python/grpcio/grpc/framework/interfaces/base/base.py
index 0d9d6b464e..013e7c66f2 100644
--- a/src/python/grpcio/grpc/framework/interfaces/base/base.py
+++ b/src/python/grpcio/grpc/framework/interfaces/base/base.py
@@ -274,7 +274,7 @@ class End(object):
   @abc.abstractmethod
   def operate(
       self, group, method, subscription, timeout, initial_metadata=None,
-      payload=None, completion=None):
+      payload=None, completion=None, protocol_options=None):
     """Commences an operation.
 
     Args:
@@ -290,6 +290,8 @@ class End(object):
       payload: An initial payload for the operation.
       completion: A Completion value indicating the end of transmission to the
         other side of the operation.
+      protocol_options: A value specified by the provider of a Base interface
+        implementation affording custom state and behavior.
 
     Returns:
       A pair of objects affording information about the operation and action
diff --git a/src/python/grpcio/grpc/framework/interfaces/face/face.py b/src/python/grpcio/grpc/framework/interfaces/face/face.py
index 948e7505b6..bc9a434a76 100644
--- a/src/python/grpcio/grpc/framework/interfaces/face/face.py
+++ b/src/python/grpcio/grpc/framework/interfaces/face/face.py
@@ -184,6 +184,16 @@ class RpcContext(object):
     """
     raise NotImplementedError()
 
+  @abc.abstractmethod
+  def protocol_context(self):
+    """Accesses a custom object specified by an implementation provider.
+
+    Returns:
+      A value specified by the provider of a Face interface implementation
+        affording custom state and behavior.
+    """
+    raise NotImplementedError()
+
 
 class Call(RpcContext):
   """Invocation-side utility object for an RPC."""
@@ -354,7 +364,8 @@ class UnaryUnaryMultiCallable(object):
 
   @abc.abstractmethod
   def __call__(
-      self, request, timeout, metadata=None, with_call=False):
+      self, request, timeout, metadata=None, with_call=False,
+      protocol_options=None):
     """Synchronously invokes the underlying RPC.
 
     Args:
@@ -364,6 +375,8 @@ class UnaryUnaryMultiCallable(object):
         the RPC.
       with_call: Whether or not to include return a Call for the RPC in addition
         to the reponse.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       The response value for the RPC, and a Call for the RPC if with_call was
@@ -375,7 +388,7 @@ class UnaryUnaryMultiCallable(object):
     raise NotImplementedError()
 
   @abc.abstractmethod
-  def future(self, request, timeout, metadata=None):
+  def future(self, request, timeout, metadata=None, protocol_options=None):
     """Asynchronously invokes the underlying RPC.
 
     Args:
@@ -383,6 +396,8 @@ class UnaryUnaryMultiCallable(object):
       timeout: A duration of time in seconds to allow for the RPC.
       metadata: A metadata value to be passed to the service-side of
         the RPC.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       An object that is both a Call for the RPC and a future.Future. In the
@@ -395,7 +410,7 @@ class UnaryUnaryMultiCallable(object):
   @abc.abstractmethod
   def event(
       self, request, receiver, abortion_callback, timeout,
-      metadata=None):
+      metadata=None, protocol_options=None):
     """Asynchronously invokes the underlying RPC.
 
     Args:
@@ -406,6 +421,8 @@ class UnaryUnaryMultiCallable(object):
       timeout: A duration of time in seconds to allow for the RPC.
       metadata: A metadata value to be passed to the service-side of
         the RPC.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       A Call for the RPC.
@@ -418,7 +435,7 @@ class UnaryStreamMultiCallable(object):
   __metaclass__ = abc.ABCMeta
 
   @abc.abstractmethod
-  def __call__(self, request, timeout, metadata=None):
+  def __call__(self, request, timeout, metadata=None, protocol_options=None):
     """Invokes the underlying RPC.
 
     Args:
@@ -426,6 +443,8 @@ class UnaryStreamMultiCallable(object):
       timeout: A duration of time in seconds to allow for the RPC.
       metadata: A metadata value to be passed to the service-side of
         the RPC.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       An object that is both a Call for the RPC and an iterator of response
@@ -437,7 +456,7 @@ class UnaryStreamMultiCallable(object):
   @abc.abstractmethod
   def event(
       self, request, receiver, abortion_callback, timeout,
-      metadata=None):
+      metadata=None, protocol_options=None):
     """Asynchronously invokes the underlying RPC.
 
     Args:
@@ -448,6 +467,8 @@ class UnaryStreamMultiCallable(object):
       timeout: A duration of time in seconds to allow for the RPC.
       metadata: A metadata value to be passed to the service-side of
         the RPC.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       A Call object for the RPC.
@@ -462,7 +483,7 @@ class StreamUnaryMultiCallable(object):
   @abc.abstractmethod
   def __call__(
       self, request_iterator, timeout, metadata=None,
-      with_call=False):
+      with_call=False, protocol_options=None):
     """Synchronously invokes the underlying RPC.
 
     Args:
@@ -472,6 +493,8 @@ class StreamUnaryMultiCallable(object):
         the RPC.
       with_call: Whether or not to include return a Call for the RPC in addition
         to the reponse.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       The response value for the RPC, and a Call for the RPC if with_call was
@@ -483,7 +506,8 @@ class StreamUnaryMultiCallable(object):
     raise NotImplementedError()
 
   @abc.abstractmethod
-  def future(self, request_iterator, timeout, metadata=None):
+  def future(
+      self, request_iterator, timeout, metadata=None, protocol_options=None):
     """Asynchronously invokes the underlying RPC.
 
     Args:
@@ -491,6 +515,8 @@ class StreamUnaryMultiCallable(object):
       timeout: A duration of time in seconds to allow for the RPC.
       metadata: A metadata value to be passed to the service-side of
         the RPC.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       An object that is both a Call for the RPC and a future.Future. In the
@@ -502,7 +528,8 @@ class StreamUnaryMultiCallable(object):
 
   @abc.abstractmethod
   def event(
-      self, receiver, abortion_callback, timeout, metadata=None):
+      self, receiver, abortion_callback, timeout, metadata=None,
+      protocol_options=None):
     """Asynchronously invokes the underlying RPC.
 
     Args:
@@ -512,6 +539,8 @@ class StreamUnaryMultiCallable(object):
       timeout: A duration of time in seconds to allow for the RPC.
       metadata: A metadata value to be passed to the service-side of
         the RPC.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       A single object that is both a Call object for the RPC and a
@@ -525,7 +554,8 @@ class StreamStreamMultiCallable(object):
   __metaclass__ = abc.ABCMeta
 
   @abc.abstractmethod
-  def __call__(self, request_iterator, timeout, metadata=None):
+  def __call__(
+      self, request_iterator, timeout, metadata=None, protocol_options=None):
     """Invokes the underlying RPC.
 
     Args:
@@ -533,6 +563,8 @@ class StreamStreamMultiCallable(object):
       timeout: A duration of time in seconds to allow for the RPC.
       metadata: A metadata value to be passed to the service-side of
         the RPC.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       An object that is both a Call for the RPC and an iterator of response
@@ -543,7 +575,8 @@ class StreamStreamMultiCallable(object):
 
   @abc.abstractmethod
   def event(
-      self, receiver, abortion_callback, timeout, metadata=None):
+      self, receiver, abortion_callback, timeout, metadata=None,
+      protocol_options=None):
     """Asynchronously invokes the underlying RPC.
 
     Args:
@@ -553,6 +586,8 @@ class StreamStreamMultiCallable(object):
       timeout: A duration of time in seconds to allow for the RPC.
       metadata: A metadata value to be passed to the service-side of
         the RPC.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       A single object that is both a Call object for the RPC and a
@@ -646,7 +681,7 @@ class GenericStub(object):
   @abc.abstractmethod
   def blocking_unary_unary(
       self, group, method, request, timeout, metadata=None,
-      with_call=False):
+      with_call=False, protocol_options=None):
     """Invokes a unary-request-unary-response method.
 
     This method blocks until either returning the response value of the RPC
@@ -661,6 +696,8 @@ class GenericStub(object):
       metadata: A metadata value to be passed to the service-side of the RPC.
       with_call: Whether or not to include return a Call for the RPC in addition
         to the reponse.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       The response value for the RPC, and a Call for the RPC if with_call was
@@ -673,7 +710,8 @@ class GenericStub(object):
 
   @abc.abstractmethod
   def future_unary_unary(
-      self, group, method, request, timeout, metadata=None):
+      self, group, method, request, timeout, metadata=None,
+      protocol_options=None):
     """Invokes a unary-request-unary-response method.
 
     Args:
@@ -682,6 +720,8 @@ class GenericStub(object):
       request: The request value for the RPC.
       timeout: A duration of time in seconds to allow for the RPC.
       metadata: A metadata value to be passed to the service-side of the RPC.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       An object that is both a Call for the RPC and a future.Future. In the
@@ -693,7 +733,8 @@ class GenericStub(object):
 
   @abc.abstractmethod
   def inline_unary_stream(
-      self, group, method, request, timeout, metadata=None):
+      self, group, method, request, timeout, metadata=None,
+      protocol_options=None):
     """Invokes a unary-request-stream-response method.
 
     Args:
@@ -702,6 +743,8 @@ class GenericStub(object):
       request: The request value for the RPC.
       timeout: A duration of time in seconds to allow for the RPC.
       metadata: A metadata value to be passed to the service-side of the RPC.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       An object that is both a Call for the RPC and an iterator of response
@@ -713,7 +756,7 @@ class GenericStub(object):
   @abc.abstractmethod
   def blocking_stream_unary(
       self, group, method, request_iterator, timeout, metadata=None,
-      with_call=False):
+      with_call=False, protocol_options=None):
     """Invokes a stream-request-unary-response method.
 
     This method blocks until either returning the response value of the RPC
@@ -728,6 +771,8 @@ class GenericStub(object):
       metadata: A metadata value to be passed to the service-side of the RPC.
       with_call: Whether or not to include return a Call for the RPC in addition
         to the reponse.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       The response value for the RPC, and a Call for the RPC if with_call was
@@ -740,7 +785,8 @@ class GenericStub(object):
 
   @abc.abstractmethod
   def future_stream_unary(
-      self, group, method, request_iterator, timeout, metadata=None):
+      self, group, method, request_iterator, timeout, metadata=None,
+      protocol_options=None):
     """Invokes a stream-request-unary-response method.
 
     Args:
@@ -749,6 +795,8 @@ class GenericStub(object):
       request_iterator: An iterator that yields request values for the RPC.
       timeout: A duration of time in seconds to allow for the RPC.
       metadata: A metadata value to be passed to the service-side of the RPC.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       An object that is both a Call for the RPC and a future.Future. In the
@@ -760,7 +808,8 @@ class GenericStub(object):
 
   @abc.abstractmethod
   def inline_stream_stream(
-      self, group, method, request_iterator, timeout, metadata=None):
+      self, group, method, request_iterator, timeout, metadata=None,
+      protocol_options=None):
     """Invokes a stream-request-stream-response method.
 
     Args:
@@ -769,6 +818,8 @@ class GenericStub(object):
       request_iterator: An iterator that yields request values for the RPC.
       timeout: A duration of time in seconds to allow for the RPC.
       metadata: A metadata value to be passed to the service-side of the RPC.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       An object that is both a Call for the RPC and an iterator of response
@@ -780,7 +831,7 @@ class GenericStub(object):
   @abc.abstractmethod
   def event_unary_unary(
       self, group, method, request, receiver, abortion_callback, timeout,
-      metadata=None):
+      metadata=None, protocol_options=None):
     """Event-driven invocation of a unary-request-unary-response method.
 
     Args:
@@ -792,6 +843,8 @@ class GenericStub(object):
         in the event of RPC abortion.
       timeout: A duration of time in seconds to allow for the RPC.
       metadata: A metadata value to be passed to the service-side of the RPC.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       A Call for the RPC.
@@ -801,7 +854,7 @@ class GenericStub(object):
   @abc.abstractmethod
   def event_unary_stream(
       self, group, method, request, receiver, abortion_callback, timeout,
-      metadata=None):
+      metadata=None, protocol_options=None):
     """Event-driven invocation of a unary-request-stream-response method.
 
     Args:
@@ -813,6 +866,8 @@ class GenericStub(object):
         in the event of RPC abortion.
       timeout: A duration of time in seconds to allow for the RPC.
       metadata: A metadata value to be passed to the service-side of the RPC.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       A Call for the RPC.
@@ -822,7 +877,7 @@ class GenericStub(object):
   @abc.abstractmethod
   def event_stream_unary(
       self, group, method, receiver, abortion_callback, timeout,
-      metadata=None):
+      metadata=None, protocol_options=None):
     """Event-driven invocation of a unary-request-unary-response method.
 
     Args:
@@ -833,6 +888,8 @@ class GenericStub(object):
         in the event of RPC abortion.
       timeout: A duration of time in seconds to allow for the RPC.
       metadata: A metadata value to be passed to the service-side of the RPC.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       A pair of a Call object for the RPC and a stream.Consumer to which the
@@ -843,7 +900,7 @@ class GenericStub(object):
   @abc.abstractmethod
   def event_stream_stream(
       self, group, method, receiver, abortion_callback, timeout,
-      metadata=None):
+      metadata=None, protocol_options=None):
     """Event-driven invocation of a unary-request-stream-response method.
 
     Args:
@@ -854,6 +911,8 @@ class GenericStub(object):
         in the event of RPC abortion.
       timeout: A duration of time in seconds to allow for the RPC.
       metadata: A metadata value to be passed to the service-side of the RPC.
+      protocol_options: A value specified by the provider of a Face interface
+        implementation affording custom state and behavior.
 
     Returns:
       A pair of a Call object for the RPC and a stream.Consumer to which the
diff --git a/src/python/grpcio/grpc/framework/interfaces/links/links.py b/src/python/grpcio/grpc/framework/interfaces/links/links.py
index b98a30a399..24f0e3b354 100644
--- a/src/python/grpcio/grpc/framework/interfaces/links/links.py
+++ b/src/python/grpcio/grpc/framework/interfaces/links/links.py
@@ -34,14 +34,13 @@ import collections
 import enum
 
 
-class Transport(collections.namedtuple('Transport', ('kind', 'value',))):
-  """A sum type for handles to an underlying transport system.
+class Protocol(collections.namedtuple('Protocol', ('kind', 'value',))):
+  """A sum type for handles to a system that transmits tickets.
 
   Attributes:
-    kind: A Kind value identifying the kind of value being passed to or from
-      the underlying transport.
-    value: The value being passed through RPC Framework between the high-level
-      application and the underlying transport.
+    kind: A Kind value identifying the kind of value being passed.
+    value: The value being passed between the high-level application and the
+      system affording ticket transport.
   """
 
   @enum.unique
@@ -56,8 +55,7 @@ class Ticket(
         'Ticket',
         ('operation_id', 'sequence_number', 'group', 'method', 'subscription',
          'timeout', 'allowance', 'initial_metadata', 'payload',
-         'terminal_metadata', 'code', 'message', 'termination',
-         'transport',))):
+         'terminal_metadata', 'code', 'message', 'termination', 'protocol',))):
   """A sum type for all values sent from a front to a back.
 
   Attributes:
@@ -99,8 +97,8 @@ class Ticket(
     termination: A Termination value describing the end of the operation, or
       None if the operation has not yet terminated. If set, no further tickets
       may be sent in the same direction.
-    transport: A Transport value or None, with further semantics being a matter
-      between high-level application and underlying transport.
+    protocol: A Protocol value or None, with further semantics being a matter
+      between high-level application and underlying ticket transport.
   """
 
   @enum.unique