Expose new core functionality to Python

7 files changed, 185 insertions, 18 deletions

diff --git a/src/python/grpcio/grpc/_adapter/_c/types.h b/src/python/grpcio/grpc/_adapter/_c/types.h
index 4e0da4a28a..f646465c63 100644
--- a/src/python/grpcio/grpc/_adapter/_c/types.h
+++ b/src/python/grpcio/grpc/_adapter/_c/types.h
@@ -113,6 +113,7 @@ Call *pygrpc_Call_new_empty(CompletionQueue *cq);
 void pygrpc_Call_dealloc(Call *self);
 PyObject *pygrpc_Call_start_batch(Call *self, PyObject *args, PyObject *kwargs);
 PyObject *pygrpc_Call_cancel(Call *self, PyObject *args, PyObject *kwargs);
+PyObject *pygrpc_Call_peer(Call *self);
 extern PyTypeObject pygrpc_Call_type;
 
 
@@ -129,6 +130,11 @@ Channel *pygrpc_Channel_new(
 void pygrpc_Channel_dealloc(Channel *self);
 Call *pygrpc_Channel_create_call(
     Channel *self, PyObject *args, PyObject *kwargs);
+PyObject *pygrpc_Channel_check_connectivity_state(Channel *self, PyObject *args,
+                                                  PyObject *kwargs);
+PyObject *pygrpc_Channel_watch_connectivity_state(Channel *self, PyObject *args,
+                                                  PyObject *kwargs);
+PyObject *pygrpc_Channel_target(Channel *self);
 extern PyTypeObject pygrpc_Channel_type;
 
 
@@ -181,6 +187,9 @@ pygrpc_tag *pygrpc_produce_request_tag(PyObject *user_tag, Call *empty_call);
 /* Construct a tag associated with a server shutdown. */
 pygrpc_tag *pygrpc_produce_server_shutdown_tag(PyObject *user_tag);
 
+/* Construct a tag associated with a channel state change. */
+pygrpc_tag *pygrpc_produce_channel_state_change_tag(PyObject *user_tag);
+
 /* Frees all resources owned by the tag and the tag itself. */
 void pygrpc_discard_tag(pygrpc_tag *tag);
 
diff --git a/src/python/grpcio/grpc/_adapter/_c/types/call.c b/src/python/grpcio/grpc/_adapter/_c/types/call.c
index 0739070044..5e46605c45 100644
--- a/src/python/grpcio/grpc/_adapter/_c/types/call.c
+++ b/src/python/grpcio/grpc/_adapter/_c/types/call.c
@@ -42,6 +42,7 @@
 PyMethodDef pygrpc_Call_methods[] = {
     {"start_batch", (PyCFunction)pygrpc_Call_start_batch, METH_KEYWORDS, ""},
     {"cancel", (PyCFunction)pygrpc_Call_cancel, METH_KEYWORDS, ""},
+    {"peer", (PyCFunction)pygrpc_Call_peer, METH_NOARGS, ""},
     {NULL}
 };
 const char pygrpc_Call_doc[] = "See grpc._adapter._types.Call.";
@@ -161,3 +162,10 @@ PyObject *pygrpc_Call_cancel(Call *self, PyObject *args, PyObject *kwargs) {
   }
   return PyInt_FromLong(errcode);
 }
+
+PyObject *pygrpc_Call_peer(Call *self) {
+  char *peer = grpc_call_get_peer(self->c_call);
+  PyObject *py_peer = PyString_FromString(peer);
+  gpr_free(peer);
+  return py_peer;
+}
diff --git a/src/python/grpcio/grpc/_adapter/_c/types/channel.c b/src/python/grpcio/grpc/_adapter/_c/types/channel.c
index 963104742f..eb9d43d154 100644
--- a/src/python/grpcio/grpc/_adapter/_c/types/channel.c
+++ b/src/python/grpcio/grpc/_adapter/_c/types/channel.c
@@ -36,10 +36,14 @@
 #define PY_SSIZE_T_CLEAN
 #include <Python.h>
 #include <grpc/grpc.h>
+#include <grpc/support/alloc.h>
 
 
 PyMethodDef pygrpc_Channel_methods[] = {
     {"create_call", (PyCFunction)pygrpc_Channel_create_call, METH_KEYWORDS, ""},
+    {"check_connectivity_state", (PyCFunction)pygrpc_Channel_check_connectivity_state, METH_KEYWORDS, ""},
+    {"watch_connectivity_state", (PyCFunction)pygrpc_Channel_watch_connectivity_state, METH_KEYWORDS, ""},
+    {"target", (PyCFunction)pygrpc_Channel_target, METH_NOARGS, ""},
     {NULL}
 };
 const char pygrpc_Channel_doc[] = "See grpc._adapter._types.Channel.";
@@ -122,7 +126,7 @@ Call *pygrpc_Channel_create_call(
   const char *host;
   double deadline;
   char *keywords[] = {"cq", "method", "host", "deadline", NULL};
-  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O!ssd:create_call", keywords,
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O!szd:create_call", keywords,
         &pygrpc_CompletionQueue_type, &cq, &method, &host, &deadline)) {
     return NULL;
   }
@@ -132,3 +136,51 @@ Call *pygrpc_Channel_create_call(
       pygrpc_cast_double_to_gpr_timespec(deadline));
   return call;
 }
+
+PyObject *pygrpc_Channel_check_connectivity_state(
+    Channel *self, PyObject *args, PyObject *kwargs) {
+  PyObject *py_try_to_connect;
+  int try_to_connect;
+  char *keywords[] = {"try_to_connect", NULL};
+  grpc_connectivity_state state;
+  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "O:connectivity_state", keywords,
+                                   &py_try_to_connect)) {
+    return NULL;
+  }
+  if (!PyBool_Check(py_try_to_connect)) {
+    Py_XDECREF(py_try_to_connect);
+    return NULL;
+  }
+  try_to_connect = Py_True == py_try_to_connect;
+  Py_DECREF(py_try_to_connect);
+  state = grpc_channel_check_connectivity_state(self->c_chan, try_to_connect);
+  return PyInt_FromLong(state);
+}
+
+PyObject *pygrpc_Channel_watch_connectivity_state(
+    Channel *self, PyObject *args, PyObject *kwargs) {
+  PyObject *tag;
+  double deadline;
+  int last_observed_state;
+  CompletionQueue *completion_queue;
+  char *keywords[] = {"last_observed_state", "deadline",
+                      "completion_queue", "tag"};
+  if (!PyArg_ParseTupleAndKeywords(
+      args, kwargs, "idO!O:watch_connectivity_state", keywords,
+      &last_observed_state, &deadline, &pygrpc_CompletionQueue_type,
+      &completion_queue, &tag)) {
+    return NULL;
+  }
+  grpc_channel_watch_connectivity_state(
+      self->c_chan, (grpc_connectivity_state)last_observed_state,
+      pygrpc_cast_double_to_gpr_timespec(deadline), completion_queue->c_cq,
+      pygrpc_produce_channel_state_change_tag(tag));
+  Py_RETURN_NONE;
+}
+
+PyObject *pygrpc_Channel_target(Channel *self) {
+  char *target = grpc_channel_get_target(self->c_chan);
+  PyObject *py_target = PyString_FromString(target);
+  gpr_free(target);
+  return py_target;
+}
diff --git a/src/python/grpcio/grpc/_adapter/_c/utility.c b/src/python/grpcio/grpc/_adapter/_c/utility.c
index 51f3c9be01..2eea0e18ef 100644
--- a/src/python/grpcio/grpc/_adapter/_c/utility.c
+++ b/src/python/grpcio/grpc/_adapter/_c/utility.c
@@ -88,6 +88,19 @@ pygrpc_tag *pygrpc_produce_server_shutdown_tag(PyObject *user_tag) {
   return tag;
 }
 
+pygrpc_tag *pygrpc_produce_channel_state_change_tag(PyObject *user_tag) {
+  pygrpc_tag *tag = gpr_malloc(sizeof(pygrpc_tag));
+  tag->user_tag = user_tag;
+  Py_XINCREF(tag->user_tag);
+  tag->call = NULL;
+  tag->ops = NULL;
+  tag->nops = 0;
+  grpc_call_details_init(&tag->request_call_details);
+  grpc_metadata_array_init(&tag->request_metadata);
+  tag->is_new_call = 0;
+  return tag;
+}
+
 void pygrpc_discard_tag(pygrpc_tag *tag) {
   if (!tag) {
     return;
@@ -139,7 +152,7 @@ PyObject *pygrpc_consume_event(grpc_event event) {
 }
 
 int pygrpc_produce_op(PyObject *op, grpc_op *result) {
-  static const int OP_TUPLE_SIZE = 5;
+  static const int OP_TUPLE_SIZE = 6;
   static const int STATUS_TUPLE_SIZE = 2;
   static const int TYPE_INDEX = 0;
   static const int INITIAL_METADATA_INDEX = 1;
@@ -148,6 +161,7 @@ int pygrpc_produce_op(PyObject *op, grpc_op *result) {
   static const int STATUS_INDEX = 4;
   static const int STATUS_CODE_INDEX = 0;
   static const int STATUS_DETAILS_INDEX = 1;
+  static const int WRITE_FLAGS_INDEX = 5;
   int type;
   Py_ssize_t message_size;
   char *message;
@@ -170,7 +184,10 @@ int pygrpc_produce_op(PyObject *op, grpc_op *result) {
     return 0;
   }
   c_op.op = type;
-  c_op.flags = 0;
+  c_op.flags = PyInt_AsLong(PyTuple_GET_ITEM(op, WRITE_FLAGS_INDEX));
+  if (PyErr_Occurred()) {
+    return 0;
+  }
   switch (type) {
   case GRPC_OP_SEND_INITIAL_METADATA:
     if (!pygrpc_cast_pyseq_to_send_metadata(
diff --git a/src/python/grpcio/grpc/_adapter/_intermediary_low.py b/src/python/grpcio/grpc/_adapter/_intermediary_low.py
index 3c7f0a2619..e7bf9dc462 100644
--- a/src/python/grpcio/grpc/_adapter/_intermediary_low.py
+++ b/src/python/grpcio/grpc/_adapter/_intermediary_low.py
@@ -127,7 +127,7 @@ class Call(object):
 
   def write(self, message, tag):
     return self._internal.start_batch([
-          _types.OpArgs.send_message(message)
+          _types.OpArgs.send_message(message, 0)
       ], _TagAdapter(tag, Event.Kind.WRITE_ACCEPTED))
 
   def complete(self, tag):
diff --git a/src/python/grpcio/grpc/_adapter/_low.py b/src/python/grpcio/grpc/_adapter/_low.py
index dcf67dbc11..06d30c1b32 100644
--- a/src/python/grpcio/grpc/_adapter/_low.py
+++ b/src/python/grpcio/grpc/_adapter/_low.py
@@ -72,6 +72,9 @@ class Call(_types.Call):
     else:
       return self.call.cancel(code, details)
 
+  def peer(self):
+    return self.call.peer()
+
 
 class Channel(_types.Channel):
 
@@ -84,6 +87,17 @@ class Channel(_types.Channel):
   def create_call(self, completion_queue, method, host, deadline=None):
     return Call(self.channel.create_call(completion_queue.completion_queue, method, host, deadline))
 
+  def check_connectivity_state(self, try_to_connect):
+    return self.channel.check_connectivity_state(try_to_connect)
+
+  def watch_connectivity_state(self, last_observed_state, deadline,
+                               completion_queue, tag):
+    self.channel.watch_connectivity_state(
+        last_observed_state, deadline, completion_queue.completion_queue, tag)
+
+  def target(self):
+    return self.channel.target()
+
 
 _NO_TAG = object()
 
diff --git a/src/python/grpcio/grpc/_adapter/_types.py b/src/python/grpcio/grpc/_adapter/_types.py
index 5ddb1774ea..5470d2de4a 100644
--- a/src/python/grpcio/grpc/_adapter/_types.py
+++ b/src/python/grpcio/grpc/_adapter/_types.py
@@ -31,13 +31,12 @@ import abc
 import collections
 import enum
 
-# TODO(atash): decide whether or not to move these enums to the _c module to
-# force build errors with upstream changes.
 
 class GrpcChannelArgumentKeys(enum.Enum):
   """Mirrors keys used in grpc_channel_args for GRPC-specific arguments."""
   SSL_TARGET_NAME_OVERRIDE = 'grpc.ssl_target_name_override'
 
+
 @enum.unique
 class CallError(enum.IntEnum):
   """Mirrors grpc_call_error in the C core."""
@@ -53,6 +52,7 @@ class CallError(enum.IntEnum):
   ERROR_INVALID_FLAGS       = 9
   ERROR_INVALID_METADATA    = 10
 
+
 @enum.unique
 class StatusCode(enum.IntEnum):
   """Mirrors grpc_status_code in the C core."""
@@ -74,6 +74,14 @@ class StatusCode(enum.IntEnum):
   DATA_LOSS           = 15
   UNAUTHENTICATED     = 16
 
+
+@enum.unique
+class OpWriteFlags(enum.IntEnum):
+  """Mirrors defined write-flag constants in the C core."""
+  WRITE_BUFFER_HINT = 1
+  WRITE_NO_COMPRESS = 2
+
+
 @enum.unique
 class OpType(enum.IntEnum):
   """Mirrors grpc_op_type in the C core."""
@@ -86,12 +94,24 @@ class OpType(enum.IntEnum):
   RECV_STATUS_ON_CLIENT   = 6
   RECV_CLOSE_ON_SERVER    = 7
 
+
 @enum.unique
 class EventType(enum.IntEnum):
   """Mirrors grpc_completion_type in the C core."""
-  QUEUE_SHUTDOWN  = 0
-  QUEUE_TIMEOUT   = 1  # if seen on the Python side, something went horridly wrong
-  OP_COMPLETE     = 2
+  QUEUE_SHUTDOWN = 0
+  QUEUE_TIMEOUT  = 1  # if seen on the Python side, something went horridly wrong
+  OP_COMPLETE    = 2
+
+
+@enum.unique
+class ConnectivityState(enum.IntEnum):
+  """Mirrors grpc_connectivity_state in the C core."""
+  IDLE              = 0
+  CONNECTING        = 1
+  READY             = 2
+  TRANSIENT_FAILURE = 3
+  FATAL_FAILURE     = 4
+
 
 class Status(collections.namedtuple(
     'Status', [
@@ -105,6 +125,7 @@ class Status(collections.namedtuple(
     details (str): ...
   """
 
+
 class CallDetails(collections.namedtuple(
     'CallDetails', [
         'method',
@@ -119,6 +140,7 @@ class CallDetails(collections.namedtuple(
     deadline (float): ...
   """
 
+
 class OpArgs(collections.namedtuple(
     'OpArgs', [
         'type',
@@ -126,6 +148,7 @@ class OpArgs(collections.namedtuple(
         'trailing_metadata',
         'message',
         'status',
+        'write_flags',
     ])):
   """Arguments passed into a GRPC operation.
 
@@ -138,39 +161,40 @@ class OpArgs(collections.namedtuple(
     message (bytes): Only valid if type == OpType.SEND_MESSAGE, else is None.
     status (Status): Only valid if type == OpType.SEND_STATUS_FROM_SERVER, else
       is None.
+    write_flags (int): a bit OR'ing of 0 or more OpWriteFlags values.
   """
 
   @staticmethod
   def send_initial_metadata(initial_metadata):
-    return OpArgs(OpType.SEND_INITIAL_METADATA, initial_metadata, None, None, None)
+    return OpArgs(OpType.SEND_INITIAL_METADATA, initial_metadata, None, None, None, 0)
 
   @staticmethod
-  def send_message(message):
-    return OpArgs(OpType.SEND_MESSAGE, None, None, message, None)
+  def send_message(message, flags):
+    return OpArgs(OpType.SEND_MESSAGE, None, None, message, None, flags)
 
   @staticmethod
   def send_close_from_client():
-    return OpArgs(OpType.SEND_CLOSE_FROM_CLIENT, None, None, None, None)
+    return OpArgs(OpType.SEND_CLOSE_FROM_CLIENT, None, None, None, None, 0)
 
   @staticmethod
   def send_status_from_server(trailing_metadata, status_code, status_details):
-    return OpArgs(OpType.SEND_STATUS_FROM_SERVER, None, trailing_metadata, None, Status(status_code, status_details))
+    return OpArgs(OpType.SEND_STATUS_FROM_SERVER, None, trailing_metadata, None, Status(status_code, status_details), 0)
 
   @staticmethod
   def recv_initial_metadata():
-    return OpArgs(OpType.RECV_INITIAL_METADATA, None, None, None, None);
+    return OpArgs(OpType.RECV_INITIAL_METADATA, None, None, None, None, 0);
 
   @staticmethod
   def recv_message():
-    return OpArgs(OpType.RECV_MESSAGE, None, None, None, None)
+    return OpArgs(OpType.RECV_MESSAGE, None, None, None, None, 0)
 
   @staticmethod
   def recv_status_on_client():
-    return OpArgs(OpType.RECV_STATUS_ON_CLIENT, None, None, None, None)
+    return OpArgs(OpType.RECV_STATUS_ON_CLIENT, None, None, None, None, 0)
 
   @staticmethod
   def recv_close_on_server():
-    return OpArgs(OpType.RECV_CLOSE_ON_SERVER, None, None, None, None)
+    return OpArgs(OpType.RECV_CLOSE_ON_SERVER, None, None, None, None, 0)
 
 
 class OpResult(collections.namedtuple(
@@ -290,6 +314,15 @@ class Call:
     """
     return CallError.ERROR
 
+  @abc.abstractmethod
+  def peer(self):
+    """Get the peer of this call.
+
+    Returns:
+      str: the peer of this call.
+    """
+    return None
+
 
 class Channel:
   __metaclass__ = abc.ABCMeta
@@ -321,6 +354,40 @@ class Channel:
     """
     return None
 
+  @abc.abstractmethod
+  def check_connectivity_state(self, try_to_connect):
+    """Check and optionally repair the connectivity state of the channel.
+
+    Args:
+      try_to_connect (bool): whether or not to try to connect the channel if
+      disconnected.
+
+    Returns:
+      ConnectivityState: state of the channel at the time of this invocation.
+    """
+    return None
+
+  @abc.abstractmethod
+  def watch_connectivity_state(self, last_observed_state, deadline,
+                               completion_queue, tag):
+    """Watch for connectivity state changes from the last_observed_state.
+
+    Args:
+      last_observed_state (ConnectivityState): ...
+      deadline (float): ...
+      completion_queue (CompletionQueue): ...
+      tag (object) ...
+    """
+
+  @abc.abstractmethod
+  def target(self):
+    """Get the target of this channel.
+
+    Returns:
+      str: the target of this channel.
+    """
+    return None
+
 
 class Server:
   __metaclass__ = abc.ABCMeta