所以我试图在 Python 中的 ZMQ 和 C/C++ 扩展中的 ZMQ 之间建立一些简单的通信。Python 设置上下文，绑定一个 inproc 套接字，并将上下文和套接字名称传递给扩展。扩展设置自己的套接字、连接和侦听消息。然后 Python 发送一个标题，然后将字典的字符串表示形式发送到扩展。使用 REQ/REP 套接字的非常简单的东西。但是，由于某种原因，我似乎找不到，对 socket.send 的调用被阻塞，并且扩展永远不会超过对 zmq_recv 的调用。我有一个测试环境，在那里我播放了几乎完全相同的场景，但套接字不会阻塞，并且我已经对代码进行了三重检查，它应该以相同的方式工作。
PYTHON：
import zmq
import cppextension
# No lectures about using threading please. I'm restricted to, in essence
# using this function because of the code base I'm working with.
from thread import start_new_thread
socket = self.zmq_context.socket(zmq.REQ)
socket_name = "inproc://agl"
socket.bind(socket_name)
t = start_native_thread(cppextension.actor,
(self.zmq_context, socket_name))
test_send = {"foo": 1, "bar": 2}
# BLOCKS ON THIS LINE VVVVV
socket.send("TEST", flags=zmq.SNDMORE)
socket.send(str(test_send))
socket.recv()
socket.send("STOP")
C/C++：
// Originally these used std::basic_string<Py_UNICODE> but I reverted
// back to normal std::string so I can use a JSON parsing library.
typedef string pystring;
typedef char pystring_t;
extern "C" PyObject *
actor(PyObject *self, PyObject *args) {
PyObject *py_context, *py_connect_to;
PyThreadState *_save;
void *context;
char *connect_to;
void *socket;
int rc;
if(!PyArg_ParseTuple(args, "OO", &py_context, &py_connect_to)) {
PyErr_SetString(PyExc_TypeError, "Expected two arguments (ZMQ context, name of socket to connect to)");
return NULL;
}
py_context = PyObject_GetAttrString(py_context, "_handle");
if(py_context == NULL) {
PyErr_SetString(PyExc_TypeError, "Could not get '_handle' from context");
return NULL;
}
if(!PyInt_Check(py_context)) {
PyErr_SetString(PyExc_TypeError, "_handle was not an integer");
return NULL;
}
context = (void*)PyInt_AsLong(py_context);
connect_to = new char[PyString_Size(py_connect_to) + 1];
strcpy(connect_to, PyString_AsString(py_connect_to));
_save = PyEval_SaveThread();
//
// GIL-less operation BEGIN
// ** WARNING: Do NOT call any functions that begin with 'Py', or touch any
// data structures that begin with 'Py' while in this section. It *WILL*
// blow up the Python interpreter.
//
socket = zmq_socket(context, ZMQ_REP);
rc = zmq_connect(socket, connect_to);
pystring TEST("TEST");
pystring STOP("STOP");
pystring SUCCESS("SUCCESS");
pystring FAILURE("FAILURE");
if(rc == 0) {
int going = 1;
// Should be able to hold a full megabyte of text, which should be enough
// for any message being passed in.
// Is there a way to query size of the incoming message...?
char buffer[1000000];
while(going) {
// BLOCKS ON THIS LINE VVVVVV
int size = zmq_recv(socket, buffer, 1000000, 0);
if(size == -1) {
// ERROR
continue;
}
// Assume we don't get larger than 1MB of data. Should put a
// check around this at some point, but not right now.
buffer[size] = 0;
pystring fullmsg(buffer);
cout << "ZMQ RECIEVED: " << fullmsg << endl;
if(fullmsg == TEST) {
size = zmq_recv(socket, &buffer, 1000000, 0);
if(size != -1) {
buffer[size] = 0;
pystring json_fullmsg(buffer);
cout << "ZMQ JSON: " << json_fullmsg << endl;
contacts.add(json_fullmsg);
zmq_send(socket, SUCCESS.c_str(), SUCCESS.size() + 1, 0);
}
else {
zmq_send(socket, FAILURE.c_str(), FAILURE.size() + 1, 0);
}
}
else if(fullmsg == STOP) {
going = 0;
zmq_send(socket, SUCCESS.c_str(), SUCCESS.size() + 1, 0);
}
}
}
else {
// ERROR
int err = zmq_errno();
switch(err) {
case EINVAL:
cout << "ZMQ CONNECT ERR: " << "Endpoint supplied is invalid" << endl;
break;
default:
cout << "ZMQ CONNECT ERR: " << err << endl;
break;
}
}
zmq_close(socket);
//
// GIL-less operation END
//
PyEval_RestoreThread(_save);
Py_INCREF(Py_None);
return Py_None;
}
任何帮助弄清楚这里发生了什么都非常感谢。
编辑：另请注意，此代码将在 gevent 对标准库进行了猴子补丁的环境中运行。这是我使用thread.start_new_thread 的部分原因，因为它是在monkeypatching 发生之前保存的，我想要一个真正的线程而不是绿色线程。