pyln: handle (ignore) notifications, and add notify_msg to send them.

We also sanity check that response id matches our request.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Added: pyln: pyln.client handles and can send progress notifications.

contrib/pyln-client/pyln/client/lightning.py

@@ -316,17 +316,26 @@ class UnixDomainSocketRpc(object):
 
         # FIXME: we open a new socket for every readobj call...
         sock = UnixSocket(self.socket_path)
+        this_id = self.next_id
         self._writeobj(sock, {
             "jsonrpc": "2.0",
             "method": method,
             "params": payload,
-            "id": self.next_id,
+            "id": this_id,
         })
         self.next_id += 1
-        resp, _ = self._readobj(sock)
-        sock.close()
+        buf = b''
+        while True:
+            resp, buf = self._readobj(sock, buf)
+            # FIXME: We should offer a callback for notifications.
+            if 'method' not in resp or 'id' in resp:
+                break
 
         self.logger.debug("Received response for %s call: %r", method, resp)
+        if 'id' in resp and resp['id'] != this_id:
+            raise ValueError("Malformed response, id is not {}: {}.".format(this_id, resp))
+        sock.close()
+
         if not isinstance(resp, dict):
             raise ValueError("Malformed response, response is not a dictionary %s." % resp)
         elif "error" in resp:

contrib/pyln-client/pyln/client/plugin.py

@@ -608,6 +608,26 @@ class Plugin(object):
         for line in message.split('\n'):
             self.notify('log', {'level': level, 'message': line})
 
+    def notify_message(self, request: Request, message: str,
+                       level: str = 'info') -> None:
+        """Send a notification message to sender of this request"""
+        self.notify("message", {"id": request.id,
+                                "level": level,
+                                "message": message})
+
+    def notify_progress(self, request: Request,
+                        progress: int, progress_total: int,
+                        stage: Optional[int] = None,
+                        stage_total: Optional[int] = None) -> None:
+        """Send a progerss message to sender of this request: if more than one stage, set stage and stage_total"""
+        d: Dict[str, Any] = {"id": request.id,
+                             "num": progress,
+                             "total": progress_total}
+        if stage_total is not None:
+            d['stage'] = {"num": stage, "total": stage_total}
+
+        self.notify("progress", d)
+
     def _parse_request(self, jsrequest: Dict[str, JSONType]) -> Request:
         i = jsrequest.get('id', None)
         if not isinstance(i, int) and i is not None: