Add `NoBsWs.connected()` predicate

piker/data/_web_bs.py

@@ -18,12 +18,20 @@
 ToOlS fOr CoPInG wITh "tHE wEB" protocols.
 
 """
-from contextlib import asynccontextmanager, AsyncExitStack
+from contextlib import (
+    asynccontextmanager,
+    AsyncExitStack,
+)
 from itertools import count
 from types import ModuleType
-from typing import Any, Optional, Callable, AsyncGenerator
+from typing import (
+    Any,
+    Optional,
+    Callable,
+    AsyncGenerator,
+    Iterable,
+)
 import json
-import sys
 
 import trio
 import trio_websocket
@@ -44,9 +52,12 @@ log = get_logger(__name__)
 
 
 class NoBsWs:
-    """Make ``trio_websocket`` sockets stay up no matter the bs.
+    '''
+    Make ``trio_websocket`` sockets stay up no matter the bs.
 
-    """
+    You can provide a ``fixture`` async-context-manager which will be
+    enter/exitted around each reconnect operation.
+    '''
     recon_errors = (
         ConnectionClosed,
         DisconnectionTimeout,
@@ -68,10 +79,16 @@ class NoBsWs:
         self._stack = stack
         self._ws: 'WebSocketConnection' = None  # noqa
 
+        # TODO: is there some method we can call
+        # on the underlying `._ws` to get this?
+        self._connected: bool = False
+
     async def _connect(
         self,
         tries: int = 1000,
     ) -> None:
+
+        self._connected = False
         while True:
             try:
                 await self._stack.aclose()
@@ -96,6 +113,8 @@ class NoBsWs:
                     assert ret is None
 
                 log.info(f'Connection success: {self.url}')
+
+                self._connected = True
                 return self._ws
 
             except self.recon_errors as err:
@@ -105,11 +124,15 @@ class NoBsWs:
                     f'{type(err)}...retry attempt {i}'
                 )
                 await trio.sleep(0.5)
+                self._connected = False
                 continue
         else:
             log.exception('ws connection fail...')
             raise last_err
 
+    def connected(self) -> bool:
+        return self._connected
+
     async def send_msg(
         self,
         data: Any,
@@ -161,6 +184,7 @@ async def open_autorecon_ws(
 '''
 JSONRPC response-request style machinery for transparent multiplexing of msgs
 over a NoBsWs.
+
 '''
 
 
@@ -170,6 +194,7 @@ class JSONRPCResult(Struct):
     result: Optional[dict] = None
     error: Optional[dict] = None
 
+
 @asynccontextmanager
 async def open_jsonrpc_session(
     url: str,
@@ -220,15 +245,16 @@ async def open_jsonrpc_session(
 
         async def recv_task():
             '''
-            receives every ws message and stores it in its corresponding result
-            field, then sets the event to wakeup original sender tasks.
-            also recieves responses to requests originated from the server side.
-            '''
+            receives every ws message and stores it in its corresponding
+            result field, then sets the event to wakeup original sender
+            tasks. also recieves responses to requests originated from
+            the server side.
 
+            '''
             async for msg in ws:
                 match msg:
                     case {
-                        'result': result,
+                        'result': _,
                         'id': mid,
                     } if res_entry := rpc_results.get(mid):
 
@@ -239,7 +265,9 @@ async def open_jsonrpc_session(
                         'result': _,
                         'id': mid,
                     } if not rpc_results.get(mid):
-                        log.warning(f'Wasn\'t expecting ws msg: {json.dumps(msg, indent=4)}')
+                        log.warning(
+                            f'Unexpected ws msg: {json.dumps(msg, indent=4)}'
+                        )
 
                     case {
                         'method': _,
@@ -259,7 +287,6 @@ async def open_jsonrpc_session(
                     case _:
                         log.warning(f'Unhandled JSON-RPC msg!?\n{msg}')
 
-
         n.start_soon(recv_task)
         yield json_rpc
         n.cancel_scope.cancel()