Add reconnect loop to `marketstore` startup test

Due to making ahabd supervisor init more async we need to be more
tolerant to mkts server startup: the grpc machinery needs to be up
otherwise a client which connects to early may just hang on requests..

Add a reconnect loop (which might end up getting factored into client
code too) so that we only block on requests once we know the client
connection is actually responsive.

tests/test_databases.py

@@ -8,40 +8,67 @@ from piker.service import marketstore
 
 def test_marketstore_startup_and_version(
     open_test_pikerd: AsyncContextManager,
-    loglevel,
+    loglevel: str,
 ):
     '''
-    Verify marketstore starts correctly
+    Verify marketstore tsdb starts up and we can
+    connect with a client to do basic API reqs.
 
     '''
     async def main():
-        # port = 5995
 
         async with (
             open_test_pikerd(
                 loglevel=loglevel,
                 tsdb=True
-            ) as (s, i, pikerd_portal, services),
+            ) as (
-            marketstore.get_client() as client
+                _,  # host
+                _,  # port
+                pikerd_portal,
+                services,
+            ),
         ):
+            # XXX NOTE: we use a retry-connect loop because it seems
+            # that if we connect *too fast* to a booting container
+            # instance (i.e. if mkts's IPC machinery isn't up early
+            # enough) the client will hang on req-resp submissions. So,
+            # instead we actually reconnect the client entirely in
+            # a loop until we get a response.
+            for _ in range(3):
+
+                # NOTE: default sockaddr is embedded within
+                async with marketstore.get_client() as client:
+
+                    with trio.move_on_after(1) as cs:
+                        syms = await client.list_symbols()
+
+                    if cs.cancelled_caught:
+                        continue
+
+
+                    # should be an empty db?
+                    assert not syms
+                    print(f'RX syms resp: {syms}')
 
                     assert (
                         len(await client.server_version()) ==
                         len('3862e9973da36cfc6004b88172c08f09269aaf01')
                     )
+                    print('VERSION CHECKED')
+
+                break  # get out of retry-connect loop
 
     trio.run(main)
 
 
 def test_elasticsearch_startup_and_version(
     open_test_pikerd: AsyncContextManager,
-    loglevel,
+    loglevel: str,
 ):
     '''
     Verify elasticsearch starts correctly
 
     '''
-
     async def main():
         port = 19200