Require `<symbol>.<provider>` format to cli

piker/ui/_chart.py

@@ -1638,8 +1638,10 @@ async def _async_main(
         )
         chart_app.search = search
 
+        symbol, _, provider = sym.rpartition('.')
+
         # this internally starts a ``chart_symbol()`` task above
-        chart_app.load_symbol(brokernames[0], sym, loglevel)
+        chart_app.load_symbol(provider, symbol, loglevel)
 
         # TODO: seems like our incentive for brokerd caching lelel
         backends = {}

piker/ui/cli.py

@@ -138,6 +138,13 @@ def chart(config, symbol, profile, pdb):
     from .. import _profile
     from ._chart import _main
 
+    if '.' not in symbol:
+        click.echo(click.style(
+            f'symbol: {symbol} must have a {symbol}.<provider> suffix',
+            fg='red',
+        ))
+        return
+
     # toggle to enable profiling
     _profile._pg_profile = profile