More prep for FSP feeds

The major change is moving the fsp "daemon" (more like wanna-be fspd)
endpoint to use the newer `tractor.Portal.open_context()` and
bi-directional streaming api.

There's a few other things in here too:
- make a helper for allocating single colume fsp shm arrays
- rename some some fsp related functions to be more explicit on their
  purposes

piker/ui/_display.py

@@ -53,6 +53,7 @@ from ..log import get_logger
 
 log = get_logger(__name__)
 
+# TODO: load these from a config.toml!
 _clear_throttle_rate: int = 58  # Hz
 _book_throttle_rate: int = 16  # Hz
 
@@ -184,6 +185,13 @@ async def update_chart_from_quotes(
             if vlm_chart:
                 # print(f"volume: {end['volume']}")
                 vlm_chart.update_curve_from_array('volume', array)
+
+                # built-in tina $vlm FSP using chl3 typical price for ohlc step
+                # last = array[-1]
+                # chl3 = (last['close'] + last['high'] + last['low']) / 3
+                # v = last['volume']
+                # dv = last['volume'] * chl3
+
                 vlm_sticky.update_from_data(*array[-1][['index', 'volume']])
 
                 if (
@@ -302,7 +310,38 @@ async def update_chart_from_quotes(
                 last_mx, last_mn = mx, mn
 
 
-async def fan_out_spawn_fsp_daemons(
+def maybe_mk_fsp_shm(
+    sym: str,
+    field_name: str,
+    display_name: Optional[str] = None,
+    readonly: bool = True,
+
+) -> (ShmArray, bool):
+    '''Allocate a single row shm array for an symbol-fsp pair.
+
+    '''
+    uid = tractor.current_actor().uid
+    if not display_name:
+        display_name = field_name
+
+    # TODO: load function here and introspect
+    # return stream type(s)
+
+    # TODO: should `index` be a required internal field?
+    fsp_dtype = np.dtype([('index', int), (field_name, float)])
+
+    key = f'{sym}.fsp.{display_name}.{".".join(uid)}'
+
+    shm, opened = maybe_open_shm_array(
+        key,
+        # TODO: create entry for each time frame
+        dtype=fsp_dtype,
+        readonly=True,
+    )
+    return shm, opened
+
+
+async def open_fspd_cluster(
 
     linkedsplits: LinkedSplits,
     fsps: dict[str, str],
@@ -321,9 +360,8 @@ async def fan_out_spawn_fsp_daemons(
     '''
     linkedsplits.focus()
 
-    uid = tractor.current_actor().uid
+    # spawns sub-processes which execute cpu bound fsp work
-
+    # which is streamed back to this parent.
-    # spawns sub-processes which execute cpu bound FSP code
     async with (
         tractor.open_nursery() as n,
         trio.open_nursery() as ln,
@@ -334,21 +372,12 @@ async def fan_out_spawn_fsp_daemons(
         # scale horizonatlly once cores are used up.
         for display_name, conf in fsps.items():
 
-            fsp_func_name = conf['fsp_func_name']
+            func_name = conf['func_name']
 
-            # TODO: load function here and introspect
+            shm, opened = maybe_mk_fsp_shm(
-            # return stream type(s)
+                sym,
-
+                field_name=func_name,
-            # TODO: should `index` be a required internal field?
+                display_name=display_name,
-            fsp_dtype = np.dtype([('index', int), (fsp_func_name, float)])
-
-            key = f'{sym}.fsp.{display_name}.{".".join(uid)}'
-
-            # this is all sync currently
-            shm, opened = maybe_open_shm_array(
-                key,
-                # TODO: create entry for each time frame
-                dtype=fsp_dtype,
                 readonly=True,
             )
 
@@ -366,13 +395,13 @@ async def fan_out_spawn_fsp_daemons(
 
             # init async
             ln.start_soon(
-                run_fsp,
+                update_chart_from_fsp,
                 portal,
                 linkedsplits,
                 brokermod,
                 sym,
                 src_shm,
-                fsp_func_name,
+                func_name,
                 display_name,
                 conf,
                 group_status_key,
@@ -383,7 +412,7 @@ async def fan_out_spawn_fsp_daemons(
 
 
 @asynccontextmanager
-async def open_sidepane(
+async def open_fsp_sidepane(
 
     linked: LinkedSplits,
     conf: dict[str, dict[str, str]],
@@ -403,8 +432,11 @@ async def open_sidepane(
             }
 
         # add parameters for selection "options"
-        defaults = config.get('params', {})
+        params = config.get('params', {})
-        for name, default in defaults.items():
+        for name, config in params.items():
+
+            default = config['default_value']
+            kwargs = config.get('widget_kwargs', {})
 
             # add to ORM schema
             schema.update({
@@ -412,6 +444,7 @@ async def open_sidepane(
                     'label': f'**{name}**:',
                     'type': 'edit',
                     'default_value': default,
+                    'kwargs': kwargs,
                 },
             })
 
@@ -424,7 +457,7 @@ async def open_sidepane(
     FspConfig = create_model(
         'FspConfig',
         name=display_name,
-        **defaults,
+        **params,
     )
     sidepane.model = FspConfig()
 
@@ -444,14 +477,15 @@ async def open_sidepane(
         yield sidepane
 
 
-async def run_fsp(
+async def update_chart_from_fsp(
+
+    portal: tractor.Portal,
 
-    portal: tractor._portal.Portal,
     linkedsplits: LinkedSplits,
     brokermod: ModuleType,
     sym: str,
     src_shm: ShmArray,
-    fsp_func_name: str,
+    func_name: str,
     display_name: str,
     conf: dict[str, dict],
     group_status_key: str,
@@ -470,7 +504,7 @@ async def run_fsp(
     )
 
     async with (
-        portal.open_stream_from(
+        portal.open_context(
 
             # chaining entrypoint
             fsp.cascade,
@@ -480,21 +514,17 @@ async def run_fsp(
             src_shm_token=src_shm.token,
             dst_shm_token=conf['shm'].token,
             symbol=sym,
-            fsp_func_name=fsp_func_name,
+            func_name=func_name,
             loglevel=loglevel,
 
-        ) as stream,
+        ) as (ctx, last_index),
+        ctx.open_stream() as stream,
 
-        open_sidepane(
+        open_fsp_sidepane(
             linkedsplits,
             {display_name: conf},
         ) as sidepane,
     ):
-
-        # receive last index for processed historical
-        # data-array as first msg
-        _ = await stream.receive()
-
         shm = conf['shm']
 
         if conf.get('overlay'):
@@ -513,7 +543,7 @@ async def run_fsp(
                 name=display_name,
                 array=shm.array,
 
-                array_key=conf['fsp_func_name'],
+                array_key=conf['func_name'],
                 sidepane=sidepane,
 
                 # curve by default
@@ -541,7 +571,7 @@ async def run_fsp(
             # XXX: fsp func names must be unique meaning we don't have
             # duplicates of the underlying data even if multiple
             # sub-charts reference it under different 'named charts'.
-            value = array[fsp_func_name][-1]
+            value = array[func_name][-1]
 
             last_val_sticky.update_from_data(-1, value)
 
@@ -552,7 +582,7 @@ async def run_fsp(
         chart.update_curve_from_array(
             display_name,
             shm.array,
-            array_key=fsp_func_name
+            array_key=func_name
         )
 
         chart.linked.resize_sidepanes()
@@ -563,11 +593,11 @@ async def run_fsp(
         # generic fills between curve types while ``PlotCurveItem`` has
         # logic inside ``.paint()`` for ``self.opts['fillLevel']`` which
         # might be the best solution?
-        # graphics = chart.update_from_array(chart.name, array[fsp_func_name])
+        # graphics = chart.update_from_array(chart.name, array[func_name])
         # graphics.curve.setBrush(50, 50, 200, 100)
         # graphics.curve.setFillLevel(50)
 
-        if fsp_func_name == 'rsi':
+        if func_name == 'rsi':
             from ._lines import level_line
             # add moveable over-[sold/bought] lines
             # and labels only for the 70/30 lines
@@ -611,7 +641,7 @@ async def run_fsp(
                 try:
                     # read last
                     array = shm.array
-                    value = array[-1][fsp_func_name]
+                    value = array[-1][func_name]
                     break
 
                 except IndexError:
@@ -625,7 +655,7 @@ async def run_fsp(
             chart.update_curve_from_array(
                 display_name,
                 array,
-                array_key=fsp_func_name,
+                array_key=func_name,
             )
 
             # set time of last graphics update
@@ -711,12 +741,26 @@ async def maybe_open_vlm_display(
         yield
         return
     else:
-        async with open_sidepane(
+
+        shm, opened = maybe_mk_fsp_shm(
+            linked.symbol.key,
+            '$_vlm',
+            readonly=True,
+        )
+
+        async with open_fsp_sidepane(
             linked, {
                 'volume': {
+
                     'params': {
-                        'price_func': 'ohl3'
+
-                    }
+                        'price_func': {
+                            'default_value': 'ohl3',
+                            # tell target ``Edit`` widget to not allow
+                            # edits for now.
+                            'widget_kwargs': {'readonly': True},
+                        },
+                    },
                 }
             },
         ) as sidepane:
@@ -872,20 +916,39 @@ async def display_symbol_data(
 
         # TODO: eventually we'll support some kind of n-compose syntax
         fsp_conf = {
+
             'rsi': {
-                'fsp_func_name': 'rsi',
+
-                'params': {'period': 14},
+                # literal python func ref lookup name
+                'func_name': 'rsi',
+
+                # map of parameters to place on the fsp sidepane widget
+                # which should map to dynamic inputs available to the
+                # fsp function at runtime.
+                'params': {
+                    'period': {
+                        'default_value': 14,
+                        'widget_kwargs': {'readonly': True},
+                    },
+                },
+
+                # ``ChartPlotWidget`` options passthrough
                 'chart_kwargs': {
                     'static_yrange': (0, 100),
                 },
             },
+
         }
 
-        if has_vlm(ohlcv):
+        if has_vlm(ohlcv): # and provider != 'binance':
+            # binance is too fast atm for FSPs until we wrap
+            # the fsp streams as throttled ``Feeds``, see
+            #
+
             # add VWAP to fsp config for downstream loading
             fsp_conf.update({
                 'vwap': {
-                    'fsp_func_name': 'vwap',
+                    'func_name': 'vwap',
                     'overlay': True,
                     'anchor': 'session',
                 },
@@ -904,7 +967,7 @@ async def display_symbol_data(
         ):
             # load initial fsp chain (otherwise known as "indicators")
             ln.start_soon(
-                fan_out_spawn_fsp_daemons,
+                open_fspd_cluster,
                 linkedsplits,
                 fsp_conf,
                 sym,