brokerd: slim RPC caps + `ib` client-id offset

Caps-sec tightening now that `brokerd` is trading-only: NO
`piker.data.*` (feed) mods are RPC-enabled in the (live,
credentialed) trading actor anymore.

Deats,
- drop `_data_mods` for a minimal `_brokerd_service_mods`
  (just `piker.brokers._daemon`); dedup-compose with the
  backend's set in `spawn_brokerd()`.
- `broker_init()` reads the backend's `_brokerd_mods`
  (fallback: `__enable_modules__` for flat backends).
- fail fast in `spawn_brokerd()` via `validate.get_eps()`
  when a backend offers NO live order-ctl eps (eg.
  `kucoin`, `deribit`) -> tells the caller to use
  paper-mode instead of booting a dead actor; analogous
  warning in `datad_init()` for datad-ep-less backends.
- offset `ib`'s default `client_id` per daemon-kind in
  `load_aio_clients()`: post-split BOTH `datad.ib` and
  `brokerd.ib` connect to the same gw/tws endpoint and the
  shared default (6116 + linear retry incrs) would collide
  and burn the full conn-timeout retry cycle; datad gets
  +16, ad-hoc (test/cli) actors +32.
- drop the import-cleanup leftovers (`exceptiongroup`,
  `_FeedsBus` type-only import) and the now-resolved
  "expose datad" TODO in `.cli`.

(this patch was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

piker/brokers/_daemon.py

@@ -25,10 +25,8 @@ from contextlib import (
 )
 from types import ModuleType
 from typing import (
-    TYPE_CHECKING,
     AsyncContextManager,
 )
-import exceptiongroup as eg
 
 import tractor
 import trio
@@ -40,27 +38,20 @@ from piker.log import (
 from . import _util
 from . import get_brokermod
 
-if TYPE_CHECKING:
-    from ..data import _FeedsBus
-
 log = get_logger(name=__name__)
 
-# `brokerd` enabled modules
-# TODO: move this def to the `.data` subpkg..
+# `brokerd`-actor-always-enabled mods.
 # NOTE: keeping this list as small as possible is part of our caps-sec
-# model and should be treated with utmost care!
-_data_mods: str = [
-    'piker.brokers.core',
-    'piker.brokers.data',
+# model and should be treated with utmost care! In particular NO
+# `piker.data.*` feed mods should be enabled in this (live,
+# credentialed) trading actor; all data-feed serving is the
+# domain of the `datad.<broker>` sibling daemon, see
+# `piker.data._daemon._datad_service_mods`.
+_brokerd_service_mods: list[str] = [
     'piker.brokers._daemon',
-    'piker.data',
-    'piker.data.feed',
-    'piker.data._sampling'
 ]
 
 
-# TODO: we should rename the daemon to datad prolly once we split up
-# broker vs. data tasks into separate actors?
 @tractor.context
 async def _setup_persistent_brokerd(
     ctx: tractor.Context,
@@ -119,8 +110,10 @@ def broker_init(
 
     This includes:
     - load the appropriate <brokername>.py pkg module,
-    - reads any declared `__enable_modules__: listr[str]` which will be
-      passed to `tractor.ActorNursery.start_actor(enabled_modules=<this>)`
+    - reads any declared `_brokerd_mods: list[str]` (falling
+      back to the full `__enable_modules__` set for
+      not-yet-split backends) which will be passed to
+      `tractor.ActorNursery.start_actor(enable_modules=)`
       at actor start time,
     - deliver a references to the daemon lifetime fixture, which
       for now is always the `_setup_persistent_brokerd()` context defined
@@ -155,8 +148,14 @@ def broker_init(
     ]
     for submodname in getattr(
         brokermod,
-        '__enable_modules__',
-        [],
+        '_brokerd_mods',
+        # fallback for (flat, less mature) backends which
+        # don't yet declare a daemon-kind mod split.
+        getattr(
+            brokermod,
+            '__enable_modules__',
+            [],
+        ),
     ):
         subpath: str = f'{modpath}.{submodname}'
         enabled.append(subpath)
@@ -184,6 +183,22 @@ async def spawn_brokerd(
         f'backend: {brokername!r}'
     )
 
+    # fail fast on (data-only) backends which don't offer
+    # ANY live order-control eps; the caller should instead
+    # be using paper-mode (and thus never spawning us)!
+    from ..data.validate import get_eps
+    brokerd_eps: dict = get_eps(
+        get_brokermod(brokername),
+        'brokerd',
+    )
+    if not brokerd_eps:
+        raise RuntimeError(
+            f'Backend {brokername!r} offers NO `brokerd` '
+            f'(live order-control) eps!?\n'
+            f'It is likely a datad-only provider, use '
+            f'paper-mode for clearing instead.\n'
+        )
+
     (
         brokermode,
         tractor_kwargs,
@@ -205,7 +220,11 @@ async def spawn_brokerd(
     dname: str = tractor_kwargs.pop('name')  # f'brokerd.{brokername}'
     portal = await Services.actor_n.start_actor(
         dname,
-        enable_modules=_data_mods + tractor_kwargs.pop('enable_modules'),
+        enable_modules=list(dict.fromkeys(
+            _brokerd_service_mods
+            +
+            tractor_kwargs.pop('enable_modules')
+        )),
         debug_mode=Services.debug_mode,
         **tractor_kwargs
     )

piker/brokers/ib/api.py

@@ -1340,6 +1340,21 @@ async def load_aio_clients(
     ib = None
     client = None
 
+    # XXX: post (brokerd vs. datad)-split BOTH per-broker
+    # daemons connect to the same API gw/tws endpoint(s); to
+    # avoid `clientId` collisions (and the long conn-timeout
+    # retry cycle they cause) we offset the data-daemon's
+    # default id-range to be disjoint from `brokerd.ib`'s
+    # (which also retries with `client_id + i` increments).
+    if client_id == 6116:  # the default from above
+        aname: str = tractor.current_actor().name
+        if 'datad' in aname:
+            client_id += 16
+        # ad-hoc (test/cli) actors get their own range to
+        # avoid clashing with any live daemon-tree's conns.
+        elif 'brokerd' not in aname:
+            client_id += 32
+
     # attempt to get connection info from config; if no .toml entry
     # exists, we try to load from a default localhost connection.
     localhost = '127.0.0.1'

piker/cli/__init__.py

@@ -250,7 +250,6 @@ def cli(
 
     # TODO: load endpoints from `conf::[network].pikerd`
     # - pikerd vs. regd, separate registry daemon?
-    # - expose datad vs. brokerd?
     # - bind emsd with certain perms on public iface?
     regaddrs: list[tuple[str, int]] = regaddr or [(
         _default_registry_host,