The 10 s concurrent-load bound also hit slow but healthy first imports. A
second agent built while a provider's import took longer than 10 s got no
memory provider for its whole session, and with checkpoint_required every
compaction then failed closed.
The bound now applies only inside plugin_loader.bounded_load_wait(), which
the per-turn gateway memory identity signature uses. Other callers (agent
builds) wait for the in-flight load. Cycle detection still breaks a
cross-thread deadlock for every caller.
Review fixes for the per-module plugin load lock:
- A second caller waits at most 10 s for another thread's load of the same
module, then refuses with a named warning and returns None. While that
import is still stuck, later callers refuse at once. A hung provider import
no longer blocks every gateway turn, and there is no inline fallback load.
- The wait polls a wait-for graph spanning the loader locks and importlib's
own module locks. When thread A holds a helper's import lock and waits on
the plugin while thread B loads the plugin and imports that helper, the
cycle is detected and the waiter takes the partial module, the same way
importlib handles a concurrent circular import. Before, both threads hung.
- The lock is still a same-thread RLock with no worker thread, so recursive
loads and ContextVars are unchanged.
- conversation_compression.py: compact the fork-checkpoint exemption so the
file stays under its line cap after the rebase.
plugins.isolation: host imports every non-bundled plugin in a host process started
on demand per profile with only that profile's environment, and hands plugins a
RemotePluginContext; Hermes registers proxies for tools, hooks, commands, skills and
provider objects (subclasses of the ABC it checks). Re-entrant: handlers may call
ctx back into Hermes while Hermes waits on them. Every user-code import path routes
to the host (general, memory/context-engine/cron, model-provider profiles via a
cached credential-free extraction, dashboard APIs via an ASGI bridge) or refuses.
One table names what cannot cross (live gateway objects); the static audit shown
by `hermes plugins validate/show` reads it. A host that dies is restarted with its
plugins (bounded). Default stays in_process: nothing changes unless opted in.
Why: shared-pool deployments must never run one tenant's plugin Python in an
interpreter holding another tenant's data, without plugins becoming tenant-aware.
utils.fast_safe_load already exists, is pinned by tests/test_fast_safe_load.py, and
its comment names exactly these payers: 'startup parses config.yaml and every plugin
manifest, so the slow path cost ~0.9 s of cold start'. The migration was started —
hermes_cli/config.py uses it eight times, hermes_cli/main.py and hermes_cli/plugins.py
too — but the file-level loaders it was written for were never converted.
The cost is config SIZE, and the size is the installer's doing: it seeds config.yaml
by copying cli-config.yaml.example, 120,897 bytes of mostly comments. Nothing caches
load_gateway_config() and it has 238 production call sites.
Profiled before assuming a cause — reader.forward 34 ms, scanner.scan_to_next_token
28 ms, reader.peek 13 ms: the pure-Python PyYAML scanner, nothing else.
Measured A/B on one realistic pass (gateway config + every bundled plugin
description), medians of five runs, __pycache__ cleared between arms:
48.8 ms -> 2.46 ms. Per path: load_gateway_config 48.3 -> 1.84 ms, managed
config.yaml 44.4 -> 1.03 ms, 105 plugin.yaml manifests 59.3 -> 5.9 ms.
Same parse, same restricted tag set, same result — only the loader changes. Drops the
three 'import yaml' statements the swap orphaned.
(cherry picked from commit a4efd6a4506043159310eba02c32b673c455b88b)
iter_plugin_dirs stat'd <child>/__init__.py inside every plugin dir, so a
single mode-000 / ACL-denied $HERMES_HOME/plugins/<x> still raised
PermissionError out of the loader, memory-provider discovery (dashboard
memory settings, hermes memory setup, plugins memory picker) and the
user cron-provider scan. Catch OSError per child and log the same
'Skipping unreadable plugin directory' warning the list path already emits.
Part of #111804
