Subscriber resilience: recreate consumer after connection failure
- Move consumer creation from Subscriber.start() into the run() loop,
matching the pattern used by Consumer. If the connection drops and the
consumer is closed in the finally block, the loop now recreates it on
the next iteration instead of spinning forever on a None consumer.
Consumer thread safety:
- Dedicated ThreadPoolExecutor per consumer so all pika operations
(create, receive, acknowledge, negative_acknowledge) run on the
same thread — pika BlockingConnection is not thread-safe
- Applies to both Consumer and Subscriber classes
Config handler type audit — fix four mismatched type registrations:
- librarian: was ["librarian"] (non-existent type), now ["flow",
"active-flow"] (matches config["flow"] that the handler reads)
- cores/service: was ["kg-core"], now ["flow"] (reads
config["flow"])
- metering/counter: was ["token-costs"], now ["token-cost"]
(singular)
- agent/mcp_tool: was ["mcp-tool"], now ["mcp"] (reads
config["mcp"])
Update tests
Replace the config push mechanism that broadcast the full config
blob on a 'state' class pub/sub queue with a lightweight notify
signal containing only the version number and affected config
types. Processors fetch the full config via request/response from
the config service when notified.
This eliminates the need for the pub/sub 'state' queue class and
stateful pub/sub services entirely. The config push queue moves
from 'state' to 'flow' class — a simple transient signal rather
than a retained message. This solves the RabbitMQ
late-subscriber problem where restarting processes never received
the current config because their fresh queue had no historical
messages.
Key changes:
- ConfigPush schema: config dict replaced with types list
- Subscribe-then-fetch startup with retry: processors subscribe
to notify queue, fetch config via request/response, then
process buffered notifies with version comparison to avoid race
conditions
- register_config_handler() accepts optional types parameter so
handlers only fire when their config types change
- Short-lived config request/response clients to avoid subscriber
contention on non-persistent response topics
- Config service passes affected types through put/delete/flow
operations
- Gateway ConfigReceiver rewritten with same notify pattern and
retry loop
Tests updated
New tests:
- register_config_handler: without types, with types, multiple
types, multiple handlers
- on_config_notify: old/same version skipped, irrelevant types
skipped (version still updated), relevant type triggers fetch,
handler without types always called, mixed handler filtering,
empty types invokes all, fetch failure handled gracefully
- fetch_config: returns config+version, raises on error response,
stops client even on exception
- fetch_and_apply_config: applies to all handlers on startup,
retries on failure
* Plugin architecture for messaging fabric
* Schemas use a technology neutral expression
* Schemas strictness has uncovered some incorrect schema use which is fixed
* Tech spec
* Address multi-tenant queue option problems in CLI
* Modified collection service to use config
* Changed storage management to use the config service definition
