When create_bridge_network or compose-up raised mid-deploy, the
deployer marked the topology FAILED and re-raised — but left every
network it had already created alive. The next deploy attempt tripped
over the orphans with 'Pool overlaps with other one on this address
space' (IPAM conflict).
Track networks created in the current attempt; on exception, tear down
the started compose stack (if any), remove the networks in reverse
order, and delete the compose file before marking FAILED. Rollback
errors are logged but never mask the original failure.
Covered by a new regression test that drives a docker client which
succeeds once then raises, and asserts every created network is also
removed.
apply_attach_decky requires an existing decky, so the MazeNET editor
had no way to grow a live topology: creating a new decky on active
topologies 409'd on the direct-CRUD createDecky call.
- Backend: new apply_add_decky that creates the decky row + its
home-LAN edge atomically, auto-allocating an IP if none pinned.
Post-apply validation still runs. Added to DISPATCH + _MUTATION_OPS
Literal + CLI help text.
- Tests: 3 new ops tests (happy path, duplicate-name rejection,
missing-LAN rejection) plus dispatch coverage update.
- Frontend: useTopologyEditor gains addDeckyToLan() composite. Pending
routes through createDecky + attachEdge as before; active routes
through a single add_decky enqueue. MazeNET.tsx drag-archetype,
duplicate, DMZ-gateway, and ctx-menu add-decky paths all use the
composite so active topologies stop 409'ing on new-decky drops.
apply_update_decky only merged payload.patch into decky_config. Since
services is a separate DB column, there was no way to replace a decky's
services list via a mutation. Add a top-level services key to the op
payload that maps straight onto the services column.
Unblocks the MazeNET editor routing service-add/service-drop actions
through the mutation queue on active topologies.
Parser now tags ``mutator`` / ``decky_mutated`` lines with ``kind="mutation"``
so the engine can route them into a sibling ``_mutations`` index keyed
by decky name instead of the per-IP attacker index. ``traversals()``
joins the two streams: every attacker gets a ``mutations_during`` list
of markers from touched deckies bounded by their first/last-seen
window. ``AttackerTraversal.to_dict()`` grows a ``mutations_during``
field and a ``timeline`` that chronologically interleaves hops and
markers, so an ``SSH at T5 → mutation at T6 → HTTP at T7`` substrate
transition is visible to UI consumers instead of reading as a silent
discontinuity.
The existing hops-only JSON shape is preserved; old clients that
ignore unknown keys keep working.
Close the lifecycle loop for the correlation graph: every decky now
enters the substrate with an explicit `trigger=creation` event
(old_services=[] ⇒ new_services=<initial>) and leaves it with
`trigger=retirement` (old=<current> ⇒ new=[]). With scheduled/operator
mutations already flowing through emit_decky_mutated, the entire decky
lifecycle is now a well-formed sequence of mutation events — the
correlator can fold substrate_state(t) at any T by replaying them.
Lazy-imports mutator.events to dodge the engine↔mutator circular
dependency. Bus is None at CLI sites; the syslog write is what the
correlator consumes. Emission is soft-failing so a broken log path
never aborts a deploy.
Mutator now emits one decky_mutated event (RFC 5424 + bus) per
successful mutation instead of the inline decky.<id>.state bus
publish. The previous state topic published new_services only;
mutation events carry old/new/trigger, which is what the correlation
engine needs to interleave substrate-change markers into attacker
traversals.
- mutate_decky gains trigger: MutationTrigger = "operator" and
captures old_services before the shuffle; replaces the inline
_publish_safely(decky.<id>.state) with emit_decky_mutated(...).
- mutate_all derives trigger internally: operator when force or
only-filter is set (CLI --all, API mutate-now, UI bus request);
scheduled on interval ticks. Passed through to each mutate_decky
call.
- Tests updated: the old decky.<id>.state assertion is replaced
with decky.<id>.mutation topic + mutation payload shape; 3 new
tests cover trigger derivation for scheduled / force / only paths.
26 tests in test_mutator.py green; 116 across mutator + topology
+ bus.
First step toward making mutation events first-class nodes in the
correlation graph. Today the graph silently reflects post-mutation
state with no marker of the transition; this helper lands the
emitter the mutator and deploy paths will call.
- decnet/mutator/events.py: emit_decky_mutated(bus, *, decky,
old_services, new_services, trigger, actor=None, log_path=None)
writes an RFC 5424 line (service=mutator, hostname=<decky>,
MSGID=decky_mutated, SD params for old/new services + trigger +
optional actor) to DECNET_INGEST_LOG_FILE, then fire-and-forget
publishes on decky.<id>.mutation. Either side failing is soft —
the other path still completes.
- MutationTrigger Literal covers creation, retirement, scheduled,
operator, behavioral, healer, federation. Reserved values for v2/v3
(behavioral + federation) stay nullable so the schema is stable.
- decnet/bus/topics.py: DECKY_MUTATION constant + decky_mutation(id)
builder. Distinct from DECKY_STATE ("current shape") because a
mutation is a transition event, not a steady-state snapshot.
- Empty-set symmetry: creation emits old_services=[], retirement
emits new_services=[]. Every decky lifecycle becomes a well-formed
fold sequence on the correlator side.
- 4 new tests: FakeBus + correlator parser round-trip; creation and
retirement empty-set cases; bus=None still writes syslog;
unwritable log path doesn't block bus publish. 95 tests green
across test_mutator + tests/bus.
The flat-fleet mutator was DB-poll-only and noisy — it logged
"no active deployment found" every 10s on idle hosts and ran
mutate_all at a fixed tick regardless of when the next decky
was due.
- mutate_all returns seconds-until-next-due; watch loop sleeps
min(next_due, poll_interval_secs) with a 1s floor.
- "No deployment" is now idle, not an error: edge-triggered log
on present<->absent transition instead of every tick.
- mutate_decky publishes decky.<name>.state on successful compose
so UIs react in real time.
- New decky.*.mutate_request subscription lets API/CLI/UI force
an immediate mutation of a specific decky without waiting for
its interval; target name feeds mutate_all(only={...}).
- system.mutator.health heartbeat via run_health_heartbeat helper,
bringing the mutator in line with DEBT-031 workers.
Tests: next_due return, only= filter, decky.<name>.state publish
on success, no publish on compose failure. Full mutator+topology-
mutator+bus suite (109) green.
All three workers now share a run_health_heartbeat helper in
decnet.bus.publish. Each publishes system.<worker>.health on a 30s tick
with {worker, ts} plus optional per-worker extras. Subscribers can
watch system.*.health to see every DECNET worker on a host at once.
- agent: heartbeat runs inside the FastAPI lifespan alongside the
existing master-facing heartbeat; bus-disabled path is a no-op.
- forwarder: heartbeat task spawned at run_forwarder entry, cancelled
in the finally block so a crashed master loop never leaks the task.
- updater: new FastAPI lifespan hosts the heartbeat.
Heartbeat helper swallows extra() failures and is cancellation-safe so
lifespan teardown never hangs on it.
Ingester connects the bus at startup, emits a batch-committed summary
(component/flushed/position) after each successful _flush_batch. Zero-
row flushes are suppressed so the topic stays meaningful.
Complements the collector's per-line system.log publishes: collector
signals ingress, ingester signals DB-persisted progress. Federation
forwarder (worker 8) will subscribe to the batch-committed leaf to
trigger its upstream push.
Bus stays optional: publish_safely swallows failures, get_bus() can
return None, DECNET_BUS_ENABLED=false leaves the ingestion loop fully
functional.
log_collector_worker connects the bus at startup, builds a thread-safe
system.log publisher, and hands it to each container-stream thread
through _stream_container's new publish_fn parameter. Publishing fires
right after the JSON record is written — same rate-limiter path, no
extra parsing, compact payload (decky/service/event_type/attacker_ip/
timestamp) so subscribers can redraw without re-reading the DB.
Bus stays optional: if get_bus() fails or DECNET_BUS_ENABLED=false the
factory returns a no-op publisher and the stream thread calls it
unconditionally. Hook failures are logged and never abort the thread.
The profiler worker threads its bus publisher through _WorkerState so
_update_profiles can emit a compact attacker.scored event for every
upsert. Payload carries the headline counts (event/service/decky/
bounty/credential) plus is_traversal, so the MazeNET attacker pool can
redraw without a round-trip.
Bus stays optional: publish_attacker=None when DECNET_BUS_ENABLED=false
or get_bus() fails, and hook exceptions are logged without breaking the
upsert path.
CorrelationEngine gains an optional publish_fn hook fired once per unique
attacker IP. The profiler worker — sole caller of the engine today —
carries the bus physically, builds a thread-safe publisher, and wraps it
with the attacker.observed topic before handing it in.
Bus stays optional: if get_bus() fails or DECNET_BUS_ENABLED=false, the
engine runs publish_fn=None and the worker degrades to DB-only. Hook
failures log a warning and never break ingestion.
Each successful JARM / HASSH / TCPfp probe fans out an
attacker.fingerprinted event; the probe family goes in event.type so a
single subscription covers all three. Payload carries the attacker IP,
port, and probe-specific hash — enough for the MazeNET live map to
render fingerprint info on observed attackers.
Lifts the thread-safe publisher helper out of the sniffer worker into
decnet/bus/publish.py so the prober (and every future worker with a
to_thread hot path) can reuse it without copy-pasting the
run_coroutine_threadsafe dance. Sniffer rewires onto the shared helper
in passing.
Adds ATTACKER_FINGERPRINTED as a new leaf — distinct from
ATTACKER_OBSERVED (correlator's first-sight signal) because an active
probe result is additional evidence about an already-observed attacker.
Note: the plan's decky.{id}.state realism-probe publish path is
deferred — the current prober fingerprints attackers, not decky
realism. Will revisit when realism probes exist.
SnifferEngine gains an optional publish_fn hook, invoked after the
dedup + syslog write for traffic-summary events only (tls_session,
tcp_flow_timing, tcp_syn_fingerprint) — intermediate parser artifacts
like tls_client_hello stay off the bus.
The sniffer worker wires get_bus() + a thread-safe shim that marshals
sync calls from the scapy sniff thread back onto the asyncio loop via
run_coroutine_threadsafe. Bus failure at startup degrades cleanly to
publish-off mode; publish failures at runtime never escape the sniff
thread.
Shared publish_safely helper at decnet/bus/publish.py so the nine
workers about to be wired into the bus don't each copy-paste the
"never raise back at the caller" contract. Mutator drops its private
copy and imports the canonical one.
topics.py gains the attacker.* hierarchy (observed, scored,
session.started, session.ended) and a system_health(worker) builder
for per-worker health heartbeats — both prerequisites for the worker
rollout under DEBT-031.
- tests/topology/test_mutator.py: reconcile_topologies publishes
applying+applied on success, applying+failed+status on failure; and
stays safe when bus=None. _wake_on_enqueue sets its asyncio.Event
on every matching enqueue event.
- tests/api/topology/test_mutations.py: POST /mutations publishes
mutation.enqueued after a successful DB write, via a FakeBus
injected in place of the app-wide bus singleton.
- tests/api/topology/test_events_stream.py: SSE route returns 401
unauthenticated, 404 for unknown topologies, and (driving the
async generator directly) emits a snapshot on connect plus
forwards a published mutation.applied as an `event: mutation.applied`
SSE frame.
Land the `decnet bus` worker and `get_bus()` factory. Transport is a
host-local UNIX-domain socket (0660, group=decnet); authz is the file
mode. Wire framing is a tiny verb-line + 4-byte-BE length + orjson body.
NATS-style wildcard topics (`*`, `>`). At-most-once, fire-and-forget —
DB stays the source of truth. `FakeBus` / `NullBus` for tests and the
disabled path. Cross-host federation is deferred to a future
`--bridge-tcp` mode; DEBT-030 is master-only and unblocked.
test_compose asserts the new decnet.topology.* labels land on both base
deckies (role=base, no service marker) and service fragments
(service=true). The stub docker client in test_deploy grew a filters
kwarg so it keeps matching the real .networks.list(filters=...) call
signature now used by the deployer.
Legacy fleet deckies live in decnet-state.json; MazeNET topology
containers don't. Tag them at compose-time with
decnet.topology.service=true and let the collector match on that label.
Spin up the agent's log collector on the first successful /topology/apply
(not in the lifespan — that would break the no-docker-on-boot invariant)
and tear it down with the app. Land log lines in DECNET_AGENT_LOG_FILE,
separate from master-side DECNET_INGEST_LOG_FILE, so a dev box running
both roles can't forward its own ingest back to itself.
When master pushes a topology that differs from whatever is pinned
locally, teardown the predecessor and accept the new one. Refusing with
409 left the agent stranded after partial deploys. record_error now
persists the hydrated blob so a later teardown can still walk the LAN
list — otherwise a half-failed apply strands containers + bridges with
no breadcrumb back to them.
Two small observability follow-ups to the phase-1 agent/topology wiring:
TopologySummary now carries needs_resync so operators can see the
heartbeat's resync flag via the topology list/detail API without
dropping into the DB.
TopologyStore.record_error becomes an upsert — when a docker/compose
failure fires during the first materialise (put() never reached), we
still land a marker row so GET /topology/state surfaces the error and
the next heartbeat carries an empty applied_version_hash. That empty
hash is what master's heartbeat check relies on to flag the topology
for resync instead of assuming the apply succeeded.
Four regression tests guarding Step 8 of the agent/topology wiring:
- Lifespan startup must not call docker.from_env even with a populated
topology.db — replace docker with a boom-stub and assert zero calls.
- GET /topology/state returns the cached row verbatim without
re-materialising bridges/containers; live observation is read-only.
- Static guard: TopologyStore must not grow a restore/replay/reapply
method without someone re-reading the module docstring.
- Raw sqlite read + a second TopologyStore instance confirm the store
is passive — nothing scrubs stale rows on open, which is the
behaviour master's resync flow depends on.
Agent heartbeats now carry an applied-topology snapshot. The master
heartbeat handler compares the reported version_hash against what
canonical_hash yields for the hydrated topology pinned to that host
and flags Topology.needs_resync on divergence (or when the agent
reports no topology at all while master expects one).
The mutator watch loop gains reconcile_agent_resyncs, which re-pushes
the current hydrated blob via AgentClient.apply_topology without
touching status, then clears the flag on success. Push failures leave
the flag set so the next tick retries.
deploy_topology and teardown_topology now branch on
target_host_uuid. When set:
- Hydrate the topology locally (validator runs exactly as before).
- Compute canonical_hash; push {hydrated, version_hash} to the
pinned agent through AgentClient.apply_topology.
- Status machine still moves PENDING -> DEPLOYING -> ACTIVE on 2xx,
PENDING -> DEPLOYING -> FAILED on error; master remains the sole
owner of the row.
Teardown flips to TEARING_DOWN, fires /topology/teardown, then
TORN_DOWN — we log a warning on agent error but still settle to
TORN_DOWN so operators can delete the row (agent garbage is cleaned
on the next re-enroll).
Unihost deploys are unchanged — the field defaults to NULL so every
existing flow takes the local path.
Step 6 of the agent <-> topology integration.
Three new RPCs mirroring the existing deploy/teardown/status pattern:
- apply_topology(hydrated, version_hash) — long-timeout (600s) for
image pulls + compose up.
- teardown_topology(topology_id) — 300s timeout; enough for a
stubborn compose-down without hanging a heartbeat.
- get_topology_state() — short control-plane read for reconcile.
The per-call timeout swap uses the same trick as .deploy().
Step 5 of the agent <-> topology integration.
New mTLS-protected routes on the agent:
- POST /topology/apply — master pushes {hydrated, version_hash}.
Validates the hash matches locally (serialisation drift guard),
runs the topology through the same validator/composer pipeline
used master-side, then creates bridges + compose up + records the
apply in topology.db.
- POST /topology/teardown — dismantles compose, removes bridges,
clears topology.db. Idempotent.
- GET /topology/state — returns applied row + live docker
observation for the heartbeat.
Implementation lives in decnet/agent/topology_ops.py; it reuses the
private compose helpers from decnet.engine.deployer so we don't
duplicate compose/project-name plumbing. The apply path is sync
under the hood (docker SDK + subprocess); we hop to a thread so the
event loop keeps servicing other agent traffic.
v1 is one-topology-per-agent; cross-topology apply returns 409.
Step 4 of the agent <-> topology integration.
Single-row sqlite tracking which topology the agent last applied and
its version hash. Sync/stdlib, same pattern as the log-forwarder
offset store. v1 is one-topology-per-agent; attempting to apply a
different topology over a populated row raises AlreadyApplied so the
endpoint can return 409. observed() snapshots live docker state
(decnet-topology-* bridges + decnet-* containers) for the heartbeat.
The store is a cache, not authority — no auto-restore on boot.
Master remains the only source of truth.
Step 3 of the agent <-> topology integration.
Tiny pure helper both master and agent will use to answer "is the
applied state the one we expect?". SHA-256 of canonical JSON with
volatile keys (timestamps, status, version, canvas x/y/w/h) stripped
so the hash only captures deployment-relevant state.
Step 2 of the agent <-> topology integration.
Adds the `target_host_uuid` FK on `Topology` plus wiring through the
two create endpoints (`POST /topologies`, `POST /topologies/blank`).
Validates the mode/host pair: `mode='agent'` now requires a known,
routable host; `mode='unihost'` must leave the field unset.
Surfaced on `TopologySummary` so list/detail responses expose it.
Purely additive at the schema level — existing unihost flows unchanged
(field defaults to `NULL`).
Step 1 of the agent <-> topology integration.
GET /api/v1/topologies — paginated list with status filter. Extends
repo.list_topologies() to accept limit/offset and adds count_topologies()
for the total envelope field.
GET /api/v1/topologies/{id} — hydrated TopologyDetail; 404 if missing.
GET /api/v1/topologies/{id}/status-events — audit trail, limit-capped.
Catalog helpers for the phase-4 canvas UI:
* GET /topologies/services — full service catalog.
* GET /topologies/next-subnet?base=172.20 — wraps SubnetAllocator against
reserved_subnets across non-torn-down topologies.
* GET /topologies/{id}/lans/{lan_id}/next-ip — IPAllocator pre-seeded
with existing decky IPs in that LAN.
All read routes are viewer-or-admin. Sub-routers are included in an
order that keeps literal catalog paths (/services, /next-subnet) from
being shadowed by the /{topology_id} trie branch.
Add Pydantic DTOs in decnet/web/db/models.py covering every phase-3
endpoint shape: TopologyGenerateRequest, TopologySummary/Detail, child
create/update requests, MutationEnqueueRequest (Literal op guard),
MutationRow with JSON-payload decoder, validation/version/not-editable
error envelopes, and the three catalog responses.
Create decnet/web/router/topology/ as an import-safe package exporting
topology_router (prefix /topologies) — sub-routers land step-by-step in
subsequent commits. Mount under the main api router alongside swarm_mgmt.
tests/api/topology/test_models.py pins repo-dict ↔ DTO parity so future
repo-row drift breaks the contract test before the endpoints.
Adds the live-mutation pipeline for active/degraded topologies:
* TopologyMutation table with composite index (state, topology_id)
so the watch-loop guard query stays O(log n).
* claim_next_mutation is a single atomic UPDATE ... WHERE
state='pending' so racing reconcilers deterministically pick one
winner; losers see rowcount=0 and skip.
* reconcile_topologies drains pending rows per live topology, applies
via decnet.mutator.ops.dispatch, and on failure marks the mutation
failed + transitions topology to degraded.
* run_watch_loop gains a gated branch: flat-fleet mutate_all runs
every tick unchanged; the reconciler only enters when the cheap
has_pending_topology_mutation guard returns True.
* apply_* ops re-check hard invariants (names, IP collisions, subnet
overlap, known services, service_config shape) after every mutation
so the repo never lands in an invalid state.
* CLI: 'decnet topology mutate' / 'mutations' subcommands.
MazeNET phase 2 step 6. Equips the repo layer with the CRUD the web
editor needs before deploy.
- TopologyNotEditable exception: raised when a pending-only method hits
a non-pending topology. The intent is "free-form edits stop at deploy;
the mutator (step 7) takes over for live topologies."
- _assert_pending helper checks status inside the session.
- update_lan / update_topology_decky accept enforce_pending=True for
pre-deploy callers (existing internal callers default to False so
behavior is unchanged).
- delete_lan: cascades edges; refuses if any decky has only one edge
(= this LAN is its home) to prevent orphans.
- delete_topology_decky: cascades edges.
- delete_topology_edge: bare-bones removal.
All four mutators accept expected_version for optimistic concurrency.
Existing tests continue to pass (no behavior change for persist/deploy).
MazeNET phase 2 step 5. Pure storage — the generator emits None for
x/y and the web canvas fills them in later. No logic changes; no
compose, deploy, or validator impact.
MazeNET phase 2 step 4. Readies the repo layer for concurrent editors
(web canvas + CLI + mutator) without lost-write races.
- Topology.version: monotonically bumped on supervised child-row writes.
- VersionConflict exception carries {current, expected} for the UI.
- _check_and_bump_version helper reads Topology in the same session,
compares against expected_version, raises on mismatch, bumps on match.
Commit happens in the caller's existing transaction so check+bump+write
are atomic per mutation.
- add_lan / update_lan / add_topology_decky / update_topology_decky /
add_topology_edge accept expected_version=None by default, preserving
every existing caller's behavior.
When expected_version is None, no check runs and version stays put —
internal callers (persist) that don't care about concurrency keep
working unchanged.
MazeNET phase 2 step 3. Blocks deploys of hand-authored topologies that
would fail mid-bring-up (orphan deckies, duplicate IPs, overlapping
subnets, unknown services) with a structured error list instead of a
docker error at startup.
Rules (one function each, composable by the editor for inline hints):
- exactly one DMZ
- every LAN has a bridge chain to the DMZ (BFS via multi-homed deckies)
- no orphan deckies
- unique LAN and decky names per topology
- no IP collisions + IPs inside their LAN's subnet
- no LAN subnet overlaps
- every service in decnet.fleet.all_service_names()
- service_config keys match the decky's declared services
deploy_topology runs the validator after hydrate, before any status
transition or Docker call; errors raise ValidationError and status
stays at pending.
MazeNET phase 2 step 2. Mirrors the flat-fleet service_config pattern
(DeckyConfig.service_config → composer → svc.compose_fragment) into the
topology compose pipeline, so a hand-authored decky can carry overrides
like {"ssh": {"password": "megapassword"}} and the ssh fragment reads
them just like the flat path does.
- _PlannedDecky gains service_config: dict[str, dict].
- persist() stores it under decky_config["service_config"].
- topology/compose.py passes cfg.get("service_config", {}).get(svc, {})
to svc.compose_fragment(service_cfg=...).
Schema unchanged — service_config lives inside the existing
decky_config JSON blob. Zero changes in decnet/services/*.
MazeNET phase 2 step 1. Pulls inline IP/subnet allocation out of the
generator into decnet/topology/allocator.py so the editor + reconciler
can reuse the same primitives without duplicating logic.
- IPAllocator: stateful host-IP handout with reserve/release/is_free.
- SubnetAllocator: /24 handout under a base prefix, skips reservations.
- reserved_subnets(repo): collects claimed subnets across every
non-torn_down topology so concurrent drafts cannot collide.
- generate() accepts reserved_subnets= to skip existing claims.
Generator output is byte-identical under seed (behavior preserved).
Covers dry-run compose emission (no status change), FAILED transition
with reason logged on daemon errors, teardown from FAILED, and a
live-marked end-to-end test that creates/removes bridge networks
against a real docker daemon (skipped on CI).
Adds per-topology compose generation (one Docker bridge network per
LAN, multi-homed bridge deckies, ip_forward sysctl for L3 forwarders)
plus async deploy_topology/teardown_topology in the engine. Leaf-first
teardown via BFS-named LAN reverse sort; partial-state safe on failure.
Adds decnet/topology/ with:
- config.TopologyConfig: pydantic model driving generation (depth,
branching_factor, deckies_per_lan_min/max, bridge_forward_probability,
cross_edge_probability, subnet_base_prefix, service selection, seed).
Emits GeneratedTopology dataclass (lans, deckies, edges).
- status.TopologyStatus + assert_transition: seven-state machine with
an explicit legal-transition table. torn_down is terminal; degraded
is schema-reserved for future Healer use.
- generator.generate: deterministic DAG generation under config.seed.
Builds a tree of LANs (DMZ at root), plants deckies in each LAN,
promotes one decky per non-DMZ LAN to a parent bridge, and rolls
cross-edges per cross_edge_probability for DAG shape.
- persistence: persist() writes a plan to the repo as pending;
transition_status() enforces state-machine legality; hydrate() loads
topology + children into a single dict.
Covered by tests/topology/{test_status,test_generator,test_persistence}.
Adds topology CRUD to BaseRepository (NotImplementedError defaults) and
implements them in SQLModelRepository: create/get/list/delete topologies,
add/update/list LANs and TopologyDeckies, add/list edges, plus an atomic
update_topology_status that appends a TopologyStatusEvent in the same
transaction. Cascade delete sweeps children before the topology row.
Covered by tests/topology/test_repo.py (roundtrip, per-topology name
uniqueness, status event log, cascade delete, status filter) and an
extension to tests/test_base_repo.py for the NotImplementedError surface.
