fix(agent): degrade log consumer db pressure

apps/api/tests/test_ai_agent_log_controlled_writeback_consumer_apply_api.py

@@ -28,6 +28,8 @@ class _FakeDb:
         self.params: list[dict] = []
 
     async def execute(self, statement, params: dict):
+        if not params:
+            return _FakeResult(None)
         self.params.append(params)
         if "fallback_operation_type" in params:
             return _FakeResult("km_linked")
@@ -50,6 +52,14 @@ class _FakeContext:
         return False
 
 
+class _FailingContext:
+    async def __aenter__(self):
+        raise TimeoutError("pool checkout unavailable")
+
+    async def __aexit__(self, _exc_type, _exc, _tb) -> bool:
+        return False
+
+
 def _consumer_readback() -> dict:
     targets = ("km", "rag", "playbook", "mcp", "verifier", "ai_agent")
     bindings = [
@@ -185,6 +195,71 @@ async def test_log_controlled_writeback_consumer_apply_writes_idempotent_rows(mo
         assert '"km_write_performed": false' in params["output"]
 
 
+@pytest.mark.asyncio
+async def test_log_controlled_writeback_consumer_apply_blocks_when_readback_degraded(
+    monkeypatch,
+):
+    degraded_readback = _consumer_readback()
+    degraded_readback["status"] = (
+        "blocked_waiting_controlled_writeback_consumer_db_readback"
+    )
+    degraded_readback["controlled_consume"]["controlled_consume_allowed"] = False
+    degraded_readback["active_blockers"] = [
+        "log_controlled_writeback_consumer_readback_db_unavailable"
+    ]
+
+    async def fake_readback(*, project_id: str):
+        assert project_id == "awoooi"
+        return degraded_readback
+
+    monkeypatch.setattr(
+        apply_module,
+        "load_latest_ai_agent_log_controlled_writeback_consumer_readback",
+        fake_readback,
+    )
+
+    payload = await consume_latest_ai_agent_log_controlled_writeback(project_id="awoooi")
+
+    assert payload["status"] == (
+        "blocked_waiting_controlled_writeback_consumer_apply_inputs"
+    )
+    assert "controlled_writeback_consumer_readback_not_ready" in payload[
+        "active_blockers"
+    ]
+    assert payload["apply_result"]["db_write_status"] == "not_attempted"
+    assert payload["operation_boundaries"]["runtime_target_write_performed"] is False
+
+
+@pytest.mark.asyncio
+async def test_log_controlled_writeback_consumer_apply_degrades_on_db_write_pressure(
+    monkeypatch,
+):
+    monkeypatch.setattr(
+        apply_module,
+        "get_db_context",
+        lambda project_id: _FailingContext(),
+    )
+
+    async def fake_readback(*, project_id: str):
+        assert project_id == "awoooi"
+        return _consumer_readback()
+
+    monkeypatch.setattr(
+        apply_module,
+        "load_latest_ai_agent_log_controlled_writeback_consumer_readback",
+        fake_readback,
+    )
+
+    payload = await consume_latest_ai_agent_log_controlled_writeback(project_id="awoooi")
+
+    assert payload["status"] == "blocked_waiting_controlled_writeback_consumer_apply_db"
+    assert "consumer_apply_db_write_unavailable" in payload["active_blockers"]
+    assert payload["apply_result"]["db_write_status"] == "unavailable"
+    assert payload["apply_result"]["error_type"] == "TimeoutError"
+    assert payload["operation_boundaries"]["consumer_context_receipt_write_performed"] is False
+    assert payload["operation_boundaries"]["runtime_target_write_performed"] is False
+
+
 def test_log_controlled_writeback_consumer_apply_endpoint_returns_receipt(monkeypatch):
     async def fake_apply():
         payload = build_ai_agent_log_controlled_writeback_consumer_apply_receipt(

apps/api/tests/test_ai_agent_log_controlled_writeback_consumer_readback_api.py

@@ -32,6 +32,8 @@ class _FakeDb:
         self.params: list[dict] = []
 
     async def execute(self, _statement, params: dict):
+        if not params:
+            return _FakeMappingResult([])
         self.params.append(params)
         if params.get("operation_type") == "log_controlled_writeback_consumed":
             return _FakeMappingResult(self.consumer_rows)
@@ -49,6 +51,14 @@ class _FakeContext:
         return False
 
 
+class _FailingContext:
+    async def __aenter__(self):
+        raise TimeoutError("pool checkout unavailable")
+
+    async def __aexit__(self, _exc_type, _exc, _tb) -> bool:
+        return False
+
+
 def _ledger_rows() -> list[dict]:
     return [
         {
@@ -147,6 +157,30 @@ async def test_log_controlled_writeback_consumer_loader_reads_apply_receipts(mon
         assert binding["target_write_receipt"]["runtime_target_write_performed"] is True
 
 
+@pytest.mark.asyncio
+async def test_log_controlled_writeback_consumer_loader_degrades_on_db_pressure(monkeypatch):
+    monkeypatch.setattr(
+        consumer_module,
+        "get_db_context",
+        lambda project_id: _FailingContext(),
+    )
+
+    payload = await load_latest_ai_agent_log_controlled_writeback_consumer_readback()
+
+    assert payload["status"] == (
+        "blocked_waiting_controlled_writeback_consumer_db_readback"
+    )
+    assert payload["readback"]["db_read_status"] == "unavailable"
+    assert payload["readback"]["error_type"] == "TimeoutError"
+    assert payload["controlled_consume"]["controlled_consume_allowed"] is False
+    assert payload["rollups"]["controlled_consumer_readback_ready"] is False
+    assert payload["active_blockers"] == [
+        "log_controlled_writeback_consumer_readback_db_unavailable"
+    ]
+    assert payload["operation_boundaries"]["metadata_ledger_read_performed"] is False
+    assert payload["operation_boundaries"]["runtime_target_write_performed"] is False
+
+
 def test_log_controlled_writeback_consumer_endpoint_returns_readback(monkeypatch):
     async def fake_loader():
         fake_db = _FakeDb(_ledger_rows())