feat: emit daemon lifecycle telemetry

python/ktx-daemon/src/ktx_daemon/__main__.py

@@ -5,6 +5,7 @@ from __future__ import annotations
 import argparse
 import json
 import sys
+import time
 from typing import Any
 
 from pydantic import ValidationError
@@ -100,8 +101,12 @@ def run_http_server(
 
     from ktx_daemon.app import create_app
 
+    started_at = time.perf_counter()
     uvicorn.run(
-        create_app(enable_code_execution=enable_code_execution),
+        create_app(
+            enable_code_execution=enable_code_execution,
+            telemetry_started_at=started_at,
+        ),
         host=host,
         port=port,
         log_level=log_level,

python/ktx-daemon/src/ktx_daemon/app.py

@@ -4,6 +4,9 @@ from __future__ import annotations
 
 import logging
 import os
+import sys
+import time
+from contextlib import asynccontextmanager
 from collections.abc import Callable
 from typing import Any
 
@@ -62,6 +65,7 @@ from ktx_daemon.table_identifier import (
     ParseTableIdentifierBatchResponse,
     parse_table_identifier_response,
 )
+from ktx_daemon.telemetry import track_telemetry_event
 
 logger = logging.getLogger(__name__)
 
@@ -81,11 +85,38 @@ def create_app(
     ]
     | None = None,
     enable_code_execution: bool = False,
+    telemetry_started_at: float | None = None,
+    clock: Callable[[], float] = time.perf_counter,
 ) -> FastAPI:
+    started_at = telemetry_started_at or clock()
+
+    @asynccontextmanager
+    async def lifespan(_: FastAPI):
+        track_telemetry_event(
+            "daemon_started",
+            {
+                "daemonVersion": os.environ.get("KTX_DAEMON_VERSION", VERSION),
+                "pythonVersion": f"{sys.version_info.major}.{sys.version_info.minor}.{sys.version_info.micro}",
+                "runtimeVersion": VERSION,
+                "startupDurationMs": max(0, (clock() - started_at) * 1000),
+            },
+        )
+        try:
+            yield
+        finally:
+            track_telemetry_event(
+                "daemon_stopped",
+                {
+                    "reason": "request",
+                    "uptimeMs": max(0, (clock() - started_at) * 1000),
+                },
+            )
+
     app = FastAPI(
         title="KTX Daemon",
         description="Stateless portable compute server for KTX.",
         version=VERSION,
+        lifespan=lifespan,
     )
 
     @app.get("/health")

python/ktx-daemon/tests/test_app.py

@@ -1,5 +1,8 @@
 from __future__ import annotations
 
+import json
+from pathlib import Path
+
 from fastapi.testclient import TestClient
 
 from ktx_daemon.app import create_app
@@ -79,6 +82,41 @@ def test_health_endpoint_returns_managed_runtime_version(monkeypatch) -> None:
     assert response.json() == {"status": "healthy", "version": "0.2.0"}
 
 
+def test_app_lifespan_emits_daemon_lifecycle_debug_events(
+    tmp_path: Path,
+    monkeypatch,
+    capsys,
+) -> None:
+    from ktx_daemon.telemetry.identity import reset_identity_cache
+
+    reset_identity_cache()
+    identity_path = tmp_path / ".ktx" / "telemetry.json"
+    identity_path.parent.mkdir(parents=True)
+    identity_path.write_text(
+        json.dumps(
+            {
+                "installId": "00000000-0000-4000-8000-000000000000",
+                "enabled": True,
+                "createdAt": "2026-05-22T14:33:02.000Z",
+            }
+        )
+        + "\n",
+        encoding="utf-8",
+    )
+    monkeypatch.setenv("HOME", str(tmp_path))
+    monkeypatch.setenv("KTX_TELEMETRY_DEBUG", "1")
+    monkeypatch.setenv("KTX_DAEMON_VERSION", "0.4.1")
+
+    with TestClient(
+        create_app(telemetry_started_at=100.0, clock=lambda: 100.125)
+    ) as client:
+        assert client.get("/health").status_code == 200
+
+    captured = capsys.readouterr()
+    assert '"event": "daemon_started"' in captured.err
+    assert '"event": "daemon_stopped"' in captured.err
+
+
 def test_database_introspect_endpoint_returns_snapshot() -> None:
     calls = []