feat: add component-aware RFC 5424 application logging system

- Modify Rfc5424Formatter to read decnet_component from LogRecord
  and use it as RFC 5424 APP-NAME field (falls back to 'decnet')
- Add get_logger(component) factory in decnet/logging/__init__.py
  with _ComponentFilter that injects decnet_component on each record
- Wire all five layers to their component tag:
    cli -> 'cli', engine -> 'engine', api -> 'api' (api.py, ingester,
    routers), mutator -> 'mutator', collector -> 'collector'
- Add structured INFO/DEBUG/WARNING/ERROR log calls throughout each
  layer per the defined vocabulary; DEBUG calls are suppressed unless
  DECNET_DEVELOPER=true
- Add tests/test_logging.py covering factory, filter, formatter
  component-awareness, fallback behaviour, and level gating

decnet/web/api.py

@@ -1,5 +1,4 @@
 import asyncio
-import logging
 import os
 from contextlib import asynccontextmanager
 from typing import Any, AsyncGenerator, Optional
@@ -11,12 +10,13 @@ from pydantic import ValidationError
 from fastapi.middleware.cors import CORSMiddleware
 
 from decnet.env import DECNET_CORS_ORIGINS, DECNET_DEVELOPER, DECNET_INGEST_LOG_FILE
+from decnet.logging import get_logger
 from decnet.web.dependencies import repo
 from decnet.collector import log_collector_worker
 from decnet.web.ingester import log_ingestion_worker
 from decnet.web.router import api_router
 
-log = logging.getLogger(__name__)
+log = get_logger("api")
 ingestion_task: Optional[asyncio.Task[Any]] = None
 collector_task: Optional[asyncio.Task[Any]] = None
 
@@ -25,9 +25,11 @@ collector_task: Optional[asyncio.Task[Any]] = None
 async def lifespan(app: FastAPI) -> AsyncGenerator[None, None]:
     global ingestion_task, collector_task
 
+    log.info("API startup initialising database")
     for attempt in range(1, 6):
         try:
             await repo.initialize()
+            log.debug("API startup DB initialised attempt=%d", attempt)
             break
         except Exception as exc:
             log.warning("DB init attempt %d/5 failed: %s", attempt, exc)
@@ -40,11 +42,13 @@ async def lifespan(app: FastAPI) -> AsyncGenerator[None, None]:
         # Start background ingestion task
         if ingestion_task is None or ingestion_task.done():
             ingestion_task = asyncio.create_task(log_ingestion_worker(repo))
+            log.debug("API startup ingest worker started")
 
         # Start Docker log collector (writes to log file; ingester reads from it)
         _log_file = os.environ.get("DECNET_INGEST_LOG_FILE", DECNET_INGEST_LOG_FILE)
         if _log_file and (collector_task is None or collector_task.done()):
             collector_task = asyncio.create_task(log_collector_worker(_log_file))
+            log.debug("API startup collector worker started log_file=%s", _log_file)
         elif not _log_file:
             log.warning("DECNET_INGEST_LOG_FILE not set — Docker log collection disabled.")
     else:
@@ -52,7 +56,7 @@ async def lifespan(app: FastAPI) -> AsyncGenerator[None, None]:
 
     yield
 
-    # Shutdown background tasks
+    log.info("API shutdown cancelling background tasks")
     for task in (ingestion_task, collector_task):
         if task and not task.done():
             task.cancel()
@@ -62,6 +66,7 @@ async def lifespan(app: FastAPI) -> AsyncGenerator[None, None]:
                 pass
             except Exception as exc:
                 log.warning("Task shutdown error: %s", exc)
+    log.info("API shutdown complete")
 
 
 app: FastAPI = FastAPI(

decnet/web/ingester.py

@@ -1,13 +1,13 @@
 import asyncio
 import os
-import logging
 import json
 from typing import Any
 from pathlib import Path
 
+from decnet.logging import get_logger
 from decnet.web.db.repository import BaseRepository
 
-logger: logging.Logger = logging.getLogger("decnet.web.ingester")
+logger = get_logger("api")
 
 async def log_ingestion_worker(repo: BaseRepository) -> None:
     """
@@ -22,7 +22,7 @@ async def log_ingestion_worker(repo: BaseRepository) -> None:
     _json_log_path: Path = Path(_base_log_file).with_suffix(".json")
     _position: int = 0
 
-    logger.info(f"Starting JSON log ingestion from {_json_log_path}")
+    logger.info("ingest worker started path=%s", _json_log_path)
 
     while True:
         try:
@@ -53,10 +53,11 @@ async def log_ingestion_worker(repo: BaseRepository) -> None:
 
                     try:
                         _log_data: dict[str, Any] = json.loads(_line.strip())
+                        logger.debug("ingest: record decky=%s event_type=%s", _log_data.get("decky"), _log_data.get("event_type"))
                         await repo.add_log(_log_data)
                         await _extract_bounty(repo, _log_data)
                     except json.JSONDecodeError:
-                        logger.error(f"Failed to decode JSON log line: {_line}")
+                        logger.error("ingest: failed to decode JSON log line: %s", _line.strip())
                         continue
 
                     # Update position after successful line read
@@ -65,10 +66,10 @@ async def log_ingestion_worker(repo: BaseRepository) -> None:
         except Exception as _e:
             _err_str = str(_e).lower()
             if "no such table" in _err_str or "no active connection" in _err_str or "connection closed" in _err_str:
-                logger.error(f"Post-shutdown or fatal DB error in ingester: {_e}")
+                logger.error("ingest: post-shutdown or fatal DB error: %s", _e)
                 break  # Exit worker — DB is gone or uninitialized
 
-            logger.error(f"Error in log ingestion worker: {_e}")
+            logger.error("ingest: error in worker: %s", _e)
             await asyncio.sleep(5)
 
         await asyncio.sleep(1)

decnet/web/router/fleet/api_deploy_deckies.py

@@ -1,9 +1,11 @@
-import logging
 import os
 
 from fastapi import APIRouter, Depends, HTTPException
 
-from decnet.config import DEFAULT_MUTATE_INTERVAL, DecnetConfig, _ROOT, log
+from decnet.logging import get_logger
+from decnet.config import DEFAULT_MUTATE_INTERVAL, DecnetConfig, _ROOT
+
+log = get_logger("api")
 from decnet.engine import deploy as _deploy
 from decnet.ini_loader import load_ini_from_string
 from decnet.network import detect_interface, detect_subnet, get_host_ip
@@ -100,7 +102,7 @@ async def api_deploy_deckies(req: DeployIniRequest, current_user: str = Depends(
         }
         await repo.set_state("deployment", new_state_payload)
     except Exception as e:
-        logging.getLogger("decnet.web.api").exception("Deployment failed: %s", e)
+        log.exception("Deployment failed: %s", e)
         raise HTTPException(status_code=500, detail="Deployment failed. Check server logs for details.")
 
     return {"message": "Deckies deployed successfully"}

decnet/web/router/stream/api_stream_events.py

@@ -1,15 +1,15 @@
 import json
 import asyncio
-import logging
 from typing import AsyncGenerator, Optional
 
 from fastapi import APIRouter, Depends, Query, Request
 from fastapi.responses import StreamingResponse
 
 from decnet.env import DECNET_DEVELOPER
+from decnet.logging import get_logger
 from decnet.web.dependencies import get_stream_user, repo
 
-log = logging.getLogger(__name__)
+log = get_logger("api")
 
 router = APIRouter()