US01-02: Establish Application and Database Foundation (#47)

photo_pipeline/logging.py

@@ -0,0 +1,44 @@
+"""Structured logging.
+
+JSON lines carrying ``job_id``, ``asset_id``, and ``operation_id`` when present,
+so later stages can correlate work across the API, worker, and jobs. Secrets are
+never passed to the logger; ``SecretStr`` masks them even if one slips through.
+"""
+
+from __future__ import annotations
+
+import json
+import logging
+import sys
+from datetime import datetime, timezone
+
+CONTEXT_FIELDS = ("job_id", "asset_id", "operation_id")
+
+
+class JsonFormatter(logging.Formatter):
+    def format(self, record: logging.LogRecord) -> str:
+        payload = {
+            "ts": datetime.fromtimestamp(record.created, timezone.utc).isoformat(),
+            "level": record.levelname,
+            "logger": record.name,
+            "message": record.getMessage(),
+        }
+        for field in CONTEXT_FIELDS:
+            value = getattr(record, field, None)
+            if value is not None:
+                payload[field] = value
+        if record.exc_info:
+            payload["exc"] = self.formatException(record.exc_info)
+        return json.dumps(payload, default=str)
+
+
+def configure_logging(level: str = "INFO", fmt: str = "json") -> None:
+    handler = logging.StreamHandler(sys.stderr)
+    if fmt == "json":
+        handler.setFormatter(JsonFormatter())
+    else:
+        handler.setFormatter(logging.Formatter("%(asctime)s %(levelname)s %(name)s %(message)s"))
+    root = logging.getLogger()
+    root.handlers.clear()
+    root.addHandler(handler)
+    root.setLevel(level.upper())