feat: key=value logging formatter

app/logging_setup.py

@@ -0,0 +1,31 @@
+import logging
+import sys
+
+
+class KeyValueFormatter(logging.Formatter):
+    """Formats records as `LEVEL msg key1=val1 key2=val2`."""
+
+    def format(self, record: logging.LogRecord) -> str:
+        base = f"{record.levelname} {record.getMessage()}"
+        # extras land in record.__dict__ but mixed with stdlib keys; filter to known-extra keys
+        reserved = {
+            "name", "msg", "args", "levelname", "levelno", "pathname", "filename",
+            "module", "exc_info", "exc_text", "stack_info", "lineno", "funcName",
+            "created", "msecs", "relativeCreated", "thread", "threadName",
+            "processName", "process", "message", "taskName",
+        }
+        extras = {k: v for k, v in record.__dict__.items() if k not in reserved}
+        if extras:
+            base += " " + " ".join(f"{k}={v}" for k, v in extras.items())
+        if record.exc_info:
+            base += "\n" + self.formatException(record.exc_info)
+        return base
+
+
+def setup_logging(level: str = "INFO") -> None:
+    handler = logging.StreamHandler(sys.stdout)
+    handler.setFormatter(KeyValueFormatter())
+    root = logging.getLogger()
+    root.handlers.clear()
+    root.addHandler(handler)
+    root.setLevel(level.upper())