From 73bbd606aa3560721d4449c9a9b139d82281911b Mon Sep 17 00:00:00 2001
From: Mika <kontakt@donau2space.de>
Date: Fri, 16 Jan 2026 11:18:58 +0000
Subject: [PATCH] Add 1_write_events/src/write_events/core.py

---
 1_write_events/src/write_events/core.py | 86 +++++++++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 1_write_events/src/write_events/core.py

diff --git a/1_write_events/src/write_events/core.py b/1_write_events/src/write_events/core.py
new file mode 100644
index 0000000..383feda
--- /dev/null
+++ b/1_write_events/src/write_events/core.py
@@ -0,0 +1,86 @@
+import json
+import os
+import datetime
+import argparse
+from pathlib import Path
+from typing import TypedDict, Any
+
+
+class WriteEvent(TypedDict):
+    timestamp: str
+    field_tag: str
+    new_value_hash: str
+    corr_id: str
+    cpu: int
+    ktime_ns: int
+
+
+class WriteEventError(Exception):
+    """Custom exception for invalid write event parameters."""
+    pass
+
+
+def _get_cpu() -> int:
+    try:
+        return os.sched_getcpu()
+    except AttributeError:
+        return -1
+
+
+def _get_ktime_ns() -> int:
+    return int(datetime.datetime.now().timestamp() * 1e9)
+
+
+def _get_event_log_path() -> Path:
+    base_dir = Path("output")
+    base_dir.mkdir(parents=True, exist_ok=True)
+    return base_dir / "write_events.json"
+
+
+def _validate_inputs(field_tag: Any, new_value_hash: Any, corr_id: Any) -> None:
+    if not all(isinstance(v, str) and v.strip() for v in (field_tag, new_value_hash, corr_id)):
+        raise WriteEventError("All parameters must be non-empty strings.")
+
+
+def _serialize_event(event: WriteEvent) -> dict:
+    return dict(event)
+
+
+def record_write_event(field_tag: str, new_value_hash: str, corr_id: str) -> None:
+    """Erfasst ein Write-Event und schreibt es als JSON in eine Log-Datei."""
+    _validate_inputs(field_tag, new_value_hash, corr_id)
+
+    event: WriteEvent = {
+        "timestamp": datetime.datetime.now().astimezone().isoformat(),
+        "field_tag": field_tag,
+        "new_value_hash": new_value_hash,
+        "corr_id": corr_id,
+        "cpu": _get_cpu(),
+        "ktime_ns": _get_ktime_ns(),
+    }
+
+    log_path = _get_event_log_path()
+
+    existing_data: list[dict] = []
+    if log_path.exists() and log_path.stat().st_size > 0:
+        try:
+            with log_path.open("r", encoding="utf-8") as f:
+                existing_data = json.load(f)
+                if not isinstance(existing_data, list):
+                    existing_data = []
+        except (json.JSONDecodeError, OSError):
+            existing_data = []
+
+    existing_data.append(_serialize_event(event))
+
+    with log_path.open("w", encoding="utf-8") as f:
+        json.dump(existing_data, f, indent=2)
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(description="Record a write event.")
+    parser.add_argument("--field-tag", required=True, help="Field tag to log.")
+    parser.add_argument("--new-value-hash", required=True, help="Hash of the new value.")
+    parser.add_argument("--corr-id", required=True, help="Correlation ID.")
+    args = parser.parse_args()
+    record_write_event(args.field_tag, args.new_value_hash, args.corr_id)
\ No newline at end of file