Add lab-02-security-as-a-system

lab-02-security-as-a-system/scenario/service_common.py

@@ -0,0 +1,47 @@
+#!/usr/bin/env python3
+
+import json
+import os
+from datetime import datetime, timezone
+
+
+def record_event(
+    evidence_log,
+    *,
+    service,
+    service_token,
+    source,
+    port,
+    result="ok",
+    **extra,
+):
+    entry = {
+        "timestamp": datetime.now(timezone.utc).isoformat(),
+        "service": service,
+        "service_token": service_token,
+        "source": source,
+        "port": port,
+        "result": result,
+    }
+
+    entry.update(extra)
+
+    line = (
+        json.dumps(
+            entry,
+            sort_keys=True,
+            separators=(",", ":"),
+        )
+        + "\n"
+    )
+
+    fd = os.open(
+        evidence_log,
+        os.O_WRONLY | os.O_CREAT | os.O_APPEND,
+        0o600,
+    )
+
+    try:
+        os.write(fd, line.encode("utf-8"))
+    finally:
+        os.close(fd)