Implement compliance key lifecycle on main service, add message retention and rate limits

backend/services/main/key_lifecycle.py

@@ -0,0 +1,200 @@
+"""
+Key lifecycle: time-based removal of compliance MEK, soft-deleted DM keys, and edit history.
+
+Uses MESSAGE_RETENTION_DAYS from the environment (see services.shared.message_retention).
+"""
+
+import logging
+from datetime import datetime
+from sqlalchemy.orm import Session
+
+from .models import DMEnvelope, MessageEditHistory, DMEditHistory
+
+logger = logging.getLogger("uvicorn.error")
+
+
+def _retention_timedelta_or_skip():
+    try:
+        from services.shared.message_retention import get_message_retention
+    except ImportError:
+        from backend.services.shared.message_retention import get_message_retention  # type: ignore
+    r = get_message_retention()
+    if not r.cleanup_enabled():
+        return None
+    return r.retention_timedelta()
+
+
+def destroy_compliance_keys_for_message(db: Session, message_id: int) -> int:
+    try:
+        envelopes = db.query(DMEnvelope).filter(DMEnvelope.id == message_id).all()
+
+        destroyed_count = 0
+        for envelope in envelopes:
+            if envelope.compliance_wrapped_mek_b64:
+                envelope.compliance_wrapped_mek_b64 = None
+                destroyed_count += 1
+
+        if destroyed_count > 0:
+            db.commit()
+            logger.info(
+                "Destroyed compliance keys for %s DM envelopes (message_id=%s)",
+                destroyed_count,
+                message_id,
+            )
+
+        return destroyed_count
+
+    except Exception as e:
+        logger.error("Failed to destroy compliance keys for message %s: %s", message_id, e)
+        db.rollback()
+        return 0
+
+
+def destroy_compliance_keys_for_dm_envelope(db: Session, dm_envelope_id: int) -> bool:
+    try:
+        envelope = db.query(DMEnvelope).filter(DMEnvelope.id == dm_envelope_id).first()
+        if envelope and envelope.compliance_wrapped_mek_b64:
+            envelope.compliance_wrapped_mek_b64 = None
+            db.commit()
+            logger.info("Destroyed compliance key for DM envelope %s", dm_envelope_id)
+            return True
+        return False
+
+    except Exception as e:
+        logger.error("Failed to destroy compliance key for DM envelope %s: %s", dm_envelope_id, e)
+        db.rollback()
+        return False
+
+
+def cleanup_expired_compliance_keys(db: Session) -> int:
+    delta = _retention_timedelta_or_skip()
+    if delta is None:
+        return 0
+
+    try:
+        cutoff_date = datetime.now() - delta
+
+        expired_envelopes = db.query(DMEnvelope).filter(
+            DMEnvelope.timestamp < cutoff_date,
+            DMEnvelope.compliance_wrapped_mek_b64.isnot(None),
+        ).all()
+
+        destroyed_count = 0
+        for envelope in expired_envelopes:
+            envelope.compliance_wrapped_mek_b64 = None
+            destroyed_count += 1
+
+        if destroyed_count > 0:
+            db.commit()
+            logger.info("Cleaned up %s expired compliance MEK fields", destroyed_count)
+
+        return destroyed_count
+
+    except Exception as e:
+        logger.error("Failed to cleanup expired compliance keys: %s", e)
+        db.rollback()
+        return 0
+
+
+def cleanup_expired_message_keys(db: Session) -> int:
+    delta = _retention_timedelta_or_skip()
+    if delta is None:
+        return 0
+
+    try:
+        cutoff_date = datetime.now() - delta
+
+        expired_messages = db.query(DMEnvelope).filter(
+            DMEnvelope.deleted_at.is_not(None),
+            DMEnvelope.deleted_at < cutoff_date,
+        ).all()
+
+        if not expired_messages:
+            return 0
+
+        keys_destroyed = 0
+
+        for message in expired_messages:
+            message.sender_wrapped_mek_b64 = ""
+            message.recipient_wrapped_mek_b64 = ""
+            keys_destroyed += 2
+
+            logger.debug(
+                "Destroyed keys for soft-deleted message id=%s (deleted %s)",
+                message.id,
+                message.deleted_at.isoformat(),
+            )
+
+        db.commit()
+        logger.info(
+            "Message key cleanup: destroyed %s keys across %s messages",
+            keys_destroyed,
+            len(expired_messages),
+        )
+
+        return keys_destroyed
+
+    except Exception as e:
+        logger.error("Failed to cleanup expired message keys: %s", e)
+        db.rollback()
+        return 0
+
+
+def cleanup_expired_edit_history(db: Session) -> int:
+    delta = _retention_timedelta_or_skip()
+    if delta is None:
+        return 0
+
+    try:
+        cutoff_date = datetime.now() - delta
+
+        public_deleted = db.query(MessageEditHistory).filter(
+            MessageEditHistory.edited_at < cutoff_date
+        ).delete(synchronize_session=False)
+
+        dm_deleted = db.query(DMEditHistory).filter(
+            DMEditHistory.edited_at < cutoff_date
+        ).delete(synchronize_session=False)
+
+        total_deleted = public_deleted + dm_deleted
+
+        if total_deleted > 0:
+            db.commit()
+            logger.info("Cleaned up %s expired edit history entries", total_deleted)
+
+        return total_deleted
+
+    except Exception as e:
+        logger.error("Failed to cleanup expired edit history: %s", e)
+        db.rollback()
+        return 0
+
+
+def run_key_lifecycle_cleanup(db: Session) -> dict:
+    stats = {
+        "compliance_keys_destroyed": cleanup_expired_compliance_keys(db),
+        "message_keys_destroyed": cleanup_expired_message_keys(db),
+        "edit_history_entries_removed": cleanup_expired_edit_history(db),
+        "timestamp": datetime.now().isoformat(),
+    }
+
+    if (
+        stats["compliance_keys_destroyed"]
+        or stats["message_keys_destroyed"]
+        or stats["edit_history_entries_removed"]
+    ):
+        logger.info("Key lifecycle cleanup completed: %s", stats)
+    return stats
+
+
+def get_key_lifecycle_config() -> dict:
+    try:
+        from services.shared.message_retention import get_message_retention
+    except ImportError:
+        from backend.services.shared.message_retention import get_message_retention  # type: ignore
+    r = get_message_retention()
+    return {
+        "message_retention_days": r.days,
+        "cleanup_enabled": r.cleanup_enabled(),
+        "never_store_compliance_mek": r.never_store_compliance_mek(),
+    }