app/__init__.py

@@ -1,4 +1,3 @@
-"""Application factory for the mini S3-compatible object store."""
 from __future__ import annotations
 
 import logging
@@ -16,6 +15,7 @@ from flask_cors import CORS
 from flask_wtf.csrf import CSRFError
 from werkzeug.middleware.proxy_fix import ProxyFix
 
+from .access_logging import AccessLoggingService
 from .acl import AclService
 from .bucket_policies import BucketPolicyStore
 from .config import AppConfig
@@ -25,6 +25,8 @@ from .extensions import limiter, csrf
 from .iam import IamService
 from .kms import KMSManager
 from .lifecycle import LifecycleManager
+from .notifications import NotificationService
+from .object_lock import ObjectLockService
 from .replication import ReplicationManager
 from .secret_store import EphemeralSecretStore
 from .storage import ObjectStorage
@@ -143,6 +145,10 @@ def create_app(
         storage = EncryptedObjectStorage(storage, encryption_manager)
 
     acl_service = AclService(storage_root)
+    object_lock_service = ObjectLockService(storage_root)
+    notification_service = NotificationService(storage_root)
+    access_logging_service = AccessLoggingService(storage_root)
+    access_logging_service.set_storage(storage)
 
     lifecycle_manager = None
     if app.config.get("LIFECYCLE_ENABLED", False):
@@ -164,6 +170,9 @@ def create_app(
     app.extensions["kms"] = kms_manager
     app.extensions["acl"] = acl_service
     app.extensions["lifecycle"] = lifecycle_manager
+    app.extensions["object_lock"] = object_lock_service
+    app.extensions["notifications"] = notification_service
+    app.extensions["access_logging"] = access_logging_service
 
     @app.errorhandler(500)
     def internal_error(error):

app/access_logging.py

@@ -0,0 +1,262 @@
+from __future__ import annotations
+
+import io
+import json
+import logging
+import queue
+import threading
+import time
+import uuid
+from dataclasses import dataclass, field
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any, Dict, List, Optional
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass
+class AccessLogEntry:
+    bucket_owner: str = "-"
+    bucket: str = "-"
+    timestamp: datetime = field(default_factory=lambda: datetime.now(timezone.utc))
+    remote_ip: str = "-"
+    requester: str = "-"
+    request_id: str = field(default_factory=lambda: uuid.uuid4().hex[:16].upper())
+    operation: str = "-"
+    key: str = "-"
+    request_uri: str = "-"
+    http_status: int = 200
+    error_code: str = "-"
+    bytes_sent: int = 0
+    object_size: int = 0
+    total_time_ms: int = 0
+    turn_around_time_ms: int = 0
+    referrer: str = "-"
+    user_agent: str = "-"
+    version_id: str = "-"
+    host_id: str = "-"
+    signature_version: str = "SigV4"
+    cipher_suite: str = "-"
+    authentication_type: str = "AuthHeader"
+    host_header: str = "-"
+    tls_version: str = "-"
+
+    def to_log_line(self) -> str:
+        time_str = self.timestamp.strftime("[%d/%b/%Y:%H:%M:%S %z]")
+        return (
+            f'{self.bucket_owner} {self.bucket} {time_str} {self.remote_ip} '
+            f'{self.requester} {self.request_id} {self.operation} {self.key} '
+            f'"{self.request_uri}" {self.http_status} {self.error_code or "-"} '
+            f'{self.bytes_sent or "-"} {self.object_size or "-"} {self.total_time_ms or "-"} '
+            f'{self.turn_around_time_ms or "-"} "{self.referrer}" "{self.user_agent}" {self.version_id}'
+        )
+
+    def to_dict(self) -> Dict[str, Any]:
+        return {
+            "bucket_owner": self.bucket_owner,
+            "bucket": self.bucket,
+            "timestamp": self.timestamp.isoformat(),
+            "remote_ip": self.remote_ip,
+            "requester": self.requester,
+            "request_id": self.request_id,
+            "operation": self.operation,
+            "key": self.key,
+            "request_uri": self.request_uri,
+            "http_status": self.http_status,
+            "error_code": self.error_code,
+            "bytes_sent": self.bytes_sent,
+            "object_size": self.object_size,
+            "total_time_ms": self.total_time_ms,
+            "referrer": self.referrer,
+            "user_agent": self.user_agent,
+            "version_id": self.version_id,
+        }
+
+
+@dataclass
+class LoggingConfiguration:
+    target_bucket: str
+    target_prefix: str = ""
+    enabled: bool = True
+
+    def to_dict(self) -> Dict[str, Any]:
+        return {
+            "LoggingEnabled": {
+                "TargetBucket": self.target_bucket,
+                "TargetPrefix": self.target_prefix,
+            }
+        }
+
+    @classmethod
+    def from_dict(cls, data: Dict[str, Any]) -> Optional["LoggingConfiguration"]:
+        logging_enabled = data.get("LoggingEnabled")
+        if not logging_enabled:
+            return None
+        return cls(
+            target_bucket=logging_enabled.get("TargetBucket", ""),
+            target_prefix=logging_enabled.get("TargetPrefix", ""),
+            enabled=True,
+        )
+
+
+class AccessLoggingService:
+    def __init__(self, storage_root: Path, flush_interval: int = 60, max_buffer_size: int = 1000):
+        self.storage_root = storage_root
+        self.flush_interval = flush_interval
+        self.max_buffer_size = max_buffer_size
+        self._configs: Dict[str, LoggingConfiguration] = {}
+        self._buffer: Dict[str, List[AccessLogEntry]] = {}
+        self._buffer_lock = threading.Lock()
+        self._shutdown = threading.Event()
+        self._storage = None
+
+        self._flush_thread = threading.Thread(target=self._flush_loop, name="access-log-flush", daemon=True)
+        self._flush_thread.start()
+
+    def set_storage(self, storage: Any) -> None:
+        self._storage = storage
+
+    def _config_path(self, bucket_name: str) -> Path:
+        return self.storage_root / ".myfsio.sys" / "buckets" / bucket_name / "logging.json"
+
+    def get_bucket_logging(self, bucket_name: str) -> Optional[LoggingConfiguration]:
+        if bucket_name in self._configs:
+            return self._configs[bucket_name]
+
+        config_path = self._config_path(bucket_name)
+        if not config_path.exists():
+            return None
+
+        try:
+            data = json.loads(config_path.read_text(encoding="utf-8"))
+            config = LoggingConfiguration.from_dict(data)
+            if config:
+                self._configs[bucket_name] = config
+            return config
+        except (json.JSONDecodeError, OSError) as e:
+            logger.warning(f"Failed to load logging config for {bucket_name}: {e}")
+            return None
+
+    def set_bucket_logging(self, bucket_name: str, config: LoggingConfiguration) -> None:
+        config_path = self._config_path(bucket_name)
+        config_path.parent.mkdir(parents=True, exist_ok=True)
+        config_path.write_text(json.dumps(config.to_dict(), indent=2), encoding="utf-8")
+        self._configs[bucket_name] = config
+
+    def delete_bucket_logging(self, bucket_name: str) -> None:
+        config_path = self._config_path(bucket_name)
+        try:
+            if config_path.exists():
+                config_path.unlink()
+        except OSError:
+            pass
+        self._configs.pop(bucket_name, None)
+
+    def log_request(
+        self,
+        bucket_name: str,
+        *,
+        operation: str,
+        key: str = "-",
+        remote_ip: str = "-",
+        requester: str = "-",
+        request_uri: str = "-",
+        http_status: int = 200,
+        error_code: str = "",
+        bytes_sent: int = 0,
+        object_size: int = 0,
+        total_time_ms: int = 0,
+        referrer: str = "-",
+        user_agent: str = "-",
+        version_id: str = "-",
+        request_id: str = "",
+    ) -> None:
+        config = self.get_bucket_logging(bucket_name)
+        if not config or not config.enabled:
+            return
+
+        entry = AccessLogEntry(
+            bucket_owner="local-owner",
+            bucket=bucket_name,
+            remote_ip=remote_ip,
+            requester=requester,
+            request_id=request_id or uuid.uuid4().hex[:16].upper(),
+            operation=operation,
+            key=key,
+            request_uri=request_uri,
+            http_status=http_status,
+            error_code=error_code,
+            bytes_sent=bytes_sent,
+            object_size=object_size,
+            total_time_ms=total_time_ms,
+            referrer=referrer,
+            user_agent=user_agent,
+            version_id=version_id,
+        )
+
+        target_key = f"{config.target_bucket}:{config.target_prefix}"
+        with self._buffer_lock:
+            if target_key not in self._buffer:
+                self._buffer[target_key] = []
+            self._buffer[target_key].append(entry)
+
+            if len(self._buffer[target_key]) >= self.max_buffer_size:
+                self._flush_buffer(target_key)
+
+    def _flush_loop(self) -> None:
+        while not self._shutdown.is_set():
+            time.sleep(self.flush_interval)
+            self._flush_all()
+
+    def _flush_all(self) -> None:
+        with self._buffer_lock:
+            targets = list(self._buffer.keys())
+
+        for target_key in targets:
+            self._flush_buffer(target_key)
+
+    def _flush_buffer(self, target_key: str) -> None:
+        with self._buffer_lock:
+            entries = self._buffer.pop(target_key, [])
+
+        if not entries or not self._storage:
+            return
+
+        try:
+            bucket_name, prefix = target_key.split(":", 1)
+        except ValueError:
+            logger.error(f"Invalid target key: {target_key}")
+            return
+
+        now = datetime.now(timezone.utc)
+        log_key = f"{prefix}{now.strftime('%Y-%m-%d-%H-%M-%S')}-{uuid.uuid4().hex[:8]}"
+
+        log_content = "\n".join(entry.to_log_line() for entry in entries) + "\n"
+
+        try:
+            stream = io.BytesIO(log_content.encode("utf-8"))
+            self._storage.put_object(bucket_name, log_key, stream, enforce_quota=False)
+            logger.info(f"Flushed {len(entries)} access log entries to {bucket_name}/{log_key}")
+        except Exception as e:
+            logger.error(f"Failed to write access log to {bucket_name}/{log_key}: {e}")
+            with self._buffer_lock:
+                if target_key not in self._buffer:
+                    self._buffer[target_key] = []
+                self._buffer[target_key] = entries + self._buffer[target_key]
+
+    def flush(self) -> None:
+        self._flush_all()
+
+    def shutdown(self) -> None:
+        self._shutdown.set()
+        self._flush_all()
+        self._flush_thread.join(timeout=5.0)
+
+    def get_stats(self) -> Dict[str, Any]:
+        with self._buffer_lock:
+            buffered = sum(len(entries) for entries in self._buffer.values())
+        return {
+            "buffered_entries": buffered,
+            "target_buckets": len(self._buffer),
+        }

app/acl.py

@@ -1,4 +1,3 @@
-"""S3-compatible Access Control List (ACL) management."""
 from __future__ import annotations
 
 import json

app/bucket_policies.py

@@ -1,4 +1,3 @@
-"""Bucket policy loader/enforcer with a subset of AWS semantics."""
 from __future__ import annotations
 
 import json

app/config.py

@@ -1,4 +1,3 @@
-"""Configuration helpers for the S3 clone application."""
 from __future__ import annotations
 
 import os

app/connections.py

@@ -1,4 +1,3 @@
-"""Manage remote S3 connections."""
 from __future__ import annotations
 
 import json

app/encrypted_storage.py

@@ -1,4 +1,3 @@
-"""Encrypted storage layer that wraps ObjectStorage with encryption support."""
 from __future__ import annotations
 
 import io

app/encryption.py

@@ -353,13 +353,113 @@ class EncryptionManager:
         return encryptor.decrypt_stream(stream, metadata)
 
 
+class SSECEncryption(EncryptionProvider):
+    """SSE-C: Server-Side Encryption with Customer-Provided Keys.
+
+    The client provides the encryption key with each request.
+    Server encrypts/decrypts but never stores the key.
+
+    Required headers for PUT:
+    - x-amz-server-side-encryption-customer-algorithm: AES256
+    - x-amz-server-side-encryption-customer-key: Base64-encoded 256-bit key
+    - x-amz-server-side-encryption-customer-key-MD5: Base64-encoded MD5 of key
+    """
+
+    KEY_ID = "customer-provided"
+
+    def __init__(self, customer_key: bytes):
+        if len(customer_key) != 32:
+            raise EncryptionError("Customer key must be exactly 256 bits (32 bytes)")
+        self.customer_key = customer_key
+
+    @classmethod
+    def from_headers(cls, headers: Dict[str, str]) -> "SSECEncryption":
+        algorithm = headers.get("x-amz-server-side-encryption-customer-algorithm", "")
+        if algorithm.upper() != "AES256":
+            raise EncryptionError(f"Unsupported SSE-C algorithm: {algorithm}. Only AES256 is supported.")
+
+        key_b64 = headers.get("x-amz-server-side-encryption-customer-key", "")
+        if not key_b64:
+            raise EncryptionError("Missing x-amz-server-side-encryption-customer-key header")
+
+        key_md5_b64 = headers.get("x-amz-server-side-encryption-customer-key-md5", "")
+
+        try:
+            customer_key = base64.b64decode(key_b64)
+        except Exception as e:
+            raise EncryptionError(f"Invalid base64 in customer key: {e}") from e
+
+        if len(customer_key) != 32:
+            raise EncryptionError(f"Customer key must be 256 bits, got {len(customer_key) * 8} bits")
+
+        if key_md5_b64:
+            import hashlib
+            expected_md5 = base64.b64encode(hashlib.md5(customer_key).digest()).decode()
+            if key_md5_b64 != expected_md5:
+                raise EncryptionError("Customer key MD5 mismatch")
+
+        return cls(customer_key)
+
+    def encrypt(self, plaintext: bytes, context: Dict[str, str] | None = None) -> EncryptionResult:
+        aesgcm = AESGCM(self.customer_key)
+        nonce = secrets.token_bytes(12)
+        ciphertext = aesgcm.encrypt(nonce, plaintext, None)
+
+        return EncryptionResult(
+            ciphertext=ciphertext,
+            nonce=nonce,
+            key_id=self.KEY_ID,
+            encrypted_data_key=b"",
+        )
+
+    def decrypt(self, ciphertext: bytes, nonce: bytes, encrypted_data_key: bytes,
+                key_id: str, context: Dict[str, str] | None = None) -> bytes:
+        aesgcm = AESGCM(self.customer_key)
+        try:
+            return aesgcm.decrypt(nonce, ciphertext, None)
+        except Exception as exc:
+            raise EncryptionError(f"SSE-C decryption failed: {exc}") from exc
+
+    def generate_data_key(self) -> tuple[bytes, bytes]:
+        return self.customer_key, b""
+
+
+@dataclass
+class SSECMetadata:
+    algorithm: str = "AES256"
+    nonce: bytes = b""
+    key_md5: str = ""
+
+    def to_dict(self) -> Dict[str, str]:
+        return {
+            "x-amz-server-side-encryption-customer-algorithm": self.algorithm,
+            "x-amz-encryption-nonce": base64.b64encode(self.nonce).decode(),
+            "x-amz-server-side-encryption-customer-key-MD5": self.key_md5,
+        }
+
+    @classmethod
+    def from_dict(cls, data: Dict[str, str]) -> Optional["SSECMetadata"]:
+        algorithm = data.get("x-amz-server-side-encryption-customer-algorithm")
+        if not algorithm:
+            return None
+        try:
+            nonce = base64.b64decode(data.get("x-amz-encryption-nonce", ""))
+            return cls(
+                algorithm=algorithm,
+                nonce=nonce,
+                key_md5=data.get("x-amz-server-side-encryption-customer-key-MD5", ""),
+            )
+        except Exception:
+            return None
+
+
 class ClientEncryptionHelper:
     """Helpers for client-side encryption.
-    
+
     Client-side encryption is performed by the client, but this helper
     provides key generation and materials for clients that need them.
     """
-    
+
     @staticmethod
     def generate_client_key() -> Dict[str, str]:
         """Generate a new client encryption key."""

app/errors.py

@@ -1,4 +1,3 @@
-"""Standardized error handling for API and UI responses."""
 from __future__ import annotations
 
 import logging

app/extensions.py

@@ -1,4 +1,3 @@
-"""Application-wide extension instances."""
 from flask import g
 from flask_limiter import Limiter
 from flask_limiter.util import get_remote_address

app/iam.py

@@ -1,4 +1,3 @@
-"""Lightweight IAM-style user and policy management."""
 from __future__ import annotations
 
 import json

app/kms.py

@@ -1,4 +1,3 @@
-"""Key Management Service (KMS) for encryption key management."""
 from __future__ import annotations
 
 import base64

app/kms_api.py

@@ -1,4 +1,3 @@
-"""KMS and encryption API endpoints."""
 from __future__ import annotations
 
 import base64

app/lifecycle.py

@@ -1,4 +1,3 @@
-"""Lifecycle rule enforcement for S3-compatible storage."""
 from __future__ import annotations
 
 import logging

app/notifications.py

@@ -0,0 +1,334 @@
+from __future__ import annotations
+
+import json
+import logging
+import queue
+import threading
+import time
+import uuid
+from dataclasses import dataclass, field
+from datetime import datetime, timezone
+from pathlib import Path
+from typing import Any, Dict, List, Optional
+from urllib.parse import urlparse
+
+import requests
+
+logger = logging.getLogger(__name__)
+
+
+@dataclass
+class NotificationEvent:
+    event_name: str
+    bucket_name: str
+    object_key: str
+    object_size: int = 0
+    etag: str = ""
+    version_id: Optional[str] = None
+    timestamp: datetime = field(default_factory=lambda: datetime.now(timezone.utc))
+    request_id: str = field(default_factory=lambda: uuid.uuid4().hex)
+    source_ip: str = ""
+    user_identity: str = ""
+
+    def to_s3_event(self) -> Dict[str, Any]:
+        return {
+            "Records": [
+                {
+                    "eventVersion": "2.1",
+                    "eventSource": "myfsio:s3",
+                    "awsRegion": "local",
+                    "eventTime": self.timestamp.strftime("%Y-%m-%dT%H:%M:%S.000Z"),
+                    "eventName": self.event_name,
+                    "userIdentity": {
+                        "principalId": self.user_identity or "ANONYMOUS",
+                    },
+                    "requestParameters": {
+                        "sourceIPAddress": self.source_ip or "127.0.0.1",
+                    },
+                    "responseElements": {
+                        "x-amz-request-id": self.request_id,
+                        "x-amz-id-2": self.request_id,
+                    },
+                    "s3": {
+                        "s3SchemaVersion": "1.0",
+                        "configurationId": "notification",
+                        "bucket": {
+                            "name": self.bucket_name,
+                            "ownerIdentity": {"principalId": "local"},
+                            "arn": f"arn:aws:s3:::{self.bucket_name}",
+                        },
+                        "object": {
+                            "key": self.object_key,
+                            "size": self.object_size,
+                            "eTag": self.etag,
+                            "versionId": self.version_id or "null",
+                            "sequencer": f"{int(time.time() * 1000):016X}",
+                        },
+                    },
+                }
+            ]
+        }
+
+
+@dataclass
+class WebhookDestination:
+    url: str
+    headers: Dict[str, str] = field(default_factory=dict)
+    timeout_seconds: int = 30
+    retry_count: int = 3
+    retry_delay_seconds: int = 1
+
+    def to_dict(self) -> Dict[str, Any]:
+        return {
+            "url": self.url,
+            "headers": self.headers,
+            "timeout_seconds": self.timeout_seconds,
+            "retry_count": self.retry_count,
+            "retry_delay_seconds": self.retry_delay_seconds,
+        }
+
+    @classmethod
+    def from_dict(cls, data: Dict[str, Any]) -> "WebhookDestination":
+        return cls(
+            url=data.get("url", ""),
+            headers=data.get("headers", {}),
+            timeout_seconds=data.get("timeout_seconds", 30),
+            retry_count=data.get("retry_count", 3),
+            retry_delay_seconds=data.get("retry_delay_seconds", 1),
+        )
+
+
+@dataclass
+class NotificationConfiguration:
+    id: str
+    events: List[str]
+    destination: WebhookDestination
+    prefix_filter: str = ""
+    suffix_filter: str = ""
+
+    def matches_event(self, event_name: str, object_key: str) -> bool:
+        event_match = False
+        for pattern in self.events:
+            if pattern.endswith("*"):
+                base = pattern[:-1]
+                if event_name.startswith(base):
+                    event_match = True
+                    break
+            elif pattern == event_name:
+                event_match = True
+                break
+
+        if not event_match:
+            return False
+
+        if self.prefix_filter and not object_key.startswith(self.prefix_filter):
+            return False
+        if self.suffix_filter and not object_key.endswith(self.suffix_filter):
+            return False
+
+        return True
+
+    def to_dict(self) -> Dict[str, Any]:
+        return {
+            "Id": self.id,
+            "Events": self.events,
+            "Destination": self.destination.to_dict(),
+            "Filter": {
+                "Key": {
+                    "FilterRules": [
+                        {"Name": "prefix", "Value": self.prefix_filter},
+                        {"Name": "suffix", "Value": self.suffix_filter},
+                    ]
+                }
+            },
+        }
+
+    @classmethod
+    def from_dict(cls, data: Dict[str, Any]) -> "NotificationConfiguration":
+        prefix = ""
+        suffix = ""
+        filter_data = data.get("Filter", {})
+        key_filter = filter_data.get("Key", {})
+        for rule in key_filter.get("FilterRules", []):
+            if rule.get("Name") == "prefix":
+                prefix = rule.get("Value", "")
+            elif rule.get("Name") == "suffix":
+                suffix = rule.get("Value", "")
+
+        return cls(
+            id=data.get("Id", uuid.uuid4().hex),
+            events=data.get("Events", []),
+            destination=WebhookDestination.from_dict(data.get("Destination", {})),
+            prefix_filter=prefix,
+            suffix_filter=suffix,
+        )
+
+
+class NotificationService:
+    def __init__(self, storage_root: Path, worker_count: int = 2):
+        self.storage_root = storage_root
+        self._configs: Dict[str, List[NotificationConfiguration]] = {}
+        self._queue: queue.Queue[tuple[NotificationEvent, WebhookDestination]] = queue.Queue()
+        self._workers: List[threading.Thread] = []
+        self._shutdown = threading.Event()
+        self._stats = {
+            "events_queued": 0,
+            "events_sent": 0,
+            "events_failed": 0,
+        }
+
+        for i in range(worker_count):
+            worker = threading.Thread(target=self._worker_loop, name=f"notification-worker-{i}", daemon=True)
+            worker.start()
+            self._workers.append(worker)
+
+    def _config_path(self, bucket_name: str) -> Path:
+        return self.storage_root / ".myfsio.sys" / "buckets" / bucket_name / "notifications.json"
+
+    def get_bucket_notifications(self, bucket_name: str) -> List[NotificationConfiguration]:
+        if bucket_name in self._configs:
+            return self._configs[bucket_name]
+
+        config_path = self._config_path(bucket_name)
+        if not config_path.exists():
+            return []
+
+        try:
+            data = json.loads(config_path.read_text(encoding="utf-8"))
+            configs = [NotificationConfiguration.from_dict(c) for c in data.get("configurations", [])]
+            self._configs[bucket_name] = configs
+            return configs
+        except (json.JSONDecodeError, OSError) as e:
+            logger.warning(f"Failed to load notification config for {bucket_name}: {e}")
+            return []
+
+    def set_bucket_notifications(
+        self, bucket_name: str, configurations: List[NotificationConfiguration]
+    ) -> None:
+        config_path = self._config_path(bucket_name)
+        config_path.parent.mkdir(parents=True, exist_ok=True)
+
+        data = {"configurations": [c.to_dict() for c in configurations]}
+        config_path.write_text(json.dumps(data, indent=2), encoding="utf-8")
+        self._configs[bucket_name] = configurations
+
+    def delete_bucket_notifications(self, bucket_name: str) -> None:
+        config_path = self._config_path(bucket_name)
+        try:
+            if config_path.exists():
+                config_path.unlink()
+        except OSError:
+            pass
+        self._configs.pop(bucket_name, None)
+
+    def emit_event(self, event: NotificationEvent) -> None:
+        configurations = self.get_bucket_notifications(event.bucket_name)
+        if not configurations:
+            return
+
+        for config in configurations:
+            if config.matches_event(event.event_name, event.object_key):
+                self._queue.put((event, config.destination))
+                self._stats["events_queued"] += 1
+                logger.debug(
+                    f"Queued notification for {event.event_name} on {event.bucket_name}/{event.object_key}"
+                )
+
+    def emit_object_created(
+        self,
+        bucket_name: str,
+        object_key: str,
+        *,
+        size: int = 0,
+        etag: str = "",
+        version_id: Optional[str] = None,
+        request_id: str = "",
+        source_ip: str = "",
+        user_identity: str = "",
+        operation: str = "Put",
+    ) -> None:
+        event = NotificationEvent(
+            event_name=f"s3:ObjectCreated:{operation}",
+            bucket_name=bucket_name,
+            object_key=object_key,
+            object_size=size,
+            etag=etag,
+            version_id=version_id,
+            request_id=request_id or uuid.uuid4().hex,
+            source_ip=source_ip,
+            user_identity=user_identity,
+        )
+        self.emit_event(event)
+
+    def emit_object_removed(
+        self,
+        bucket_name: str,
+        object_key: str,
+        *,
+        version_id: Optional[str] = None,
+        request_id: str = "",
+        source_ip: str = "",
+        user_identity: str = "",
+        operation: str = "Delete",
+    ) -> None:
+        event = NotificationEvent(
+            event_name=f"s3:ObjectRemoved:{operation}",
+            bucket_name=bucket_name,
+            object_key=object_key,
+            version_id=version_id,
+            request_id=request_id or uuid.uuid4().hex,
+            source_ip=source_ip,
+            user_identity=user_identity,
+        )
+        self.emit_event(event)
+
+    def _worker_loop(self) -> None:
+        while not self._shutdown.is_set():
+            try:
+                event, destination = self._queue.get(timeout=1.0)
+            except queue.Empty:
+                continue
+
+            try:
+                self._send_notification(event, destination)
+                self._stats["events_sent"] += 1
+            except Exception as e:
+                self._stats["events_failed"] += 1
+                logger.error(f"Failed to send notification: {e}")
+            finally:
+                self._queue.task_done()
+
+    def _send_notification(self, event: NotificationEvent, destination: WebhookDestination) -> None:
+        payload = event.to_s3_event()
+        headers = {"Content-Type": "application/json", **destination.headers}
+
+        last_error = None
+        for attempt in range(destination.retry_count):
+            try:
+                response = requests.post(
+                    destination.url,
+                    json=payload,
+                    headers=headers,
+                    timeout=destination.timeout_seconds,
+                )
+                if response.status_code < 400:
+                    logger.info(
+                        f"Notification sent: {event.event_name} -> {destination.url} (status={response.status_code})"
+                    )
+                    return
+                last_error = f"HTTP {response.status_code}: {response.text[:200]}"
+            except requests.RequestException as e:
+                last_error = str(e)
+
+            if attempt < destination.retry_count - 1:
+                time.sleep(destination.retry_delay_seconds * (attempt + 1))
+
+        raise RuntimeError(f"Failed after {destination.retry_count} attempts: {last_error}")
+
+    def get_stats(self) -> Dict[str, int]:
+        return dict(self._stats)
+
+    def shutdown(self) -> None:
+        self._shutdown.set()
+        for worker in self._workers:
+            worker.join(timeout=5.0)

app/object_lock.py

@@ -0,0 +1,234 @@
+from __future__ import annotations
+
+import json
+from dataclasses import dataclass
+from datetime import datetime, timezone
+from enum import Enum
+from pathlib import Path
+from typing import Any, Dict, Optional
+
+
+class RetentionMode(Enum):
+    GOVERNANCE = "GOVERNANCE"
+    COMPLIANCE = "COMPLIANCE"
+
+
+class ObjectLockError(Exception):
+    pass
+
+
+@dataclass
+class ObjectLockRetention:
+    mode: RetentionMode
+    retain_until_date: datetime
+
+    def to_dict(self) -> Dict[str, str]:
+        return {
+            "Mode": self.mode.value,
+            "RetainUntilDate": self.retain_until_date.isoformat(),
+        }
+
+    @classmethod
+    def from_dict(cls, data: Dict[str, Any]) -> Optional["ObjectLockRetention"]:
+        if not data:
+            return None
+        mode_str = data.get("Mode")
+        date_str = data.get("RetainUntilDate")
+        if not mode_str or not date_str:
+            return None
+        try:
+            mode = RetentionMode(mode_str)
+            retain_until = datetime.fromisoformat(date_str.replace("Z", "+00:00"))
+            return cls(mode=mode, retain_until_date=retain_until)
+        except (ValueError, KeyError):
+            return None
+
+    def is_expired(self) -> bool:
+        return datetime.now(timezone.utc) > self.retain_until_date
+
+
+@dataclass
+class ObjectLockConfig:
+    enabled: bool = False
+    default_retention: Optional[ObjectLockRetention] = None
+
+    def to_dict(self) -> Dict[str, Any]:
+        result: Dict[str, Any] = {"ObjectLockEnabled": "Enabled" if self.enabled else "Disabled"}
+        if self.default_retention:
+            result["Rule"] = {
+                "DefaultRetention": {
+                    "Mode": self.default_retention.mode.value,
+                    "Days": None,
+                    "Years": None,
+                }
+            }
+        return result
+
+    @classmethod
+    def from_dict(cls, data: Dict[str, Any]) -> "ObjectLockConfig":
+        enabled = data.get("ObjectLockEnabled") == "Enabled"
+        default_retention = None
+        rule = data.get("Rule")
+        if rule and "DefaultRetention" in rule:
+            dr = rule["DefaultRetention"]
+            mode_str = dr.get("Mode", "GOVERNANCE")
+            days = dr.get("Days")
+            years = dr.get("Years")
+            if days or years:
+                from datetime import timedelta
+                now = datetime.now(timezone.utc)
+                if years:
+                    delta = timedelta(days=int(years) * 365)
+                else:
+                    delta = timedelta(days=int(days))
+                default_retention = ObjectLockRetention(
+                    mode=RetentionMode(mode_str),
+                    retain_until_date=now + delta,
+                )
+        return cls(enabled=enabled, default_retention=default_retention)
+
+
+class ObjectLockService:
+    def __init__(self, storage_root: Path):
+        self.storage_root = storage_root
+        self._config_cache: Dict[str, ObjectLockConfig] = {}
+
+    def _bucket_lock_config_path(self, bucket_name: str) -> Path:
+        return self.storage_root / ".myfsio.sys" / "buckets" / bucket_name / "object_lock.json"
+
+    def _object_lock_meta_path(self, bucket_name: str, object_key: str) -> Path:
+        safe_key = object_key.replace("/", "_").replace("\\", "_")
+        return (
+            self.storage_root / ".myfsio.sys" / "buckets" / bucket_name /
+            "locks" / f"{safe_key}.lock.json"
+        )
+
+    def get_bucket_lock_config(self, bucket_name: str) -> ObjectLockConfig:
+        if bucket_name in self._config_cache:
+            return self._config_cache[bucket_name]
+
+        config_path = self._bucket_lock_config_path(bucket_name)
+        if not config_path.exists():
+            return ObjectLockConfig(enabled=False)
+
+        try:
+            data = json.loads(config_path.read_text(encoding="utf-8"))
+            config = ObjectLockConfig.from_dict(data)
+            self._config_cache[bucket_name] = config
+            return config
+        except (json.JSONDecodeError, OSError):
+            return ObjectLockConfig(enabled=False)
+
+    def set_bucket_lock_config(self, bucket_name: str, config: ObjectLockConfig) -> None:
+        config_path = self._bucket_lock_config_path(bucket_name)
+        config_path.parent.mkdir(parents=True, exist_ok=True)
+        config_path.write_text(json.dumps(config.to_dict()), encoding="utf-8")
+        self._config_cache[bucket_name] = config
+
+    def enable_bucket_lock(self, bucket_name: str) -> None:
+        config = self.get_bucket_lock_config(bucket_name)
+        config.enabled = True
+        self.set_bucket_lock_config(bucket_name, config)
+
+    def is_bucket_lock_enabled(self, bucket_name: str) -> bool:
+        return self.get_bucket_lock_config(bucket_name).enabled
+
+    def get_object_retention(self, bucket_name: str, object_key: str) -> Optional[ObjectLockRetention]:
+        meta_path = self._object_lock_meta_path(bucket_name, object_key)
+        if not meta_path.exists():
+            return None
+        try:
+            data = json.loads(meta_path.read_text(encoding="utf-8"))
+            return ObjectLockRetention.from_dict(data.get("retention", {}))
+        except (json.JSONDecodeError, OSError):
+            return None
+
+    def set_object_retention(
+        self,
+        bucket_name: str,
+        object_key: str,
+        retention: ObjectLockRetention,
+        bypass_governance: bool = False,
+    ) -> None:
+        existing = self.get_object_retention(bucket_name, object_key)
+        if existing and not existing.is_expired():
+            if existing.mode == RetentionMode.COMPLIANCE:
+                raise ObjectLockError(
+                    "Cannot modify retention on object with COMPLIANCE mode until retention expires"
+                )
+            if existing.mode == RetentionMode.GOVERNANCE and not bypass_governance:
+                raise ObjectLockError(
+                    "Cannot modify GOVERNANCE retention without bypass-governance permission"
+                )
+
+        meta_path = self._object_lock_meta_path(bucket_name, object_key)
+        meta_path.parent.mkdir(parents=True, exist_ok=True)
+
+        existing_data: Dict[str, Any] = {}
+        if meta_path.exists():
+            try:
+                existing_data = json.loads(meta_path.read_text(encoding="utf-8"))
+            except (json.JSONDecodeError, OSError):
+                pass
+
+        existing_data["retention"] = retention.to_dict()
+        meta_path.write_text(json.dumps(existing_data), encoding="utf-8")
+
+    def get_legal_hold(self, bucket_name: str, object_key: str) -> bool:
+        meta_path = self._object_lock_meta_path(bucket_name, object_key)
+        if not meta_path.exists():
+            return False
+        try:
+            data = json.loads(meta_path.read_text(encoding="utf-8"))
+            return data.get("legal_hold", False)
+        except (json.JSONDecodeError, OSError):
+            return False
+
+    def set_legal_hold(self, bucket_name: str, object_key: str, enabled: bool) -> None:
+        meta_path = self._object_lock_meta_path(bucket_name, object_key)
+        meta_path.parent.mkdir(parents=True, exist_ok=True)
+
+        existing_data: Dict[str, Any] = {}
+        if meta_path.exists():
+            try:
+                existing_data = json.loads(meta_path.read_text(encoding="utf-8"))
+            except (json.JSONDecodeError, OSError):
+                pass
+
+        existing_data["legal_hold"] = enabled
+        meta_path.write_text(json.dumps(existing_data), encoding="utf-8")
+
+    def can_delete_object(
+        self,
+        bucket_name: str,
+        object_key: str,
+        bypass_governance: bool = False,
+    ) -> tuple[bool, str]:
+        if self.get_legal_hold(bucket_name, object_key):
+            return False, "Object is under legal hold"
+
+        retention = self.get_object_retention(bucket_name, object_key)
+        if retention and not retention.is_expired():
+            if retention.mode == RetentionMode.COMPLIANCE:
+                return False, f"Object is locked in COMPLIANCE mode until {retention.retain_until_date.isoformat()}"
+            if retention.mode == RetentionMode.GOVERNANCE:
+                if not bypass_governance:
+                    return False, f"Object is locked in GOVERNANCE mode until {retention.retain_until_date.isoformat()}"
+
+        return True, ""
+
+    def can_overwrite_object(
+        self,
+        bucket_name: str,
+        object_key: str,
+        bypass_governance: bool = False,
+    ) -> tuple[bool, str]:
+        return self.can_delete_object(bucket_name, object_key, bypass_governance)
+
+    def delete_object_lock_metadata(self, bucket_name: str, object_key: str) -> None:
+        meta_path = self._object_lock_meta_path(bucket_name, object_key)
+        try:
+            if meta_path.exists():
+                meta_path.unlink()
+        except OSError:
+            pass

app/replication.py

@@ -1,4 +1,3 @@
-"""Background replication worker."""
 from __future__ import annotations
 
 import json
@@ -32,13 +31,9 @@ REPLICATION_MODE_ALL = "all"
 
 def _create_s3_client(connection: RemoteConnection, *, health_check: bool = False) -> Any:
     """Create a boto3 S3 client for the given connection.
-
     Args:
         connection: Remote S3 connection configuration
         health_check: If True, use minimal retries for quick health checks
-
-    Returns:
-        Configured boto3 S3 client
     """
     config = Config(
         user_agent_extra=REPLICATION_USER_AGENT,

app/s3_api.py

@@ -16,10 +16,14 @@ from xml.etree.ElementTree import Element, SubElement, tostring, fromstring, Par
 from flask import Blueprint, Response, current_app, jsonify, request, g
 from werkzeug.http import http_date
 
+from .access_logging import AccessLoggingService, LoggingConfiguration
 from .acl import AclService
 from .bucket_policies import BucketPolicyStore
+from .encryption import SSECEncryption, SSECMetadata, EncryptionError
 from .extensions import limiter
 from .iam import IamError, Principal
+from .notifications import NotificationService, NotificationConfiguration, WebhookDestination
+from .object_lock import ObjectLockService, ObjectLockRetention, ObjectLockConfig, ObjectLockError, RetentionMode
 from .replication import ReplicationManager
 from .storage import ObjectStorage, StorageError, QuotaExceededError
 
@@ -49,6 +53,18 @@ def _bucket_policies() -> BucketPolicyStore:
     return store
 
 
+def _object_lock() -> ObjectLockService:
+    return current_app.extensions["object_lock"]
+
+
+def _notifications() -> NotificationService:
+    return current_app.extensions["notifications"]
+
+
+def _access_logging() -> AccessLoggingService:
+    return current_app.extensions["access_logging"]
+
+
 def _xml_response(element: Element, status: int = 200) -> Response:
     xml_bytes = tostring(element, encoding="utf-8")
     return Response(xml_bytes, status=status, mimetype="application/xml")
@@ -897,6 +913,9 @@ def _maybe_handle_bucket_subresource(bucket_name: str) -> Response | None:
         "versions": _bucket_list_versions_handler,
         "lifecycle": _bucket_lifecycle_handler,
         "quota": _bucket_quota_handler,
+        "object-lock": _bucket_object_lock_handler,
+        "notification": _bucket_notification_handler,
+        "logging": _bucket_logging_handler,
     }
     requested = [key for key in handlers if key in request.args]
     if not requested:
@@ -1567,6 +1586,336 @@ def _bucket_quota_handler(bucket_name: str) -> Response:
     return Response(status=204)
 
 
+def _bucket_object_lock_handler(bucket_name: str) -> Response:
+    if request.method not in {"GET", "PUT"}:
+        return _method_not_allowed(["GET", "PUT"])
+
+    principal, error = _require_principal()
+    if error:
+        return error
+    try:
+        _authorize_action(principal, bucket_name, "policy")
+    except IamError as exc:
+        return _error_response("AccessDenied", str(exc), 403)
+
+    storage = _storage()
+    if not storage.bucket_exists(bucket_name):
+        return _error_response("NoSuchBucket", "Bucket does not exist", 404)
+
+    lock_service = _object_lock()
+
+    if request.method == "GET":
+        config = lock_service.get_bucket_lock_config(bucket_name)
+        root = Element("ObjectLockConfiguration", xmlns="http://s3.amazonaws.com/doc/2006-03-01/")
+        SubElement(root, "ObjectLockEnabled").text = "Enabled" if config.enabled else "Disabled"
+        return _xml_response(root)
+
+    payload = request.get_data(cache=False) or b""
+    if not payload.strip():
+        return _error_response("MalformedXML", "Request body is required", 400)
+
+    try:
+        root = fromstring(payload)
+    except ParseError:
+        return _error_response("MalformedXML", "Unable to parse XML document", 400)
+
+    enabled_el = root.find("{*}ObjectLockEnabled") or root.find("ObjectLockEnabled")
+    enabled = (enabled_el.text or "").strip() == "Enabled" if enabled_el is not None else False
+
+    config = ObjectLockConfig(enabled=enabled)
+    lock_service.set_bucket_lock_config(bucket_name, config)
+
+    current_app.logger.info("Bucket object lock updated", extra={"bucket": bucket_name, "enabled": enabled})
+    return Response(status=200)
+
+
+def _bucket_notification_handler(bucket_name: str) -> Response:
+    if request.method not in {"GET", "PUT", "DELETE"}:
+        return _method_not_allowed(["GET", "PUT", "DELETE"])
+
+    principal, error = _require_principal()
+    if error:
+        return error
+    try:
+        _authorize_action(principal, bucket_name, "policy")
+    except IamError as exc:
+        return _error_response("AccessDenied", str(exc), 403)
+
+    storage = _storage()
+    if not storage.bucket_exists(bucket_name):
+        return _error_response("NoSuchBucket", "Bucket does not exist", 404)
+
+    notification_service = _notifications()
+
+    if request.method == "GET":
+        configs = notification_service.get_bucket_notifications(bucket_name)
+        root = Element("NotificationConfiguration", xmlns="http://s3.amazonaws.com/doc/2006-03-01/")
+        for config in configs:
+            webhook_el = SubElement(root, "WebhookConfiguration")
+            SubElement(webhook_el, "Id").text = config.id
+            for event in config.events:
+                SubElement(webhook_el, "Event").text = event
+            dest_el = SubElement(webhook_el, "Destination")
+            SubElement(dest_el, "Url").text = config.destination.url
+            if config.prefix_filter or config.suffix_filter:
+                filter_el = SubElement(webhook_el, "Filter")
+                key_el = SubElement(filter_el, "S3Key")
+                if config.prefix_filter:
+                    rule_el = SubElement(key_el, "FilterRule")
+                    SubElement(rule_el, "Name").text = "prefix"
+                    SubElement(rule_el, "Value").text = config.prefix_filter
+                if config.suffix_filter:
+                    rule_el = SubElement(key_el, "FilterRule")
+                    SubElement(rule_el, "Name").text = "suffix"
+                    SubElement(rule_el, "Value").text = config.suffix_filter
+        return _xml_response(root)
+
+    if request.method == "DELETE":
+        notification_service.delete_bucket_notifications(bucket_name)
+        current_app.logger.info("Bucket notifications deleted", extra={"bucket": bucket_name})
+        return Response(status=204)
+
+    payload = request.get_data(cache=False) or b""
+    if not payload.strip():
+        notification_service.delete_bucket_notifications(bucket_name)
+        return Response(status=200)
+
+    try:
+        root = fromstring(payload)
+    except ParseError:
+        return _error_response("MalformedXML", "Unable to parse XML document", 400)
+
+    configs: list[NotificationConfiguration] = []
+    for webhook_el in root.findall("{*}WebhookConfiguration") or root.findall("WebhookConfiguration"):
+        config_id = _find_element_text(webhook_el, "Id") or uuid.uuid4().hex
+        events = [el.text for el in webhook_el.findall("{*}Event") or webhook_el.findall("Event") if el.text]
+
+        dest_el = _find_element(webhook_el, "Destination")
+        url = _find_element_text(dest_el, "Url") if dest_el else ""
+        if not url:
+            return _error_response("InvalidArgument", "Destination URL is required", 400)
+
+        prefix = ""
+        suffix = ""
+        filter_el = _find_element(webhook_el, "Filter")
+        if filter_el:
+            key_el = _find_element(filter_el, "S3Key")
+            if key_el:
+                for rule_el in key_el.findall("{*}FilterRule") or key_el.findall("FilterRule"):
+                    name = _find_element_text(rule_el, "Name")
+                    value = _find_element_text(rule_el, "Value")
+                    if name == "prefix":
+                        prefix = value
+                    elif name == "suffix":
+                        suffix = value
+
+        configs.append(NotificationConfiguration(
+            id=config_id,
+            events=events,
+            destination=WebhookDestination(url=url),
+            prefix_filter=prefix,
+            suffix_filter=suffix,
+        ))
+
+    notification_service.set_bucket_notifications(bucket_name, configs)
+    current_app.logger.info("Bucket notifications updated", extra={"bucket": bucket_name, "configs": len(configs)})
+    return Response(status=200)
+
+
+def _bucket_logging_handler(bucket_name: str) -> Response:
+    if request.method not in {"GET", "PUT", "DELETE"}:
+        return _method_not_allowed(["GET", "PUT", "DELETE"])
+
+    principal, error = _require_principal()
+    if error:
+        return error
+    try:
+        _authorize_action(principal, bucket_name, "policy")
+    except IamError as exc:
+        return _error_response("AccessDenied", str(exc), 403)
+
+    storage = _storage()
+    if not storage.bucket_exists(bucket_name):
+        return _error_response("NoSuchBucket", "Bucket does not exist", 404)
+
+    logging_service = _access_logging()
+
+    if request.method == "GET":
+        config = logging_service.get_bucket_logging(bucket_name)
+        root = Element("BucketLoggingStatus", xmlns="http://s3.amazonaws.com/doc/2006-03-01/")
+        if config and config.enabled:
+            logging_enabled = SubElement(root, "LoggingEnabled")
+            SubElement(logging_enabled, "TargetBucket").text = config.target_bucket
+            SubElement(logging_enabled, "TargetPrefix").text = config.target_prefix
+        return _xml_response(root)
+
+    if request.method == "DELETE":
+        logging_service.delete_bucket_logging(bucket_name)
+        current_app.logger.info("Bucket logging deleted", extra={"bucket": bucket_name})
+        return Response(status=204)
+
+    payload = request.get_data(cache=False) or b""
+    if not payload.strip():
+        logging_service.delete_bucket_logging(bucket_name)
+        return Response(status=200)
+
+    try:
+        root = fromstring(payload)
+    except ParseError:
+        return _error_response("MalformedXML", "Unable to parse XML document", 400)
+
+    logging_enabled = _find_element(root, "LoggingEnabled")
+    if logging_enabled is None:
+        logging_service.delete_bucket_logging(bucket_name)
+        return Response(status=200)
+
+    target_bucket = _find_element_text(logging_enabled, "TargetBucket")
+    if not target_bucket:
+        return _error_response("InvalidArgument", "TargetBucket is required", 400)
+
+    if not storage.bucket_exists(target_bucket):
+        return _error_response("InvalidTargetBucketForLogging", "Target bucket does not exist", 400)
+
+    target_prefix = _find_element_text(logging_enabled, "TargetPrefix")
+
+    config = LoggingConfiguration(
+        target_bucket=target_bucket,
+        target_prefix=target_prefix,
+        enabled=True,
+    )
+    logging_service.set_bucket_logging(bucket_name, config)
+
+    current_app.logger.info(
+        "Bucket logging updated",
+        extra={"bucket": bucket_name, "target_bucket": target_bucket, "target_prefix": target_prefix}
+    )
+    return Response(status=200)
+
+
+def _object_retention_handler(bucket_name: str, object_key: str) -> Response:
+    if request.method not in {"GET", "PUT"}:
+        return _method_not_allowed(["GET", "PUT"])
+
+    principal, error = _require_principal()
+    if error:
+        return error
+    try:
+        _authorize_action(principal, bucket_name, "write" if request.method == "PUT" else "read", object_key=object_key)
+    except IamError as exc:
+        return _error_response("AccessDenied", str(exc), 403)
+
+    storage = _storage()
+    if not storage.bucket_exists(bucket_name):
+        return _error_response("NoSuchBucket", "Bucket does not exist", 404)
+
+    try:
+        storage.get_object_path(bucket_name, object_key)
+    except StorageError:
+        return _error_response("NoSuchKey", "Object does not exist", 404)
+
+    lock_service = _object_lock()
+
+    if request.method == "GET":
+        retention = lock_service.get_object_retention(bucket_name, object_key)
+        if not retention:
+            return _error_response("NoSuchObjectLockConfiguration", "No retention policy", 404)
+
+        root = Element("Retention", xmlns="http://s3.amazonaws.com/doc/2006-03-01/")
+        SubElement(root, "Mode").text = retention.mode.value
+        SubElement(root, "RetainUntilDate").text = retention.retain_until_date.strftime("%Y-%m-%dT%H:%M:%S.000Z")
+        return _xml_response(root)
+
+    payload = request.get_data(cache=False) or b""
+    if not payload.strip():
+        return _error_response("MalformedXML", "Request body is required", 400)
+
+    try:
+        root = fromstring(payload)
+    except ParseError:
+        return _error_response("MalformedXML", "Unable to parse XML document", 400)
+
+    mode_str = _find_element_text(root, "Mode")
+    retain_until_str = _find_element_text(root, "RetainUntilDate")
+
+    if not mode_str or not retain_until_str:
+        return _error_response("InvalidArgument", "Mode and RetainUntilDate are required", 400)
+
+    try:
+        mode = RetentionMode(mode_str)
+    except ValueError:
+        return _error_response("InvalidArgument", f"Invalid retention mode: {mode_str}", 400)
+
+    try:
+        retain_until = datetime.fromisoformat(retain_until_str.replace("Z", "+00:00"))
+    except ValueError:
+        return _error_response("InvalidArgument", f"Invalid date format: {retain_until_str}", 400)
+
+    bypass = request.headers.get("x-amz-bypass-governance-retention", "").lower() == "true"
+
+    retention = ObjectLockRetention(mode=mode, retain_until_date=retain_until)
+    try:
+        lock_service.set_object_retention(bucket_name, object_key, retention, bypass_governance=bypass)
+    except ObjectLockError as exc:
+        return _error_response("AccessDenied", str(exc), 403)
+
+    current_app.logger.info(
+        "Object retention set",
+        extra={"bucket": bucket_name, "key": object_key, "mode": mode_str, "until": retain_until_str}
+    )
+    return Response(status=200)
+
+
+def _object_legal_hold_handler(bucket_name: str, object_key: str) -> Response:
+    if request.method not in {"GET", "PUT"}:
+        return _method_not_allowed(["GET", "PUT"])
+
+    principal, error = _require_principal()
+    if error:
+        return error
+    try:
+        _authorize_action(principal, bucket_name, "write" if request.method == "PUT" else "read", object_key=object_key)
+    except IamError as exc:
+        return _error_response("AccessDenied", str(exc), 403)
+
+    storage = _storage()
+    if not storage.bucket_exists(bucket_name):
+        return _error_response("NoSuchBucket", "Bucket does not exist", 404)
+
+    try:
+        storage.get_object_path(bucket_name, object_key)
+    except StorageError:
+        return _error_response("NoSuchKey", "Object does not exist", 404)
+
+    lock_service = _object_lock()
+
+    if request.method == "GET":
+        enabled = lock_service.get_legal_hold(bucket_name, object_key)
+        root = Element("LegalHold", xmlns="http://s3.amazonaws.com/doc/2006-03-01/")
+        SubElement(root, "Status").text = "ON" if enabled else "OFF"
+        return _xml_response(root)
+
+    payload = request.get_data(cache=False) or b""
+    if not payload.strip():
+        return _error_response("MalformedXML", "Request body is required", 400)
+
+    try:
+        root = fromstring(payload)
+    except ParseError:
+        return _error_response("MalformedXML", "Unable to parse XML document", 400)
+
+    status = _find_element_text(root, "Status")
+    if status not in {"ON", "OFF"}:
+        return _error_response("InvalidArgument", "Status must be ON or OFF", 400)
+
+    lock_service.set_legal_hold(bucket_name, object_key, status == "ON")
+
+    current_app.logger.info(
+        "Object legal hold set",
+        extra={"bucket": bucket_name, "key": object_key, "status": status}
+    )
+    return Response(status=200)
+
+
 def _bulk_delete_handler(bucket_name: str) -> Response:
     principal, error = _require_principal()
     if error:
@@ -1871,6 +2220,12 @@ def object_handler(bucket_name: str, object_key: str):
     if "tagging" in request.args:
         return _object_tagging_handler(bucket_name, object_key)
 
+    if "retention" in request.args:
+        return _object_retention_handler(bucket_name, object_key)
+
+    if "legal-hold" in request.args:
+        return _object_legal_hold_handler(bucket_name, object_key)
+
     if request.method == "POST":
         if "uploads" in request.args:
             return _initiate_multipart_upload(bucket_name, object_key)
@@ -1886,22 +2241,28 @@ def object_handler(bucket_name: str, object_key: str):
         if copy_source:
             return _copy_object(bucket_name, object_key, copy_source)
 
-        _, error = _object_principal("write", bucket_name, object_key)
+        principal, error = _object_principal("write", bucket_name, object_key)
         if error:
             return error
-        
+
+        bypass_governance = request.headers.get("x-amz-bypass-governance-retention", "").lower() == "true"
+        lock_service = _object_lock()
+        can_overwrite, lock_reason = lock_service.can_overwrite_object(bucket_name, object_key, bypass_governance=bypass_governance)
+        if not can_overwrite:
+            return _error_response("AccessDenied", lock_reason, 403)
+
         stream = request.stream
         content_encoding = request.headers.get("Content-Encoding", "").lower()
         if "aws-chunked" in content_encoding:
             stream = AwsChunkedDecoder(stream)
 
         metadata = _extract_request_metadata()
-        
+
         content_type = request.headers.get("Content-Type")
         validation_error = _validate_content_type(object_key, content_type)
         if validation_error:
             return _error_response("InvalidArgument", validation_error, 400)
-        
+
         try:
             meta = storage.put_object(
                 bucket_name,
@@ -1922,10 +2283,21 @@ def object_handler(bucket_name: str, object_key: str):
         )
         response = Response(status=200)
         response.headers["ETag"] = f'"{meta.etag}"'
-        
+
+        _notifications().emit_object_created(
+            bucket_name,
+            object_key,
+            size=meta.size,
+            etag=meta.etag,
+            request_id=getattr(g, "request_id", ""),
+            source_ip=request.remote_addr or "",
+            user_identity=principal.access_key if principal else "",
+            operation="Put",
+        )
+
         if "S3ReplicationAgent" not in request.headers.get("User-Agent", ""):
             _replication_manager().trigger_replication(bucket_name, object_key, action="write")
-            
+
         return response
 
     if request.method in {"GET", "HEAD"}:
@@ -2048,13 +2420,30 @@ def object_handler(bucket_name: str, object_key: str):
     _, error = _object_principal("delete", bucket_name, object_key)
     if error:
         return error
+
+    bypass_governance = request.headers.get("x-amz-bypass-governance-retention", "").lower() == "true"
+    lock_service = _object_lock()
+    can_delete, lock_reason = lock_service.can_delete_object(bucket_name, object_key, bypass_governance=bypass_governance)
+    if not can_delete:
+        return _error_response("AccessDenied", lock_reason, 403)
+
     storage.delete_object(bucket_name, object_key)
+    lock_service.delete_object_lock_metadata(bucket_name, object_key)
     current_app.logger.info("Object deleted", extra={"bucket": bucket_name, "key": object_key})
-    
+
+    principal, _ = _require_principal()
+    _notifications().emit_object_removed(
+        bucket_name,
+        object_key,
+        request_id=getattr(g, "request_id", ""),
+        source_ip=request.remote_addr or "",
+        user_identity=principal.access_key if principal else "",
+    )
+
     user_agent = request.headers.get("User-Agent", "")
     if "S3ReplicationAgent" not in user_agent:
         _replication_manager().trigger_replication(bucket_name, object_key, action="delete")
-        
+
     return Response(status=204)
 
 

app/secret_store.py

@@ -1,4 +1,3 @@
-"""Ephemeral store for one-time secrets communicated to the UI."""
 from __future__ import annotations
 
 import secrets

app/storage.py

@@ -1,4 +1,3 @@
-"""Filesystem-backed object storage helpers."""
 from __future__ import annotations
 
 import hashlib

app/ui.py

@@ -1,4 +1,3 @@
-"""Authenticated HTML UI for browsing buckets and objects."""
 from __future__ import annotations
 
 import json

app/version.py

@@ -1,4 +1,3 @@
-"""Central location for the application version string."""
 from __future__ import annotations
 
 APP_VERSION = "0.2.0"