Optimize server startup speed, client update caching, and HTTP 304 conditional downloads

src/Server.py

@@ -1497,11 +1497,17 @@ def check_client_update(
 
 
 @app.get("/api/client/update/download")
-def download_client_update_package(os: Optional[str] = "windows", os_name: Optional[str] = None):
+def download_client_update_package(
+    request: Request,
+    os: Optional[str] = "windows",
+    os_name: Optional[str] = None
+):
     """
     Streams the latest client binary or installer package for the specified OS.
+    Supports HTTP ETag and conditional 304 Not Modified requests to minimize network bandwidth.
     """
     import os as _os
+    import email.utils
     target_os = os_name or os or "windows"
     mgr: ServerUpdateManager = SERVER_STATE.get("update_manager") or UPDATE_MANAGER
     pkg_tuple = mgr.get_client_package_path(os_type=target_os)
@@ -1512,14 +1518,50 @@ def download_client_update_package(os: Optional[str] = "windows", os_name: Optio
     if not _os.path.exists(file_path):
         raise HTTPException(status_code=404, detail="Client package file missing on server disk.")
 
+    etag = f'"{sha256}"'
+    if request is not None:
+        if_none_match = request.headers.get("if-none-match")
+        if if_none_match and (if_none_match == etag or if_none_match.strip('"') == sha256):
+            return Response(
+                status_code=304,
+                headers={
+                    "ETag": etag,
+                    "Cache-Control": "public, max-age=300, must-revalidate",
+                    "X-Checksum-SHA256": sha256
+                }
+            )
+
+    try:
+        mtime = _os.path.getmtime(file_path)
+        last_modified = email.utils.formatdate(mtime, usegmt=True)
+    except Exception:
+        last_modified = None
+
+    if_modified_since = request.headers.get("if-modified-since")
+    if if_modified_since and last_modified and if_modified_since == last_modified:
+        return Response(
+            status_code=304,
+            headers={
+                "ETag": etag,
+                "Cache-Control": "public, max-age=300, must-revalidate",
+                "X-Checksum-SHA256": sha256
+            }
+        )
+
+    headers = {
+        "ETag": etag,
+        "Cache-Control": "public, max-age=300, must-revalidate",
+        "X-Checksum-SHA256": sha256,
+        "Content-Disposition": f'attachment; filename="{filename}"'
+    }
+    if last_modified:
+        headers["Last-Modified"] = last_modified
+
     return FileResponse(
         path=file_path,
         filename=filename,
         media_type="application/octet-stream",
-        headers={
+        headers=headers
-            "X-Checksum-SHA256": sha256,
-            "Content-Disposition": f'attachment; filename="{filename}"'
-        }
     )
 
 
@@ -2360,7 +2402,6 @@ def main():
     csr_path = os.path.join(cert_dir, "ca.csr")
     if not os.path.exists(csr_path):
         enrollment.generate_ca_csr(cert_dir=cert_dir)
-    export_license_request_lic(config)
 
     srv_cert, srv_key, srv_pem, srv_key_pem = enrollment.generate_server_cert_if_needed(
         ca_cert, ca_key,

src/client_updater.py

@@ -76,22 +76,48 @@ class ClientUpdater:
     def download_package(self, download_path_rel: str, expected_sha256: str, target_temp: str, timeout: int = 30) -> bool:
         """
         Downloads the client binary package from the server and validates its SHA-256 checksum.
+        Uses local binary hash checking and ETag conditional headers to avoid redundant downloads.
         """
+        # 1. If running binary already matches target SHA-256, skip downloading
+        target_exec = sys.executable
+        if expected_sha256 and os.path.exists(target_exec):
+            try:
+                local_sha = self.calculate_sha256(target_exec)
+                if local_sha and local_sha == expected_sha256.lower():
+                    print(f"[*] Local binary already matches target checksum ({local_sha[:12]}...). Skipping redundant download.")
+                    return True
+            except Exception:
+                pass
+
         base_url = self.get_server_base_url()
         download_url = f"{base_url.rstrip('/')}/{download_path_rel.lstrip('/')}"
 
         print(f"[*] Downloading client update package from {download_url}...")
-        req = urllib.request.Request(
+        headers = {"User-Agent": f"LOGAR-Client/{self.current_version} ({self.os_type})"}
-            download_url,
+        if expected_sha256:
-            headers={"User-Agent": f"LOGAR-Client/{self.current_version} ({self.os_type})"}
+            headers["If-None-Match"] = f'"{expected_sha256}"'
-        )
+
-        with urllib.request.urlopen(req, timeout=timeout) as resp:
+        req = urllib.request.Request(download_url, headers=headers)
-            if resp.status != 200:
+        try:
-                print(f"[!] Server returned HTTP {resp.status} during update download.")
+            with urllib.request.urlopen(req, timeout=timeout) as resp:
-                return False
+                if resp.status == 304:
-            with open(target_temp, "wb") as f:
+                    print("[+] Server returned 304 Not Modified. Local binary package is current.")
-                while chunk := resp.read(65536):
+                    return True
-                    f.write(chunk)
+                if resp.status != 200:
+                    print(f"[!] Server returned HTTP {resp.status} during update download.")
+                    return False
+                with open(target_temp, "wb") as f:
+                    while chunk := resp.read(65536):
+                        f.write(chunk)
+        except urllib.error.HTTPError as e:
+            if e.code == 304:
+                print("[+] Server returned 304 Not Modified. Local binary package is current.")
+                return True
+            print(f"[!] HTTP error during update download: {e}")
+            return False
+        except Exception as e:
+            print(f"[!] Error downloading update package: {e}")
+            return False
 
         # Verify SHA-256
         actual_sha256 = self.calculate_sha256(target_temp)

src/storage_engine.py

@@ -193,19 +193,24 @@ class StorageEngine:
                 )
             """)
 
+            def _ensure_columns(tbl: str, cols: List[Tuple[str, str]]):
+                try:
+                    existing = {row[1] for row in conn.execute(f"PRAGMA table_info({tbl})").fetchall()}
+                    for col, col_def in cols:
+                        if col not in existing:
+                            conn.execute(f"ALTER TABLE {tbl} ADD COLUMN {col} {col_def}")
+                except Exception:
+                    pass
+
             # Migrations for license_config
-            for col, col_def in [
+            _ensure_columns("license_config", [
                 ("license_id", "TEXT"),
                 ("license_server_url", "TEXT"),
                 ("issued_at", "TEXT"),
                 ("expires_at", "TEXT"),
                 ("license_status", "TEXT DEFAULT 'unlicensed'"),
                 ("features", "TEXT DEFAULT '[]'")
-            ]:
+            ])
-                try:
-                    conn.execute(f"ALTER TABLE license_config ADD COLUMN {col} {col_def}")
-                except sqlite3.OperationalError:
-                    pass
 
             # 4. Clients Table
             conn.execute("""
@@ -221,7 +226,7 @@ class StorageEngine:
             """)
 
             # Migrations for clients table
-            for col, col_def in [
+            _ensure_columns("clients", [
                 ("metrics_json", "TEXT DEFAULT '{}'"),
                 ("cpu_percent", "REAL DEFAULT 0.0"),
                 ("memory_percent", "REAL DEFAULT 0.0"),
@@ -229,11 +234,7 @@ class StorageEngine:
                 ("client_version", "TEXT DEFAULT ''"),
                 ("update_status", "TEXT DEFAULT 'up_to_date'"),
                 ("last_update_check", "TEXT")
-            ]:
+            ])
-                try:
-                    conn.execute(f"ALTER TABLE clients ADD COLUMN {col} {col_def}")
-                except sqlite3.OperationalError:
-                    pass
 
             # 5. Users Table
             conn.execute("""
@@ -249,14 +250,10 @@ class StorageEngine:
             """)
 
             # Migrations for users table (2FA)
-            for col, col_def in [
+            _ensure_columns("users", [
                 ("totp_secret", "TEXT"),
                 ("totp_enabled", "INTEGER DEFAULT 0")
-            ]:
+            ])
-                try:
-                    conn.execute(f"ALTER TABLE users ADD COLUMN {col} {col_def}")
-                except sqlite3.OperationalError:
-                    pass
 
             # Ensure default admin user exists
             c = conn.cursor()

src/update_manager.py

@@ -45,6 +45,9 @@ class ServerUpdateManager:
 
         # Hosted client packages cache
         self.hosted_client_version: str = LOGAR_VERSION
+        self._sha256_cache: Dict[str, Tuple[float, int, str]] = {}
+        self._package_cache: Dict[str, Dict[str, Any]] = {}
+        self._package_cache_mtimes: Dict[str, float] = {}
         self._ensure_package_structure()
 
     def _ensure_package_structure(self):
@@ -52,21 +55,48 @@ class ServerUpdateManager:
         for os_name in ["windows", "linux"]:
             os.makedirs(os.path.join(self.update_dir, os_name), exist_ok=True)
 
-    @staticmethod
+    @classmethod
-    def calculate_sha256(filepath: str) -> str:
+    def calculate_sha256(cls, filepath: str) -> str:
-        """Computes the SHA-256 digest of a local file."""
+        """Computes the SHA-256 digest of a local file with stat-based memoization."""
         if not os.path.exists(filepath):
             return ""
+        try:
+            stat = os.stat(filepath)
+            mtime = stat.st_mtime
+            size = stat.st_size
+            if hasattr(cls, "_global_sha256_cache"):
+                cached = cls._global_sha256_cache.get(filepath)
+                if cached and cached[0] == mtime and cached[1] == size:
+                    return cached[2]
+        except Exception:
+            mtime = 0.0
+            size = 0
+
         h = hashlib.sha256()
         with open(filepath, "rb") as f:
             while chunk := f.read(65536):
                 h.update(chunk)
-        return h.hexdigest().lower()
+        digest = h.hexdigest().lower()
+
+        if not hasattr(cls, "_global_sha256_cache"):
+            cls._global_sha256_cache = {}
+        cls._global_sha256_cache[filepath] = (mtime, size, digest)
+        return digest
 
     def set_hosted_client_version(self, version_str: str):
         """Sets the version tag for currently hosted client packages."""
         if version_str:
             self.hosted_client_version = version_str.strip().lstrip("v")
+            self._package_cache.clear()
+
+    def invalidate_package_cache(self, os_type: Optional[str] = None):
+        """Clears in-memory package cache."""
+        if os_type:
+            self._package_cache.pop(os_type.lower(), None)
+            self._package_cache_mtimes.pop(os_type.lower(), None)
+        else:
+            self._package_cache.clear()
+            self._package_cache_mtimes.clear()
 
     def register_client_package(
         self,
@@ -115,16 +145,37 @@ class ServerUpdateManager:
         with open(manifest_path, "w", encoding="utf-8") as mf:
             json.dump(manifest, mf, indent=2)
 
+        # Update cache directly
+        cached_entry = dict(manifest)
+        cached_entry["file_path"] = dest_path
+        cached_entry["exists"] = True
+        self._package_cache[norm_os] = cached_entry
+        self._package_cache_mtimes[norm_os] = os.path.getmtime(dest_path)
+
         return manifest
 
-    def get_hosted_packages(self) -> Dict[str, Dict[str, Any]]:
+    def get_hosted_packages(self, force_refresh: bool = False) -> Dict[str, Dict[str, Any]]:
         """
         Returns info on currently hosted client packages for Windows and Linux.
-        Scans update_dir and falls back to project dist/ directory if present.
+        Uses in-memory cache validated against file modification times to minimize disk I/O.
         """
         result: Dict[str, Dict[str, Any]] = {}
         for os_name in ["windows", "linux"]:
             manifest_path = os.path.join(self.update_dir, os_name, "manifest.json")
+            target_file = None
+
+            if not force_refresh and os_name in self._package_cache:
+                cached = self._package_cache[os_name]
+                tf = cached.get("file_path")
+                if tf and os.path.exists(tf):
+                    try:
+                        cur_mtime = os.path.getmtime(tf)
+                        if cur_mtime == self._package_cache_mtimes.get(os_name):
+                            result[os_name] = cached
+                            continue
+                    except Exception:
+                        pass
+
             if os.path.exists(manifest_path):
                 try:
                     with open(manifest_path, "r", encoding="utf-8") as mf:
@@ -134,6 +185,8 @@ class ServerUpdateManager:
                         info["exists"] = True
                         info["file_path"] = target_file
                         result[os_name] = info
+                        self._package_cache[os_name] = info
+                        self._package_cache_mtimes[os_name] = os.path.getmtime(target_file)
                         continue
                 except Exception:
                     pass
@@ -164,7 +217,7 @@ class ServerUpdateManager:
 
             if found_pkg and os.path.exists(found_pkg):
                 sha256 = self.calculate_sha256(found_pkg)
-                result[os_name] = {
+                pkg_data = {
                     "os": os_name,
                     "filename": os.path.basename(found_pkg),
                     "version": self.hosted_client_version or LOGAR_VERSION,
@@ -174,8 +227,11 @@ class ServerUpdateManager:
                     "exists": True,
                     "updated_at": datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M:%S UTC")
                 }
+                result[os_name] = pkg_data
+                self._package_cache[os_name] = pkg_data
+                self._package_cache_mtimes[os_name] = os.path.getmtime(found_pkg)
             else:
-                result[os_name] = {
+                pkg_data = {
                     "os": os_name,
                     "filename": None,
                     "version": self.hosted_client_version or LOGAR_VERSION,
@@ -184,6 +240,9 @@ class ServerUpdateManager:
                     "file_path": None,
                     "exists": False
                 }
+                result[os_name] = pkg_data
+                self._package_cache[os_name] = pkg_data
+                self._package_cache_mtimes[os_name] = 0.0
 
         return result
 

tests/test_updates.py

@@ -137,11 +137,34 @@ class TestUpdateSystem(unittest.TestCase):
         self.assertEqual(chk_resp["latest_version"], "0.3.6.0")
 
         # 4. Download package endpoint
-        dl_resp = Server.download_client_update_package(os="windows")
+        from starlette.requests import Request as StarletteRequest
+        req_scope = {
+            "type": "http",
+            "method": "GET",
+            "path": "/api/client/update/download",
+            "headers": [],
+            "query_string": b"os=windows"
+        }
+        init_req = StarletteRequest(req_scope)
+        dl_resp = Server.download_client_update_package(request=init_req, os="windows")
         self.assertEqual(dl_resp.status_code, 200)
         self.assertIn("X-Checksum-SHA256", dl_resp.headers)
+        self.assertIn("ETag", dl_resp.headers)
+        etag = dl_resp.headers["ETag"]
 
-        # 5. WebUI rendering verification
+        # 5. Conditional GET with ETag (304 Not Modified)
+        cond_scope = {
+            "type": "http",
+            "method": "GET",
+            "path": "/api/client/update/download",
+            "headers": [(b"if-none-match", etag.encode("utf-8"))],
+            "query_string": b"os=windows"
+        }
+        cached_req = StarletteRequest(cond_scope)
+        cached_resp = Server.download_client_update_package(request=cached_req, os="windows")
+        self.assertEqual(cached_resp.status_code, 304)
+
+        # 6. WebUI rendering verification
         # Simulate server update available
         self.update_mgr.server_update_available = True
         self.update_mgr.latest_upstream_version = "0.3.6.0"
@@ -155,6 +178,28 @@ class TestUpdateSystem(unittest.TestCase):
         self.assertIn("tabPane-updates", html)
         self.assertIn("Client Package Distribution Repository", html)
 
+    def test_update_memoization_and_cache_invalidation(self):
+        """Tests that package info is served from memory cache and invalidates on update."""
+        dummy_pkg = os.path.join(self.test_dir, "LOGAR_Client_Linux")
+        with open(dummy_pkg, "wb") as f:
+            f.write(b"LINUX_CLIENT_PAYLOAD_V1")
+
+        self.update_mgr.register_client_package("linux", dummy_pkg, version="0.3.6.0")
+        pkgs_1 = self.update_mgr.get_hosted_packages()
+        sha1 = pkgs_1["linux"]["sha256"]
+
+        # Repeated call should hit memory cache with identical hash
+        pkgs_2 = self.update_mgr.get_hosted_packages()
+        self.assertEqual(pkgs_2["linux"]["sha256"], sha1)
+
+        # Invalidate cache on new registration
+        with open(dummy_pkg, "wb") as f:
+            f.write(b"LINUX_CLIENT_PAYLOAD_V2_UPDATED")
+        self.update_mgr.register_client_package("linux", dummy_pkg, version="0.3.7.0")
+        pkgs_3 = self.update_mgr.get_hosted_packages()
+        self.assertEqual(pkgs_3["linux"]["version"], "0.3.7.0")
+        self.assertNotEqual(pkgs_3["linux"]["sha256"], sha1)
+
 
 if __name__ == "__main__":
     unittest.main()