improvement: cache Daytona client and improve error handling

_client.py

@@ -1,13 +1,27 @@
+import hashlib
+import logging
 from typing import Any
 
-from daytona import Daytona, DaytonaConfig, DaytonaNotFoundError, Sandbox
+from daytona import Daytona, DaytonaConfig, DaytonaError, DaytonaNotFoundError, Sandbox
+
+logger = logging.getLogger(__name__)
+
+_client_cache: dict[str, Daytona] = {}
+
+
+def _cache_key(credentials: dict[str, Any]) -> str:
+    raw = f"{credentials.get('api_key', '')}:{credentials.get('api_url', '')}"
+    return hashlib.sha256(raw.encode()).hexdigest()
 
 
 def build_client(credentials: dict[str, Any]) -> Daytona:
-    config = DaytonaConfig(api_key=credentials["api_key"])
-    if api_url := credentials.get("api_url"):
-        config.api_url = api_url
-    return Daytona(config)
+    key = _cache_key(credentials)
+    if key not in _client_cache:
+        config = DaytonaConfig(api_key=credentials["api_key"])
+        if api_url := credentials.get("api_url"):
+            config.api_url = api_url
+        _client_cache[key] = Daytona(config)
+    return _client_cache[key]
 
 
 def get_sandbox(client: Daytona, sandbox_id: str) -> Sandbox:
@@ -17,6 +31,8 @@ def get_sandbox(client: Daytona, sandbox_id: str) -> Sandbox:
         sandbox = client.get(sandbox_id)
     except DaytonaNotFoundError as e:
         raise ValueError(f"Sandbox '{sandbox_id}' not found") from e
+    except DaytonaError as e:
+        raise ValueError(f"Failed to retrieve sandbox '{sandbox_id}': {e}") from e
     if sandbox is None:
         raise ValueError(f"Sandbox '{sandbox_id}' not found")
     return sandbox