feat: add sandbox and local impl

backend/src/sandbox/sandbox_provider.py

@@ -0,0 +1,53 @@
+from abc import ABC, abstractmethod
+
+from src.config import get_app_config
+from src.reflection import resolve_class
+from src.sandbox.sandbox import Sandbox
+
+
+class SandboxProvider(ABC):
+    """Abstract base class for sandbox providers"""
+
+    @abstractmethod
+    def acquire(self) -> str:
+        """Acquire a sandbox environment.
+
+        Returns:
+            The ID of the acquired sandbox environment.
+        """
+        pass
+
+    @abstractmethod
+    def get(self, sandbox_id: str) -> Sandbox:
+        """Get a sandbox environment by ID.
+
+        Args:
+            sandbox_id: The ID of the sandbox environment to retain.
+        """
+        pass
+
+    @abstractmethod
+    def release(self, sandbox_id: str) -> None:
+        """Release a sandbox environment.
+
+        Args:
+            sandbox_id: The ID of the sandbox environment to destroy.
+        """
+        pass
+
+
+_default_sandbox_provider: SandboxProvider | None = None
+
+
+def get_sandbox_provider() -> SandboxProvider:
+    """Get the sandbox provider.
+
+    Returns:
+        A sandbox provider.
+    """
+    global _default_sandbox_provider
+    if _default_sandbox_provider is None:
+        config = get_app_config()
+        cls = resolve_class(config.sandbox.use, SandboxProvider)
+        _default_sandbox_provider = cls()
+    return _default_sandbox_provider