fix sandbox backend hardening and stabilize remote backend tests

Agent-Logs-Url: https://github.com/MervinPraison/PraisonAI/sessions/4bc8984f-6a71-42f9-b345-acfff0df8234

Co-authored-by: MervinPraison <454862+MervinPraison@users.noreply.github.com>

Author: Copilot

src/praisonai/praisonai/sandbox/modal.py

@@ -18,6 +18,7 @@
 )
 
 logger = logging.getLogger(__name__)
+TIMEOUT_EXIT_CODE = 124
 
 
 class ModalSandbox:
@@ -85,6 +86,7 @@ async def start(self) -> None:
 
         try:
             import modal
+            execution_timeout = self.timeout
 
             # Create Modal app
             self._app = modal.App(self.app_name)
@@ -117,10 +119,12 @@ async def start(self) -> None:
             )
             def execute_code(code: str, language: str = "python", env_vars: Dict[str, str] = None):
                 """Execute code in Modal environment."""
+                import logging
                 import subprocess
                 import tempfile
                 import os
                 import sys
+                execute_logger = logging.getLogger(__name__)
 
                 extension_map = {
                     "python": "py",
@@ -161,7 +165,7 @@ def execute_code(code: str, language: str = "python", env_vars: Dict[str, str] =
                         cmd,
                         capture_output=True,
                         text=True,
-                        timeout=self.timeout,
+                        timeout=execution_timeout,
                         env=execution_env,
                     )
 
@@ -172,7 +176,7 @@ def execute_code(code: str, language: str = "python", env_vars: Dict[str, str] =
                     }
                 except subprocess.TimeoutExpired:
                     return {
-                        "exit_code": 124,  # Timeout exit code
+                        "exit_code": TIMEOUT_EXIT_CODE,
                         "stdout": "",
                         "stderr": "Execution timed out",
                     }
@@ -186,8 +190,10 @@ def execute_code(code: str, language: str = "python", env_vars: Dict[str, str] =
                     # Clean up temp file
                     try:
                         os.unlink(temp_file)
-                    except OSError:
-                        pass
+                    except OSError as e:
+                        execute_logger.debug(
+                            f"Failed to remove temporary file {temp_file}: {e}"
+                        )
 
             self._function = execute_code
             self._is_running = True

src/praisonai/praisonai/sandbox/ssh.py

@@ -447,14 +447,23 @@ def _build_command(
         env: Optional[Dict[str, str]]
     ) -> str:
         """Build execution command for language."""
+        java_command = None
+        if language.lower() == "java":
+            java_class_name = os.path.splitext(os.path.basename(file_path))[0]
+            if not re.match(r"^[A-Za-z_][A-Za-z0-9_]*$", java_class_name):
+                raise ValueError(f"Invalid Java class name derived from file path: {java_class_name}")
+            java_command = f"javac {shlex.quote(file_path)} && java {shlex.quote(java_class_name)}"
+
         interpreters = {
             "python": f"python3 {shlex.quote(file_path)}",
             "bash": f"bash {shlex.quote(file_path)}",
             "shell": f"bash {shlex.quote(file_path)}",
             "javascript": f"node {shlex.quote(file_path)}",
             "typescript": f"npx ts-node {shlex.quote(file_path)}",
-            "java": f"javac {shlex.quote(file_path)} && java {shlex.quote(os.path.splitext(os.path.basename(file_path))[0])}",
         }
+
+        if java_command:
+            interpreters["java"] = java_command
 
         base_command = interpreters.get(language.lower(), f"cat {shlex.quote(file_path)}")