community[patch]: Basic Logging and Human input to ShellTool (#15932)

- **Description:** As Shell tool is very versatile, while integrating it
into applications as openai functions, developers have no clue about
what command is being executed using the ShellTool. All one can see is:

![image](https://github.com/langchain-ai/langchain/assets/60742358/540e274a-debc-4564-9027-046b91424df3)

Summarising my feature request:
1. There's no visibility about what command was executed.
2. There's no mechanism to prevent a command to be executed using
ShellTool, like a y/n human input which can be accepted from user to
proceed with executing the command.,
  - **Issue:** the issue #15931 it fixes if applicable,
  - **Dependencies:** There isn't any dependancy,
  - **Twitter handle:** @krishnashed

libs/community/langchain_community/tools/shell/tool.py

@@ -1,3 +1,4 @@
+import logging
 import platform
 import warnings
 from typing import Any, List, Optional, Type, Union
@@ -8,6 +9,8 @@ from langchain_core.callbacks import (
 from langchain_core.pydantic_v1 import BaseModel, Field, root_validator
 from langchain_core.tools import BaseTool
 
+logger = logging.getLogger(__name__)
+
 
 class ShellInput(BaseModel):
     """Commands for the Bash Shell tool."""
@@ -68,10 +71,32 @@ class ShellTool(BaseTool):
     args_schema: Type[BaseModel] = ShellInput
     """Schema for input arguments."""
 
+    ask_human_input: bool = False
+    """
+    If True, prompts the user for confirmation (y/n) before executing 
+    a command generated by the language model in the bash shell.
+    """
+
     def _run(
         self,
         commands: Union[str, List[str]],
         run_manager: Optional[CallbackManagerForToolRun] = None,
     ) -> str:
         """Run commands and return final output."""
+
+        print(f"Executing command:\n {commands}")
+
+        try:
+            if self.ask_human_input:
+                user_input = input("Proceed with command execution? (y/n): ").lower()
+                if user_input == "y":
                     return self.process.run(commands)
+                else:
+                    logger.info("Invalid input. User aborted command execution.")
+                    return None
+            else:
+                return self.process.run(commands)
+
+        except Exception as e:
+            logger.error(f"Error during command execution: {e}")
+            return None

libs/community/tests/unit_tests/tools/shell/test_shell.py

@@ -1,5 +1,6 @@
 import warnings
 from typing import List
+from unittest.mock import patch
 
 from langchain_community.tools.shell.tool import ShellInput, ShellTool
 
@@ -65,3 +66,29 @@ def test_shell_tool_run_str() -> None:
     shell_tool = ShellTool(process=placeholder)
     result = shell_tool._run(commands="echo 'Hello, World!'")
     assert result.strip() == "hello"
+
+
+async def test_shell_tool_arun_with_user_confirmation() -> None:
+    placeholder = PlaceholderProcess(output="hello")
+    shell_tool = ShellTool(process=placeholder, ask_human_input=True)
+
+    with patch("builtins.input", return_value="y"):
+        result = await shell_tool._arun(commands=test_commands)
+        assert result.strip() == "hello"
+
+    with patch("builtins.input", return_value="n"):
+        result = await shell_tool._arun(commands=test_commands)
+        assert result is None
+
+
+def test_shell_tool_run_with_user_confirmation() -> None:
+    placeholder = PlaceholderProcess(output="hello")
+    shell_tool = ShellTool(process=placeholder, ask_human_input=True)
+
+    with patch("builtins.input", return_value="y"):
+        result = shell_tool._run(commands="echo 'Hello, World!'")
+        assert result.strip() == "hello"
+
+    with patch("builtins.input", return_value="n"):
+        result = shell_tool._run(commands="echo 'Hello, World!'")
+        assert result is None