ai-agent-book 精选快照（<2MB 代码与文档，来自 github.com/bojieli/ai-agent-book）

chapter5/coding-agent/tools/bash_output_tool.py

@@ -0,0 +1,64 @@
+"""
+BashOutput tool - Retrieve output from background bash jobs
+"""
+
+import os
+import re
+from typing import Dict, Any
+from .base import BaseTool
+from .shell_session import get_background_log_path
+
+
+class BashOutputTool(BaseTool):
+    """Retrieves output from running or completed background bash shells"""
+    
+    @property
+    def name(self) -> str:
+        return "BashOutput"
+    
+    def _execute_impl(self, params: Dict[str, Any]) -> Dict[str, Any]:
+        """
+        Get output from background bash job
+        
+        - Retrieves output from a running or completed background bash shell
+        - Takes a bash_id parameter identifying the shell
+        - Always returns only new output since the last check
+        - Supports optional regex filtering
+        """
+        bash_id = params["bash_id"]
+        filter_pattern = params.get("filter")
+        
+        log_file = get_background_log_path(bash_id)
+        
+        if not os.path.exists(log_file):
+            return {"error": f"Bash job not found (no output log) for bash_id: {bash_id}"}
+        
+        try:
+            # Return only what has been appended since the last check, as the
+            # tool description promises. The offset is per bash_id and lives in
+            # SystemState so it survives across calls.
+            previous_offset = self.state.bash_output_offsets.get(bash_id, 0)
+            if os.path.getsize(log_file) < previous_offset:
+                # Log was truncated or rotated — start over rather than
+                # seeking past the end and returning nothing forever.
+                previous_offset = 0
+
+            with open(log_file, 'r', encoding='utf-8', errors='replace') as f:
+                f.seek(previous_offset)
+                output = f.read()
+                self.state.bash_output_offsets[bash_id] = f.tell()
+
+            if filter_pattern:
+                # Filter lines matching pattern
+                lines = output.split('\n')
+                filtered_lines = [line for line in lines if re.search(filter_pattern, line)]
+                output = '\n'.join(filtered_lines)
+            
+            return {
+                "bash_id": bash_id,
+                "output": output,
+                "output_size": len(output)
+            }
+            
+        except Exception as e:
+            return {"error": f"Error reading bash output: {str(e)}"}