Source code for atloop.tools.filesystem.read_file
"""Read file tool with enhanced capabilities."""
import shlex
from typing import Any, Dict, Optional
from atloop.runtime.sandbox_adapter import SandboxAdapter
from atloop.tools.base import BaseTool, ToolResult
[docs]
class ReadFileTool(BaseTool):
"""
Tool for reading files from the sandbox workspace with type detection and chunked reading.
**Features:**
- Automatic file type detection (text/binary)
- Support for large files via line range reading
- Binary file detection and handling
- File size limits (10MB max for full read)
**Use cases:**
- Reading source code files
- Reading configuration files
- Reading documentation files
- Reading log files (with line ranges)
**Note**: This tool reads from the sandbox workspace (/workspace), not from the local machine.
For reading skill files (stored locally), use `read_skill_file` instead.
"""
[docs]
def __init__(self, sandbox: SandboxAdapter):
"""
Initialize read file tool.
Args:
sandbox: Sandbox adapter instance
"""
self.sandbox = sandbox
@property
def name(self) -> str:
"""Tool name."""
return "read_file"
@property
def description(self) -> str:
"""Tool description."""
return "读取文件内容（增强的文件读取工具，支持类型检测和大文件分块）"
[docs]
def validate_args(self, args: Dict[str, Any]) -> tuple[bool, Optional[str]]:
"""Validate arguments."""
if "path" not in args:
return False, "Missing required argument: 'path'"
if not isinstance(args["path"], str):
return False, "Argument 'path' must be a string"
if "offset" in args and not isinstance(args.get("offset"), int):
return False, "Argument 'offset' must be an integer"
if "limit" in args and not isinstance(args.get("limit"), int):
return False, "Argument 'limit' must be an integer"
return True, None
[docs]
def execute(self, args: Dict[str, Any]) -> ToolResult:
"""
Execute read file tool.
**Args:**
args: Tool arguments dictionary
- path (str, required): File path. Relative paths are relative to /workspace.
Absolute paths are used as-is.
- offset (int, optional): Start line number (1-indexed). Default: 1 (start of file).
Use this for reading large files in chunks.
- limit (int, optional): Number of lines to read. If not specified, reads from
offset to end of file. Use this for reading large files in chunks.
**Returns:**
ToolResult with:
- ok (bool): True if file was read successfully (no errors in stderr)
- stdout (str): File content (or metadata for binary/large files)
- stderr (str): Error messages if any (empty string means success)
- meta (dict): Contains path, file_type, file_size, start_line, end_line
**Examples:**
# Read entire file
read_file(path="src/main.py")
# Read first 100 lines
read_file(path="src/main.py", offset=1, limit=100)
# Read lines 50-100
read_file(path="src/main.py", offset=50, limit=51)
# Read from line 200 to end
read_file(path="src/main.py", offset=200)
**Behavior:**
- **Text files**: Returns file content in stdout
- **Binary files**: Returns metadata message (file type, size) instead of content
- **Large files (>10MB)**: Returns metadata message, suggests using line ranges
- **File not found**: Returns ok=False with error message in stderr
- **Line ranges**: If offset/limit specified, only reads those lines
**Path Handling:**
- All commands run with workdir="/workspace"
- Relative paths are resolved relative to /workspace
- Absolute paths are used as-is
**Error Handling:**
- Success is determined by stderr content, not exit code
- If stderr is empty, the operation succeeded
- Check stderr for specific error messages if ok=False
"""
path = args["path"]
offset = args.get("offset")
limit = args.get("limit")
# Handle paths - sandbox runs in /workspace directory
# Relative paths are already relative to /workspace (consistent with other tools)
# Use relative path directly since workdir is /workspace
path_escaped = shlex.quote(path)
# Check if file exists (relative to /workspace)
check_cmd = f"test -f {path_escaped} && echo 'exists' || echo 'not_found'"
check_result = self._run_command(check_cmd, timeout_sec=5)
if "not_found" in check_result["stdout"]:
return ToolResult(
ok=False,
stdout="",
stderr=f"File not found: {path}",
meta={"path": path, "file_type": "not_found"},
)
# Detect file type
detect_cmd = f"file -b {path_escaped} 2>/dev/null || echo 'unknown'"
file_type_result = self._run_command(detect_cmd, timeout_sec=5)
file_type_info = (
file_type_result["stdout"].strip()
if not file_type_result.get("stderr", "").strip()
else "unknown"
)
# Check file size
size_cmd = f"wc -c < {path_escaped} 2>/dev/null || echo '0'"
size_result = self._run_command(size_cmd, timeout_sec=5)
try:
file_size = int(size_result["stdout"].strip())
except (ValueError, AttributeError):
file_size = 0
# Check if binary
is_binary = False
if file_size > 0:
check_binary_cmd = f"head -c 512 {path_escaped} 2>/dev/null | od -An -tx1 | grep -q ' 00 ' && echo 'binary' || echo 'text'"
binary_check = self._run_command(check_binary_cmd, timeout_sec=5)
if not binary_check.get("stderr", "").strip():
is_binary = "binary" in binary_check["stdout"]
else:
is_binary = (
"text" not in file_type_info.lower() and "ascii" not in file_type_info.lower()
)
# If binary or too large, return metadata only
max_file_size = 10 * 1024 * 1024 # 10MB
is_text_file = (
"text" in file_type_info.lower()
or "ascii" in file_type_info.lower()
or "python" in file_type_info.lower()
or "script" in file_type_info.lower()
)
if (is_binary and not is_text_file) or file_size > max_file_size:
return ToolResult(
ok=True,
stdout=f"[File: {path}]\nType: {file_type_info}\nSize: {file_size} bytes\n\nThis file is binary or too large to display. Use specific line ranges if needed.",
stderr="",
meta={
"path": path,
"file_type": "binary" if is_binary else "large",
"file_size": file_size,
"file_type_info": file_type_info,
},
)
# Determine line range
start_line = offset if offset is not None else 1
if limit is not None:
end_line = start_line + limit - 1 if start_line > 0 else limit
else:
end_line = None
# Read file content
if end_line is None:
# Read from start_line to end of file
if start_line == 1:
cmd = f"cat {path_escaped} 2>/dev/null"
else:
# Use sed to read from start_line to end
cmd = f"sed -n '{start_line},$p' {path_escaped} 2>/dev/null"
else:
cmd = f"sed -n '{start_line},{end_line}p' {path_escaped} 2>/dev/null || head -n {end_line} {path_escaped} | tail -n +{start_line}"
result = self._run_command(cmd, timeout_sec=30)
# Determine success based on stderr content, not exit code
stderr = result.get("stderr", "")
ok = not bool(stderr.strip()) # Success if no error messages in stderr
return ToolResult(
ok=ok,
stdout=result.get("stdout", ""),
stderr=stderr,
meta={
"path": path,
"file_type": "text",
"file_size": file_size,
"file_type_info": file_type_info,
"start_line": start_line,
"end_line": end_line,
},
)
def _run_command(self, cmd: str, timeout_sec: int = 600) -> Dict[str, Any]:
"""Run a shell command in sandbox."""
return self.sandbox.exec_shell(
command=cmd,
workdir="/workspace",
timeout_seconds=timeout_sec,
)