rengine/tools/runner/executor.py

"""Generic CLI tool executor wrapped by tool-specific clients (dnsx, nuclei, etc.)."""

import contextlib
import json
import os
import shutil
import subprocess
import tempfile
import threading
import time
from collections.abc import Callable, Iterator
from pathlib import Path

from shared.definitions.constants import MAX_COMMAND_OUTPUT
from shared.logging import get_logger
from shared.services.scan_resolve import redact_command
from tools.runner.models import (
    CommandRecorder,
    OutputFormat,
    StreamOutcome,
    ToolResult,
)

logger = get_logger(__name__)

# go binaries, ahead of same-named venv console scripts on PATH
_TOOL_BIN = os.environ.get("RENGINE_TOOL_BIN", "/root/go/bin")

# how often a streaming run checks whether the caller has cancelled
_STOP_POLL_SECONDS = 2.0


class ToolNotFoundError(Exception):
    """Raised when a CLI tool binary is not found in PATH."""


class ToolExecutionError(Exception):
    """Raised when tool execution fails unexpectedly."""


# a tool that bails on a bad flag may say so on stdout; only a short one is a complaint
_MAX_STDOUT_AS_ERROR = 2000


def _failure_excerpt(stderr: str | None, stdout: str | None) -> str:
    text = (stderr or "").strip()
    if text:
        return text[:500]
    out = (stdout or "").strip()
    return out[:500] if 0 < len(out) <= _MAX_STDOUT_AS_ERROR else ""


class CLIToolRunner:
    """Generic CLI tool executor managing the full run lifecycle (validate, run, parse, cleanup)."""

    def __init__(
        self,
        binary: str,
        default_timeout: int = 300,
        recorder: CommandRecorder | None = None,
        tool: str | None = None,
        extra_args: list[str] | None = None,
    ) -> None:
        self.binary = binary
        self.default_timeout = default_timeout
        self._recorder = recorder
        self._tool = tool
        self._extra_args = extra_args or []
        self._binary_path: str | None = None
        self._verify_binary()

    def _verify_binary(self) -> None:
        """Check that the binary exists in PATH."""
        lookup = f"{_TOOL_BIN}{os.pathsep}{os.environ.get('PATH', '')}"
        path = shutil.which(self.binary, path=lookup)
        if not path:
            msg = (
                f"Binary '{self.binary}' not found in PATH. "
                f"Ensure it is installed in the worker container."
            )
            raise ToolNotFoundError(msg)
        self._binary_path = path
        logger.debug(f"Found {self.binary} at {path}")

    def run(  # noqa: PLR0915
        self,
        args: list[str] | None = None,
        input_data: str | list[str] | None = None,
        input_flag: str = "-l",
        use_stdin: bool = False,
        use_output_file: bool = True,
        output_flag: str = "-o",
        output_format: OutputFormat = OutputFormat.PLAIN,
        json_flag: str = "-json",
        timeout: int | None = None,
        env: dict[str, str] | None = None,
        silent: bool = True,
        silent_flag: str = "-silent",
        recorder: CommandRecorder | None = None,
        tool: str | None = None,
        extra_args: list[str] | None = None,
    ) -> ToolResult:
        """Execute the CLI tool and return parsed results."""
        timeout = timeout or self.default_timeout
        args = list(args) if args else []
        recorder = recorder if recorder is not None else self._recorder
        tool = tool if tool is not None else self._tool
        args.extend(extra_args if extra_args is not None else self._extra_args)

        input_file: Path | None = None
        output_file: Path | None = None
        stdin_data: str | None = None
        start_time = time.monotonic()
        cmd_str = self.binary
        handle = None
        finished = False

        def _finish(return_code: int, output: str, error: str | None) -> None:
            nonlocal finished
            if recorder is None or handle is None or finished:
                return
            finished = True
            try:
                recorder.finish(
                    handle,
                    return_code=return_code,
                    output=output,
                    error=error,
                    duration_seconds=round(time.monotonic() - start_time, 3),
                )
            except Exception:
                logger.warning("command recorder.finish failed", exc_info=True)

        try:
            if input_data is not None:
                raw_input = self._normalize_input(input_data)
                if use_stdin:
                    stdin_data = raw_input
                else:
                    input_file = self._write_temp_file(raw_input, prefix="input_")
                    args.extend([input_flag, str(input_file)])

            if use_output_file:
                output_file = self._create_temp_path(prefix="output_")
                args.extend([output_flag, str(output_file)])

            if output_format == OutputFormat.JSONL and json_flag not in args:
                args.append(json_flag)

            if silent and silent_flag not in args:
                args.append(silent_flag)

            cmd = [self._binary_path, *args]
            cmd_str = " ".join(cmd)
            logger.info("Executing: %s", redact_command(cmd_str))

            if recorder is not None:
                handle = recorder.start(tool or self.binary, cmd_str)

            process_result = subprocess.run(  # noqa: S603
                cmd,
                input=stdin_data,
                capture_output=True,
                text=True,
                # a tool reporting bytes it read off the wire is not always utf-8,
                # and one bad byte must not discard the whole run
                errors="replace",
                timeout=timeout,
                check=False,
                env=self._build_env(env),
                cwd=tempfile.gettempdir(),
            )

            duration = time.monotonic() - start_time

            raw_output = self._read_output(
                output_file=output_file,
                stdout=process_result.stdout,
                use_output_file=use_output_file,
            )

            output_lines: list[str] = []
            json_records: list[dict] = []

            if output_format == OutputFormat.JSONL:
                json_records = self._parse_jsonl(raw_output)
            else:
                output_lines = self._parse_lines(raw_output)

            success = process_result.returncode == 0
            error = None
            if not success:
                excerpt = _failure_excerpt(process_result.stderr, process_result.stdout)
                error = (
                    f"{self.binary} exited with code {process_result.returncode}"
                    + (f": {excerpt}" if excerpt else "")
                )
                logger.warning(error)

            _finish(
                process_result.returncode,
                (process_result.stdout or "")[:MAX_COMMAND_OUTPUT]
                + (process_result.stderr or "")[:MAX_COMMAND_OUTPUT],
                error,
            )

            return ToolResult(
                success=success,
                stdout=process_result.stdout or "",
                stderr=process_result.stderr or "",
                exit_code=process_result.returncode,
                output_lines=output_lines,
                json_records=json_records,
                duration_seconds=round(duration, 3),
                command=cmd_str,
                error=error,
            )

        except subprocess.TimeoutExpired:
            duration = time.monotonic() - start_time
            logger.error(f"{self.binary} timed out after {timeout}s")
            timeout_error = f"{self.binary} timed out after {timeout} seconds"
            # the tool wrote as it went — keep what landed instead of discarding the run
            raw_output = self._read_output(
                output_file=output_file, stdout="", use_output_file=use_output_file
            )
            partial_lines: list[str] = []
            partial_records: list[dict] = []
            if output_format == OutputFormat.JSONL:
                partial_records = self._parse_jsonl(raw_output)
            else:
                partial_lines = self._parse_lines(raw_output)
            _finish(-1, "", timeout_error)
            return ToolResult(
                success=False,
                exit_code=-1,
                output_lines=partial_lines,
                json_records=partial_records,
                duration_seconds=round(duration, 3),
                command=cmd_str,
                error=timeout_error,
                timed_out=True,
            )

        except Exception as e:
            msg = f"Unexpected error running {self.binary}: {e}"
            logger.error(msg)
            _finish(-1, "", msg)
            raise ToolExecutionError(msg) from e

        finally:
            self._cleanup(input_file, output_file)

    @contextlib.contextmanager
    def stream_json(  # noqa: PLR0915
        self,
        *,
        args: list[str] | None = None,
        input_data: str | list[str] | None = None,
        input_flag: str = "-l",
        json_flag: str = "-json",
        silent: bool = True,
        silent_flag: str = "-silent",
        timeout: int | None = None,
        idle_timeout: int | None = None,
        env: dict[str, str] | None = None,
        recorder: CommandRecorder | None = None,
        tool: str | None = None,
        extra_args: list[str] | None = None,
        stderr_sink: Callable[[str], None] | None = None,
        should_stop: Callable[[], bool] | None = None,
    ) -> Iterator[StreamOutcome]:
        """Stream-parse the tool's JSONL stdout; killed when it stalls past idle_timeout, or exceeds timeout (0 = no ceiling)."""
        timeout = self.default_timeout if timeout is None else timeout
        args = list(args) if args else []
        recorder = recorder if recorder is not None else self._recorder
        tool = tool if tool is not None else self._tool
        args.extend(extra_args if extra_args is not None else self._extra_args)

        input_file: Path | None = None
        start_time = time.monotonic()
        handle = None
        proc: subprocess.Popen | None = None
        timer: threading.Timer | None = None
        stderr_thread: threading.Thread | None = None
        stderr_chunks: list[str] = []
        killed_for: list[str] = [""]
        outcome = StreamOutcome(records=iter(()))
        try:
            # go's flag parser stops at the first non-flag arg, so these lead —
            # a malformed later flag must not be able to strip our input/output
            lead: list[str] = []
            if input_data is not None:
                raw_input = self._normalize_input(input_data)
                input_file = self._write_temp_file(raw_input, prefix="input_")
                lead.extend([input_flag, str(input_file)])
            if json_flag not in args:
                lead.append(json_flag)
            if silent and silent_flag not in args:
                lead.append(silent_flag)

            cmd = [self._binary_path, *lead, *args]
            logger.info("Executing (stream): %s", redact_command(" ".join(cmd)))
            if recorder is not None:
                handle = recorder.start(tool or self.binary, " ".join(cmd))

            proc = subprocess.Popen(  # noqa: S603
                cmd,
                stdout=subprocess.PIPE,
                stderr=subprocess.PIPE,
                text=True,
                errors="replace",
                env=self._build_env(env),
                cwd=tempfile.gettempdir(),
            )
            stdout = proc.stdout
            last_seen = [time.monotonic()]

            def _kill(reason: str) -> None:
                killed_for[0] = reason
                with contextlib.suppress(Exception):
                    if proc is not None:
                        proc.kill()

            if idle_timeout:
                # progress, not volume, decides liveness — a slow-but-producing tool is healthy
                def _watch_idle() -> None:
                    while proc is not None and proc.poll() is None:
                        if time.monotonic() - last_seen[0] > idle_timeout:
                            _kill(f"no output for {idle_timeout}s")
                            return
                        time.sleep(_STOP_POLL_SECONDS)

                threading.Thread(target=_watch_idle, daemon=True).start()
            if timeout:
                timer = threading.Timer(timeout, lambda: _kill(f"exceeded {timeout}s"))
                timer.start()

            # drain stderr concurrently — else a full 64KB stderr pipe deadlocks our stdout read
            def _drain_stderr() -> None:
                if proc is None or proc.stderr is None:
                    return
                size = 0
                for line in proc.stderr:
                    last_seen[0] = time.monotonic()
                    if size < MAX_COMMAND_OUTPUT:
                        stderr_chunks.append(line)
                        size += len(line)
                    if stderr_sink is not None:
                        with contextlib.suppress(Exception):
                            stderr_sink(line)

            stderr_thread = threading.Thread(target=_drain_stderr, daemon=True)
            stderr_thread.start()

            # a cancelled scan must stop the tool even while it is producing nothing to read
            if should_stop is not None:

                def _watch_stop() -> None:
                    while proc is not None and proc.poll() is None:
                        if should_stop():
                            with contextlib.suppress(Exception):
                                proc.kill()
                            return
                        time.sleep(_STOP_POLL_SECONDS)

                threading.Thread(target=_watch_stop, daemon=True).start()

            def _records() -> Iterator[dict]:
                if stdout is None:
                    return
                for line in stdout:
                    last_seen[0] = time.monotonic()
                    stripped = line.strip()
                    if not stripped:
                        continue
                    try:
                        obj = json.loads(stripped)
                    except json.JSONDecodeError:
                        continue
                    if isinstance(obj, dict):
                        outcome.record_count += 1
                        yield obj

            outcome.records = _records()
            yield outcome
        finally:
            if timer is not None:
                timer.cancel()
            return_code = -1
            if proc is not None:
                with contextlib.suppress(Exception):
                    return_code = proc.wait(timeout=10)
                if proc.poll() is None:
                    with contextlib.suppress(Exception):
                        proc.kill()
                        proc.wait(timeout=5)
                    return_code = proc.returncode if proc.returncode is not None else -1
            if stderr_thread is not None:
                stderr_thread.join(timeout=5)
            stderr = "".join(stderr_chunks)
            outcome.return_code = return_code
            outcome.timed_out = bool(killed_for[0])
            outcome.stderr = stderr
            if killed_for[0]:
                logger.warning("%s killed: %s", self.binary, killed_for[0])
            if recorder is not None and handle is not None:
                err = (
                    None
                    if return_code == 0 and not killed_for[0]
                    else (
                        f"{self.binary} killed: {killed_for[0]}"
                        if killed_for[0]
                        else f"{self.binary} exited with code {return_code}"
                    )
                    + (f": {stderr.strip()[:500]}" if stderr.strip() else "")
                )
                with contextlib.suppress(Exception):
                    recorder.finish(
                        handle,
                        return_code=return_code,
                        output=(stderr or "")[:MAX_COMMAND_OUTPUT],
                        error=err,
                        duration_seconds=round(time.monotonic() - start_time, 3),
                    )
            self._cleanup(input_file)

    @staticmethod
    def _normalize_input(data: str | list[str]) -> str:
        """Convert input data to newline-separated string."""
        if isinstance(data, list):
            return "\n".join(data) + "\n"
        return data.strip() + "\n"

    @staticmethod
    def _write_temp_file(content: str, prefix: str = "tool_") -> Path:
        """Write content to a named temp file, return its path."""
        fd, path_str = tempfile.mkstemp(prefix=prefix, suffix=".txt")
        filepath = Path(path_str)
        try:
            with os.fdopen(fd, "w") as f:
                f.write(content)
        except Exception:
            os.close(fd)
            filepath.unlink(missing_ok=True)
            raise
        return filepath

    @staticmethod
    def _create_temp_path(prefix: str = "tool_") -> Path:
        """Create a temp file path (file created empty, tool will write to it)."""
        fd, path_str = tempfile.mkstemp(prefix=prefix, suffix=".txt")
        os.close(fd)
        return Path(path_str)

    @staticmethod
    def _read_output(
        output_file: Path | None,
        stdout: str,
        use_output_file: bool,
    ) -> str:
        """Read tool output from file or stdout."""
        if use_output_file and output_file and output_file.exists():
            try:
                content = output_file.read_text(encoding="utf-8", errors="replace")
                if content.strip():
                    return content
            except OSError as e:
                logger.warning(f"Failed to read output file {output_file}: {e}")
        return stdout or ""

    @staticmethod
    def _parse_jsonl(raw: str) -> list[dict]:
        """Parse JSONL (one JSON object per line) output."""
        records = []
        for raw_line in raw.strip().splitlines():
            stripped = raw_line.strip()
            if not stripped:
                continue
            try:
                obj = json.loads(stripped)
                if isinstance(obj, dict):
                    records.append(obj)
                else:
                    logger.debug(f"Skipping non-dict JSON line: {type(obj)}")
            except json.JSONDecodeError as e:
                logger.debug(f"Skipping invalid JSON line: {e} | {stripped[:100]}")
        return records

    @staticmethod
    def _parse_lines(raw: str) -> list[str]:
        """Parse plain text output into non-empty lines."""
        return [line.strip() for line in raw.strip().splitlines() if line.strip()]

    @staticmethod
    def _build_env(extra: dict[str, str] | None) -> dict[str, str]:
        """Build subprocess environment, merging extra vars with current env."""
        env = os.environ.copy()
        if extra:
            env.update(extra)
        return env

    @staticmethod
    def _cleanup(*files: Path | None) -> None:
        """Remove temp files, silently ignoring errors."""
        for f in files:
            if f is not None:
                with contextlib.suppress(OSError):
                    f.unlink(missing_ok=True)