Files
hermes-agent/tools/environments/docker.py
Bartok9 8cdbbcaaa2 fix(docker): auto-mount host CWD to /workspace
Fixes #1445 — When using Docker backend, the user's current working
directory is now automatically bind-mounted to /workspace inside the
container. This allows users to run `cd my-project && hermes` and have
their project files accessible to the agent without manual volume config.

Changes:
- Add host_cwd and auto_mount_cwd parameters to DockerEnvironment
- Capture original host CWD in _get_env_config() before container fallback
- Pass host_cwd through _create_environment() to Docker backend
- Add TERMINAL_DOCKER_NO_AUTO_MOUNT env var to disable if needed
- Skip auto-mount when /workspace is already explicitly mounted
- Add tests for auto-mount behavior
- Add documentation for the new feature

The auto-mount is skipped when:
1. TERMINAL_DOCKER_NO_AUTO_MOUNT=true is set
2. User configured docker_volumes with :/workspace
3. persistent_filesystem=true (persistent sandbox mode)

This makes the Docker backend behave more intuitively — the agent
operates on the user's actual project directory by default.
2026-03-16 05:20:21 -07:00

427 lines
16 KiB
Python

"""Docker execution environment wrapping mini-swe-agent's DockerEnvironment.
Adds security hardening (cap-drop ALL, no-new-privileges, PID limits),
configurable resource limits (CPU, memory, disk), and optional filesystem
persistence via bind mounts.
"""
import logging
import os
import shutil
import subprocess
import sys
import threading
import time
from typing import Optional
from tools.environments.base import BaseEnvironment
from tools.interrupt import is_interrupted
logger = logging.getLogger(__name__)
# Common Docker Desktop install paths checked when 'docker' is not in PATH.
# macOS Intel: /usr/local/bin, macOS Apple Silicon (Homebrew): /opt/homebrew/bin,
# Docker Desktop app bundle: /Applications/Docker.app/Contents/Resources/bin
_DOCKER_SEARCH_PATHS = [
"/usr/local/bin/docker",
"/opt/homebrew/bin/docker",
"/Applications/Docker.app/Contents/Resources/bin/docker",
]
_docker_executable: Optional[str] = None # resolved once, cached
def find_docker() -> Optional[str]:
"""Locate the docker CLI binary.
Checks ``shutil.which`` first (respects PATH), then probes well-known
install locations on macOS where Docker Desktop may not be in PATH
(e.g. when running as a gateway service via launchd).
Returns the absolute path, or ``None`` if docker cannot be found.
"""
global _docker_executable
if _docker_executable is not None:
return _docker_executable
found = shutil.which("docker")
if found:
_docker_executable = found
return found
for path in _DOCKER_SEARCH_PATHS:
if os.path.isfile(path) and os.access(path, os.X_OK):
_docker_executable = path
logger.info("Found docker at non-PATH location: %s", path)
return path
return None
# Security flags applied to every container.
# The container itself is the security boundary (isolated from host).
# We drop all capabilities then add back the minimum needed:
# DAC_OVERRIDE - root can write to bind-mounted dirs owned by host user
# CHOWN/FOWNER - package managers (pip, npm, apt) need to set file ownership
# Block privilege escalation and limit PIDs.
# /tmp is size-limited and nosuid but allows exec (needed by pip/npm builds).
_SECURITY_ARGS = [
"--cap-drop", "ALL",
"--cap-add", "DAC_OVERRIDE",
"--cap-add", "CHOWN",
"--cap-add", "FOWNER",
"--security-opt", "no-new-privileges",
"--pids-limit", "256",
"--tmpfs", "/tmp:rw,nosuid,size=512m",
"--tmpfs", "/var/tmp:rw,noexec,nosuid,size=256m",
"--tmpfs", "/run:rw,noexec,nosuid,size=64m",
]
_storage_opt_ok: Optional[bool] = None # cached result across instances
def _ensure_docker_available() -> None:
"""Best-effort check that the docker CLI is available before use.
Reuses ``find_docker()`` so this preflight stays consistent with the rest of
the Docker backend, including known non-PATH Docker Desktop locations.
"""
docker_exe = find_docker()
if not docker_exe:
logger.error(
"Docker backend selected but no docker executable was found in PATH "
"or known install locations. Install Docker Desktop and ensure the "
"CLI is available."
)
raise RuntimeError(
"Docker executable not found in PATH or known install locations. "
"Install Docker and ensure the 'docker' command is available."
)
try:
result = subprocess.run(
[docker_exe, "version"],
capture_output=True,
text=True,
timeout=5,
)
except FileNotFoundError:
logger.error(
"Docker backend selected but the resolved docker executable '%s' could "
"not be executed.",
docker_exe,
exc_info=True,
)
raise RuntimeError(
"Docker executable could not be executed. Check your Docker installation."
)
except subprocess.TimeoutExpired:
logger.error(
"Docker backend selected but '%s version' timed out. "
"The Docker daemon may not be running.",
docker_exe,
exc_info=True,
)
raise RuntimeError(
"Docker daemon is not responding. Ensure Docker is running and try again."
)
except Exception:
logger.error(
"Unexpected error while checking Docker availability.",
exc_info=True,
)
raise
else:
if result.returncode != 0:
logger.error(
"Docker backend selected but '%s version' failed "
"(exit code %d, stderr=%s)",
docker_exe,
result.returncode,
result.stderr.strip(),
)
raise RuntimeError(
"Docker command is available but 'docker version' failed. "
"Check your Docker installation."
)
class DockerEnvironment(BaseEnvironment):
"""Hardened Docker container execution with resource limits and persistence.
Security: all capabilities dropped, no privilege escalation, PID limits,
size-limited tmpfs for scratch dirs. The container itself is the security
boundary — the filesystem inside is writable so agents can install packages
(pip, npm, apt) as needed. Writable workspace via tmpfs or bind mounts.
Persistence: when enabled, bind mounts preserve /workspace and /root
across container restarts.
Auto-mount: when host_cwd is provided (the user's original working directory),
it is automatically bind-mounted to /workspace unless auto_mount_cwd=False
or the path is already covered by an explicit volume mount.
"""
def __init__(
self,
image: str,
cwd: str = "/root",
timeout: int = 60,
cpu: float = 0,
memory: int = 0,
disk: int = 0,
persistent_filesystem: bool = False,
task_id: str = "default",
volumes: list = None,
network: bool = True,
host_cwd: str = None,
auto_mount_cwd: bool = True,
):
if cwd == "~":
cwd = "/root"
super().__init__(cwd=cwd, timeout=timeout)
self._base_image = image
self._persistent = persistent_filesystem
self._task_id = task_id
self._container_id: Optional[str] = None
logger.info(f"DockerEnvironment volumes: {volumes}")
# Ensure volumes is a list (config.yaml could be malformed)
if volumes is not None and not isinstance(volumes, list):
logger.warning(f"docker_volumes config is not a list: {volumes!r}")
volumes = []
# Fail fast if Docker is not available rather than surfacing a cryptic
# FileNotFoundError deep inside the mini-swe-agent stack.
_ensure_docker_available()
from minisweagent.environments.docker import DockerEnvironment as _Docker
# Build resource limit args
resource_args = []
if cpu > 0:
resource_args.extend(["--cpus", str(cpu)])
if memory > 0:
resource_args.extend(["--memory", f"{memory}m"])
if disk > 0 and sys.platform != "darwin":
if self._storage_opt_supported():
resource_args.extend(["--storage-opt", f"size={disk}m"])
else:
logger.warning(
"Docker storage driver does not support per-container disk limits "
"(requires overlay2 on XFS with pquota). Container will run without disk quota."
)
if not network:
resource_args.append("--network=none")
# Persistent workspace via bind mounts from a configurable host directory
# (TERMINAL_SANDBOX_DIR, default ~/.hermes/sandboxes/). Non-persistent
# mode uses tmpfs (ephemeral, fast, gone on cleanup).
from tools.environments.base import get_sandbox_dir
self._workspace_dir: Optional[str] = None
self._home_dir: Optional[str] = None
if self._persistent:
sandbox = get_sandbox_dir() / "docker" / task_id
self._workspace_dir = str(sandbox / "workspace")
self._home_dir = str(sandbox / "home")
os.makedirs(self._workspace_dir, exist_ok=True)
os.makedirs(self._home_dir, exist_ok=True)
writable_args = [
"-v", f"{self._workspace_dir}:/workspace",
"-v", f"{self._home_dir}:/root",
]
else:
writable_args = [
"--tmpfs", "/workspace:rw,exec,size=10g",
"--tmpfs", "/home:rw,exec,size=1g",
"--tmpfs", "/root:rw,exec,size=1g",
]
# All containers get security hardening (capabilities dropped, no privilege
# escalation, PID limits). The container filesystem is writable so agents
# can install packages as needed.
# User-configured volume mounts (from config.yaml docker_volumes)
volume_args = []
for vol in (volumes or []):
if not isinstance(vol, str):
logger.warning(f"Docker volume entry is not a string: {vol!r}")
continue
vol = vol.strip()
if not vol:
continue
if ":" in vol:
volume_args.extend(["-v", vol])
else:
logger.warning(f"Docker volume '{vol}' missing colon, skipping")
# Auto-mount host CWD to /workspace when enabled (fixes #1445).
# This allows users to run `cd my-project && hermes` and have Docker
# automatically mount their project directory into the container.
# Disabled when: auto_mount_cwd=False, host_cwd is not a valid directory,
# or /workspace is already covered by writable_args or a user volume.
auto_mount_disabled = os.getenv("TERMINAL_DOCKER_NO_AUTO_MOUNT", "").lower() in ("1", "true", "yes")
if host_cwd and auto_mount_cwd and not auto_mount_disabled:
host_cwd_abs = os.path.abspath(os.path.expanduser(host_cwd))
if os.path.isdir(host_cwd_abs):
# Check if /workspace is already being mounted by persistence or user config
workspace_already_mounted = any(
":/workspace" in arg for arg in writable_args
) or any(
":/workspace" in arg for arg in volume_args
)
if not workspace_already_mounted:
logger.info(f"Auto-mounting host CWD to /workspace: {host_cwd_abs}")
volume_args.extend(["-v", f"{host_cwd_abs}:/workspace"])
else:
logger.debug(f"Skipping auto-mount: /workspace already mounted")
else:
logger.debug(f"Skipping auto-mount: host_cwd is not a valid directory: {host_cwd}")
logger.info(f"Docker volume_args: {volume_args}")
all_run_args = list(_SECURITY_ARGS) + writable_args + resource_args + volume_args
logger.info(f"Docker run_args: {all_run_args}")
# Resolve the docker executable once so it works even when
# /usr/local/bin is not in PATH (common on macOS gateway/service).
docker_exe = find_docker() or "docker"
self._inner = _Docker(
image=image, cwd=cwd, timeout=timeout,
run_args=all_run_args,
executable=docker_exe,
)
self._container_id = self._inner.container_id
@staticmethod
def _storage_opt_supported() -> bool:
"""Check if Docker's storage driver supports --storage-opt size=.
Only overlay2 on XFS with pquota supports per-container disk quotas.
Ubuntu (and most distros) default to ext4, where this flag errors out.
"""
global _storage_opt_ok
if _storage_opt_ok is not None:
return _storage_opt_ok
try:
docker = find_docker() or "docker"
result = subprocess.run(
[docker, "info", "--format", "{{.Driver}}"],
capture_output=True, text=True, timeout=10,
)
driver = result.stdout.strip().lower()
if driver != "overlay2":
_storage_opt_ok = False
return False
# overlay2 only supports storage-opt on XFS with pquota.
# Probe by attempting a dry-ish run — the fastest reliable check.
probe = subprocess.run(
[docker, "create", "--storage-opt", "size=1m", "hello-world"],
capture_output=True, text=True, timeout=15,
)
if probe.returncode == 0:
# Clean up the created container
container_id = probe.stdout.strip()
if container_id:
subprocess.run([docker, "rm", container_id],
capture_output=True, timeout=5)
_storage_opt_ok = True
else:
_storage_opt_ok = False
except Exception:
_storage_opt_ok = False
logger.debug("Docker --storage-opt support: %s", _storage_opt_ok)
return _storage_opt_ok
def execute(self, command: str, cwd: str = "", *,
timeout: int | None = None,
stdin_data: str | None = None) -> dict:
exec_command, sudo_stdin = self._prepare_command(command)
work_dir = cwd or self.cwd
effective_timeout = timeout or self.timeout
# Merge sudo password (if any) with caller-supplied stdin_data.
if sudo_stdin is not None and stdin_data is not None:
effective_stdin = sudo_stdin + stdin_data
elif sudo_stdin is not None:
effective_stdin = sudo_stdin
else:
effective_stdin = stdin_data
# docker exec -w doesn't expand ~, so prepend a cd into the command
if work_dir == "~" or work_dir.startswith("~/"):
exec_command = f"cd {work_dir} && {exec_command}"
work_dir = "/"
assert self._inner.container_id, "Container not started"
cmd = [self._inner.config.executable, "exec"]
if effective_stdin is not None:
cmd.append("-i")
cmd.extend(["-w", work_dir])
for key in self._inner.config.forward_env:
if (value := os.getenv(key)) is not None:
cmd.extend(["-e", f"{key}={value}"])
for key, value in self._inner.config.env.items():
cmd.extend(["-e", f"{key}={value}"])
cmd.extend([self._inner.container_id, "bash", "-lc", exec_command])
try:
_output_chunks = []
proc = subprocess.Popen(
cmd,
stdout=subprocess.PIPE, stderr=subprocess.STDOUT,
stdin=subprocess.PIPE if effective_stdin else subprocess.DEVNULL,
text=True,
)
if effective_stdin:
try:
proc.stdin.write(effective_stdin)
proc.stdin.close()
except Exception:
pass
def _drain():
try:
for line in proc.stdout:
_output_chunks.append(line)
except Exception:
pass
reader = threading.Thread(target=_drain, daemon=True)
reader.start()
deadline = time.monotonic() + effective_timeout
while proc.poll() is None:
if is_interrupted():
proc.terminate()
try:
proc.wait(timeout=1)
except subprocess.TimeoutExpired:
proc.kill()
reader.join(timeout=2)
return {
"output": "".join(_output_chunks) + "\n[Command interrupted]",
"returncode": 130,
}
if time.monotonic() > deadline:
proc.kill()
reader.join(timeout=2)
return self._timeout_result(effective_timeout)
time.sleep(0.2)
reader.join(timeout=5)
return {"output": "".join(_output_chunks), "returncode": proc.returncode}
except Exception as e:
return {"output": f"Docker execution error: {e}", "returncode": 1}
def cleanup(self):
"""Stop and remove the container. Bind-mount dirs persist if persistent=True."""
self._inner.cleanup()
if not self._persistent:
import shutil
for d in (self._workspace_dir, self._home_dir):
if d:
shutil.rmtree(d, ignore_errors=True)