left4me/l4d2host/instances.py
mwiegand 985df970f8
feat(l4d2-web): per-overlay server.cfg aliases — expose checkbox + auto-exec
Each linked overlay gets a checkbox on the blueprint detail page that opts
its server.cfg in as exec server_overlay_<id>. The web app builds the
spec with {path, alias} per overlay and prepends exec server_overlay_<id>
lines to the blueprint config in lowest-overlay-first order. The host
stages those copies in the overlayfs upper layer before mounting (avoids
copy-up writes against a sandbox-uid file). A live preview block above the
Config textarea shows what gets auto-executed.

Schema:
- alembic 0007: BlueprintOverlay.expose_server_cfg BOOLEAN

Spec contract:
- l4d2host OverlayRef(path, alias?). load_spec accepts both bare-string
  and {path, alias} entries.

Side effects folded in (same file in l4d2_facade):
- start_server auto-initializes; the manual Initialize step is no longer
  needed before Start.
- initialize_server no longer runs blueprint builders — builds happen on
  overlay save, not on every server Start.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-05-09 01:26:31 +02:00

270 lines
8.7 KiB
Python

import os
from pathlib import Path
import shutil
import subprocess
from typing import Callable
from l4d2host.fs.kernel_overlayfs import KernelOverlayFSMounter
from l4d2host.paths import DEFAULT_LEFT4ME_ROOT, get_left4me_root, overlay_path, validate_instance_name
from l4d2host.service_control import start_service, stop_service
from l4d2host.spec import load_spec
from l4d2host.logging import emit_step
_mounter = KernelOverlayFSMounter()
DEFAULT_ROOT = DEFAULT_LEFT4ME_ROOT
def initialize_instance(
name: str,
spec_path: Path,
*,
root: Path | None = None,
on_stdout: Callable[[str], None] | None = None,
on_stderr: Callable[[str], None] | None = None,
passthrough: bool = False,
should_cancel: Callable[[], bool] | None = None,
) -> None:
name = validate_instance_name(name)
root = get_left4me_root() if root is None else Path(root)
spec = load_spec(spec_path)
emit_step("creating instance directories...", on_stdout, passthrough)
instance_dir = root / "instances" / name
runtime_dir = root / "runtime" / name
(runtime_dir / "upper").mkdir(parents=True, exist_ok=True)
(runtime_dir / "work").mkdir(parents=True, exist_ok=True)
(runtime_dir / "merged").mkdir(parents=True, exist_ok=True)
instance_dir.mkdir(parents=True, exist_ok=True)
lowerdirs = [str(overlay_path(o.path, root=root)) for o in spec.overlays]
lowerdirs.append(str(root / "installation"))
emit_step("writing instance.env...", on_stdout, passthrough)
instance_env = "\n".join(
[
f"L4D2_PORT={spec.port}",
f"L4D2_ARGS={' '.join(spec.arguments)}",
f"L4D2_LOWERDIRS={':'.join(lowerdirs)}",
]
) + "\n"
(instance_dir / "instance.env").write_text(instance_env)
emit_step("writing server.cfg...", on_stdout, passthrough)
server_cfg = "\n".join(spec.config) if spec.config else ""
(instance_dir / "server.cfg").write_text(server_cfg)
emit_step("persisting spec...", on_stdout, passthrough)
shutil.copy2(spec_path, instance_dir / "spec.yaml")
emit_step("initialization complete.", on_stdout, passthrough)
def _load_instance_env(path: Path) -> dict[str, str]:
result: dict[str, str] = {}
for line in path.read_text().splitlines():
if "=" not in line:
continue
key, value = line.split("=", 1)
result[key] = value
return result
def start_instance(
name: str,
*,
root: Path | None = None,
on_stdout: Callable[[str], None] | None = None,
on_stderr: Callable[[str], None] | None = None,
passthrough: bool = False,
should_cancel: Callable[[], bool] | None = None,
) -> None:
name = validate_instance_name(name)
root = get_left4me_root() if root is None else Path(root)
instance_dir = root / "instances" / name
runtime_dir = root / "runtime" / name
env = _load_instance_env(instance_dir / "instance.env")
merged = runtime_dir / "merged"
if os.path.ismount(merged):
# Kernel overlayfs mounts persist when the web worker dies (unlike
# fuse daemons, which were reaped with their cgroup). Refuse rather
# than double-mount.
raise subprocess.CalledProcessError(
returncode=1,
cmd=["start_instance"],
stderr=f"runtime overlay already mounted at {merged}; refusing to double-mount",
)
# Stage cfg files in the upper layer BEFORE mounting. Writing through
# merged after the mount triggers overlayfs copy-up, which preserves the
# lower file's ownership — and a script-sandbox-built `server.cfg` is
# owned by `l4d2-sandbox`, not the worker. Pre-mount writes go straight to
# upper with the worker's uid; the kernel just shows them at the top of
# the merged stack once mounted.
emit_step("staging server.cfg + per-overlay aliases in upper layer...", on_stdout, passthrough)
upper_cfg_dir = runtime_dir / "upper" / "left4dead2" / "cfg"
upper_cfg_dir.mkdir(parents=True, exist_ok=True)
for stale in upper_cfg_dir.glob("server*.cfg"):
stale.unlink()
shutil.copy2(instance_dir / "server.cfg", upper_cfg_dir / "server.cfg")
spec = load_spec(instance_dir / "spec.yaml")
for o in spec.overlays:
if not o.alias:
continue
src = root / "overlays" / o.path / "left4dead2" / "cfg" / "server.cfg"
if not src.exists():
continue
shutil.copy2(src, upper_cfg_dir / f"server_{o.alias}.cfg")
emit_step("mounting runtime overlay...", on_stdout, passthrough)
_mounter.mount(
lowerdirs=env["L4D2_LOWERDIRS"],
upperdir=runtime_dir / "upper",
workdir=runtime_dir / "work",
merged=merged,
on_stdout=on_stdout,
on_stderr=on_stderr,
passthrough=passthrough,
should_cancel=should_cancel,
)
emit_step("starting systemd service...", on_stdout, passthrough)
start_service(
name,
on_stdout=on_stdout,
on_stderr=on_stderr,
passthrough=passthrough,
should_cancel=should_cancel,
)
emit_step("start complete.", on_stdout, passthrough)
def stop_instance(
name: str,
*,
root: Path | None = None,
on_stdout: Callable[[str], None] | None = None,
on_stderr: Callable[[str], None] | None = None,
passthrough: bool = False,
should_cancel: Callable[[], bool] | None = None,
) -> None:
name = validate_instance_name(name)
root = get_left4me_root() if root is None else Path(root)
emit_step("stopping systemd service...", on_stdout, passthrough)
stop_service(
name,
on_stdout=on_stdout,
on_stderr=on_stderr,
passthrough=passthrough,
should_cancel=should_cancel,
)
emit_step("unmounting runtime overlay (if mounted)...", on_stdout, passthrough)
try:
_mounter.unmount(
merged=root / "runtime" / name / "merged",
on_stdout=on_stdout,
on_stderr=on_stderr,
passthrough=passthrough,
should_cancel=should_cancel,
)
except subprocess.CalledProcessError:
pass
emit_step("stop complete.", on_stdout, passthrough)
def _purge_instance(
name: str,
*,
root: Path,
on_stdout: Callable[[str], None] | None,
on_stderr: Callable[[str], None] | None,
passthrough: bool,
should_cancel: Callable[[], bool] | None,
) -> None:
instance_dir = root / "instances" / name
runtime_dir = root / "runtime" / name
emit_step("stopping systemd service (if running)...", on_stdout, passthrough)
try:
stop_service(
name,
on_stdout=on_stdout,
on_stderr=on_stderr,
passthrough=passthrough,
should_cancel=should_cancel,
)
except subprocess.CalledProcessError:
pass
emit_step("unmounting runtime overlay (if mounted)...", on_stdout, passthrough)
try:
_mounter.unmount(
merged=runtime_dir / "merged",
on_stdout=on_stdout,
on_stderr=on_stderr,
passthrough=passthrough,
should_cancel=should_cancel,
)
except subprocess.CalledProcessError:
pass
emit_step("removing instance files...", on_stdout, passthrough)
if instance_dir.exists():
shutil.rmtree(instance_dir)
if runtime_dir.exists():
shutil.rmtree(runtime_dir)
def delete_instance(
name: str,
*,
root: Path | None = None,
on_stdout: Callable[[str], None] | None = None,
on_stderr: Callable[[str], None] | None = None,
passthrough: bool = False,
should_cancel: Callable[[], bool] | None = None,
) -> None:
name = validate_instance_name(name)
root = get_left4me_root() if root is None else Path(root)
instance_dir = root / "instances" / name
runtime_dir = root / "runtime" / name
if not instance_dir.exists() and not runtime_dir.exists():
return
_purge_instance(
name,
root=root,
on_stdout=on_stdout,
on_stderr=on_stderr,
passthrough=passthrough,
should_cancel=should_cancel,
)
emit_step("delete complete.", on_stdout, passthrough)
def reset_instance(
name: str,
*,
root: Path | None = None,
on_stdout: Callable[[str], None] | None = None,
on_stderr: Callable[[str], None] | None = None,
passthrough: bool = False,
should_cancel: Callable[[], bool] | None = None,
) -> None:
name = validate_instance_name(name)
root = get_left4me_root() if root is None else Path(root)
_purge_instance(
name,
root=root,
on_stdout=on_stdout,
on_stderr=on_stderr,
passthrough=passthrough,
should_cancel=should_cancel,
)
emit_step("reset complete; next start will reinitialize from blueprint.", on_stdout, passthrough)