feat: run smolmachines sidecar as vm

bot_bottle/backend/smolmachines/sidecar_bundle.py

@@ -23,6 +23,8 @@ Plans (EgressPlan, …) lands in chunk 2d."""
 
 from __future__ import annotations
 
+import os
+import socket
 import subprocess
 from dataclasses import dataclass, field
 from pathlib import Path
@@ -34,6 +36,7 @@ from ..docker.sidecar_bundle import (
     SIDECAR_BUNDLE_DOCKERFILE,
     SIDECAR_BUNDLE_IMAGE,
 )
+from . import smolvm as _smolvm
 
 
 _REPO_DIR = str(Path(__file__).resolve().parent.parent.parent.parent)
@@ -54,6 +57,11 @@ def bundle_container_name(slug: str) -> str:
     return f"bot-bottle-sidecars-{slug}"
 
 
+def bundle_machine_name(slug: str) -> str:
+    """Sidecar smolVM machine name."""
+    return bundle_container_name(slug)
+
+
 @dataclass(frozen=True)
 class BundleLaunchSpec:
     """Everything `start_bundle` needs to bring up one bundle
@@ -92,6 +100,11 @@ class BundleLaunchSpec:
     publish_host_ip: str = "127.0.0.1"
 
 
+@dataclass(frozen=True)
+class BundleVmLaunch:
+    raw_ports: dict[int, int]
+
+
 def ensure_bundle_image(image: str = SIDECAR_BUNDLE_IMAGE) -> None:
     """Build the sidecar bundle image before `docker run`.
 
@@ -107,6 +120,70 @@ def ensure_bundle_image(image: str = SIDECAR_BUNDLE_IMAGE) -> None:
     )
 
 
+def allocate_raw_host_ports(container_ports: Sequence[int]) -> dict[int, int]:
+    """Reserve candidate host loopback ports for smolVM `-p HOST:GUEST`.
+
+    The sockets are closed before smolVM binds them, so this remains
+    best-effort. smolVM failing to bind a selected port is fatal in
+    the caller's launch path."""
+    out: dict[int, int] = {}
+    for container_port in container_ports:
+        with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as sock:
+            sock.bind(("127.0.0.1", 0))
+            out[container_port] = int(sock.getsockname()[1])
+    return out
+
+
+def start_bundle_vm(
+    spec: BundleLaunchSpec,
+    *,
+    from_path: Path,
+    host_env: dict[str, str] | None = None,
+) -> BundleVmLaunch:
+    """Create and start the sidecar bundle as a smolVM.
+
+    smolVM's own published ports are raw host-loopback ports. The
+    launch flow wraps them with per-bottle address-bound forwarders
+    before exposing anything to the agent VM."""
+    raw_ports = allocate_raw_host_ports(spec.ports_to_publish)
+    effective_host_env = host_env if host_env is not None else os.environ
+    env: dict[str, str] = {"BOT_BOTTLE_SIDECAR_DAEMONS": spec.daemons_csv}
+    for entry in spec.environment:
+        name, sep, value = entry.partition("=")
+        if sep:
+            env[name] = value
+        elif entry in effective_host_env:
+            env[entry] = effective_host_env[entry]
+    name = bundle_machine_name(spec.slug)
+    _smolvm.machine_create(
+        name,
+        from_path=from_path,
+        net=True,
+        env=env,
+        volumes=spec.volumes,
+        ports=tuple(
+            (host_port, guest_port)
+            for guest_port, host_port in raw_ports.items()
+        ),
+    )
+    _smolvm.machine_start(name)
+    _smolvm.wait_exec_ready(name)
+    return BundleVmLaunch(raw_ports=raw_ports)
+
+
+def stop_bundle_vm(slug: str) -> None:
+    """Best-effort sidecar VM teardown."""
+    name = bundle_machine_name(slug)
+    try:
+        _smolvm.machine_stop(name)
+    except _smolvm.SmolvmError as exc:
+        warn(f"smolvm machine stop {name} failed: {exc}")
+    try:
+        _smolvm.machine_delete(name)
+    except _smolvm.SmolvmError as exc:
+        warn(f"smolvm machine delete {name} failed: {exc}")
+
+
 def create_bundle_network(network_name: str, subnet: str, gateway: str) -> None:
     """`docker network create` with an explicit subnet + gateway
     so the bundle's `--ip` lands on the address the Smolfile's