feat(orchestrator): slice 4 — consolidated per-host sidecar (#352)

The core consolidation win: one persistent sidecar per host, shared by
every bottle, instead of a sidecar bundle per bottle. Safe to share
because the attribution invariant (source IP + identity token) lets the
sidecar map each request to the right bottle.

  * orchestrator/sidecar.py — a backend-neutral `Sidecar` lifecycle
    contract (mirrors LaunchBroker) + a `DockerSidecar` impl. The defining
    behaviour is idempotent singleton: `ensure_running` starts the instance
    if absent and is a no-op if it's already up, so N launches never spawn
    N sidecars; `stop` is idempotent.
  * orchestrator/dockerutil.py — a shared `run_docker` helper; DockerBroker
    now uses it too (DRY with slice 3).
  * service.py — the Orchestrator holds an optional `Sidecar`, exposes
    `ensure_sidecar()` + `sidecar_status()`.
  * control_plane.py — `GET /sidecar` reports it; __main__ gains
    `--sidecar-image` and ensures the single sidecar on startup.

Tests: unit (docker mocked) — is_running, ensure idempotent (no-op when up,
starts when absent), failure raises, stop idempotent; Orchestrator sidecar
wiring/status; control-plane /sidecar; integration (gated) — ensure is a
real idempotent singleton (one container after two ensures), stop removes.
Full suite green (only pre-existing /bin/sleep errors); integration
verified locally against real docker.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01WBMWTEtQdJ4W5UrWuLHCck

bot_bottle/orchestrator/__main__.py

@@ -21,6 +21,7 @@ from .control_plane import make_server
 from .docker_broker import DockerBroker
 from .registry import RegistryStore, default_db_path
 from .service import Orchestrator
+from .sidecar import DockerSidecar, Sidecar
 
 
 def main(argv: list[str] | None = None) -> int:
@@ -36,6 +37,10 @@ def main(argv: list[str] | None = None) -> int:
         "--broker", choices=("stub", "docker"), default="stub",
         help="launch broker: 'stub' records requests; 'docker' runs containers",
     )
+    parser.add_argument(
+        "--sidecar-image", default=None,
+        help="if set, run one consolidated per-host sidecar from this image",
+    )
     args = parser.parse_args(argv)
 
     registry = RegistryStore(args.db)
@@ -46,7 +51,13 @@ def main(argv: list[str] | None = None) -> int:
     # anything; 'docker' runs real containers (firecracker drops in later).
     secret = secrets.token_bytes(32)
     broker: LaunchBroker = DockerBroker(secret) if args.broker == "docker" else StubBroker(secret)
-    orchestrator = Orchestrator(registry, broker, secret)
+    sidecar: Sidecar | None = DockerSidecar(args.sidecar_image) if args.sidecar_image else None
+    orchestrator = Orchestrator(registry, broker, secret, sidecar)
+
+    # One persistent per-host sidecar, shared by every bottle (idempotent).
+    if sidecar is not None:
+        orchestrator.ensure_sidecar()
+        log.info("consolidated sidecar ensured", context={"name": sidecar.name})
 
     server = make_server(orchestrator, host=args.host, port=args.port)
     bound_host, bound_port = server.server_address[0], server.server_address[1]