refactor(gateway): parameterize git-gate provisioning transport (Stage B prep)

git-gate provisioning into the running gateway was hard-wired to docker
exec/cp. Extract a backend-neutral `GatewayTransport` (exec + cp_into) so
the same provisioning logic serves both the docker gateway container and
the firecracker gateway VM (over SSH, added with the launch swap).

- `provision_git_gate` / `deprovision_git_gate` now take a transport
  instead of a gateway name; `DockerGatewayTransport` wraps the existing
  docker exec/cp behavior. deprovision is best-effort (catches the
  transport error) — matching the prior idempotent teardown.
- both consolidated_launch callers pass `DockerGatewayTransport(name)` —
  no behavior change; the firecracker swap flips only its own to SSH.

Pure refactor: docker path unchanged, gateway_provision tests updated to
construct the transport, all green.

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

bot_bottle/backend/docker/consolidated_launch.py

@@ -29,7 +29,11 @@ from ...orchestrator.gateway import GATEWAY_NAME, GATEWAY_NETWORK
 from ...orchestrator.lifecycle import OrchestratorService
 from ...orchestrator.registration import registration_inputs
 from .gateway_net import next_free_ip
-from .gateway_provision import deprovision_git_gate, provision_git_gate
+from .gateway_provision import (
+    DockerGatewayTransport,
+    deprovision_git_gate,
+    provision_git_gate,
+)
 
 
 class ConsolidatedLaunchError(RuntimeError):
@@ -121,7 +125,8 @@ def launch_consolidated(
         metadata=inputs.metadata, tokens=tokens,
     )
     try:
-        provision_git_gate(gateway_name, reg.bottle_id, git_gate_plan)
+        provision_git_gate(
+            DockerGatewayTransport(gateway_name), reg.bottle_id, git_gate_plan)
     except Exception:
         # Roll the registration back so a provisioning failure leaves no orphan.
         client.teardown_bottle(reg.bottle_id)
@@ -142,7 +147,7 @@ def teardown_consolidated(
     """Deregister the bottle and remove its git-gate state from the gateway.
     Both steps are idempotent so this is safe from a cleanup trap."""
     OrchestratorClient(orchestrator_url).teardown_bottle(bottle_id)
-    deprovision_git_gate(gateway_name, bottle_id)
+    deprovision_git_gate(DockerGatewayTransport(gateway_name), bottle_id)
 
 
 __all__ = [

bot_bottle/backend/docker/gateway_provision.py

@@ -15,14 +15,15 @@ bottle's push credentials out of another's repos on the shared gateway.
 from __future__ import annotations
 
 import re
+from typing import Protocol
 
 from ...docker_cmd import run_docker
 from ...git_gate import GitGatePlan, git_gate_render_provision
 
 # bottle ids index the gateway's per-bottle repo + creds dirs; they land in
-# `docker cp`/`rm` path arguments, so validate before any path is built (a
-# traversal id like "../etc" must never reach the container). Registry ids are
-# token_hex — this is defense in depth at the docker boundary.
+# exec/cp path arguments, so validate before any path is built (a traversal
+# id like "../etc" must never reach the gateway). Registry ids are token_hex —
+# this is defense in depth at the transport boundary.
 _SAFE_BOTTLE_ID = re.compile(r"[A-Za-z0-9_-]+")
 
 
@@ -30,6 +31,42 @@ class GatewayProvisionError(RuntimeError):
     """A git-gate provisioning step against the running gateway failed."""
 
 
+class GatewayTransport(Protocol):
+    """How the launcher stages files + runs commands in the running gateway.
+    Backend-neutral so the same provisioning logic serves the docker gateway
+    (exec/cp over the docker socket) and the firecracker gateway VM (over
+    SSH)."""
+
+    def exec(self, argv: list[str]) -> None:
+        """Run `argv` in the gateway, raising `GatewayProvisionError` on
+        failure."""
+
+    def cp_into(self, src: str, dest: str) -> None:
+        """Copy host file `src` to `dest` in the gateway, raising on
+        failure."""
+
+
+class DockerGatewayTransport:
+    """`GatewayTransport` for the docker gateway container (exec/cp)."""
+
+    def __init__(self, gateway: str) -> None:
+        self.gateway = gateway
+
+    def exec(self, argv: list[str]) -> None:
+        proc = run_docker(["docker", "exec", self.gateway, *argv])
+        if proc.returncode != 0:
+            raise GatewayProvisionError(
+                f"gateway exec {argv!r} failed: {proc.stderr.strip()}"
+            )
+
+    def cp_into(self, src: str, dest: str) -> None:
+        proc = run_docker(["docker", "cp", src, f"{self.gateway}:{dest}"])
+        if proc.returncode != 0:
+            raise GatewayProvisionError(
+                f"gateway cp {src} -> {dest} failed: {proc.stderr.strip()}"
+            )
+
+
 def _require_safe(bottle_id: str) -> None:
     if not _SAFE_BOTTLE_ID.fullmatch(bottle_id):
         raise GatewayProvisionError(f"unsafe bottle id {bottle_id!r}")
@@ -39,27 +76,11 @@ def _creds_dir(bottle_id: str) -> str:
     return f"/git-gate/creds/{bottle_id}"
 
 
-def _exec(gateway: str, argv: list[str]) -> None:
-    """`docker exec` a command in the gateway, raising on non-zero exit."""
-    proc = run_docker(["docker", "exec", gateway, *argv])
-    if proc.returncode != 0:
-        raise GatewayProvisionError(
-            f"gateway exec {argv!r} failed: {proc.stderr.strip()}"
-        )
-
-
-def _cp_into(gateway: str, src: str, dest: str) -> None:
-    """`docker cp` a host file into the gateway, raising on non-zero exit."""
-    proc = run_docker(["docker", "cp", src, f"{gateway}:{dest}"])
-    if proc.returncode != 0:
-        raise GatewayProvisionError(
-            f"gateway cp {src} -> {dest} failed: {proc.stderr.strip()}"
-        )
-
-
-def provision_git_gate(gateway: str, bottle_id: str, plan: GitGatePlan) -> None:
-    """Place `bottle_id`'s git-gate credentials into the running `gateway`
-    container and init its bare repos under `/git/<bottle_id>/`.
+def provision_git_gate(
+    transport: GatewayTransport, bottle_id: str, plan: GitGatePlan,
+) -> None:
+    """Place `bottle_id`'s git-gate credentials into the running gateway and
+    init its bare repos under `/git/<bottle_id>/`.
 
     Copies each upstream's identity key (and known_hosts, when present) into
     `/git-gate/creds/<bottle_id>/`, then runs the namespaced provisioning
@@ -70,31 +91,36 @@ def provision_git_gate(gateway: str, bottle_id: str, plan: GitGatePlan) -> None:
     # The pre-receive + access hooks are bottle-agnostic and shared by every
     # bottle's repos; install them into the gateway (idempotent — same content
     # each time). The per-bottle model cp'd these into each bundle at start.
-    _exec(gateway, ["mkdir", "-p", "/etc/git-gate"])
-    _cp_into(gateway, str(plan.hook_script), "/etc/git-gate/pre-receive")
-    _cp_into(gateway, str(plan.access_hook_script), "/etc/git-gate/access-hook")
+    transport.exec(["mkdir", "-p", "/etc/git-gate"])
+    transport.cp_into(str(plan.hook_script), "/etc/git-gate/pre-receive")
+    transport.cp_into(str(plan.access_hook_script), "/etc/git-gate/access-hook")
     creds = _creds_dir(bottle_id)
-    _exec(gateway, ["mkdir", "-p", creds])
+    transport.exec(["mkdir", "-p", creds])
     for u in plan.upstreams:
         if u.identity_file:
-            _cp_into(gateway, u.identity_file, f"{creds}/{u.name}-key")
+            transport.cp_into(u.identity_file, f"{creds}/{u.name}-key")
         known_hosts = str(u.known_hosts_file)
         if known_hosts and known_hosts != ".":
-            _cp_into(gateway, known_hosts, f"{creds}/{u.name}-known_hosts")
+            transport.cp_into(known_hosts, f"{creds}/{u.name}-known_hosts")
     # Init the bare repos + per-repo credential config for this namespace.
     script = git_gate_render_provision(bottle_id, plan.upstreams)
-    _exec(gateway, ["sh", "-c", script])
+    transport.exec(["sh", "-c", script])
 
 
-def deprovision_git_gate(gateway: str, bottle_id: str) -> None:
+def deprovision_git_gate(transport: GatewayTransport, bottle_id: str) -> None:
     """Remove a bottle's repos + creds from the gateway on teardown. Idempotent
     — an already-absent namespace is a clean no-op (best effort; a stray dir
     can't leak, since attribution is by source IP and the bottle is gone)."""
     _require_safe(bottle_id)
-    run_docker([
-        "docker", "exec", gateway, "rm", "-rf",
-        f"/git/{bottle_id}", _creds_dir(bottle_id),
-    ])
+    try:
+        transport.exec([
+            "rm", "-rf", f"/git/{bottle_id}", _creds_dir(bottle_id),
+        ])
+    except GatewayProvisionError:
+        pass  # best-effort teardown; absent namespace is success
 
 
-__all__ = ["provision_git_gate", "deprovision_git_gate", "GatewayProvisionError"]
+__all__ = [
+    "provision_git_gate", "deprovision_git_gate",
+    "GatewayProvisionError", "GatewayTransport", "DockerGatewayTransport",
+]

bot_bottle/backend/firecracker/consolidated_launch.py

@@ -44,7 +44,11 @@ from ...orchestrator.lifecycle import (
 )
 from ...orchestrator.registration import registration_inputs
 from ..docker.egress import EGRESS_PORT
-from ..docker.gateway_provision import deprovision_git_gate, provision_git_gate
+from ..docker.gateway_provision import (
+    DockerGatewayTransport,
+    deprovision_git_gate,
+    provision_git_gate,
+)
 from ...supervise import SUPERVISE_PORT
 
 _GIT_HTTP_PORT = 9420
@@ -126,7 +130,8 @@ def launch_consolidated(
         metadata=inputs.metadata, tokens=tokens,
     )
     try:
-        provision_git_gate(gateway_name, reg.bottle_id, git_gate_plan)
+        provision_git_gate(
+            DockerGatewayTransport(gateway_name), reg.bottle_id, git_gate_plan)
     except Exception:
         client.teardown_bottle(reg.bottle_id)
         raise
@@ -152,7 +157,7 @@ def teardown_consolidated(
     """Deregister the bottle and remove its git-gate state from the gateway.
     Both steps are idempotent so this is safe from a cleanup trap."""
     OrchestratorClient(orchestrator_url).teardown_bottle(bottle_id)
-    deprovision_git_gate(gateway_name, bottle_id)
+    deprovision_git_gate(DockerGatewayTransport(gateway_name), bottle_id)
 
 
 __all__ = [

tests/unit/test_gateway_provision.py

@@ -8,6 +8,7 @@ from unittest.mock import Mock, patch
 
 from bot_bottle.backend.docker.gateway_provision import (
     GatewayProvisionError,
+    DockerGatewayTransport,
     deprovision_git_gate,
     provision_git_gate,
 )
@@ -54,7 +55,7 @@ class TestProvisionGitGate(unittest.TestCase):
     def test_copies_creds_and_runs_namespaced_init(self) -> None:
         calls: list[list[str]] = []
         with patch(_RUN, side_effect=_recorder(calls)):
-            provision_git_gate("gw", "bottle1", _plan(_up("foo", known_hosts="/host/kh")))
+            provision_git_gate(DockerGatewayTransport("gw"), "bottle1", _plan(_up("foo", known_hosts="/host/kh")))
 
         cps = [c for c in calls if c[:2] == ["docker", "cp"]]
         self.assertIn(["docker", "cp", "/host/keys/id", "gw:/git-gate/creds/bottle1/foo-key"], cps)
@@ -71,32 +72,32 @@ class TestProvisionGitGate(unittest.TestCase):
     def test_omits_known_hosts_copy_when_absent(self) -> None:
         calls: list[list[str]] = []
         with patch(_RUN, side_effect=_recorder(calls)):
-            provision_git_gate("gw", "b1", _plan(_up("foo")))  # no known_hosts
+            provision_git_gate(DockerGatewayTransport("gw"), "b1", _plan(_up("foo")))  # no known_hosts
         creds_cps = [c for c in calls if c[:2] == ["docker", "cp"] and "/git-gate/creds/" in c[3]]
         self.assertEqual(1, len(creds_cps))  # only the key, not known_hosts
         self.assertTrue(creds_cps[0][3].endswith("/foo-key"))
 
     def test_no_upstreams_is_noop(self) -> None:
         with patch(_RUN) as m:
-            provision_git_gate("gw", "b1", _plan())
+            provision_git_gate(DockerGatewayTransport("gw"), "b1", _plan())
         m.assert_not_called()
 
     def test_raises_on_docker_failure(self) -> None:
         with patch(_RUN, return_value=_proc(returncode=1, stderr="boom")):
             with self.assertRaises(GatewayProvisionError):
-                provision_git_gate("gw", "b1", _plan(_up("foo")))
+                provision_git_gate(DockerGatewayTransport("gw"), "b1", _plan(_up("foo")))
 
     def test_rejects_unsafe_bottle_id_before_any_docker(self) -> None:
         with patch(_RUN) as m:
             with self.assertRaises(GatewayProvisionError):
-                provision_git_gate("gw", "../etc", _plan(_up("foo")))
+                provision_git_gate(DockerGatewayTransport("gw"), "../etc", _plan(_up("foo")))
         m.assert_not_called()  # rejected before a single docker call
 
 
 class TestDeprovision(unittest.TestCase):
     def test_removes_repo_and_creds(self) -> None:
         with patch(_RUN, return_value=_proc()) as m:
-            deprovision_git_gate("gw", "b1")
+            deprovision_git_gate(DockerGatewayTransport("gw"), "b1")
         argv = m.call_args.args[0]
         self.assertEqual(["docker", "exec", "gw", "rm", "-rf"], argv[:5])
         self.assertIn("/git/b1", argv)
@@ -105,7 +106,7 @@ class TestDeprovision(unittest.TestCase):
     def test_rejects_unsafe_bottle_id(self) -> None:
         with patch(_RUN) as m:
             with self.assertRaises(GatewayProvisionError):
-                deprovision_git_gate("gw", "a/b")
+                deprovision_git_gate(DockerGatewayTransport("gw"), "a/b")
         m.assert_not_called()