refactor(backend): pass Bottle to provisioners instead of target string

Closes #178.

The backend provision functions now receive a Bottle handle with
exec / cp_in methods instead of a raw target string. Provisioner
modules use bottle.exec and bottle.cp_in in place of inlined
subprocess.run(["docker", "exec"/"cp", ...]) and direct
_smolvm.machine_cp / machine_exec calls. This decouples the
provisioners from backend-specific runtime primitives so future
refactors (e.g. the supervise rework) can swap the bottle's exec
implementation without touching every provisioner.

Each launch.py constructs the Bottle handle before calling
provision so it can be passed in; provision_prompt's return value
is wired back onto the bottle's prompt path attribute after the
fact.

bot_bottle/backend/smolmachines/provision/git.py

@@ -26,12 +26,13 @@ git_gate module."""
 from __future__ import annotations
 
 import os
+import shlex
 import tempfile
 from pathlib import Path
 
 from ....git_gate import git_gate_render_gitconfig
 from ....log import info
-from .. import smolvm as _smolvm
+from ... import Bottle
 from ..bottle_plan import SmolmachinesBottlePlan
 
 
@@ -46,15 +47,15 @@ def _guest_home() -> str:
     return os.environ.get("BOT_BOTTLE_GUEST_HOME", _DEFAULT_GUEST_HOME)
 
 
-def provision_git(plan: SmolmachinesBottlePlan, target: str) -> None:
+def provision_git(plan: SmolmachinesBottlePlan, bottle: Bottle) -> None:
     """Set up git inside the guest. Runs all three subcases; each
     no-ops when its condition isn't met."""
-    _provision_cwd_git(plan, target)
-    _provision_git_gate_config(plan, target)
-    _provision_git_user(plan, target)
+    _provision_cwd_git(plan, bottle)
+    _provision_git_gate_config(plan, bottle)
+    _provision_git_user(plan, bottle)
 
 
-def _provision_cwd_git(plan: SmolmachinesBottlePlan, target: str) -> None:
+def _provision_cwd_git(plan: SmolmachinesBottlePlan, bottle: Bottle) -> None:
     """If --cwd was set and the host cwd has a .git directory, copy
     it into <guest_home>/workspace/.git and fix ownership. No-op
     otherwise."""
@@ -63,25 +64,26 @@ def _provision_cwd_git(plan: SmolmachinesBottlePlan, target: str) -> None:
         return
     guest_workspace_git = f"{workspace.guest_path}/.git"
     host_git = str(workspace.host_path / ".git")
-    info(f"copying {host_git} -> {target}:{guest_workspace_git}")
-    # mkdir -p the workspace dir so `machine cp` lands the .git
+    info(f"copying {host_git} -> {bottle.name}:{guest_workspace_git}")
+    # mkdir -p the workspace dir so cp_in lands the .git
     # directly there even on first-time bottles.
-    _smolvm.machine_exec(target, ["mkdir", "-p", workspace.guest_path])
-    _smolvm.machine_cp(
-        host_git, f"{target}:{guest_workspace_git}",
-    )
-    # `machine cp` lands files as root; the agent runs as node so
+    bottle.exec(f"mkdir -p {shlex.quote(workspace.guest_path)}", user="root")
+    bottle.cp_in(host_git, guest_workspace_git)
+    # cp_in lands files as root; the agent runs as node so
     # the workspace tree must be chowned over.
-    _smolvm.machine_exec(
-        target, ["chown", "-R", workspace.owner, guest_workspace_git],
+    bottle.exec(
+        f"chown -R {shlex.quote(workspace.owner)} {shlex.quote(guest_workspace_git)}",
+        user="root",
     )
 
 
-def _provision_git_gate_config(plan: SmolmachinesBottlePlan, target: str) -> None:
+def _provision_git_gate_config(
+    plan: SmolmachinesBottlePlan, bottle: Bottle
+) -> None:
     """Write ~/.gitconfig in the guest with the git-gate insteadOf
     rules. No-op when the bottle has no `git` entries."""
-    bottle = plan.spec.manifest.bottle_for(plan.spec.agent_name)
-    if not bottle.git:
+    manifest_bottle = plan.spec.manifest.bottle_for(plan.spec.agent_name)
+    if not manifest_bottle.git:
         return
 
     # `<loopback alias>:<host port>` form: the bundle's git-gate
@@ -90,11 +92,11 @@ def _provision_git_gate_config(plan: SmolmachinesBottlePlan, target: str) -> Non
     # TSI, not the docker bridge IP) can dial it. launch.py
     # populates `plan.agent_git_gate_host` after bundle bringup.
     content = git_gate_render_gitconfig(
-        bottle.git, plan.agent_git_gate_host, scheme="http",
+        manifest_bottle.git, plan.agent_git_gate_host, scheme="http",
     )
 
     guest_gitconfig = f"{_guest_home()}/.gitconfig"
-    # Stage the file under the plan's stage_dir so `machine cp`
+    # Stage the file under the plan's stage_dir so cp_in
     # has a stable host path. The plan's stage_dir is cleaned up
     # by start.py's session-end teardown.
     with tempfile.NamedTemporaryFile(
@@ -105,41 +107,38 @@ def _provision_git_gate_config(plan: SmolmachinesBottlePlan, target: str) -> Non
         config_file = Path(f.name)
     os.chmod(config_file, 0o600)
 
-    info(f"writing {guest_gitconfig} with {len(bottle.git)} insteadOf rule(s)")
-    _smolvm.machine_cp(str(config_file), f"{target}:{guest_gitconfig}")
-    _smolvm.machine_exec(target, ["chown", "node:node", guest_gitconfig])
-    _smolvm.machine_exec(target, ["chmod", "644", guest_gitconfig])
+    info(f"writing {guest_gitconfig} with {len(manifest_bottle.git)} insteadOf rule(s)")
+    bottle.cp_in(str(config_file), guest_gitconfig)
+    bottle.exec(
+        f"chown node:node {shlex.quote(guest_gitconfig)} && "
+        f"chmod 644 {shlex.quote(guest_gitconfig)}",
+        user="root",
+    )
 
 
 def _provision_git_user(
-    plan: SmolmachinesBottlePlan, target: str,
+    plan: SmolmachinesBottlePlan, bottle: Bottle,
 ) -> None:
     """Apply `git config --global user.{name,email}` inside the
     guest as the node user so --global lands in the same
     `/home/node/.gitconfig` that `_provision_git_gate_config`
     writes to. No-op when the bottle didn't declare `git.user`.
 
-    Runs via `runuser -u node --`; HOME is forced via smolvm's
-    `-e` flag because runuser (without -l) inherits root's
-    HOME=/root, which would put --global in the wrong file."""
-    bottle = plan.spec.manifest.bottle_for(plan.spec.agent_name)
-    gu = bottle.git_user
+    SmolmachinesBottle.exec(user="node") automatically sets
+    HOME=/home/node so --global writes to /home/node/.gitconfig."""
+    manifest_bottle = plan.spec.manifest.bottle_for(plan.spec.agent_name)
+    gu = manifest_bottle.git_user
     if gu.is_empty():
         return
-    env = {"HOME": _guest_home(), "USER": "node"}
     if gu.name:
         info(f"git config --global user.name = {gu.name!r}")
-        _smolvm.machine_exec(
-            target,
-            ["runuser", "-u", "node", "--",
-             "git", "config", "--global", "user.name", gu.name],
-            env=env,
+        bottle.exec(
+            f"git config --global user.name {shlex.quote(gu.name)}",
+            user="node",
         )
     if gu.email:
         info(f"git config --global user.email = {gu.email!r}")
-        _smolvm.machine_exec(
-            target,
-            ["runuser", "-u", "node", "--",
-             "git", "config", "--global", "user.email", gu.email],
-            env=env,
+        bottle.exec(
+            f"git config --global user.email {shlex.quote(gu.email)}",
+            user="node",
         )