didericis-claude
f2775101a0
smolvm machine exec requires stdout to be a pipe, not a regular file descriptor. Passing stdout=file caused smolvm to return non-zero with no stderr (the error was silently swallowed or went to the regular-file fd instead of reaching us). Switch _snapshot_running_vm to a new _exec_tar_to_file helper that uses Popen with stdout=PIPE and streams the tar to disk via shutil.copyfileobj. A background thread drains stderr concurrently to prevent deadlock when the stderr pipe buffer fills while we are writing stdout data.
129 lines
4.5 KiB
Python
129 lines
4.5 KiB
Python
"""SmolmachinesFreezer — snapshot a smolmachines bottle.
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`smolvm pack create --from-vm` requires the VM to be stopped, and smolvm
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removes VMs when stopped (same issue as Apple Container). Instead, exec
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into the running VM as root and stream the root filesystem via tar, build
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a Docker image from the archive, convert it to a smolmachine artifact via
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the existing registry pipeline, and record the sidecar path. The VM stays
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running throughout."""
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from __future__ import annotations
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import shutil
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import subprocess
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import tempfile
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import threading
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from pathlib import Path
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from .. import ActiveAgent
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from ..freeze import Freezer
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from ..docker import util as docker_mod
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from .local_registry import crane_push_tarball, ephemeral_registry
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from .smolvm import pack_create
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from ...bottle_state import bottle_state_dir
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from ...log import die, info
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class SmolmachinesFreezer(Freezer):
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"""Freezes a smolmachines bottle via exec-tar + Docker image + smolmachine pack.
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The VM is NOT stopped. smolvm machine exec streams the root filesystem
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via tar; we build a Docker image from it and run the same image→registry→
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pack_create pipeline that _ensure_smolmachine uses for fresh builds."""
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backend_name = "smolmachines"
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def _freeze(self, agent: ActiveAgent) -> str:
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machine = f"bot-bottle-{agent.slug}"
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image_ref = f"bot-bottle-committed-{agent.slug}:latest"
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output_dir = bottle_state_dir(agent.slug)
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output_dir.mkdir(parents=True, exist_ok=True)
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binary = output_dir / "committed-smolmachine"
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sidecar = output_dir / "committed-smolmachine.smolmachine"
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_snapshot_running_vm(machine, image_ref, binary)
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return str(sidecar)
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def _export_hint(self, slug: str, image_ref: str) -> None:
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info(f"to export for migration: cp {image_ref} {slug}.smolmachine")
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def _snapshot_running_vm(machine: str, image_ref: str, binary: Path) -> None:
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"""Exec-tar the running VM, build a Docker image, and pack to a smolmachine.
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binary: destination for the launcher (sibling .smolmachine is the artifact
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that machine_create --from consumes, same convention as pack_create).
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"""
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with tempfile.TemporaryDirectory(prefix="bot-bottle-vm-commit.") as tmp:
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tmp_path = Path(tmp)
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rootfs_tar = tmp_path / "rootfs.tar"
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dockerfile = tmp_path / "Dockerfile"
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_exec_tar_to_file(machine, rootfs_tar)
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dockerfile.write_text(
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"FROM scratch\n"
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"ADD rootfs.tar /\n"
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"USER node\n"
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"WORKDIR /home/node\n"
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)
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docker_mod.build_image(image_ref, str(tmp_path), dockerfile=str(dockerfile))
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image_tarball = binary.parent / "committed.image.tar"
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docker_mod.save(image_ref, str(image_tarball))
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try:
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with ephemeral_registry() as handle:
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digest = docker_mod.image_id(image_ref).split(":", 1)[-1][:16]
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push_ref = f"{handle.push_endpoint}/bot-bottle-committed:{digest}"
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pack_ref = f"{handle.pull_endpoint}/bot-bottle-committed:{digest}"
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crane_push_tarball(handle, str(image_tarball), push_ref)
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pack_create(pack_ref, binary)
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finally:
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image_tarball.unlink(missing_ok=True)
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def _exec_tar_to_file(machine: str, dest: Path) -> None:
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"""Stream the VM root filesystem as a tar archive to `dest`.
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smolvm machine exec requires stdout to be a pipe, not a regular file.
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We use Popen with stdout=PIPE and drain stderr in a background thread
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to avoid deadlock if either buffer fills while we're writing the other."""
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proc = subprocess.Popen(
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[
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"smolvm", "machine", "exec",
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"--name", machine, "--",
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"tar", "--create",
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"--exclude=./proc",
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"--exclude=./sys",
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"--exclude=./dev",
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"--exclude=./run",
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"--file=-",
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"--directory=/",
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".",
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],
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stdout=subprocess.PIPE,
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stderr=subprocess.PIPE,
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)
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stderr_chunks: list[bytes] = []
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def _drain_stderr() -> None:
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assert proc.stderr is not None
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stderr_chunks.append(proc.stderr.read())
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t = threading.Thread(target=_drain_stderr, daemon=True)
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t.start()
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assert proc.stdout is not None
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with open(dest, "wb") as out:
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shutil.copyfileobj(proc.stdout, out, length=65536)
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t.join()
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returncode = proc.wait()
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stderr = b"".join(stderr_chunks).decode(errors="replace").strip()
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if returncode != 0:
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die(
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f"smolvm exec tar {machine!r} failed: "
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f"{stderr or '<no stderr>'}"
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)
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