ceamac
dd66886de8
Idempotent: does nothing if images/busybox.tar already exists (your own unofficial build, or a previous fetch). Otherwise tries skopeo, then podman, then docker, in that order -- skopeo/podman both reliably produce a genuine OCI Image Layout tar; a plain `docker save` only does if the containerd image store happens to be enabled, so the result is verified (oci-layout/index.json actually present at the tar root) regardless of which tool produced it, falling through to the next option otherwise. Clear instructions + nonzero exit if none of the three are available and no fixture already exists. Verified the no-op (already-present) path and the no-tools-available error path directly (temporarily moved the existing images/busybox.tar aside and back) -- this dev machine has none of skopeo/podman/docker installed, so the actual fetch path itself is unverified here; the format-verification step (looks_like_oci_layout()) is what protects against a `docker save` that produced the legacy Docker tar format on some other machine. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01Gv3s5jckJKzh6JkMoi2Akz
109 lines
3.7 KiB
Python
Executable File
109 lines
3.7 KiB
Python
Executable File
#!/usr/bin/env python3
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"""Fetches a real, runnable busybox OCI Image Layout tar for the
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[integration][net] test categories (tests/support/fixtures.h's
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find_busybox_fixture() looks for it at images/busybox.tar, relative to the
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repo root -- the same directory this project's own manual testing has
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always used, see CLAUDE.md).
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Idempotent: if images/busybox.tar already exists (your own unofficial
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build, or a previously-fetched one), does nothing. Otherwise looks for
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skopeo, then podman, then docker, in that preference order -- skopeo and
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podman both reliably produce a genuine OCI Image Layout tar (what
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oci_image.cpp actually parses: oci-layout + index.json + blobs/sha256/*);
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a plain `docker save` only does if Docker's containerd image store happens
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to be enabled, so the result is verified either way before being accepted.
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"""
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import shutil
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import subprocess
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import sys
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import tarfile
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from pathlib import Path
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REPO_ROOT = Path(__file__).resolve().parent.parent
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TARGET = REPO_ROOT / "images" / "busybox.tar"
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IMAGE = "docker.io/library/busybox:latest"
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def looks_like_oci_layout(path: Path) -> bool:
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try:
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with tarfile.open(path) as tar:
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names = set(tar.getnames())
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except tarfile.TarError:
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return False
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return "oci-layout" in names and "index.json" in names
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def fetch_with_skopeo() -> bool:
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print("fetching busybox via skopeo...")
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result = subprocess.run(
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["skopeo", "copy", f"docker://{IMAGE.removeprefix('docker.io/')}", f"oci-archive:{TARGET}:latest"]
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)
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return result.returncode == 0
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def fetch_with_podman() -> bool:
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print("fetching busybox via podman...")
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if subprocess.run(["podman", "pull", IMAGE]).returncode != 0:
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return False
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result = subprocess.run(["podman", "save", "--format", "oci-archive", "-o", str(TARGET), IMAGE])
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return result.returncode == 0
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def fetch_with_docker() -> bool:
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print("fetching busybox via docker (only works if the containerd image store is enabled)...")
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if subprocess.run(["docker", "pull", IMAGE]).returncode != 0:
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return False
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result = subprocess.run(["docker", "save", "-o", str(TARGET), IMAGE])
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return result.returncode == 0
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def main() -> int:
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if TARGET.exists():
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print(f"already present: {TARGET}")
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return 0
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TARGET.parent.mkdir(parents=True, exist_ok=True)
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fetchers = [
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("skopeo", fetch_with_skopeo),
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("podman", fetch_with_podman),
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("docker", fetch_with_docker),
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]
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for tool, fetch in fetchers:
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if not shutil.which(tool):
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continue
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try:
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ok = fetch()
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except OSError as exc:
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print(f"{tool} failed to run: {exc}", file=sys.stderr)
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ok = False
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if not ok:
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TARGET.unlink(missing_ok=True)
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print(f"{tool} was found but fetching busybox with it failed; trying the next option", file=sys.stderr)
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continue
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if not looks_like_oci_layout(TARGET):
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TARGET.unlink(missing_ok=True)
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print(
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f"{tool} produced {TARGET.name}, but it isn't a genuine OCI Image Layout tar "
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"(no oci-layout/index.json at its root) -- if that was docker, this usually means "
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"the containerd image store isn't enabled; trying the next option",
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file=sys.stderr,
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)
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continue
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print(f"fetched: {TARGET}")
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return 0
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print(
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"no usable image tool found (checked skopeo, podman, docker) and "
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f"{TARGET} doesn't already exist.\n"
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"Install one of skopeo/podman/docker, or supply your own busybox-like "
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f"OCI Image Layout tar at {TARGET} directly.",
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file=sys.stderr,
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)
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return 1
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if __name__ == "__main__":
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sys.exit(main())
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