scripts/public_tunnel_fixture.py

Rama main · réplica de lectura del repositorio original.

"""Build offline OCI fixtures for the disposable public Tunnel QA app."""

import gzip
import hashlib
import io
import json
import struct
import tarfile


def digest(data):
    return "sha256:" + hashlib.sha256(data).hexdigest()


def static_elf_arch(binary):
    """Refuse non-Linux-format, unsupported, or dynamically linked executables."""
    if len(binary) < 64 or binary[:6] != b"\x7fELF\x02\x01":
        raise ValueError("fixture must be a 64-bit little-endian ELF executable")
    kind, machine = struct.unpack_from("<HH", binary, 16)
    architecture = {62: "amd64", 183: "arm64"}.get(machine)
    if kind not in (2, 3) or not architecture:
        raise ValueError("fixture must be an x86_64 or aarch64 executable")
    offset = struct.unpack_from("<Q", binary, 32)[0]
    entry_size, count = struct.unpack_from("<HH", binary, 54)
    if entry_size < 56 or not count or offset + entry_size * count > len(binary):
        raise ValueError("invalid ELF program headers")
    segments = [struct.unpack_from("<I", binary, offset + entry_size * i)[0] for i in range(count)]
    if 3 in segments or 1 not in segments:
        raise ValueError("fixture must be statically linked")
    return architecture


def image_fixture(binary, label):
    """Return the same (digest, manifest, blobs) tuple as ci-qa-deploy.py."""
    if label not in ("A", "B"):
        raise ValueError("fixture label must be A or B")
    architecture = static_elf_arch(binary)
    layer = io.BytesIO()
    with tarfile.open(fileobj=layer, mode="w") as archive:
        directory = tarfile.TarInfo("bin")
        directory.type = tarfile.DIRTYPE
        directory.mode = 0o755
        archive.addfile(directory)
        executable = tarfile.TarInfo("bin/public-tunnel-fixture")
        executable.mode = 0o755
        executable.size = len(binary)
        archive.addfile(executable, io.BytesIO(binary))
    raw = layer.getvalue()
    compressed = gzip.compress(raw, mtime=0)
    config = json.dumps({"architecture": architecture, "os": "linux",
                         "rootfs": {"type": "layers", "diff_ids": [digest(raw)]},
                         "config": {"Entrypoint": ["/bin/public-tunnel-fixture", label]}},
                        separators=(",", ":")).encode()
    manifest = json.dumps({"schemaVersion": 2, "mediaType": "application/vnd.oci.image.manifest.v1+json",
                           "config": {"mediaType": "application/vnd.oci.image.config.v1+json",
                                      "digest": digest(config), "size": len(config)},
                           "layers": [{"mediaType": "application/vnd.oci.image.layer.v1.tar+gzip",
                                       "digest": digest(compressed), "size": len(compressed)}]},
                          separators=(",", ":")).encode()
    return digest(manifest), manifest, {digest(config): config, digest(compressed): compressed}