update_stable.py

#!/usr/bin/env python3

import json
import subprocess
import sys
from datetime import datetime
from textwrap import dedent
from typing import List, Tuple

DOCKER_SYNTAX = "docker/dockerfile:1.14"

DOCKER_FILES_TO_IMAGES: list[tuple[str, str]] = [
    ("docker/rust-stable.dockerfile", "docker.gosh.sh/rust"),
    ("docker/debian-stable.dockerfile", "docker.gosh.sh/debian"),
    ("docker/debian-stable-slim.dockerfile", "docker.gosh.sh/debian:slim"),
]


def run_command(cmd: List[str]) -> Tuple[str, str, int]:
    """Run a command and return stdout, stderr, and return code."""
    process = subprocess.run(cmd, capture_output=True, text=True)
    return process.stdout.strip(), process.stderr.strip(), process.returncode


def get_digest_for_platform(manifest: str, architecture: str) -> str:
    """Gets the digest for a given platform from a docker manifest."""
    stdout, stderr, rc = run_command(["docker", "manifest", "inspect", manifest])
    if rc != 0:
        raise RuntimeError(f"Failed to inspect manifest {manifest}: {stderr}")

    try:
        manifest_data = json.loads(stdout)
        for manifest_item in manifest_data.get("manifests", []):
            if manifest_item.get("platform", {}).get("architecture") == architecture:
                return manifest_item.get("digest")
    except json.JSONDecodeError:
        raise ValueError("Failed to parse manifest data")

    raise ValueError(f"Could not get digest for {manifest} {architecture}")


def update_dockerfile(dockerfile_path: str, manifest_base: str) -> None:
    """Updates a dockerfile with the latest digests for amd64 and arm64 architectures."""
    manifest_without_tag = manifest_base.split(":")[0]

    amd64_digest = get_digest_for_platform(manifest_base, "amd64")
    arm64_digest = get_digest_for_platform(manifest_base, "arm64")

    print(dedent(f"""\
        Current digests for {manifest_base} are
        amd64: {amd64_digest}
        arm64: {arm64_digest}"""))

    dockerfile_content = f"""# syntax={DOCKER_SYNTAX}

#
# This file is automatically generated by `./update_stable.py` at {datetime.now()}
# Manual modifications will be overwritten
#

FROM --platform=linux/amd64 {manifest_without_tag}@{amd64_digest} AS base-amd64
FROM --platform=linux/arm64 {manifest_without_tag}@{arm64_digest} AS base-arm64

FROM base-${{TARGETARCH}}
"""

    with open(dockerfile_path, "w") as f:
        f.write(dockerfile_content)

    print(f"{dockerfile_path} updated successfully")


def main():
    for docker_file, image_base in DOCKER_FILES_TO_IMAGES:
        print(f"Updating {docker_file} with {image_base}")
        try:
            update_dockerfile(docker_file, image_base)
        except Exception as e:
            print(f"Failed to update {docker_file}: {e}")
            sys.exit(1)

if __name__ == "__main__":
    main()