tools/update-distro-hash: rename, fetch the repository if appropriate

Let's rename the tool to tools/fetch-distro. It's useful to be able to fetch
the distro directly. But when that functionality is added, the old name is
confusing.

Now --update/-u must be specified to update the commits.

--reference-if-able is used to speed up the clone of debian.
It saves about 75% of the download.

1 files changed, 121 insertions, 0 deletions

diff --git a/tools/fetch-distro.py b/tools/fetch-distro.py
new file mode 100755
index 0000000000..dacaf28bca
--- /dev/null
+++ b/tools/fetch-distro.py
@@ -0,0 +1,121 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: LGPL-2.1-or-later
+
+"""
+Check out pkg/{distribution}.
+With -u, fetch commits, and if changed, commit the latest hash.
+"""
+
+import argparse
+import json
+import shlex
+import subprocess
+from pathlib import Path
+
+def parse_args():
+    p = argparse.ArgumentParser(
+        description=__doc__,
+    )
+    p.add_argument(
+        'distribution',
+        nargs='+',
+    )
+    p.add_argument(
+        '--no-fetch',
+        dest='fetch',
+        action='store_false',
+        default=True,
+    )
+    p.add_argument(
+        '--update', '-u',
+        action='store_true',
+        default=False,
+    )
+    return p.parse_args()
+
+def read_config(distro: str):
+    cmd = ['mkosi', '--json', '-d', distro, 'summary']
+    print(f"+ {shlex.join(cmd)}")
+    text = subprocess.check_output(cmd, text=True)
+
+    data = json.loads(text)
+    images = {image["Image"]: image for image in data["Images"]}
+    return images["build"]
+
+def commit_file(distro: str, file: Path, commit: str, changes: str):
+    message = '\n'.join((
+        f'mkosi: update {distro} commit reference',
+        '',
+        changes))
+
+    cmd = ['git', 'commit', '-m', message, str(file)]
+    print(f"+ {shlex.join(cmd)}")
+    subprocess.check_call(cmd)
+
+def checkout_distro(args, distro: str, config: dict):
+    dest = Path(f'pkg/{distro}')
+    if dest.exists():
+        print(f'{dest} already exists.')
+        return
+
+    url = config['Environment']['GIT_URL']
+    branch = config['Environment']['GIT_BRANCH']
+
+    # Only debian uses source-git for now…
+    reference = [f'--reference-if-able=.'] if distro == 'debian' else []
+
+    cmd = [
+        'git', 'clone', url,
+        f'--branch={branch}',
+        dest.as_posix(),
+        *reference,
+    ]
+    print(f"+ {shlex.join(cmd)}")
+    subprocess.check_call(cmd)
+
+    args.fetch = False  # no need to fetch if we just cloned
+
+def update_distro(args, distro: str, config: dict):
+    cmd = ['git', '-C', f'pkg/{distro}', 'fetch']
+    print(f"+ {shlex.join(cmd)}")
+    subprocess.check_call(cmd)
+
+    branch = config['Environment']['GIT_BRANCH']
+    old_commit = config['Environment']['GIT_COMMIT']
+
+    cmd = ['git', '-C', f'pkg/{distro}', 'rev-parse', f'refs/remotes/origin/{branch}']
+    print(f"+ {shlex.join(cmd)}")
+    new_commit = subprocess.check_output(cmd, text=True).strip()
+
+    if old_commit == new_commit:
+        print(f'{distro}: commit {new_commit!s} is still fresh')
+        return
+
+    cmd = ['git', '-C', f'pkg/{distro}', 'log', '--graph',
+           '--pretty=oneline', '--no-decorate', '--abbrev-commit', '--abbrev=10',
+           f'{old_commit}..{new_commit}']
+    print(f"+ {shlex.join(cmd)}")
+    changes = subprocess.check_output(cmd, text=True).strip()
+
+    conf_dir = Path('mkosi.images/build/mkosi.conf.d')
+    files = conf_dir.glob('*/*.conf')
+    for file in files:
+        s = file.read_text()
+        if old_commit in s:
+            print(f'{distro}: {file}: found old hash, updating…')
+            new = s.replace(old_commit, new_commit)
+            assert new != s
+            file.write_text(new)
+            commit_file(distro, file, new_commit, changes)
+            break
+    else:
+        raise ValueError(f'{distro}: hash {new_commit} not found under {conf_dir}')
+
+if __name__ == '__main__':
+    args = parse_args()
+
+    for distro in args.distribution:
+        config = read_config(distro)
+        checkout_distro(args, distro, config)
+        if args.update:
+            update_distro(args, distro, config)