Add script to commit repodata/

Let's match the securedrop-apt-prod process by generating metadata at
commit-time instead of doing it on the server.

CI verifies the generated metadata is up to date and fully reproducible.

.gitattributes

@@ -1,2 +1,4 @@
 *.deb filter=lfs diff=lfs merge=lfs -text
 *.rpm filter=lfs diff=lfs merge=lfs -text
+*.gz filter=lfs diff=lfs merge=lfs -text
+*.bz2 filter=lfs diff=lfs merge=lfs -text

.github/workflows/ci.yml

@@ -23,3 +23,25 @@ jobs:
                 wget https://github.com/freedomofpress/securedrop-debian-packaging/raw/main/securedrop-keyring/securedrop-keyring.gpg
                 gpg --import securedrop-keyring.gpg && gpg --armor --export > securedrop-keyring.asc
                 ./tools/check-signed securedrop-keyring.asc
+
+    metadata:
+        runs-on: ubuntu-latest
+        container: debian:bookworm
+        steps:
+            - name: Install dependencies
+              run: |
+                apt-get update && apt-get install --yes python3 git git-lfs createrepo-c
+            - name: Checkout
+              uses: actions/checkout@v3
+              with:
+                lfs: true
+                fetch-depth: 0
+            - name: Check repository metadata is up-to-date
+              run: |
+                git config --global --add safe.directory '*'
+                shopt -s globstar
+                # Parse the value out of <revision></revision>
+                export SOURCE_DATE_EPOCH=$(grep -m 1 "revision" public/**/repomd.xml | cut -d '>' -f 2 | cut -d '<' -f 1)
+                ./tools/publish-real
+                git status
+                git diff --exit-code

tools/publish

@@ -0,0 +1,6 @@
+#!/bin/bash
+# Pull the latest image
+podman pull debian:bookworm
+# Mount the git repo to /srv, install necessary packages and run the publish script
+podman run --rm -it -v $(git rev-parse --show-toplevel):/srv:Z debian:bookworm \
+    bash -c "apt-get update && apt-get install -y python3 createrepo-c && /srv/tools/publish-real"

tools/publish-real

@@ -0,0 +1,44 @@
+#!/usr/bin/env python3
+"""
+Script for generating yum repository metadata. Files are
+copied into public/ and metadata is generated there.
+"""
+import os
+import shutil
+import subprocess
+from pathlib import Path
+
+
+def main():
+    root = Path(__file__).parent.parent
+    public = root / "public"
+    workstation = root / "workstation"
+    # Reset public, copy the workstation/ tree into it
+    if public.exists():
+        shutil.rmtree(public)
+    public.mkdir()
+    shutil.copytree(workstation, public / "workstation")
+    # Folders are public/workstation/dom0/fXX, run createrepo_c in each one
+    for folder in public.glob("*/*/*/"):
+        if not folder.is_dir():
+            continue
+        print(f"Generating metadata for {folder}")
+        args = ["createrepo_c"]
+        if "SOURCE_DATE_EPOCH" in os.environ:
+            # The <revision> and <timestamp> fields are set to the current UNIX time
+            # unless we explicitly override them. In most cases we want to use
+            # the current time except when we're doing reproducibility testing.
+            args.extend(
+                [
+                    "--revision",
+                    os.environ["SOURCE_DATE_EPOCH"],
+                    "--set-timestamp-to-revision",
+                ]
+            )
+        args.append(str(folder))
+        subprocess.check_call(args)
+    print("Done!")
+
+
+if __name__ == "__main__":
+    main()