feature: Caddy serves static web sites from folders on the router, defined in their own database, with files uploaded through the web service or WebDAV, and an optional PowerDNS name server answers for a zone of the sites.

debian-package/src/usr/lib/vpn-router/install-packages

@@ -0,0 +1,36 @@
+#!/usr/bin/python3
+"""Install the packages of a feature from the Ubuntu archive, then restart vpn-router-setup without waiting.
+
+Run by vpn-router-install@<feature>.service, which vpn-router-setup starts when the feature is on and its packages are
+missing: webdav (rclone) and dns (PowerDNS with its gpgsql backend). Recommended packages are left out, so PowerDNS
+comes without its bind backend. A failure is a message on standard error and the exit status 1.
+
+  install-packages FEATURE
+"""
+
+import os
+import subprocess
+import sys
+
+#: The packages of each feature.
+FEATURES = {'webdav': ['rclone'], 'dns': ['pdns-server', 'pdns-backend-pgsql']}
+
+#: apt-get, waiting up to ten minutes for dpkg's lock, which a package installation that runs setup holds.
+APT = ['apt-get', '-o', 'DPkg::Lock::Timeout=600']
+
+
+def main():
+    if len(sys.argv) != 2 or sys.argv[1] not in FEATURES:
+        sys.exit(f'usage: install-packages {"|".join(FEATURES)}')
+    environment = dict(os.environ, DEBIAN_FRONTEND='noninteractive')
+    for args in ([*APT, 'update'], [*APT, '-y', '--no-install-recommends', '-o', 'Dpkg::Options::=--force-confdef',
+                                    '-o', 'Dpkg::Options::=--force-confold', 'install', *FEATURES[sys.argv[1]]]):
+        print(f'$ {" ".join(args)}', flush=True)
+        if subprocess.run(args, env=environment).returncode != 0:
+            sys.exit(f'install-packages: {args[0]} failed')
+    subprocess.run(['systemctl', 'restart', '--no-block', 'vpn-router-setup.service'])
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main())