upgrades: Add button to activate backports

Signed-off-by: James Valleroy <jvalleroy@mailbox.org>
Reviewed-by: Sunil Mohan Adapa <sunil@medhas.org>

plinth/modules/upgrades/__init__.py

@@ -58,7 +58,7 @@ class UpgradesApp(app_module.App):
         # Check every day for setting up apt backport sources, every 3 minutes
         # in debug mode.
         interval = 180 if cfg.develop else 24 * 3600
-        glib.schedule(interval, _setup_repositories)
+        glib.schedule(interval, setup_repositories)
 
     def _show_new_release_notification(self):
         """When upgraded to new release, show a notification."""
@@ -111,7 +111,7 @@ def setup(helper, old_version=None):
 
     # Try to setup apt repositories, if needed, if possible, on first install
     # and on version increment.
-    helper.call('post', _setup_repositories, None)
+    helper.call('post', setup_repositories, None)
 
 
 def is_enabled():
@@ -130,7 +130,7 @@ def disable():
     actions.superuser_run('upgrades', ['disable-auto'])
 
 
-def _setup_repositories(data):
+def setup_repositories(data):
     """Setup apt backport repositories."""
     actions.superuser_run('upgrades', ['setup-repositories'])
 
@@ -146,3 +146,16 @@ def get_backports_in_use():
                 return True
 
     return False
+
+
+def can_activate_backports():
+    """Return whether backports can be activated."""
+    if get_backports_in_use():
+        return False
+
+    release = subprocess.check_output(['lsb_release', '--release',
+                                       '--short']).decode().strip()
+    if release in ['testing', 'unstable']:
+        return False
+
+    return True

plinth/modules/upgrades/templates/upgrades_configure.html

@@ -8,6 +8,40 @@
 {% load static %}
 
 {% block extra_content %}
+  {% if can_activate_backports %}
+    <h3>{% trans "Backports" %}</h3>
+    <p>
+      {% blocktrans trimmed %}
+        Backports can be activated. This will allow a limited set of software,
+        including FreedomBox service, to be upgraded to newer versions from
+        Debian backports repository.
+      {% endblocktrans %}
+    </p>
+    <p>
+      {% blocktrans trimmed %}
+        Please note that backports packages do not have security support from
+        Debian. However, they are maintained on a best-effort basis by
+        contributors in Debian and FreedomBox community.
+      {% endblocktrans %}
+    </p>
+    <div class="alert alert-warning" role="alert">
+      {% url 'snapshot:index' as snapshot_url %}
+      {% blocktrans trimmed %}
+        <strong>Warning!</strong> Once backports are activated, they cannot be
+        easily deactivated. You may wish to take a snapshot using
+        <a href="{{ snapshot_url }}">Storage Snapshots</a> before continuing.
+      {% endblocktrans %}
+    </div>
+    <p>
+      <form class="form" method="post"
+            action="{% url 'upgrades:activate-backports' %}">
+        {% csrf_token %}
+        <input type="submit" class="btn btn-warning"
+               value="{% trans 'Activate backports' %}"/>
+      </form>
+    </p>
+  {% endif %}
+
   <h3>{% trans "Manual update" %}</h3>
   {% if is_busy %}
     <p>

plinth/modules/upgrades/urls.py

@@ -10,5 +10,7 @@ from . import views
 urlpatterns = [
     url(r'^sys/upgrades/$', views.UpgradesConfigurationView.as_view(),
         name='index'),
+    url(r'^sys/upgrades/activate-backports/$', views.activate_backports,
+        name='activate-backports'),
     url(r'^sys/upgrades/upgrade/$', views.upgrade, name='upgrade'),
 ]

plinth/modules/upgrades/views.py

@@ -28,6 +28,7 @@ class UpgradesConfigurationView(AppView):
 
     def get_context_data(self, *args, **kwargs):
         context = super().get_context_data(*args, **kwargs)
+        context['can_activate_backports'] = upgrades.can_activate_backports()
         context['is_busy'] = package.is_package_manager_busy()
         context['log'] = get_log()
         context['refresh_page_sec'] = 3 if context['is_busy'] else None
@@ -77,3 +78,12 @@ def upgrade(request):
             messages.error(request, _('Starting upgrade failed.'))
 
     return redirect(reverse_lazy('upgrades:index'))
+
+
+def activate_backports(request):
+    """Activate backports."""
+    if request.method == 'POST':
+        upgrades.setup_repositories(None)
+        messages.success(request, _('Backports activated.'))
+
+    return redirect(reverse_lazy('upgrades:index'))