action_utils: Implement utilities for managing uwsgi configurations

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

plinth/action_utils.py

@@ -30,6 +30,9 @@ from django.utils.translation import ugettext as _
 
 logger = logging.getLogger(__name__)
 
+UWSGI_ENABLED_PATH = '/etc/uwsgi/apps-enabled/{config_name}.ini'
+UWSGI_AVAILABLE_PATH = '/etc/uwsgi/apps-available/{config_name}.ini'
+
 
 def is_systemd_running():
     """Return if we are running under systemd."""
@@ -245,6 +248,43 @@ class WebserverChange(object):
         self.actions_required.add(action_required)
 
 
+def uwsgi_is_enabled(config_name):
+    """Return whether a config is enabled in Radicale."""
+    enabled_path = UWSGI_ENABLED_PATH.format(config_name=config_name)
+    return os.path.exists(enabled_path)
+
+
+def uwsgi_enable(config_name):
+    """Enable a uwsgi configuration that runs under uwsgi."""
+    if uwsgi_is_enabled(config_name):
+        return
+
+    # uwsgi is started/stopped using init script. We don't know if it can
+    # handle some configuration already running against newly enabled
+    # configuration. So, stop first before enabling new configuration.
+    service_stop('uwsgi')
+
+    enabled_path = UWSGI_ENABLED_PATH.format(config_name=config_name)
+    available_path = UWSGI_AVAILABLE_PATH.format(config_name=config_name)
+    os.symlink(available_path, enabled_path)
+
+    service_enable('uwsgi')
+    service_start('uwsgi')
+
+
+def uwsgi_disable(config_name):
+    """Disable a uwsgi configuration that runs under uwsgi."""
+    if not uwsgi_is_enabled(config_name):
+        return
+
+    # If uwsgi is restarted later, it won't stop the just disabled
+    # configuration due to how init scripts are written for uwsgi.
+    service_stop('uwsgi')
+    enabled_path = UWSGI_ENABLED_PATH.format(config_name=config_name)
+    os.unlink(enabled_path)
+    service_start('uwsgi')
+
+
 def diagnose_port_listening(port, kind='tcp', listen_address=None):
     """Run a diagnostic on whether a port is being listened on.