[IMP] runbot: allow runbot builder to handle sighup

When the main nginx process is is restarted e.g. during unattended
upgrades, it happens that the nginx process handled by the runbot
builder needs to be restarted. Otherwise we loose conections with
running instances.

With this commit, the runbot builder now handles the SIGHUP signal and
reloads restart its nginx process in that case. That way, the main nginx
service could be configured to send a SIGHUP signal to the runbot
builder service.

Author: d-fence

runbot/models/runbot.py

@@ -152,7 +152,7 @@ def _allocate_builds(self, host, nb_slots, domain=None):
                     RETURNING id""", host.name, query.select(), nb_slots))
         return self.env.cr.fetchall()
 
-    def _reload_nginx(self):
+    def _reload_nginx(self, force=False):
         env = self.env
         settings = {}
         settings['port'] = config.get('http_port')
@@ -174,7 +174,7 @@ def _reload_nginx(self):
         if os.path.isfile(nginx_conf_path):
             with file_open(nginx_conf_path, 'r') as f:
                 content = f.read()
-        if content != nginx_config:
+        if content != nginx_config or force:
             _logger.info('reload nginx')
             with open(nginx_conf_path, 'w') as f:
                 f.write(str(nginx_config))

runbot_builder/tools.py

@@ -44,6 +44,7 @@ def main_loop(self):
         signal.signal(signal.SIGINT, self.signal_handler)
         signal.signal(signal.SIGTERM, self.signal_handler)
         signal.signal(signal.SIGQUIT, self.dump_stack)
+        signal.signal(signal.SIGHUP, self.reload)
         self.host = self.env['runbot.host']._get_current()
         self.update_next_git_gc_date()
         self.host._bootstrap()
@@ -96,6 +97,9 @@ def dump_stack(self, _signal, _frame):
         import odoo
         odoo.tools.misc.dumpstacks()
 
+    def reload(self):
+        self.env['runbot.runbot']._reload_nginx(force=True)
+
     def sleep(self, t):
         self.ask_interrupt.wait(t)