Examples

The following example demonstrates how to initialize the status handler for the base application status page.

import tornado.ioloop
import tornado.web
from sprockets.handlers import status


application = tornado.web.Application([
    ('/status', status.StatusHandler),
])

if __name__ == '__main__':

    # Set the application name to the local package
    status.set_application('mypackage')

    application.listen(8888)
    tornado.ioloop.IOLoop.current().start()

You can change the status by setting the status attribute on RequestHandler.application, but note this does it for the single running process and should be coordinated across all backends using an external synchronization mechanism.

The following example uses Consul to determine if a request is in maintenance mode.

import json
import socket

from tornado import gen
from tornado import httpclient
from sprockets.handlers import status

class ConsulStatusHandler(status.StatusHandler):

    HEALTH_URL_FORMAT = 'http://localhost:8500/v1/health/node/{0}

    @gen.coroutine
    def prepare(self):
        result = yield self._maintenance_enabled()
        if result:
            setattr(self.application, 'status', status.MAINTENANCE)
        else:
            setattr(self.application, 'status', status.OK)

    @gen.coroutine
    def _maintenance_enabled(self)
        client = httpclient.AsyncHTTPClient()
        url = self.HEALTH_URL_FORMAT.format(socket.gethostname())
        result = yield client.fetch()
        return self._in_maintenance(json.loads(result.body))

    @staticmethod
    def _in_maintenance(self, checks):
        for check in checks:
             if check['CheckID'] == '_node_maintenance':
                return check['Status'] == 'critical'
        return False