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Summary

Emergency service for mass events satisfying the functional requirements has been successfully implemented, deployed and stress tested. The solution is ready for friends and family tests, and it could be used to measure the interest of event agencies. However, the standards of fault tolerance, high availability and horizontal scalability of the system have not been achieved.

The design of the system takes into account conditions of mass events by focusing on text communication via WebSocket and Participant UI targeting mobile devices. It does provide some degree of fault tolerance with the microservices architecture (system can function without the chat server) and chats storage could be later configured for high availability and horizontal scalability.

Implementation allows organizers to register, manage their event agencies and start chats with queued participants requesting help. Chats offer responsiveness and basic features present in popular public safety software and customer service applications, including tracking the geolocation of the participant. What makes the service different from other solutions is the focus on mass events and mobile UI allowing to find specific event and request help on it.

Nevertheless, Messenger API responsible for WebSocket communication between organizers and participants is not yet prepared for horizontal scalability and cannot be running on more than one server. In the future, already present messaging interface could be used to develop horizontal scalability of the chat service without making significant changes in other microservices.

The results of the performance tests allow to roughly estimate the throughput limits of the Messenger API for real time messaging:

  • 257 active chats with 10 messages per second in each chat,
  • or 731 active chats with 1 message per second in each chat,
  • or 1590 active chats with 1 message per 10 seconds in each chat.

Future of the system depends on the demand for its features and business needs of potential users. The source code of the application is open source and it is licensed under the MIT License. Anyone can use it as a base for the next version.