Building Resilient Apps

KevKev
4 min read

It all started with a client who managed sporting events across various stadiums. Everything seemed perfect — players, schedules, and the excitement of the game. But there was one nagging issue: internet connectivity. In large stadiums with patchy network coverage, the client’s app struggled to handle the creation of matches, associating players with those matches, and tagging real-time events to players. This caused significant disruptions and frustration. The matches were happening, but the system couldn’t keep up.

They needed a solution to ensure their app was robust, even with unstable connections, and that’s when we realized we needed to think differently. This wasn’t just about managing data; it was about ensuring seamless experiences regardless of internet conditions.

The Inspiration

The problem the client faced wasn’t uncommon. In many industries — be it logistics, healthcare, or even sports — applications are often expected to operate in environments where connectivity is unreliable. But these applications still need to process events, sync data, and ensure nothing is missed. For the client, this became critical. The system had to handle a high volume of match events and sync them with a central server, but it also had to be resilient enough to work offline, logging every event and syncing it back up once the connection was restored.

This inspired me to build Queue in Background (qbg) (Link), a package that could solve these real-world issues with an elegant, flexible, and offline-ready solution.

The Solution

Queue in Background (qbg) isn’t just another queuing system — it’s designed specifically for environments where internet connectivity is unpredictable. Imagine you’re at a stadium where thousands of fans are all connected to the same network. If your application relies on stable internet, good luck keeping it running smoothly.

With qbg, however, we’ve taken a different approach:

  • Queue-Based Architecture: Actions, like creating matches, associating players, or tagging events, are queued. This means that even if the network goes down, the app keeps functioning, storing every action in the queue.

  • Sequential Processing: Actions are executed one after another, ensuring the order of events is maintained, even when offline.

  • Offline-Ready: If the network drops, the queue doesn’t stop. Once connectivity is restored, the actions are replayed to the server, syncing everything perfectly.

A Real-World Use Case: Sports Events

Let’s go back to the stadium scenario. The client needed to handle not just match events but also player associations and substitutions — all in real-time. The qbg package enabled the app to queue these actions in the background. When a player was substituted, it would create an event tagging that player and sync it later when the connection was back. Even if other events happened during the downtime, qbg maintains the order.

This approach made the app feel seamless for end users. They didn’t know — or need to know — that the internet had dropped. To them, everything was happening in real time, as it should.

Why It Works

The power of qbg lies in its flexibility:

  • Just-in-time Payload Transformation: Before each action is executed, qbg allows you to transform the payload. Need to add extra information just before sending? No problem.

  • Persistent Queue: The queue isn’t volatile. If the app shuts down or crashes, the queue can be restored from where it left off, ensuring no data loss.

  • Custom Error Handling: Errors happen, and qbg is designed to handle them. Whether retrying failed actions or moving them to a dead-letter queue for manual processing, qbg adapts to your needs.

Architecting Offline-Ready Apps

The beauty of qbg isn’t just in solving a stadium problem. It’s about architecting applications that can handle unreliable environments. Whether it’s a delivery service in rural areas, an app used in remote locations, or a healthcare app operating in critical, low-connectivity zones, qbg lets you architect offline-ready apps that use a replay strategy to sync events when the network is back.

You can queue server actions, associate user data, or sync vital transactions — without worrying about network availability.

The Result

With qbg in place, the client’s app transformed. Matches were created smoothly, players were tagged with events in real-time, and fans never noticed a hitch, even in stadiums with unstable connections. The stress of managing match data disappeared, and qbg took care of syncing everything the moment the connection was restored.

Conclusion

The Queue in Background (qbg) package was born out of a real-world problem, but its applications go far beyond the sporting world. If your app deals with intermittent connectivity, you don’t need to stress anymore. With qbg, you can build offline-ready applications that keep running, keep syncing, and keep your users happy — no matter where they are or how good the connection is.

Whether you’re in a crowded stadium, on a remote construction site, or managing healthcare in a low-network zone, qbg is ready to solve those headaches. It’s more than just code — it’s peace of mind.

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Written by

Kev
Kev

My hair is a mess, but so am I. My typos are unforced errors. Maybe I'll write a book someday #Programmer #StartupLife #NonConformist #LiverpoolFC