BokBank

This is a demo project written for a talk on OpenTelemetry given at /dev/world in May 2024.

Warning

This code is for demonstration purposes only. Its mostly functional but was thrown together in a hurry. It's not robust, its not secure, it takes a lot of shortcuts. It comes with no warranty and no support.

Overview

This project includes two components: a minimal iOS bank app that shows your account balance, a list of transactions, and allows you to make transfers between your accounts. It also includes a minimal API using Hummingbird to facilitate it. Both ends use GRDB to support database access and value observation (reactive reads), and employ a WebSocket connection between client and server to replicate those reads to the client side.

The purpose of this project is to show usage of swift-distributed-tracing and how you might employ that in an iOS app and on a backend and tie the two traces together.

Getting Started

This project requires Swift 5.10 or higher for the server, and Xcode 15.3 or higher for the app.

1. Choose a telemetry backend and get it going. For the demo I used Honeycomb's free tier, but Jaeger or Grafana are also good open-source choices.
2. I recommend running an OpenTelemetry Collector in docker on your local machine and configuring it to forward traces to your backend.
3. Build and run the server, either using swift run in the Server directory, or using the server scheme in Xcode.
4. Build and run the app.
5. You should see traces flowing through to your telemetry backend.

If you get stuck you can pass -v to the longer form of the server command (swift run server serve -v) and it'll log debug output, including the gRPC telemetry export. Likewise if you're running an OpenTelemetry collector looking at its log output will help (docker logs -f <collector-container>).

License

This project is available under the MIT license. See the LICENSE file for more info.