This talk will provide an overview of observability in server-side Swift, with a focus on Distributed Tracing. I’ll start off by talking about some of the design decisions that went into building the swift-distributed-tracing library, which I co-created as part of Google Summer of Code in 2020. The talk will not only compare it to other Swift observability libraries (swift-log, swift-metrics), but also highlight some of the differences between Distributed Tracing in Swift compared to other ecosystems. My personal highlight is the fact that we eliminated the need for support libraries such as “OTel instrumentation for this specific web framework” by implementing swift-distributed-tracing to be used by libraries directly. During the next part, I’ll cover what it means to build a tracer implementation for swift-distributed-tracing with plenty of examples from my OpenTelemetry client swift-otel. I’ll finish the talk with an end-to-end example of a server-side Swift application using the Hummingbird web framework, fully instrumented using Logging, Metrics, and Distributed Tracing, including context propagation and log correlation. This example exports logs, metrics, and spans via the OpenTelemetry Protocol (OTLP) to both a standalone OTel Collector instance and other observability backends that support OTLP natively.

Links: - GitHub: apple/swift-distributed-tracing - GitHub: slashmo/swift-otel - OpenTelemetry Website