Swift OTel

An OpenTelemetry Protocol (OTLP) backend for Swift Log, Swift Metrics, and Swift Distributed Tracing.

Note: This package does not provide an OTel instrumentation API, or general-purpose OTel SDK.

• 📚 Documentation is available on the Swift Package Index
• 💻 Examples are available in the Examples directory
• 🪪 License is Apache 2.0, repeated in LICENSE
• 🔀 Related Repositories:
  • swift-log Logging API package for Swift.
  • swift-metrics Metrics API package for Swift.
  • swift-distributed-tracing Tracing API package for Swift.
  • opentelemetry-swift OpenTelemetry API and SDK package.

Quickstart

Add the dependencies to your package and target:

// swift-tools-version: 6.1
import PackageDescription

let package = Package(
    name: "Application",
    platforms: [.macOS("13.0")],
    dependencies: [
        // ...
        .package(url: "https://github.com/swift-otel/swift-otel.git", from: "1.0.0"),
    ],
    targets: [
        .executableTarget(
            name: "Server",
            dependencies: [
                // ...
                .product(name: "OTel", package: "swift-otel"),
            ]
        )
    ]
)

Then in your target:

import OTel

// Bootstrap observability backends.
let observability = try OTel.bootstrap()

// Run the observability background tasks, alongside your application logic.
await withThrowingTaskGroup { group in
    group.addTask { try await observability.run() }
    // Your application logic here...
}

Swift Service Lifecycle integration

The value returned from the bootstrap API conforms to Service so it can be run within a ServiceGroup:

import OTel
import ServiceLifecycle

// Bootstrap observability backends.
let observability = try OTel.bootstrap()

// Run observability services in a service group with your services.
let service: Service = // ...
let serviceGroup = ServiceGroup(services: [observability, service], logger: .init(label: "ServiceGroup"))
try await serviceGroup.run()

Or, if another dependency has APIs for running additional services, you can use those. For example, using Hummingbird:

import OTel
import Hummingbird

// Bootstrap observability backends.
let observability = try OTel.bootstrap()

// Create an HTTP server with instrumentation middlewares.
let router = Router()
router.middlewares.add(TracingMiddleware())
router.middlewares.add(MetricsMiddleware())
router.middlewares.add(LogRequestsMiddleware(.info))
router.get("hello") { _, _ in "hello" }
var app = Application(router: router)

// Add the observability service to the Hummingbird service group and run the server.
app.addServices(observability)
try await app.runService()

Tip

This, and other examples, can be be found in the Examples directory.