Getting Started

Get telemetry for your app in less than 5 minutes!

This page will show you how to get started with OpenTelemetry in Swift.

You will learn how you can instrument a simple application, in such a way that traces are emitted to the console.

Prerequisites

Ensure that you have the following installed locally:

Example Application

The following example uses a basic Vapor application. If you are not using Vapor, that’s OK — you can use OpenTelemetry Swift with any Swift application, no matter if they run on a server or on an iOS device.

For more examples, see examples.

Dependencies

To begin, create a file called Package.swift in a new directory with the following content:

// swift-tools-version:5.9
import PackageDescription

let package = Package(
    name: "dice-server",
    platforms: [
       .macOS(.v13)
    ],
    dependencies: [
        .package(url: "https://github.com/vapor/vapor.git", from: "4.83.1")
    ],
    targets: [
        .executableTarget(
            name: "DiceApp",
            dependencies: [
                .product(name: "Vapor", package: "vapor")
            ],
            path: "."
        )
    ]
)

Create and launch an HTTP Server

In the same folder, create a file called main.swift and add the following code to the file:

import Vapor

@main
enum Entrypoint {
    static func main() async throws {
        let app = try Application(.detect())
        defer { app.shutdown() }
        app.get("rolldice") { req in
            let result = Int.random(in: 1..<7)
            return result
        }
        try app.run()
    }
}

Build and run the application with the following command, then open http://localhost:8080/rolldice in your web browser to ensure it is working.

$ swift run
Building for debugging...
Build complete! (0.31s)
2023-10-04T17:16:13+0200 notice codes.vapor.application : [Vapor] Server starting on http://127.0.0.1:8080

Instrumentation

To add OpenTelemetry to your application, update the Package.swift with the following additional dependencies:

// swift-tools-version:5.9
import PackageDescription


let package = Package(
    name: "dice-server",
    platforms: [
       .macOS(.v13)
    ],
    dependencies: [
        .package(url: "https://github.com/vapor/vapor.git", from: "4.83.1"),
        .package(url: "https://github.com/open-telemetry/opentelemetry-swift", from: "1.0.0"),
    ],
    targets: [
        .executableTarget(
            name: "DiceApp",
            dependencies: [
                .product(name: "Vapor", package: "vapor"),
                .product(name: "OpenTelemetryApi", package: "opentelemetry-swift"),
                .product(name: "OpenTelemetrySdk", package: "opentelemetry-swift"),
                .product(name: "StdoutExporter", package: "opentelemetry-swift"),
                .product(name: "ResourceExtension", package: "opentelemetry-swift"),
            ],
            path: "."
        )
    ]
)

Update the main.swift file with code to initialize a tracer and to emit spans when the rolldice request handler is called:

import Vapor
import OpenTelemetryApi
import OpenTelemetrySdk
import StdoutExporter
import ResourceExtension

@main
enum Entrypoint {
    static func main() async throws {

        let spanExporter = StdoutExporter();
        let spanProcessor = SimpleSpanProcessor(spanExporter: spanExporter)
        let resources = DefaultResources().get()

        let instrumentationScopeName = "DiceServer"
        let instrumentationScopeVersion = "semver:0.1.0"

        OpenTelemetry.registerTracerProvider(tracerProvider:
            TracerProviderBuilder()
                .add(spanProcessor: spanProcessor)
                .with(resource: resources)
                .build()
        )
        let tracer = OpenTelemetry.instance.tracerProvider.get(instrumentationName: instrumentationScopeName, instrumentationVersion: instrumentationScopeVersion) as! TracerSdk


        let app = try Application(.detect())
        defer { app.shutdown() }

        app.get("rolldice") { req in
            let span = tracer.spanBuilder(spanName: "GET /rolldice").setSpanKind(spanKind: .client).startSpan()
            let result = Int.random(in: 1..<7)
            span.end();
            return result
        }

        try app.run()
    }
}

Start your server again:

swift run

When you send a request to the server at http://localhost:8080/rolldice, you’ll see a span being emitted to the console (output is pretty printed for convenience):

{
  "attributes": {},
  "duration": 2.70605087280273e-5,
  "parentSpanId": "0000000000000000",
  "span": "GET /rolldice",
  "spanId": "635455eb236a1592",
  "spanKind": "client",
  "start": 718126321.210727,
  "traceFlags": {
    "sampled": true
  },
  "traceId": "c751f7af0586dac8ef3607c6fc128884",
  "traceState": {
    "entries": []
  }
}

Next Steps

Enrich your instrumentation generated automatically with manual instrumentation of your own codebase. This gets you customized observability data.

Take a look at available instrumentation libraries that generate telemetry data for popular frameworks and libraries.


Last modified January 15, 2024: [IA] Rename /docs/instrumentation to /docs/languages, and Manual subpages to Instrumentation (#3761) (06837fe1)