chore: make testing distributed header injection easier in Example app

Datadog/Datadog.xcodeproj/project.pbxproj

@@ -53,6 +53,7 @@
 		3C5D636D2B55513500FEB4BA /* OTelTraceState+DatadogTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3C5D636B2B55513500FEB4BA /* OTelTraceState+DatadogTests.swift */; };
 		3C5D691F2B76825500C4E07E /* OpenTelemetryApi.xcframework in Frameworks */ = {isa = PBXBuildFile; fileRef = 3C1F88222B767CE200821579 /* OpenTelemetryApi.xcframework */; };
 		3C5D69222B76826000C4E07E /* OpenTelemetryApi.xcframework in Frameworks */ = {isa = PBXBuildFile; fileRef = 3C1F88222B767CE200821579 /* OpenTelemetryApi.xcframework */; };
+		3C62C3612C3E852F00C7E336 /* MultiSelector.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3C62C3602C3E852F00C7E336 /* MultiSelector.swift */; };
 		3C6C7FE72B459AAA006F5CBC /* OTelSpan.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3C6C7FE02B459AAA006F5CBC /* OTelSpan.swift */; };
 		3C6C7FE82B459AAA006F5CBC /* OTelSpan.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3C6C7FE02B459AAA006F5CBC /* OTelSpan.swift */; };
 		3C6C7FE92B459AAA006F5CBC /* OTelSpanBuilder.swift in Sources */ = {isa = PBXBuildFile; fileRef = 3C6C7FE12B459AAA006F5CBC /* OTelSpanBuilder.swift */; };
@@ -2105,6 +2106,7 @@
 		3C43A3862C188970000BFB21 /* WatchdogTerminationMonitorTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = WatchdogTerminationMonitorTests.swift; sourceTree = "<group>"; };
 		3C5D63682B55512B00FEB4BA /* OTelTraceState+Datadog.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "OTelTraceState+Datadog.swift"; sourceTree = "<group>"; };
 		3C5D636B2B55513500FEB4BA /* OTelTraceState+DatadogTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "OTelTraceState+DatadogTests.swift"; sourceTree = "<group>"; };
+		3C62C3602C3E852F00C7E336 /* MultiSelector.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MultiSelector.swift; sourceTree = "<group>"; };
 		3C6C7FE02B459AAA006F5CBC /* OTelSpan.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OTelSpan.swift; sourceTree = "<group>"; };
 		3C6C7FE12B459AAA006F5CBC /* OTelSpanBuilder.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = OTelSpanBuilder.swift; sourceTree = "<group>"; };
 		3C6C7FE22B459AAA006F5CBC /* OTelTraceId+Datadog.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = "OTelTraceId+Datadog.swift"; sourceTree = "<group>"; };
@@ -4616,6 +4618,7 @@
 				61441C902461A648003D8BB8 /* ConsoleOutputInterceptor.swift */,
 				61441C912461A648003D8BB8 /* UIButton+Disabling.swift */,
 				D2F44FC1299BD5600074B0D9 /* UIViewController+KeyboardControlling.swift */,
+				3C62C3602C3E852F00C7E336 /* MultiSelector.swift */,
 			);
 			path = Utils;
 			sourceTree = "<group>";
@@ -8411,6 +8414,7 @@
 				618236892710560900125326 /* DebugWebviewViewController.swift in Sources */,
 				61F74AF426F20E4600E5F5ED /* DebugCrashReportingWithRUMViewController.swift in Sources */,
 				1434A4662B7F8D880072E3BB /* DebugOTelTracingViewController.swift in Sources */,
+				3C62C3612C3E852F00C7E336 /* MultiSelector.swift in Sources */,
 				61E5333824B84EE2003D6C4E /* DebugRUMViewController.swift in Sources */,
 				61441C0524616DE9003D8BB8 /* ExampleAppDelegate.swift in Sources */,
 				61020C2C2758E853005EEAEA /* DebugBackgroundEventsViewController.swift in Sources */,

Datadog/Example/Debugging/DebugManualTraceInjectionViewController.swift

@@ -16,18 +16,32 @@ internal class DebugManualTraceInjectionViewController: UIHostingController<Debu
 
 private var currentSession: URLSession? = nil
 
+extension TraceContextInjection {
+    func toString() -> String {
+        switch self {
+        case .all:
+            return "All"
+        case .sampled:
+            return "Sampled"
+        }
+    }
+}
+
 @available(iOS 14.0, *)
 internal struct DebugManualTraceInjectionView: View {
-    enum TraceHeaderType: String, CaseIterable {
+    enum TraceHeaderType: String, CaseIterable, Identifiable {
         case datadog = "Datadog"
         case w3c = "W3C"
         case b3Single = "B3-Single"
         case b3Multiple = "B3-Multiple"
+
+        var id: String { rawValue }
     }
 
     @State private var spanName = "network request"
-    @State private var requestURL = "http://127.0.0.1:8000"
-    @State private var selectedTraceHeaderType: TraceHeaderType = .datadog
+    @State private var requestURL = "https://httpbin.org/get"
+    @State private var selectedTraceHeaderTypes: Set<TraceHeaderType> = [.datadog, .w3c]
+    @State private var selectedTraceContextInjection: TraceContextInjection = .all
     @State private var sampleRate: Float = 100.0
     @State private var isRequestPending = false
 
@@ -59,12 +73,18 @@ internal struct DebugManualTraceInjectionView: View {
                 Section(header: Text("Span name:")) {
                     TextField("", text: $spanName)
                 }
-                Picker("Trace header type:", selection: $selectedTraceHeaderType) {
-                    ForEach(TraceHeaderType.allCases, id: \.self) { headerType in
-                        Text(headerType.rawValue)
+                Picker("Trace context injection:", selection: $selectedTraceContextInjection) {
+                    ForEach(TraceContextInjection.allCases, id: \.self) { headerType in
+                        Text(headerType.toString())
                     }
                 }
                 .pickerStyle(.inline)
+                MultiSelector(
+                    label: Text("Trace header type:"),
+                    options: TraceHeaderType.allCases,
+                    optionToString: { $0.rawValue },
+                    selected: $selectedTraceHeaderTypes
+                )
                 Section(header: Text("Trace sample Rate")) {
                     Slider(
                         value: $sampleRate,
@@ -101,42 +121,44 @@ internal struct DebugManualTraceInjectionView: View {
         }
 
         var request = URLRequest(url: url)
-        request.httpMethod = "POST"
+        request.httpMethod = "GET"
 
         let span = Tracer.shared().startRootSpan(operationName: spanName)
 
-        switch selectedTraceHeaderType {
-        case .datadog:
-            let writer = HTTPHeadersWriter(
-                samplingStrategy: .custom(sampleRate: sampleRate),
-                traceContextInjection: .all
-            )
-            Tracer.shared().inject(spanContext: span.context, writer: writer)
-            writer.traceHeaderFields.forEach { request.setValue($0.value, forHTTPHeaderField: $0.key) }
-        case .w3c:
-            let writer = W3CHTTPHeadersWriter(
-                samplingStrategy: .custom(sampleRate: sampleRate),
-                tracestate: [:],
-                traceContextInjection: .all
-            )
-            Tracer.shared().inject(spanContext: span.context, writer: writer)
-            writer.traceHeaderFields.forEach { request.setValue($0.value, forHTTPHeaderField: $0.key) }
-        case .b3Single:
-            let writer = B3HTTPHeadersWriter(
-                samplingStrategy: .custom(sampleRate: sampleRate),
-                injectEncoding: .single,
-                traceContextInjection: .all
-            )
-            Tracer.shared().inject(spanContext: span.context, writer: writer)
-            writer.traceHeaderFields.forEach { request.setValue($0.value, forHTTPHeaderField: $0.key) }
-        case .b3Multiple:
-            let writer = B3HTTPHeadersWriter(
-                samplingStrategy: .custom(sampleRate: sampleRate),
-                injectEncoding: .multiple,
-                traceContextInjection: .all
-            )
-            Tracer.shared().inject(spanContext: span.context, writer: writer)
-            writer.traceHeaderFields.forEach { request.setValue($0.value, forHTTPHeaderField: $0.key) }
+        for selectedTraceHeaderType in selectedTraceHeaderTypes {
+            switch selectedTraceHeaderType {
+            case .datadog:
+                let writer = HTTPHeadersWriter(
+                    samplingStrategy: .custom(sampleRate: sampleRate),
+                    traceContextInjection: selectedTraceContextInjection
+                )
+                Tracer.shared().inject(spanContext: span.context, writer: writer)
+                writer.traceHeaderFields.forEach { request.setValue($0.value, forHTTPHeaderField: $0.key) }
+            case .w3c:
+                let writer = W3CHTTPHeadersWriter(
+                    samplingStrategy: .custom(sampleRate: sampleRate),
+                    tracestate: [:],
+                    traceContextInjection: selectedTraceContextInjection
+                )
+                Tracer.shared().inject(spanContext: span.context, writer: writer)
+                writer.traceHeaderFields.forEach { request.setValue($0.value, forHTTPHeaderField: $0.key) }
+            case .b3Single:
+                let writer = B3HTTPHeadersWriter(
+                    samplingStrategy: .custom(sampleRate: sampleRate),
+                    injectEncoding: .single,
+                    traceContextInjection: selectedTraceContextInjection
+                )
+                Tracer.shared().inject(spanContext: span.context, writer: writer)
+                writer.traceHeaderFields.forEach { request.setValue($0.value, forHTTPHeaderField: $0.key) }
+            case .b3Multiple:
+                let writer = B3HTTPHeadersWriter(
+                    samplingStrategy: .custom(sampleRate: sampleRate),
+                    injectEncoding: .multiple,
+                    traceContextInjection: selectedTraceContextInjection
+                )
+                Tracer.shared().inject(spanContext: span.context, writer: writer)
+                writer.traceHeaderFields.forEach { request.setValue($0.value, forHTTPHeaderField: $0.key) }
+            }
         }
 
         send(request: request) {
@@ -147,7 +169,17 @@ internal struct DebugManualTraceInjectionView: View {
 
     private func send(request: URLRequest, completion: @escaping () -> Void) {
         isRequestPending = true
-        let task = session.dataTask(with: request) { _, _, _ in
+        let task = session.dataTask(with: request) { data, response, _ in
+            let httpResponse = response as! HTTPURLResponse
+            print("🚀 Request completed with status code: \(httpResponse.statusCode)")
+
+            // pretty print response
+            if let data = data {
+                let json = try? JSONSerialization.jsonObject(with: data, options: [])
+                if let json = json {
+                    print("🚀 Response: \(json)")
+                }
+            }
             completion()
             DispatchQueue.main.async { self.isRequestPending = false }
         }

Datadog/Example/Utils/MultiSelector.swift

@@ -0,0 +1,85 @@
+/*
+ * Unless explicitly stated otherwise all files in this repository are licensed under the Apache License Version 2.0.
+ * This product includes software developed at Datadog (https://www.datadoghq.com/).
+ * Copyright 2019-Present Datadog, Inc.
+ */
+
+import SwiftUI
+
+@available(iOS 14.0, *)
+struct MultiSelector<LabelView: View, Selectable: Identifiable & Hashable>: View {
+    let label: LabelView
+    let options: [Selectable]
+    let optionToString: (Selectable) -> String
+
+    var selected: Binding<Set<Selectable>>
+
+    private var formattedSelectedListString: String {
+        ListFormatter.localizedString(
+            byJoining: selected.wrappedValue.map {
+                optionToString($0)
+            }
+        )
+    }
+
+    var body: some View {
+        NavigationLink(destination: multiSelectionView()) {
+            HStack {
+                label
+                Spacer()
+                Text(formattedSelectedListString)
+                    .foregroundColor(.gray)
+                    .multilineTextAlignment(.trailing)
+            }
+        }
+    }
+
+    private func multiSelectionView() -> some View {
+        MultiSelectionView(
+            options: options,
+            optionToString: optionToString,
+            selected: selected
+        )
+    }
+}
+
+
+@available(iOS 13.0, *)
+struct MultiSelectionView<Selectable: Identifiable & Hashable>: View {
+    let options: [Selectable]
+    let optionToString: (Selectable) -> String
+
+    @Binding var selected: Set<Selectable>
+
+    var body: some View {
+        List {
+            ForEach(options) { selectable in
+                Button(action: {
+                    toggleSelection(selectable: selectable)
+                }) {
+                    HStack {
+                        Text(optionToString(selectable))
+                            .foregroundColor(.black)
+                        Spacer()
+                        if selected.contains(where: {
+                            $0.id == selectable.id
+                        }) {
+                            Image(systemName: "checkmark")
+                                .foregroundColor(.accentColor)
+                        }
+                    }
+                }
+                .tag(selectable.id)
+            }
+        }
+        .listStyle(GroupedListStyle())
+    }
+
+    private func toggleSelection(selectable: Selectable) {
+        if let existingIndex = selected.firstIndex(where: { $0.id == selectable.id }) {
+            selected.remove(at: existingIndex)
+        } else {
+            selected.insert(selectable)
+        }
+    }
+}

DatadogInternal/Sources/NetworkInstrumentation/TraceContextInjection.swift

@@ -7,7 +7,7 @@
 import Foundation
 
 /// Defines whether the trace context should be injected into all requests or only sampled ones.
-public enum TraceContextInjection {
+public enum TraceContextInjection: CaseIterable {
     /// Injects trace context into all requests irrespective of the sampling decision.
     case all