Merge pull request #230 from bugsnag/PLAT-11373-defer-view-span-end

[PLAT-11373] Add support for deferring view load span end

Example/Example/SomeView.swift

@@ -11,13 +11,50 @@ import SwiftUI
 
 @available(iOS 13.0.0, *)
 struct SomeView: View {
+    @State var data: Data?
+    @State var deferringViewLoadSpan = true
+
     var body: some View {
-        let span = BugsnagPerformance.startViewLoadSpan(
-            name: "SomeView", viewType: .swiftUI) 
-        Text("Hello from SwiftUI 🙃")
-            .onAppear {
-                span.end()
-            }.bugsnagTraced("My text view")
+
+        // Fake a background data load.
+        // On iOS 15+ you'd use a .task()
+        defer {
+            DispatchQueue.global().async {
+                data = Data()
+            }
+        }
+
+        return VStack {
+            if data == nil {
+                // .bugsnagDeferEndUntilViewDisappears() will hold the current
+                // view load span open until this Text view disappears.
+                //
+                // When this Text view disappears, its defer is resolved.
+                // That would in theory leave the view load span free to end,
+                // but there are still other defers to resolve!
+                Text("SwiftUI is loading")
+                .bugsnagTraced("loading")
+                .bugsnagDeferEndUntilViewDisappears()
+            } else {
+                Text("Hello from SwiftUI 🙃")
+                .bugsnagTraced("loaded")
+
+                if deferringViewLoadSpan {
+                    // Defer the view load span end until this button disappears.
+                    Button("Stop deferring the view load span") {
+                        deferringViewLoadSpan = false
+                    }
+                    .bugsnagDeferEndUntilViewDisappears()
+                }
+            }
+        }
+        .bugsnagDeferEndUntil {
+            // Defer the view load span end until this function returns a true value.
+            //
+            // This is technically redundant since the above button is deferring the
+            // view load span based on the same @State value (deferringViewLoadSpan).
+            return !deferringViewLoadSpan
+        }
     }
 }
 

Gemfile.lock

@@ -80,19 +80,19 @@ GEM
       uri_template (~> 0.7)
     mime-types (3.5.1)
       mime-types-data (~> 3.2015)
-    mime-types-data (3.2023.1003)
+    mime-types-data (3.2023.1205)
     multi_test (0.1.2)
-    nokogiri (1.15.4-arm64-darwin)
+    nokogiri (1.15.5-arm64-darwin)
       racc (~> 1.4)
-    nokogiri (1.15.4-x86_64-darwin)
+    nokogiri (1.15.5-x86_64-darwin)
       racc (~> 1.4)
     optimist (3.0.1)
     os (1.0.1)
     power_assert (2.0.3)
-    racc (1.7.1)
+    racc (1.7.3)
     rack (2.2.8)
     rake (12.3.3)
-    regexp_parser (2.8.2)
+    regexp_parser (2.8.3)
     rexml (3.2.6)
     rubyzip (2.3.2)
     selenium-webdriver (4.5.0)
@@ -109,7 +109,7 @@ GEM
     tomlrb (2.0.3)
     unf (0.1.4)
       unf_ext
-    unf_ext (0.0.8.2)
+    unf_ext (0.0.9.1)
     uri_template (0.7.0)
     webrick (1.7.0)
     websocket (1.2.10)

Sources/BugsnagPerformanceSwiftUI/BugsnagPerformanceSwiftUIInstrumentation.swift

@@ -11,7 +11,9 @@ import BugsnagPerformance
 
 @available(iOS 13, macOS 10.15, tvOS 13, watchOS 6.0, *)
 final class BugsnagViewContext: ObservableObject {
-    public var firstViewLoadSpan: BugsnagPerformanceSpan? = nil
+    public var isFirstBodyThisCycle = true
+    public var parentViewLoadSpan: BugsnagPerformanceSpan? = nil
+    public var unresolvedDeferCount = 0
 }
 
 @available(iOS 13, macOS 10.15, tvOS 13, watchOS 6.0, *)
@@ -36,53 +38,110 @@ extension View {
 
 @available(iOS 13, macOS 10.15, tvOS 13, watchOS 6.0, *)
 public extension View {
+
+    /**
+     * Trace this view through Bugsnag.
+     * If viewName is not specified, one will be generated based on the struct's class.
+     */
     func bugsnagTraced(_ viewName: String? = nil) -> some View {
         return BugsnagTracedView(viewName) {
             return self
         }
     }
+
+    /**
+     * Defer ending the overarching view load span until the supplied function returns true during a body build cycle.
+     * The view load span will not be ended until ALL deferred-end conditions are true.
+     */
+    func bugsnagDeferEndUntil(deferUntil: @escaping ()->(Bool)) -> some View {
+        return BugsnagDeferredTraceEndView(deferUntil: deferUntil) {self}
+    }
+
+    /**
+     * Defer ending the overarching view load span until this view disappears from the view hierarchy.
+     * The view load span will not be ended until ALL deferred-end conditions are true.
+     */
+    func bugsnagDeferEndUntilViewDisappears() -> some View {
+        return self.bugsnagDeferEndUntil {
+            return false
+        }
+    }
+}
+
+private func generateNameFromContent(content: Any) -> String {
+    let viewName = String(describing: content)
+    if let angleBracketIndex = viewName.firstIndex(of: "<") {
+        return String(viewName[viewName.startIndex ..< angleBracketIndex])
+    }
+    return viewName
 }
 
 @available(iOS 13, macOS 10.15, tvOS 13, watchOS 6.0, *)
-public struct BugsnagTracedView<Content: View>: View {
+public struct BugsnagDeferredTraceEndView<Content: View>: View {
     @Environment(\.keyBSGViewContext) private var bsgViewContext: BugsnagViewContext
 
-    let content: () -> Content
-    let name: String
+    private let content: () -> Content
+    private let deferUntilCondition: ()->(Bool)
 
-    public init(_ viewName: String? = nil, content: @escaping () -> Content) {
+    public init(deferUntil: @escaping ()->(Bool), content: @escaping () -> Content) {
         self.content = content
-        self.name = viewName ?? BugsnagTracedView.getViewName(content: Content.self)
+        self.deferUntilCondition = deferUntil
     }
 
-    private static func getViewName(content: Any) -> String {
-        let viewName = String(describing: content)
-        if let angleBracketIndex = viewName.firstIndex(of: "<") {
-            return String(viewName[viewName.startIndex ..< angleBracketIndex])
+    public var body: some View {
+        if !deferUntilCondition() {
+            bsgViewContext.unresolvedDeferCount += 1
         }
-        return viewName
+
+        // We're not generating our own content; merely passing through the content
+        // of the body we wrapped. The rendered scene will not contain any Bugsnag views.
+        return content()
+    }
+}
+
+@available(iOS 13, macOS 10.15, tvOS 13, watchOS 6.0, *)
+public struct BugsnagTracedView<Content: View>: View {
+    @Environment(\.keyBSGViewContext) private var bsgViewContext: BugsnagViewContext
+
+    private let content: () -> Content
+    private let name: String
+
+    public init(_ viewName: String? = nil, content: @escaping () -> Content) {
+        self.content = content
+        self.name = viewName ?? generateNameFromContent(content: Content.self)
     }
 
     public var body: some View {
-        var firstViewLoadSpan = bsgViewContext.firstViewLoadSpan
-
-        if firstViewLoadSpan == nil {
-            let opts = BugsnagPerformanceSpanOptions()
-            opts.setParentContext(nil)
-            let thisViewLoadSpan = BugsnagPerformance.startViewLoadSpan(name: name, viewType: BugsnagPerformanceViewType.swiftUI, options: opts)
-            firstViewLoadSpan = thisViewLoadSpan
-            bsgViewContext.firstViewLoadSpan = thisViewLoadSpan
+        var parentViewLoadSpan = bsgViewContext.parentViewLoadSpan
+
+        if bsgViewContext.isFirstBodyThisCycle {
+            bsgViewContext.isFirstBodyThisCycle = false
+
+            if parentViewLoadSpan == nil {
+                let opts = BugsnagPerformanceSpanOptions()
+                opts.setParentContext(nil)
+                let thisViewLoadSpan = BugsnagPerformance.startViewLoadSpan(name: name, viewType: BugsnagPerformanceViewType.swiftUI, options: opts)
+                parentViewLoadSpan = thisViewLoadSpan
+                bsgViewContext.parentViewLoadSpan = thisViewLoadSpan
+            }
+
             DispatchQueue.main.async {
-                thisViewLoadSpan.end()
+                if bsgViewContext.unresolvedDeferCount == 0 {
+                    bsgViewContext.parentViewLoadSpan?.end()
+                    bsgViewContext.parentViewLoadSpan = nil
+                }
+                bsgViewContext.unresolvedDeferCount = 0
+                bsgViewContext.isFirstBodyThisCycle = true
             }
         }
 
         let opts = BugsnagPerformanceSpanOptions()
-        opts.setParentContext(firstViewLoadSpan)
-        let thisViewLoadSpan = BugsnagPerformance.startViewLoadPhaseSpan(name: name, phase: "body", parentContext: firstViewLoadSpan!)
-        defer {
-            thisViewLoadSpan.end()
-        }
+        opts.setParentContext(parentViewLoadSpan)
+        // We are actually recording a point here, not measuring a duration.
+        BugsnagPerformance.startViewLoadPhaseSpan(name: name, phase: "body", parentContext: parentViewLoadSpan!).end()
+
+        // We're not generating our own content; merely passing through the content
+        // of the body we wrapped. The rendered scene will not contain any Bugsnag views.
         return content()
     }
 }

features/default/automatic_spans.feature

@@ -248,7 +248,7 @@ Feature: Automatic instrumentation spans
     * the trace payload field "resourceSpans.0.resource" string attribute "telemetry.sdk.name" equals "bugsnag.performance.cocoa"
     * the trace payload field "resourceSpans.0.resource" string attribute "telemetry.sdk.version" matches the regex "[0-9]\.[0-9]\.[0-9]"
 
-  Scenario: AutoInstrumentSwiftUIScenario
+  Scenario: AutoInstrumentSwiftUIScenario no change
     Given I run "AutoInstrumentSwiftUIScenario"
     And I wait for 3 spans
     Then the trace "Content-Type" header equals "application/json"
@@ -272,6 +272,121 @@ Feature: Automatic instrumentation spans
     * the trace payload field "resourceSpans.0.resource" string attribute "telemetry.sdk.name" equals "bugsnag.performance.cocoa"
     * the trace payload field "resourceSpans.0.resource" string attribute "telemetry.sdk.version" matches the regex "[0-9]\.[0-9]\.[0-9]"
 
+  Scenario: AutoInstrumentSwiftUIScenario with change
+    Given I run "AutoInstrumentSwiftUIScenario"
+    And I wait for 3 spans
+    Then the trace "Content-Type" header equals "application/json"
+    * the trace "Bugsnag-Sent-At" header matches the regex "^\d\d\d\d-\d\d-\d\dT\d\d:\d\d:\d\d\.\d\d\dZ$"
+    * a span field "name" equals "[ViewLoad/SwiftUI]/My VStack view"
+    * a span field "name" equals "[ViewLoadPhase/body]/My VStack view"
+    * a span field "name" equals "[ViewLoadPhase/body]/My Image view"
+    * every span field "spanId" matches the regex "^[A-Fa-f0-9]{16}$"
+    * every span field "traceId" matches the regex "^[A-Fa-f0-9]{32}$"
+    * every span field "kind" equals 1
+    * every span field "startTimeUnixNano" matches the regex "^[0-9]+$"
+    * every span field "endTimeUnixNano" matches the regex "^[0-9]+$"
+    * a span string attribute "bugsnag.span.category" equals "view_load"
+    * a span string attribute "bugsnag.span.category" equals "view_load_phase"
+    * a span string attribute "bugsnag.view.name" equals "My VStack view"
+    * a span string attribute "bugsnag.view.name" equals "My Image view"
+    * a span bool attribute "bugsnag.span.first_class" is true
+    * a span string attribute "bugsnag.view.type" equals "SwiftUI"
+    * the trace payload field "resourceSpans.0.resource" string attribute "service.name" equals "com.bugsnag.fixtures.PerformanceFixture"
+    * the trace payload field "resourceSpans.0.resource" string attribute "telemetry.sdk.name" equals "bugsnag.performance.cocoa"
+    * the trace payload field "resourceSpans.0.resource" string attribute "telemetry.sdk.version" matches the regex "[0-9]\.[0-9]\.[0-9]"
+    And I discard every trace
+    And I invoke "switchView"
+    Then I wait for 2 spans
+    * a span field "name" equals "[ViewLoad/SwiftUI]/Text"
+    * a span field "name" equals "[ViewLoadPhase/body]/Text"
+    * every span field "spanId" matches the regex "^[A-Fa-f0-9]{16}$"
+    * every span field "traceId" matches the regex "^[A-Fa-f0-9]{32}$"
+    * every span field "kind" equals 1
+    * every span field "startTimeUnixNano" matches the regex "^[0-9]+$"
+    * every span field "endTimeUnixNano" matches the regex "^[0-9]+$"
+    * a span string attribute "bugsnag.span.category" equals "view_load"
+    * a span string attribute "bugsnag.span.category" equals "view_load_phase"
+    * every span string attribute "bugsnag.view.name" equals "Text"
+    * a span bool attribute "bugsnag.span.first_class" is true
+    * a span string attribute "bugsnag.view.type" equals "SwiftUI"
+
+  Scenario: AutoInstrumentSwiftUIDeferredScenario toggleEndSpanDefer
+    Given I run "AutoInstrumentSwiftUIDeferredScenario"
+    And I wait for 2 spans
+    Then the trace "Content-Type" header equals "application/json"
+    * the trace "Bugsnag-Sent-At" header matches the regex "^\d\d\d\d-\d\d-\d\dT\d\d:\d\d:\d\d\.\d\d\dZ$"
+    * a span field "name" equals "[ViewLoadPhase/body]/vstack1"
+    * a span field "name" equals "[ViewLoadPhase/body]/text1"
+    * every span field "spanId" matches the regex "^[A-Fa-f0-9]{16}$"
+    * every span field "traceId" matches the regex "^[A-Fa-f0-9]{32}$"
+    * every span field "kind" equals 1
+    * every span field "startTimeUnixNano" matches the regex "^[0-9]+$"
+    * every span field "endTimeUnixNano" matches the regex "^[0-9]+$"
+    * every span string attribute "bugsnag.span.category" equals "view_load_phase"
+    * a span string attribute "bugsnag.view.name" equals "vstack1"
+    * a span string attribute "bugsnag.view.name" equals "text1"
+    * the trace payload field "resourceSpans.0.resource" string attribute "service.name" equals "com.bugsnag.fixtures.PerformanceFixture"
+    * the trace payload field "resourceSpans.0.resource" string attribute "telemetry.sdk.name" equals "bugsnag.performance.cocoa"
+    * the trace payload field "resourceSpans.0.resource" string attribute "telemetry.sdk.version" matches the regex "[0-9]\.[0-9]\.[0-9]"
+    Then I discard every trace
+    And I invoke "toggleEndSpanDefer"
+    And I wait for 2 spans
+    * a span field "name" equals "[ViewLoadPhase/body]/vstack1"
+    * a span field "name" equals "[ViewLoadPhase/body]/text1"
+    * every span field "spanId" matches the regex "^[A-Fa-f0-9]{16}$"
+    * every span field "traceId" matches the regex "^[A-Fa-f0-9]{32}$"
+    * every span field "kind" equals 1
+    * every span field "startTimeUnixNano" matches the regex "^[0-9]+$"
+    * every span field "endTimeUnixNano" matches the regex "^[0-9]+$"
+    * every span string attribute "bugsnag.span.category" equals "view_load_phase"
+    * a span string attribute "bugsnag.view.name" equals "vstack1"
+    * a span string attribute "bugsnag.view.name" equals "text1"
+
+  Scenario: AutoInstrumentSwiftUIDeferredScenario toggle everything
+    Given I run "AutoInstrumentSwiftUIDeferredScenario"
+    And I wait for 2 spans
+    Then the trace "Content-Type" header equals "application/json"
+    * the trace "Bugsnag-Sent-At" header matches the regex "^\d\d\d\d-\d\d-\d\dT\d\d:\d\d:\d\d\.\d\d\dZ$"
+    * a span field "name" equals "[ViewLoadPhase/body]/vstack1"
+    * a span field "name" equals "[ViewLoadPhase/body]/text1"
+    * every span field "spanId" matches the regex "^[A-Fa-f0-9]{16}$"
+    * every span field "traceId" matches the regex "^[A-Fa-f0-9]{32}$"
+    * every span field "kind" equals 1
+    * every span field "startTimeUnixNano" matches the regex "^[0-9]+$"
+    * every span field "endTimeUnixNano" matches the regex "^[0-9]+$"
+    * every span string attribute "bugsnag.span.category" equals "view_load_phase"
+    * a span string attribute "bugsnag.view.name" equals "vstack1"
+    * a span string attribute "bugsnag.view.name" equals "text1"
+    * the trace payload field "resourceSpans.0.resource" string attribute "service.name" equals "com.bugsnag.fixtures.PerformanceFixture"
+    * the trace payload field "resourceSpans.0.resource" string attribute "telemetry.sdk.name" equals "bugsnag.performance.cocoa"
+    * the trace payload field "resourceSpans.0.resource" string attribute "telemetry.sdk.version" matches the regex "[0-9]\.[0-9]\.[0-9]"
+    Then I discard every trace
+    And I invoke "toggleEndSpanDefer"
+    And I wait for 2 spans
+    * a span field "name" equals "[ViewLoadPhase/body]/vstack1"
+    * a span field "name" equals "[ViewLoadPhase/body]/text1"
+    * every span field "spanId" matches the regex "^[A-Fa-f0-9]{16}$"
+    * every span field "traceId" matches the regex "^[A-Fa-f0-9]{32}$"
+    * every span field "kind" equals 1
+    * every span field "startTimeUnixNano" matches the regex "^[0-9]+$"
+    * every span field "endTimeUnixNano" matches the regex "^[0-9]+$"
+    * every span string attribute "bugsnag.span.category" equals "view_load_phase"
+    * a span string attribute "bugsnag.view.name" equals "vstack1"
+    * a span string attribute "bugsnag.view.name" equals "text1"
+    Then I discard every trace
+    And I invoke "toggleHideText1"
+    And I wait for 2 spans
+    * a span field "name" equals "[ViewLoad/SwiftUI]/vstack1"
+    * a span field "name" equals "[ViewLoadPhase/body]/vstack1"
+    * every span field "spanId" matches the regex "^[A-Fa-f0-9]{16}$"
+    * every span field "traceId" matches the regex "^[A-Fa-f0-9]{32}$"
+    * every span field "kind" equals 1
+    * every span field "startTimeUnixNano" matches the regex "^[0-9]+$"
+    * every span field "endTimeUnixNano" matches the regex "^[0-9]+$"
+    * a span string attribute "bugsnag.span.category" equals "view_load"
+    * a span string attribute "bugsnag.span.category" equals "view_load_phase"
+    * every span string attribute "bugsnag.view.name" equals "vstack1"
+
   Scenario: Automatically start a network span that has a parent
     Given I run "AutoInstrumentNetworkWithParentScenario"
     And I wait for 2 seconds