Add W3C.TraceParent

Author: slashmo

Sources/W3CTraceContext/TraceContext.swift

@@ -10,3 +10,4 @@
 // SPDX-License-Identifier: Apache-2.0
 //
 //===----------------------------------------------------------------------===//
+public enum W3C {}

Sources/W3CTraceContext/TraceParent.swift

@@ -0,0 +1,67 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift W3C Trace Context open source project
+//
+// Copyright (c) YEARS Moritz Lang and the Swift W3C Trace Context project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+extension W3C {
+    public struct TraceParent {
+        public let traceID: String
+        public let parentID: String
+        public let traceFlags: String
+
+        public var sampled: Bool {
+            self.traceFlags == "01"
+        }
+
+        static let version = "00"
+    }
+
+    // TODO: Trace State
+}
+
+extension W3C.TraceParent: Equatable {
+    public static func == (lhs: Self, rhs: Self) -> Bool {
+        lhs.traceID == rhs.traceID
+            && lhs.parentID == rhs.parentID
+    }
+}
+
+extension W3C.TraceParent: RawRepresentable {
+    public init?(rawValue: String) {
+        let components = rawValue.split(separator: "-")
+        guard components.count == 4 else { return nil }
+
+        // version
+        let versionComponent = components[0]
+        guard versionComponent == Self.version else { return nil }
+
+        // trace-id
+        let traceIDComponent = components[1]
+        guard traceIDComponent.count == 32 else { return nil }
+        guard traceIDComponent != String(repeating: "0", count: 32) else { return nil }
+        self.traceID = String(traceIDComponent)
+
+        // parent-id
+        let parentIDComponent = components[2]
+        guard parentIDComponent.count == 16 else { return nil }
+        guard parentIDComponent != String(repeating: "0", count: 16) else { return nil }
+        self.parentID = String(parentIDComponent)
+
+        // trace-flags
+        let traceFlagsComponent = components[3]
+        guard traceFlagsComponent.count == 2 else { return nil }
+        self.traceFlags = String(traceFlagsComponent)
+    }
+
+    public var rawValue: String {
+        "\(Self.version)-\(self.traceID)-\(self.parentID)-\(self.traceFlags)"
+    }
+}

Tests/W3CTraceContextTests/TraceContextTests.swift

@@ -0,0 +1,121 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift W3C Trace Context open source project
+//
+// Copyright (c) YEARS Moritz Lang and the Swift W3C Trace Context project authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+@testable import W3CTraceContext
+import XCTest
+
+final class TraceParentRawRepresentableTests: XCTestCase {
+    // MARK: - Trace Parent -
+
+    func testDecodeValidTraceParentStringWithSampledFlag() {
+        let rawValue = "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01"
+        guard let traceParent = W3C.TraceParent(rawValue: rawValue) else {
+            XCTFail("Could not decode valid trace parent")
+            return
+        }
+
+        XCTAssertEqual(
+            traceParent,
+            W3C.TraceParent(traceID: "0af7651916cd43dd8448eb211c80319c", parentID: "b7ad6b7169203331", traceFlags: "01")
+        )
+
+        XCTAssert(traceParent.sampled)
+    }
+
+    func testDecodeValidTraceParentStringWithoutSampledFlag() {
+        let rawValue = "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-00"
+        guard let traceParent = W3C.TraceParent(rawValue: rawValue) else {
+            XCTFail("Could not decode valid trace parent")
+            return
+        }
+
+        XCTAssertEqual(
+            traceParent,
+            W3C.TraceParent(traceID: "0af7651916cd43dd8448eb211c80319c", parentID: "b7ad6b7169203331", traceFlags: "00")
+        )
+
+        XCTAssertFalse(traceParent.sampled)
+    }
+
+    func testEncodesToValidRawValue() {
+        let traceParent = W3C.TraceParent(
+            traceID: "0af7651916cd43dd8448eb211c80319c",
+            parentID: "b7ad6b7169203331",
+            traceFlags: "01"
+        )
+
+        XCTAssertEqual(traceParent.rawValue, "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01")
+    }
+
+    func testDecodeFailsWithTooManyComponents() {
+        let rawValue = "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01-additional-components"
+        XCTAssertUninitializedTraceParent(rawValue)
+    }
+
+    func testDecodeFailsWithTooFewComponents() {
+        let rawValue = "00-0af7651916cd43dd8448eb211c80319c"
+        XCTAssertUninitializedTraceParent(rawValue)
+    }
+
+    func testDecodeFailsWithInvalidVersionComponent() {
+        let rawValue = "ff-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01"
+        XCTAssertUninitializedTraceParent(rawValue)
+    }
+
+    func testDecodeFailsWithTooLongTraceID() {
+        let rawValue = "00-0af7651916cd43dd8448eb211c80319cclearlylongerthan16bytes-b7ad6b7169203331-01"
+        XCTAssertUninitializedTraceParent(rawValue)
+    }
+
+    func testDecodeFailsWithTooShortTraceID() {
+        let rawValue = "00-tooshort-b7ad6b7169203331-01"
+        XCTAssertUninitializedTraceParent(rawValue)
+    }
+
+    func testDecodeFailsWithAllZeroesTraceID() {
+        let rawValue = "00-00000000000000000000000000000000-b7ad6b7169203331-01"
+        XCTAssertUninitializedTraceParent(rawValue)
+    }
+
+    func testDecodeFailsWithTooShortParentID() {
+        let rawValue = "00-0af7651916cd43dd8448eb211c80319c-tooshort-01"
+        XCTAssertUninitializedTraceParent(rawValue)
+    }
+
+    func testDecodeFailsWithAllZeroesParentID() {
+        let rawValue = "00-0af7651916cd43dd8448eb211c80319c-0000000000000000-01"
+        XCTAssertUninitializedTraceParent(rawValue)
+    }
+
+    func testDecodeFailsWithTooLongTraceFlags() {
+        let rawValue = "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-toolong"
+        XCTAssertUninitializedTraceParent(rawValue)
+    }
+
+    func testDecodeFailsWithTooShortTraceFlags() {
+        let rawValue = "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-0"
+        XCTAssertUninitializedTraceParent(rawValue)
+    }
+
+    // TODO: Trace State
+}
+
+private func XCTAssertUninitializedTraceParent(_ rawValue: String, file: StaticString = #file, line: UInt = #line) {
+    if let traceParent = W3C.TraceParent(rawValue: rawValue) {
+        XCTFail(
+            "Expected trace parent not to be initialized from invalid raw value: \(traceParent)",
+            file: file,
+            line: line
+        )
+    }
+}