[Sessions] Setup Sessions SDK Class Structure and Tests (#10297)

Author: samedson

.github/workflows/sessions.yml

@@ -0,0 +1,73 @@
+name: sessions
+
+on:
+  pull_request:
+    paths:
+    - 'FirebaseSessions**'
+    - 'FirebaseSessions.podspec'
+    - '.github/workflows/sessions.yml'
+    - 'Gemfile*'
+  schedule:
+    # Run every day at 9am (PST) - cron uses UTC times
+    - cron:  '0 1 * * *'
+
+concurrency:
+    group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
+    cancel-in-progress: true
+
+jobs:
+
+  pod-lib-lint:
+    # Don't run on private repo unless it is a PR.
+    if: (github.repository == 'Firebase/firebase-ios-sdk' && github.event_name == 'schedule') || github.event_name == 'pull_request'
+
+    runs-on: macos-12
+
+    strategy:
+      matrix:
+        target: [ios, tvos, macos, watchos --skip-tests]
+    steps:
+    - uses: actions/checkout@v2
+    - uses: ruby/setup-ruby@v1
+    - name: Setup Bundler
+      run: scripts/setup_bundler.sh
+    - name: Build and test
+      run: |
+        scripts/third_party/travis/retry.sh scripts/pod_lib_lint.rb FirebaseSessions.podspec --platforms=${{ matrix.target }}
+
+  #
+  # Uncomment below when Swift Package Manager is implemented
+  #
+  # spm:
+  #   # Don't run on private repo unless it is a PR.
+  #   if: (github.repository == 'Firebase/firebase-ios-sdk' && github.event_name == 'schedule') || github.event_name == 'pull_request'
+  #   runs-on: macos-12
+  #   strategy:
+  #     matrix:
+  #       target: [iOS, tvOS, macOS, catalyst, watchOS]
+  #   steps:
+  #   - uses: actions/checkout@v2
+  #   - uses: mikehardy/buildcache-action@50738c6c77de7f34e66b870e4f8ede333b69d077
+  #     with:
+  #       cache_key: ${{ matrix.os }}
+  #   - name: Initialize xcodebuild
+  #     run: scripts/setup_spm_tests.sh
+  #   - name: Unit Tests
+  #     run: scripts/third_party/travis/retry.sh ./scripts/build.sh FirebaseSessions ${{ matrix.target }} spmbuildonly
+
+
+  catalyst:
+    # Don't run on private repo unless it is a PR.
+    if: (github.repository == 'Firebase/firebase-ios-sdk' && github.event_name == 'schedule') || github.event_name == 'pull_request'
+
+    runs-on: macos-12
+    steps:
+    - uses: actions/checkout@v2
+    - uses: mikehardy/buildcache-action@50738c6c77de7f34e66b870e4f8ede333b69d077
+      with:
+        cache_key: ${{ matrix.os }}
+    - uses: ruby/setup-ruby@v1
+    - name: Setup Bundler
+      run: scripts/setup_bundler.sh
+    - name: Setup project and Build for Catalyst
+      run: scripts/test_catalyst.sh FirebaseSessions test FirebaseSessions-Unit-unit

FirebaseSessions.podspec

@@ -33,7 +33,10 @@ Pod::Spec.new do |s|
   s.cocoapods_version = '>= 1.4.0'
   s.prefix_header_file = false
 
-  s.source_files = "FirebaseSessions/Sources/**/*.swift"
+  base_dir = "FirebaseSessions/"
+  s.source_files = [
+    base_dir + 'Sources/**/*.swift',
+  ]
 
   s.dependency 'FirebaseCore', '~> 10.0'
   s.dependency 'FirebaseCoreExtension', '~> 10.0'
@@ -43,4 +46,18 @@ Pod::Spec.new do |s|
     'GCC_C_LANGUAGE_STANDARD' => 'c99',
     'HEADER_SEARCH_PATHS' => '"${PODS_TARGET_SRCROOT}"'
   }
+
+  s.test_spec 'unit' do |unit_tests|
+    unit_tests.scheme = { :code_coverage => true }
+    unit_tests.platforms = {
+      :ios => ios_deployment_target,
+      :osx => osx_deployment_target,
+      :tvos => tvos_deployment_target,
+      # https://github.com/CocoaPods/CocoaPods/issues/8283
+      # :watchos => watchos_deployment_target,
+    }
+    unit_tests.source_files = base_dir + 'Tests/Unit/**/*.swift'
+    unit_tests.resources = base_dir + 'Tests/Fixtures/**/*'
+    unit_tests.requires_app_host = true
+  end
 end

FirebaseSessions/Sources/FirebaseSessions.swift

@@ -13,7 +13,9 @@
 // limitations under the License.
 
 import Foundation
+
 import FirebaseCore
+import FirebaseInstallations
 
 // Avoids exposing internal FirebaseCore APIs to Swift users.
 @_implementationOnly import FirebaseCoreExtension
@@ -23,16 +25,44 @@ protocol SessionsProvider {
   @objc static func sessions() -> Void
 }
 
-@objc(FIRSessions) class Sessions: NSObject, Library, SessionsProvider {
+@objc(FIRSessions) final class Sessions: NSObject, Library, SessionsProvider {
   // MARK: - Private Variables
 
-  /// The app associated with all sessions.
-  private let googleAppID: String
+  /// The Firebase App ID associated with Sessions.
+  private let appID: String
+
+  /// Top-level Classes in the Sessions SDK
+  private let coordinator: SessionCoordinator
+  private let initiator: SessionInitiator
+  private let identifiers: Identifiers
 
   // MARK: - Initializers
 
-  required init(app: FirebaseApp) {
-    googleAppID = app.options.googleAppID
+  required convenience init(appID: String, installations: InstallationsProtocol) {
+    let identifiers = Identifiers(installations: installations)
+    let coordinator = SessionCoordinator(identifiers: identifiers)
+    let initiator = SessionInitiator()
+
+    self.init(appID: appID,
+              identifiers: identifiers,
+              coordinator: coordinator,
+              initiator: initiator)
+  }
+
+  init(appID: String, identifiers: Identifiers, coordinator: SessionCoordinator,
+       initiator: SessionInitiator) {
+    self.appID = appID
+
+    self.identifiers = identifiers
+    self.coordinator = coordinator
+    self.initiator = initiator
+
+    super.init()
+
+    self.initiator.beginListening {
+      self.identifiers.generateNewSessionID()
+      self.coordinator.runMain()
+    }
   }
 
   // MARK: - Library conformance
@@ -44,7 +74,8 @@ protocol SessionsProvider {
         // Sessions SDK only works for the default app
         guard let app = container.app, app.isDefaultApp else { return nil }
         isCacheable.pointee = true
-        return self.init(app: app)
+        let installations = Installations.installations(app: app)
+        return self.init(appID: app.options.googleAppID, installations: installations)
       }]
   }
 

FirebaseSessions/Sources/Identifiers.swift

@@ -0,0 +1,109 @@
+//
+// Copyright 2022 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import Foundation
+import FirebaseInstallations
+
+let sessionIDUserDefaultsKey = "com.firebase.sessions.sessionID"
+let lastSessionIDUserDefaultsKey = "com.firebase.sessions.lastSessionID"
+
+protocol IdentifierProvider {
+  var installationID: String {
+    get
+  }
+
+  var sessionID: String {
+    get
+  }
+
+  var lastSessionID: String {
+    get
+  }
+}
+
+///
+/// Identifiers is responsible for:
+///   1) Getting the Installation ID from Installations
+///   2) Generating the Session ID
+///   3) Persisting and reading the Session ID from the last session
+///   (Maybe) 4) Persisting, reading, and incrementing an increasing index
+///
+class Identifiers: IdentifierProvider {
+  private let installations: InstallationsProtocol
+
+  private var uuid: UUID
+
+  init(installations: InstallationsProtocol) {
+    self.installations = installations
+    uuid = UUID()
+  }
+
+  func generateNewSessionID() {
+    uuid = UUID()
+
+    let lastStoredSessionID = UserDefaults.standard.string(forKey: sessionIDUserDefaultsKey) ?? ""
+    UserDefaults.standard.set(lastStoredSessionID, forKey: lastSessionIDUserDefaultsKey)
+
+    let newSessionID = uuid.uuidString.replacingOccurrences(of: "-", with: "").lowercased()
+    UserDefaults.standard.set(newSessionID, forKey: sessionIDUserDefaultsKey)
+  }
+
+  // This method must be run on a background thread due to how Firebase Installations
+  // handles threading.
+  var installationID: String {
+    if Thread.isMainThread {
+      Logger
+        .logError(
+          "Error: Identifiers.installationID getter must be called on a background thread. Using an empty ID"
+        )
+      return ""
+    }
+
+    var localInstallationID = ""
+
+    let semaphore = DispatchSemaphore(value: 0)
+
+    installations.installationID { result in
+      switch result {
+      case let .success(fiid):
+        localInstallationID = fiid
+      case let .failure(error):
+        Logger
+          .logError(
+            "Error getting Firebase Installation ID: \(error). Using an empty ID"
+          )
+      }
+
+      semaphore.signal()
+    }
+
+    switch semaphore.wait(timeout: DispatchTime.now() + 1.0) {
+    case .success:
+      break
+    case .timedOut:
+      Logger.logError("Error: took too long to get the Firebase Installation ID. Using an empty ID")
+    }
+
+    return localInstallationID
+  }
+
+  var sessionID: String {
+    return UserDefaults.standard.string(forKey: sessionIDUserDefaultsKey) ?? ""
+  }
+
+  var lastSessionID: String {
+    return UserDefaults.standard.string(forKey: lastSessionIDUserDefaultsKey) ?? ""
+  }
+}

FirebaseSessions/Sources/Installations+InstallationsProtocol.swift

@@ -0,0 +1,33 @@
+//
+// Copyright 2022 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import Foundation
+import FirebaseInstallations
+
+protocol InstallationsProtocol {
+  func installationID(completion: @escaping (Result<String, Error>) -> Void)
+}
+
+extension Installations: InstallationsProtocol {
+  func installationID(completion: @escaping (Result<String, Error>) -> Void) {
+    installationID { (installationID: String?, error: Error?) in
+      if let installationID = installationID {
+        completion(.success(installationID))
+      } else if let error = error {
+        completion(.failure(error))
+      }
+    }
+  }
+}

FirebaseSessions/Sources/Logger.swift

@@ -0,0 +1,59 @@
+//
+// Copyright 2022 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import Foundation
+
+@_implementationOnly import FirebaseCoreExtension
+
+enum Logger {
+  private static let logServiceTag = "[FirebaseSessions]"
+  private static let logCode = "I-SES000000"
+
+  static func logInfo(_ message: String) {
+    FirebaseLogger.log(
+      level: .info,
+      service: logServiceTag,
+      code: logCode,
+      message: message
+    )
+  }
+
+  static func logDebug(_ message: String) {
+    FirebaseLogger.log(
+      level: .debug,
+      service: logServiceTag,
+      code: logCode,
+      message: message
+    )
+  }
+
+  static func logWarning(_ message: String) {
+    FirebaseLogger.log(
+      level: .warning,
+      service: logServiceTag,
+      code: logCode,
+      message: message
+    )
+  }
+
+  static func logError(_ message: String) {
+    FirebaseLogger.log(
+      level: .error,
+      service: logServiceTag,
+      code: logCode,
+      message: message
+    )
+  }
+}