mobile: fix setRuntimeGuard Swift API (envoyproxy#26013)

This was never fully hooked up to the C++ builder in
`-[EnvoyConfiguration applyToCXXBuilder]`.

Co-authored-by: Rafał Augustyniak <[email protected]>
Signed-off-by: JP Simard <[email protected]>

mobile/library/objective-c/EnvoyConfiguration.h

@@ -96,6 +96,13 @@ NS_ASSUME_NONNULL_BEGIN
                                        (NSDictionary<NSString *, id<EnvoyKeyValueStore>> *)
                                            keyValueStores
                                        statsSinks:(NSArray<NSString *> *)statsSinks;
+
+/**
+ Generate a string description of the C++ Envoy bootstrap from this configuration.
+ For testing purposes only.
+ */
+- (NSString *)bootstrapDebugDescription;
+
 @end
 
 NS_ASSUME_NONNULL_END

mobile/library/objective-c/EnvoyConfiguration.mm

@@ -177,6 +177,11 @@ - (instancetype)initWithAdminInterfaceEnabled:(BOOL)adminInterfaceEnabled
   builder.enableGzipDecompression(self.enableGzipDecompression);
   builder.enableBrotliDecompression(self.enableBrotliDecompression);
 
+  for (NSString *key in self.runtimeGuards) {
+    BOOL value = [[self.runtimeGuards objectForKey:key] isEqualToString:@"true"];
+    builder.setRuntimeGuard([key toCXXString], value);
+  }
+
   for (EMODirectResponse *directResponse in self.typedDirectResponses) {
     builder.addDirectResponse([directResponse toCXX]);
   }
@@ -244,4 +249,9 @@ - (instancetype)initWithAdminInterfaceEnabled:(BOOL)adminInterfaceEnabled
   }
 }
 
+- (NSString *)bootstrapDebugDescription {
+  std::unique_ptr<envoy::config::bootstrap::v3::Bootstrap> bootstrap = [self generateBootstrap];
+  return @(bootstrap->ShortDebugString().c_str());
+}
+
 @end

mobile/library/swift/EngineBuilder.swift

@@ -571,7 +571,44 @@ open class EngineBuilder: NSObject {
     let engine = self.engineType.init(runningCallback: self.onEngineRunning, logger: self.logger,
                                       eventTracker: self.eventTracker,
                                       networkMonitoringMode: Int32(self.monitoringMode.rawValue))
-    let config = EnvoyConfiguration(
+    let config = self.makeConfig()
+
+    switch self.base {
+    case .custom(let yaml):
+      return EngineImpl(yaml: yaml, config: config, logLevel: self.logLevel, engine: engine)
+    case .standard:
+      return EngineImpl(config: config, logLevel: self.logLevel, engine: engine)
+    }
+  }
+
+  // MARK: - Internal
+
+  /// Add a specific implementation of `EnvoyEngine` to use for starting Envoy.
+  /// A new instance of this engine will be created when `build()` is called.
+  /// Used for testing, as initializing with `EnvoyEngine.Type` results in a
+  /// segfault: https://github.com/envoyproxy/envoy-mobile/issues/334
+  ///
+  /// - parameter engineType: The specific implementation of `EnvoyEngine` to use for starting
+  ///                         Envoy.
+  ///
+  /// - returns: This builder.
+  @discardableResult
+  func addEngineType(_ engineType: EnvoyEngine.Type) -> Self {
+    self.engineType = engineType
+    return self
+  }
+
+  /// Add a direct response to be used when configuring the engine.
+  /// This function is internal so it is not publicly exposed to production builders,
+  /// but is available for use by the `TestEngineBuilder`.
+  ///
+  /// - parameter directResponse: The response configuration to add.
+  func addDirectResponseInternal(_ directResponse: DirectResponse) {
+    self.directResponses.append(directResponse)
+  }
+
+  func makeConfig() -> EnvoyConfiguration {
+    EnvoyConfiguration(
       adminInterfaceEnabled: self.adminInterfaceEnabled,
       grpcStatsDomain: self.grpcStatsDomain,
       connectTimeoutSeconds: self.connectTimeoutSeconds,
@@ -610,38 +647,9 @@ open class EngineBuilder: NSObject {
       keyValueStores: self.keyValueStores,
       statsSinks: self.statsSinks
     )
-
-    switch self.base {
-    case .custom(let yaml):
-      return EngineImpl(yaml: yaml, config: config, logLevel: self.logLevel, engine: engine)
-    case .standard:
-      return EngineImpl(config: config, logLevel: self.logLevel, engine: engine)
-    }
   }
 
-  // MARK: - Internal
-
-  /// Add a specific implementation of `EnvoyEngine` to use for starting Envoy.
-  /// A new instance of this engine will be created when `build()` is called.
-  /// Used for testing, as initializing with `EnvoyEngine.Type` results in a
-  /// segfault: https://github.com/envoyproxy/envoy-mobile/issues/334
-  ///
-  /// - parameter engineType: The specific implementation of `EnvoyEngine` to use for starting
-  ///                         Envoy.
-  ///
-  /// - returns: This builder.
-  @discardableResult
-  func addEngineType(_ engineType: EnvoyEngine.Type) -> Self {
-    self.engineType = engineType
-    return self
-  }
-
-  /// Add a direct response to be used when configuring the engine.
-  /// This function is internal so it is not publicly exposed to production builders,
-  /// but is available for use by the `TestEngineBuilder`.
-  ///
-  /// - parameter directResponse: The response configuration to add.
-  func addDirectResponseInternal(_ directResponse: DirectResponse) {
-    self.directResponses.append(directResponse)
+  func bootstrapDebugDescription() -> String {
+    self.makeConfig().bootstrapDebugDescription()
   }
 }

mobile/test/swift/EngineBuilderTests.swift

@@ -30,6 +30,19 @@ final class EngineBuilderTests: XCTestCase {
     MockEnvoyEngine.onRunWithYAML = nil
   }
 
+  func testSetRuntimeGuard() {
+    let bootstrapDebugDescription = EngineBuilder()
+      .setRuntimeGuard("test_feature_false", true)
+      .setRuntimeGuard("test_feature_true", false)
+      .bootstrapDebugDescription()
+    XCTAssertTrue(
+      bootstrapDebugDescription.contains(#""test_feature_false" value { bool_value: true }"#)
+    )
+    XCTAssertTrue(
+      bootstrapDebugDescription.contains(#""test_feature_true" value { bool_value: false }"#)
+    )
+  }
+
   func testMonitoringModeDefaultsToPathMonitor() {
     let builder = EngineBuilder()
     XCTAssertEqual(builder.monitoringMode, .pathMonitor)