Add custom signals support in Remote Config. (#6539)

feat(rc): Add support to set custom signals for Remote Config Custom
targeting

Author: tusharkhandelwal8

firebase-config/CHANGELOG.md

@@ -1,5 +1,5 @@
 # Unreleased
-
+* [feature] Added support for custom signal targeting in Remote Config. Use `setCustomSignals` API for setting custom signals and use them to build custom targeting conditions in Remote Config.
 
 # 22.0.1
 * [changed] Updated protobuf dependency to `3.25.5` to fix

firebase-config/api.txt

@@ -16,6 +16,17 @@ package com.google.firebase.remoteconfig {
     method public void remove();
   }
 
+  public class CustomSignals {
+  }
+
+  public static class CustomSignals.Builder {
+    ctor public CustomSignals.Builder();
+    method @NonNull public com.google.firebase.remoteconfig.CustomSignals build();
+    method @NonNull public com.google.firebase.remoteconfig.CustomSignals.Builder put(@NonNull String, @Nullable String);
+    method @NonNull public com.google.firebase.remoteconfig.CustomSignals.Builder put(@NonNull String, long);
+    method @NonNull public com.google.firebase.remoteconfig.CustomSignals.Builder put(@NonNull String, double);
+  }
+
   public class FirebaseRemoteConfig {
     method @NonNull public com.google.android.gms.tasks.Task<java.lang.Boolean> activate();
     method @NonNull public com.google.firebase.remoteconfig.ConfigUpdateListenerRegistration addOnConfigUpdateListener(@NonNull com.google.firebase.remoteconfig.ConfigUpdateListener);
@@ -35,6 +46,7 @@ package com.google.firebase.remoteconfig {
     method @NonNull public com.google.firebase.remoteconfig.FirebaseRemoteConfigValue getValue(@NonNull String);
     method @NonNull public com.google.android.gms.tasks.Task<java.lang.Void> reset();
     method @NonNull public com.google.android.gms.tasks.Task<java.lang.Void> setConfigSettingsAsync(@NonNull com.google.firebase.remoteconfig.FirebaseRemoteConfigSettings);
+    method @NonNull public com.google.android.gms.tasks.Task<java.lang.Void> setCustomSignals(@NonNull com.google.firebase.remoteconfig.CustomSignals);
     method @NonNull public com.google.android.gms.tasks.Task<java.lang.Void> setDefaultsAsync(@NonNull java.util.Map<java.lang.String,java.lang.Object>);
     method @NonNull public com.google.android.gms.tasks.Task<java.lang.Void> setDefaultsAsync(@XmlRes int);
     field public static final boolean DEFAULT_VALUE_FOR_BOOLEAN = false;
@@ -121,6 +133,7 @@ package com.google.firebase.remoteconfig {
   }
 
   public final class RemoteConfigKt {
+    method @NonNull public static com.google.firebase.remoteconfig.CustomSignals customSignals(@NonNull kotlin.jvm.functions.Function1<? super com.google.firebase.remoteconfig.CustomSignals.Builder,kotlin.Unit> builder);
     method @NonNull public static operator com.google.firebase.remoteconfig.FirebaseRemoteConfigValue get(@NonNull com.google.firebase.remoteconfig.FirebaseRemoteConfig, @NonNull String key);
     method @NonNull public static kotlinx.coroutines.flow.Flow<com.google.firebase.remoteconfig.ConfigUpdate> getConfigUpdates(@NonNull com.google.firebase.remoteconfig.FirebaseRemoteConfig);
     method @NonNull public static com.google.firebase.remoteconfig.FirebaseRemoteConfig getRemoteConfig(@NonNull com.google.firebase.Firebase);

firebase-config/ktx/src/test/kotlin/com/google/firebase/remoteconfig/TestConstructorUtil.kt

@@ -23,8 +23,8 @@ import com.google.firebase.installations.FirebaseInstallationsApi
 import com.google.firebase.remoteconfig.internal.ConfigCacheClient
 import com.google.firebase.remoteconfig.internal.ConfigFetchHandler
 import com.google.firebase.remoteconfig.internal.ConfigGetParameterHandler
-import com.google.firebase.remoteconfig.internal.ConfigMetadataClient
 import com.google.firebase.remoteconfig.internal.ConfigRealtimeHandler
+import com.google.firebase.remoteconfig.internal.ConfigSharedPrefsClient
 import com.google.firebase.remoteconfig.internal.rollouts.RolloutsStateSubscriptionsHandler
 import java.util.concurrent.Executor
 
@@ -41,7 +41,7 @@ fun createRemoteConfig(
   defaultConfigsCache: ConfigCacheClient,
   fetchHandler: ConfigFetchHandler,
   getHandler: ConfigGetParameterHandler,
-  frcMetadata: ConfigMetadataClient,
+  frcSharedPrefs: ConfigSharedPrefsClient,
   realtimeHandler: ConfigRealtimeHandler,
   rolloutsStateSubscriptionsHandler: RolloutsStateSubscriptionsHandler
 ): FirebaseRemoteConfig {
@@ -56,7 +56,7 @@ fun createRemoteConfig(
     defaultConfigsCache,
     fetchHandler,
     getHandler,
-    frcMetadata,
+    frcSharedPrefs,
     realtimeHandler,
     rolloutsStateSubscriptionsHandler
   )

firebase-config/ktx/src/test/kotlin/com/google/firebase/remoteconfig/ktx/RemoteConfigTests.kt

@@ -32,8 +32,8 @@ import com.google.firebase.remoteconfig.createRemoteConfig
 import com.google.firebase.remoteconfig.internal.ConfigCacheClient
 import com.google.firebase.remoteconfig.internal.ConfigFetchHandler
 import com.google.firebase.remoteconfig.internal.ConfigGetParameterHandler
-import com.google.firebase.remoteconfig.internal.ConfigMetadataClient
 import com.google.firebase.remoteconfig.internal.ConfigRealtimeHandler
+import com.google.firebase.remoteconfig.internal.ConfigSharedPrefsClient
 import com.google.firebase.remoteconfig.internal.rollouts.RolloutsStateSubscriptionsHandler
 import org.junit.After
 import org.junit.Before
@@ -142,7 +142,7 @@ class ConfigTests : BaseTestCase() {
         defaultConfigsCache = mock(ConfigCacheClient::class.java),
         fetchHandler = mock(ConfigFetchHandler::class.java),
         getHandler = mockGetHandler,
-        frcMetadata = mock(ConfigMetadataClient::class.java),
+        frcSharedPrefs = mock(ConfigSharedPrefsClient::class.java),
         realtimeHandler = mock(ConfigRealtimeHandler::class.java),
         rolloutsStateSubscriptionsHandler = mock(RolloutsStateSubscriptionsHandler::class.java)
       )

firebase-config/src/androidTest/java/com/google/firebase/remoteconfig/FirebaseRemoteConfigIntegrationTest.java

@@ -35,8 +35,8 @@
 import com.google.firebase.remoteconfig.internal.ConfigContainer;
 import com.google.firebase.remoteconfig.internal.ConfigFetchHandler;
 import com.google.firebase.remoteconfig.internal.ConfigGetParameterHandler;
-import com.google.firebase.remoteconfig.internal.ConfigMetadataClient;
 import com.google.firebase.remoteconfig.internal.ConfigRealtimeHandler;
+import com.google.firebase.remoteconfig.internal.ConfigSharedPrefsClient;
 import com.google.firebase.remoteconfig.internal.rollouts.RolloutsStateSubscriptionsHandler;
 import java.util.Date;
 import java.util.HashMap;
@@ -60,7 +60,7 @@ public class FirebaseRemoteConfigIntegrationTest {
   @Mock private ConfigCacheClient mockDefaultsCache;
   @Mock private ConfigFetchHandler mockFetchHandler;
   @Mock private ConfigGetParameterHandler mockGetHandler;
-  @Mock private ConfigMetadataClient metadataClient;
+  @Mock private ConfigSharedPrefsClient sharedPrefsClient;
   @Mock private ConfigRealtimeHandler mockConfigRealtimeHandler;
   @Mock private RolloutsStateSubscriptionsHandler mockRolloutsStateSubscriptionHandler;
 
@@ -112,7 +112,7 @@ public void setUp() {
             mockDefaultsCache,
             mockFetchHandler,
             mockGetHandler,
-            metadataClient,
+            sharedPrefsClient,
             mockConfigRealtimeHandler,
             mockRolloutsStateSubscriptionHandler);
   }

firebase-config/src/main/java/com/google/firebase/remoteconfig/CustomSignals.java

@@ -0,0 +1,86 @@
+// Copyright 2024 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.
+
+package com.google.firebase.remoteconfig;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+import java.util.HashMap;
+import java.util.Map;
+
+/**
+ * A container type to represent key/value pairs of heterogeneous types to be set as custom signals
+ * in {@link FirebaseRemoteConfig#setCustomSignals}.
+ */
+public class CustomSignals {
+  final Map<String, String> customSignals;
+
+  /** Builder for constructing {@link CustomSignals} instances. */
+  public static class Builder {
+    private Map<String, String> customSignals = new HashMap<String, String>();
+
+    /**
+     * Adds a custom signal with a value that can be a string or null to the builder.
+     *
+     * @param key The key for the custom signal.
+     * @param value The string value associated with the key. Can be null.
+     * @return This Builder instance to allow chaining of method calls.
+     */
+    @NonNull
+    public Builder put(@NonNull String key, @Nullable String value) {
+      customSignals.put(key, value);
+      return this;
+    }
+
+    /**
+     * Adds a custom signal with a long value to the builder.
+     *
+     * @param key The key for the custom signal.
+     * @param value The long value for the custom signal.
+     * @return This Builder instance to allow chaining of method calls.
+     */
+    @NonNull
+    public Builder put(@NonNull String key, long value) {
+      customSignals.put(key, Long.toString(value));
+      return this;
+    }
+
+    /**
+     * Adds a custom signal with a double value to the builder.
+     *
+     * @param key The key for the custom signal.
+     * @param value The double value for the custom signal.
+     * @return This Builder instance to allow chaining of method calls.
+     */
+    @NonNull
+    public Builder put(@NonNull String key, double value) {
+      customSignals.put(key, Double.toString(value));
+      return this;
+    }
+
+    /**
+     * Creates a {@link CustomSignals} instance with the added custom signals.
+     *
+     * @return The constructed {@link CustomSignals} instance.
+     */
+    @NonNull
+    public CustomSignals build() {
+      return new CustomSignals(this);
+    }
+  }
+
+  CustomSignals(@NonNull Builder builder) {
+    this.customSignals = builder.customSignals;
+  }
+}

firebase-config/src/main/java/com/google/firebase/remoteconfig/FirebaseRemoteConfig.java

@@ -33,8 +33,8 @@
 import com.google.firebase.remoteconfig.internal.ConfigFetchHandler;
 import com.google.firebase.remoteconfig.internal.ConfigFetchHandler.FetchResponse;
 import com.google.firebase.remoteconfig.internal.ConfigGetParameterHandler;
-import com.google.firebase.remoteconfig.internal.ConfigMetadataClient;
 import com.google.firebase.remoteconfig.internal.ConfigRealtimeHandler;
+import com.google.firebase.remoteconfig.internal.ConfigSharedPrefsClient;
 import com.google.firebase.remoteconfig.internal.DefaultsXmlParser;
 import com.google.firebase.remoteconfig.internal.rollouts.RolloutsStateSubscriptionsHandler;
 import java.util.ArrayList;
@@ -160,7 +160,7 @@ public static FirebaseRemoteConfig getInstance(@NonNull FirebaseApp app) {
   private final ConfigCacheClient defaultConfigsCache;
   private final ConfigFetchHandler fetchHandler;
   private final ConfigGetParameterHandler getHandler;
-  private final ConfigMetadataClient frcMetadata;
+  private final ConfigSharedPrefsClient frcSharedPrefs;
   private final FirebaseInstallationsApi firebaseInstallations;
   private final ConfigRealtimeHandler configRealtimeHandler;
   private final RolloutsStateSubscriptionsHandler rolloutsStateSubscriptionsHandler;
@@ -181,7 +181,7 @@ public static FirebaseRemoteConfig getInstance(@NonNull FirebaseApp app) {
       ConfigCacheClient defaultConfigsCache,
       ConfigFetchHandler fetchHandler,
       ConfigGetParameterHandler getHandler,
-      ConfigMetadataClient frcMetadata,
+      ConfigSharedPrefsClient frcSharedPrefs,
       ConfigRealtimeHandler configRealtimeHandler,
       RolloutsStateSubscriptionsHandler rolloutsStateSubscriptionsHandler) {
     this.context = context;
@@ -194,7 +194,7 @@ public static FirebaseRemoteConfig getInstance(@NonNull FirebaseApp app) {
     this.defaultConfigsCache = defaultConfigsCache;
     this.fetchHandler = fetchHandler;
     this.getHandler = getHandler;
-    this.frcMetadata = frcMetadata;
+    this.frcSharedPrefs = frcSharedPrefs;
     this.configRealtimeHandler = configRealtimeHandler;
     this.rolloutsStateSubscriptionsHandler = rolloutsStateSubscriptionsHandler;
   }
@@ -208,18 +208,18 @@ public Task<FirebaseRemoteConfigInfo> ensureInitialized() {
     Task<ConfigContainer> activatedConfigsTask = activatedConfigsCache.get();
     Task<ConfigContainer> defaultsConfigsTask = defaultConfigsCache.get();
     Task<ConfigContainer> fetchedConfigsTask = fetchedConfigsCache.get();
-    Task<FirebaseRemoteConfigInfo> metadataTask = Tasks.call(executor, this::getInfo);
+    Task<FirebaseRemoteConfigInfo> sharedPrefsTask = Tasks.call(executor, this::getInfo);
     Task<String> installationIdTask = firebaseInstallations.getId();
     Task<InstallationTokenResult> installationTokenTask = firebaseInstallations.getToken(false);
 
     return Tasks.whenAllComplete(
             activatedConfigsTask,
             defaultsConfigsTask,
             fetchedConfigsTask,
-            metadataTask,
+            sharedPrefsTask,
             installationIdTask,
             installationTokenTask)
-        .continueWith(executor, (unusedListOfCompletedTasks) -> metadataTask.getResult());
+        .continueWith(executor, (unusedListOfCompletedTasks) -> sharedPrefsTask.getResult());
   }
 
   /**
@@ -475,7 +475,7 @@ public Map<String, FirebaseRemoteConfigValue> getAll() {
    */
   @NonNull
   public FirebaseRemoteConfigInfo getInfo() {
-    return frcMetadata.getInfo();
+    return frcSharedPrefs.getInfo();
   }
 
   /**
@@ -488,7 +488,7 @@ public Task<Void> setConfigSettingsAsync(@NonNull FirebaseRemoteConfigSettings s
     return Tasks.call(
         executor,
         () -> {
-          frcMetadata.setConfigSettings(settings);
+          frcSharedPrefs.setConfigSettings(settings);
 
           // Return value required; return null for Void.
           return null;
@@ -548,14 +548,14 @@ public Task<Void> setDefaultsAsync(@XmlRes int resourceId) {
   @NonNull
   public Task<Void> reset() {
     // Use a Task to avoid throwing potential file I/O errors to the caller and because
-    // frcMetadata's clear call is blocking.
+    // frcSharedPrefs's clear call is blocking.
     return Tasks.call(
         executor,
         () -> {
           activatedConfigsCache.clear();
           fetchedConfigsCache.clear();
           defaultConfigsCache.clear();
-          frcMetadata.clear();
+          frcSharedPrefs.clear();
           return null;
         });
   }
@@ -652,6 +652,30 @@ private Task<Void> setDefaultsWithStringsMapAsync(Map<String, String> defaultsSt
         FirebaseExecutors.directExecutor(), (unusedContainer) -> Tasks.forResult(null));
   }
 
+  /**
+   * Asynchronously changes the custom signals for this {@link FirebaseRemoteConfig} instance.
+   *
+   * <p>Custom signals are subject to limits on the size of key/value pairs and the total
+   * number of signals. Any calls that exceed these limits will be discarded.
+   *
+   * @param customSignals The custom signals to set for this instance.
+   * <ol>
+   *   <li>New keys will add new key-value pairs in the custom signals.
+   *   <li>Existing keys with new values will update the corresponding signals.
+   *   <li>Setting a key's value to {@code null} will remove the associated signal.
+   * </ol>
+   */
+  // TODO(b/385028620): Add link to documentation about custom signal limits.
+  @NonNull
+  public Task<Void> setCustomSignals(@NonNull CustomSignals customSignals) {
+    return Tasks.call(
+        executor,
+        () -> {
+          frcSharedPrefs.setCustomSignals(customSignals.customSignals);
+          return null;
+        });
+  }
+
   /**
    * Notifies the Firebase A/B Testing SDK about activated experiments.
    *

firebase-config/src/main/java/com/google/firebase/remoteconfig/RemoteConfig.kt

@@ -48,6 +48,9 @@ fun remoteConfigSettings(
   return builder.build()
 }
 
+fun customSignals(builder: CustomSignals.Builder.() -> Unit) =
+  CustomSignals.Builder().apply(builder).build()
+
 /**
  * Starts listening for config updates from the Remote Config backend and emits [ConfigUpdate]s via
  * a [Flow]. See [FirebaseRemoteConfig.addOnConfigUpdateListener] for more information.