Rc realtime dev

firebase-config/api.txt

@@ -2,7 +2,7 @@
 package com.google.firebase.remoteconfig {
 
   public interface ConfigUpdateListener {
-    method public void onError(Exception);
+    method public void onError(@NonNull Exception);
     method public void onEvent();
   }
 
@@ -65,6 +65,16 @@ package com.google.firebase.remoteconfig {
     method public int getLastFetchStatus();
   }
 
+  public class FirebaseRemoteConfigRealtimeUpdateFetchException extends com.google.firebase.remoteconfig.FirebaseRemoteConfigException {
+    ctor public FirebaseRemoteConfigRealtimeUpdateFetchException(@NonNull String);
+    ctor public FirebaseRemoteConfigRealtimeUpdateFetchException(@NonNull String, @Nullable Throwable);
+  }
+
+  public class FirebaseRemoteConfigRealtimeUpdateStreamException extends com.google.firebase.remoteconfig.FirebaseRemoteConfigException {
+    ctor public FirebaseRemoteConfigRealtimeUpdateStreamException(@NonNull String);
+    ctor public FirebaseRemoteConfigRealtimeUpdateStreamException(@NonNull String, @Nullable Throwable);
+  }
+
   public class FirebaseRemoteConfigServerException extends com.google.firebase.remoteconfig.FirebaseRemoteConfigException {
     ctor public FirebaseRemoteConfigServerException(int, @NonNull String);
     ctor public FirebaseRemoteConfigServerException(int, @NonNull String, @Nullable Throwable);

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

@@ -0,0 +1,37 @@
+// 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.
+
+package com.google.firebase.remoteconfig;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+/**
+ * A Firebase Remote Config exception caused by the auto-fetch component of Realtime config updates.
+ *
+ * @author Quan Pham
+ */
+public class FirebaseRemoteConfigRealtimeUpdateFetchException
+    extends FirebaseRemoteConfigException {
+  /** Creates a Firebase Remote Config Realtime fetch exception with the given message. */
+  public FirebaseRemoteConfigRealtimeUpdateFetchException(@NonNull String detailMessage) {
+    super(detailMessage);
+  }
+
+  /** Creates a Firebase Remote Config Realtime fetch exception with the given message and cause. */
+  public FirebaseRemoteConfigRealtimeUpdateFetchException(
+      @NonNull String detailMessage, @Nullable Throwable cause) {
+    super(detailMessage, cause);
+  }
+}

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

@@ -0,0 +1,39 @@
+// 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.
+
+package com.google.firebase.remoteconfig;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+/**
+ * A Firebase Remote Config exception caused by the stream component of Realtime config updates.
+ *
+ * @author Quan Pham
+ */
+public class FirebaseRemoteConfigRealtimeUpdateStreamException
+    extends FirebaseRemoteConfigException {
+  /** Creates a Firebase Remote Config Realtime stream exception with the given message. */
+  public FirebaseRemoteConfigRealtimeUpdateStreamException(@NonNull String detailMessage) {
+    super(detailMessage);
+  }
+
+  /**
+   * Creates a Firebase Remote Config Realtime stream exception with the given message and cause.
+   */
+  public FirebaseRemoteConfigRealtimeUpdateStreamException(
+      @NonNull String detailMessage, @Nullable Throwable cause) {
+    super(detailMessage, cause);
+  }
+}

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

@@ -27,6 +27,8 @@
 public final class RemoteConfigConstants {
   public static final String FETCH_REGEX_URL =
       "https://firebaseremoteconfig.googleapis.com/v1/projects/%s/namespaces/%s:fetch";
+  public static final String REALTIME_REGEX_URL =
+      "https://firebaseremoteconfig.googleapis.com/v1/projects/%s/namespaces/%s:streamFetchInvalidations";
 
   /**
    * Keys of fields in the Fetch request body that the client sends to the Firebase Remote Config
@@ -73,14 +75,16 @@ public final class RemoteConfigConstants {
     ResponseFieldKey.ENTRIES,
     ResponseFieldKey.EXPERIMENT_DESCRIPTIONS,
     ResponseFieldKey.PERSONALIZATION_METADATA,
-    ResponseFieldKey.STATE
+    ResponseFieldKey.STATE,
+    ResponseFieldKey.TEMPLATE_VERSION_NUMBER
   })
   @Retention(RetentionPolicy.SOURCE)
   public @interface ResponseFieldKey {
     String ENTRIES = "entries";
     String EXPERIMENT_DESCRIPTIONS = "experimentDescriptions";
     String PERSONALIZATION_METADATA = "personalizationMetadata";
     String STATE = "state";
+    String TEMPLATE_VERSION_NUMBER = "templateVersion";
   }
 
   /**

firebase-config/src/main/java/com/google/firebase/remoteconfig/internal/ConfigAutoFetch.java

@@ -0,0 +1,182 @@
+// 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.
+
+package com.google.firebase.remoteconfig.internal;
+
+import static com.google.firebase.remoteconfig.FirebaseRemoteConfig.TAG;
+
+import android.util.Log;
+import androidx.annotation.GuardedBy;
+import androidx.annotation.VisibleForTesting;
+import com.google.android.gms.tasks.Task;
+import com.google.android.gms.tasks.Tasks;
+import com.google.firebase.remoteconfig.ConfigUpdateListener;
+import com.google.firebase.remoteconfig.FirebaseRemoteConfigException;
+import com.google.firebase.remoteconfig.FirebaseRemoteConfigRealtimeUpdateFetchException;
+import com.google.firebase.remoteconfig.FirebaseRemoteConfigRealtimeUpdateStreamException;
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.net.HttpURLConnection;
+import java.util.Random;
+import java.util.Set;
+import java.util.concurrent.Executor;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+public class ConfigAutoFetch {
+
+  private static final int FETCH_RETRY = 3;
+
+  @GuardedBy("this")
+  private final Set<ConfigUpdateListener> eventListeners;
+
+  @GuardedBy("this")
+  private final HttpURLConnection httpURLConnection;
+
+  private final ConfigFetchHandler configFetchHandler;
+  private final ConfigUpdateListener retryCallback;
+  private final ScheduledExecutorService scheduledExecutorService;
+  private final Random random;
+  private final Executor executor;
+
+  public ConfigAutoFetch(
+      HttpURLConnection httpURLConnection,
+      ConfigFetchHandler configFetchHandler,
+      Set<ConfigUpdateListener> eventListeners,
+      ConfigUpdateListener retryCallback,
+      Executor executor,
+      ScheduledExecutorService scheduledExecutorService) {
+    this.httpURLConnection = httpURLConnection;
+    this.configFetchHandler = configFetchHandler;
+    this.eventListeners = eventListeners;
+    this.retryCallback = retryCallback;
+    this.scheduledExecutorService = scheduledExecutorService;
+    this.random = new Random();
+    this.executor = executor;
+  }
+
+  public void beginAutoFetch() {
+    executor.execute(
+        new Runnable() {
+          @Override
+          public void run() {
+            listenForNotifications();
+          }
+        });
+  }
+
+  private synchronized void propagateErrors(FirebaseRemoteConfigException exception) {
+    for (ConfigUpdateListener listener : eventListeners) {
+      listener.onError(exception);
+    }
+  }
+
+  private synchronized void executeAllListenerCallbacks() {
+    for (ConfigUpdateListener listener : eventListeners) {
+      listener.onEvent();
+    }
+  }
+
+  // Check connection and establish InputStream
+  @VisibleForTesting
+  public synchronized void listenForNotifications() {
+    if (httpURLConnection != null) {
+      try {
+        int responseCode = httpURLConnection.getResponseCode();
+        if (responseCode == 200) {
+          InputStream inputStream = httpURLConnection.getInputStream();
+          handleNotifications(inputStream);
+          inputStream.close();
+        } else {
+          propagateErrors(
+              new FirebaseRemoteConfigRealtimeUpdateStreamException(
+                  "Http connection responded with error: " + responseCode));
+        }
+      } catch (IOException ex) {
+        propagateErrors(
+            new FirebaseRemoteConfigRealtimeUpdateFetchException(
+                "Error handling stream messages while fetching.", ex.getCause()));
+      }
+    }
+    retryCallback.onEvent();
+  }
+
+  // Auto-fetch new config and execute callbacks on each new message
+  private void handleNotifications(InputStream inputStream) throws IOException {
+    BufferedReader reader = new BufferedReader((new InputStreamReader(inputStream, "utf-8")));
+    String message;
+    while ((message = reader.readLine()) != null) {
+      long targetTemplateVersion = configFetchHandler.getTemplateVersionNumber();
+      try {
+        JSONObject jsonObject = new JSONObject(message);
+        if (jsonObject.has("latestTemplateVersionNumber")) {
+          targetTemplateVersion = jsonObject.getLong("latestTemplateVersionNumber");
+        }
+      } catch (JSONException ex) {
+        Log.i(TAG, "Unable to parse latest config update message.");
+      }
+
+      autoFetch(FETCH_RETRY, targetTemplateVersion);
+    }
+    reader.close();
+  }
+
+  private void autoFetch(int remainingAttempts, long targetVersion) {
+    if (remainingAttempts == 0) {
+      propagateErrors(
+          new FirebaseRemoteConfigRealtimeUpdateFetchException("Unable to fetch latest version."));
+      return;
+    }
+
+    // Needs fetch to occur between 2 - 12 seconds. Randomize to not cause ddos alerts in backend
+    int timeTillFetch = random.nextInt(6) + 1;
+    scheduledExecutorService.schedule(
+        new Runnable() {
+          @Override
+          public void run() {
+            fetchLatestConfig(remainingAttempts, targetVersion);
+          }
+        },
+        timeTillFetch,
+        TimeUnit.SECONDS);
+  }
+
+  @VisibleForTesting
+  public synchronized void fetchLatestConfig(int remainingAttempts, long targetVersion) {
+    Task<ConfigFetchHandler.FetchResponse> fetchTask = configFetchHandler.fetch(0L);
+    fetchTask.onSuccessTask(
+        (fetchResponse) -> {
+          long newTemplateVersion = 0;
+          if (fetchResponse.getFetchedConfigs() != null) {
+            newTemplateVersion = fetchResponse.getFetchedConfigs().getTemplateVersionNumber();
+          }
+
+          if (newTemplateVersion >= targetVersion) {
+            executeAllListenerCallbacks();
+          } else {
+            Log.i(
+                TAG,
+                "Fetched template version is the same as SDK's current version."
+                    + " Retrying fetch.");
+            // Continue fetching until template version number if greater then current.
+            autoFetch(remainingAttempts - 1, targetVersion);
+          }
+          return Tasks.forResult(null);
+        });
+  }
+}