feat(metrics): [Trace Metrics 15] Android Metrics batch processor and factory

sentry-android-core/api/sentry-android-core.api

@@ -100,6 +100,18 @@ public class io/sentry/android/core/AndroidMemoryCollector : io/sentry/IPerforma
 	public fun setup ()V
 }
 
+public final class io/sentry/android/core/AndroidMetricsBatchProcessor : io/sentry/metrics/MetricsBatchProcessor, io/sentry/android/core/AppState$AppStateListener {
+	public fun <init> (Lio/sentry/SentryOptions;Lio/sentry/ISentryClient;)V
+	public fun close (Z)V
+	public fun onBackground ()V
+	public fun onForeground ()V
+}
+
+public final class io/sentry/android/core/AndroidMetricsBatchProcessorFactory : io/sentry/metrics/IMetricsBatchProcessorFactory {
+	public fun <init> ()V
+	public fun create (Lio/sentry/SentryOptions;Lio/sentry/SentryClient;)Lio/sentry/metrics/IMetricsBatchProcessor;
+}
+
 public class io/sentry/android/core/AndroidProfiler {
 	protected final field lock Lio/sentry/util/AutoClosableReentrantLock;
 	public fun <init> (Ljava/lang/String;ILio/sentry/android/core/internal/util/SentryFrameMetricsCollector;Lio/sentry/ISentryExecutorService;Lio/sentry/ILogger;)V

sentry-android-core/src/main/java/io/sentry/android/core/AndroidMetricsBatchProcessor.java

@@ -0,0 +1,49 @@
+package io.sentry.android.core;
+
+import io.sentry.ISentryClient;
+import io.sentry.SentryLevel;
+import io.sentry.SentryOptions;
+import io.sentry.metrics.MetricsBatchProcessor;
+import org.jetbrains.annotations.ApiStatus;
+import org.jetbrains.annotations.NotNull;
+
+@ApiStatus.Internal
+public final class AndroidMetricsBatchProcessor extends MetricsBatchProcessor
+    implements AppState.AppStateListener {
+
+  public AndroidMetricsBatchProcessor(
+      @NotNull SentryOptions options, @NotNull ISentryClient client) {
+    super(options, client);
+    AppState.getInstance().addAppStateListener(this);
+  }
+
+  @Override
+  public void onForeground() {
+    // no-op
+  }
+
+  @Override
+  public void onBackground() {
+    try {
+      options
+          .getExecutorService()
+          .submit(
+              new Runnable() {
+                @Override
+                public void run() {
+                  flush(MetricsBatchProcessor.FLUSH_AFTER_MS);
+                }
+              });
+    } catch (Throwable t) {
+      options
+          .getLogger()
+          .log(SentryLevel.ERROR, t, "Failed to submit metrics flush in onBackground()");
+    }
+  }
+
+  @Override
+  public void close(boolean isRestarting) {
+    AppState.getInstance().removeAppStateListener(this);
+    super.close(isRestarting);
+  }
+}

sentry-android-core/src/main/java/io/sentry/android/core/AndroidMetricsBatchProcessorFactory.java

@@ -0,0 +1,15 @@
+package io.sentry.android.core;
+
+import io.sentry.SentryClient;
+import io.sentry.SentryOptions;
+import io.sentry.metrics.IMetricsBatchProcessor;
+import io.sentry.metrics.IMetricsBatchProcessorFactory;
+import org.jetbrains.annotations.NotNull;
+
+public final class AndroidMetricsBatchProcessorFactory implements IMetricsBatchProcessorFactory {
+  @Override
+  public @NotNull IMetricsBatchProcessor create(
+      @NotNull SentryOptions options, @NotNull SentryClient client) {
+    return new AndroidMetricsBatchProcessor(options, client);
+  }
+}

sentry-android-core/src/main/java/io/sentry/android/core/AndroidOptionsInitializer.java

@@ -124,6 +124,7 @@ static void loadDefaultAndMetadataOptions(
     options.setDateProvider(new SentryAndroidDateProvider());
     options.setRuntimeManager(new AndroidRuntimeManager());
     options.getLogs().setLoggerBatchProcessorFactory(new AndroidLoggerBatchProcessorFactory());
+    options.getMetrics().setMetricsBatchProcessorFactory(new AndroidMetricsBatchProcessorFactory());
 
     // set a lower flush timeout on Android to avoid ANRs
     options.setFlushTimeoutMillis(DEFAULT_FLUSH_TIMEOUT_MS);

sentry-android-core/src/test/java/io/sentry/android/core/AndroidMetricsBatchProcessorFactoryTest.kt

@@ -0,0 +1,23 @@
+package io.sentry.android.core
+
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import io.sentry.SentryClient
+import kotlin.test.Test
+import kotlin.test.assertIs
+import org.junit.runner.RunWith
+import org.mockito.kotlin.mock
+
+@RunWith(AndroidJUnit4::class)
+class AndroidMetricsBatchProcessorFactoryTest {
+
+  @Test
+  fun `create returns AndroidMetricsBatchProcessor instance`() {
+    val factory = AndroidMetricsBatchProcessorFactory()
+    val options = SentryAndroidOptions()
+    val client: SentryClient = mock()
+
+    val processor = factory.create(options, client)
+
+    assertIs<AndroidMetricsBatchProcessor>(processor)
+  }
+}

sentry-android-core/src/test/java/io/sentry/android/core/AndroidMetricsBatchProcessorTest.kt

@@ -0,0 +1,96 @@
+package io.sentry.android.core
+
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import io.sentry.ISentryClient
+import io.sentry.SentryMetricsEvent
+import io.sentry.SentryOptions
+import io.sentry.protocol.SentryId
+import io.sentry.test.ImmediateExecutorService
+import kotlin.test.AfterTest
+import kotlin.test.BeforeTest
+import kotlin.test.Test
+import kotlin.test.assertNotNull
+import kotlin.test.assertTrue
+import org.junit.runner.RunWith
+import org.mockito.kotlin.any
+import org.mockito.kotlin.mock
+import org.mockito.kotlin.verify
+import org.mockito.kotlin.whenever
+
+@RunWith(AndroidJUnit4::class)
+class AndroidMetricsBatchProcessorTest {
+
+  private class Fixture {
+    val options = SentryAndroidOptions()
+    val client: ISentryClient = mock()
+
+    fun getSut(
+      useImmediateExecutor: Boolean = false,
+      config: ((SentryOptions) -> Unit)? = null,
+    ): AndroidMetricsBatchProcessor {
+      if (useImmediateExecutor) {
+        options.executorService = ImmediateExecutorService()
+      }
+      config?.invoke(options)
+      return AndroidMetricsBatchProcessor(options, client)
+    }
+  }
+
+  private val fixture = Fixture()
+
+  @BeforeTest
+  fun `set up`() {
+    AppState.getInstance().resetInstance()
+  }
+
+  @AfterTest
+  fun `tear down`() {
+    AppState.getInstance().resetInstance()
+  }
+
+  @Test
+  fun `constructor registers as AppState listener`() {
+    fixture.getSut()
+    assertNotNull(AppState.getInstance().lifecycleObserver)
+  }
+
+  @Test
+  fun `onBackground schedules flush`() {
+    val sut = fixture.getSut(useImmediateExecutor = true)
+    val metricsEvent = SentryMetricsEvent(SentryId(), 1.0, "test", "counter", 3.0)
+    sut.add(metricsEvent)
+
+    sut.onBackground()
+
+    verify(fixture.client).captureBatchedMetricsEvents(any())
+  }
+
+  @Test
+  fun `onBackground handles executor exception gracefully`() {
+    val sut =
+      fixture.getSut { options ->
+        val rejectingExecutor = mock<io.sentry.ISentryExecutorService>()
+        whenever(rejectingExecutor.submit(any())).thenThrow(RuntimeException("Rejected"))
+        options.executorService = rejectingExecutor
+      }
+
+    // Should not throw
+    sut.onBackground()
+  }
+
+  @Test
+  fun `close removes AppState listener`() {
+    val sut = fixture.getSut()
+    sut.close(false)
+
+    assertTrue(AppState.getInstance().lifecycleObserver.listeners.isEmpty())
+  }
+
+  @Test
+  fun `close with isRestarting true still removes listener`() {
+    val sut = fixture.getSut()
+    sut.close(true)
+
+    assertTrue(AppState.getInstance().lifecycleObserver.listeners.isEmpty())
+  }
+}