Add metrics API (#3205)

* Implement different metric types, add API and aggregator

* Fix typos, make executorService volatile

* Move from Calendar to long timestamps, add hooks for testing

* Rename to metrics, have Sentry.metrics() as entry point

* Add more tests, use cr32 for hashing strings

* Enrich tags, add more tests

* Cleanup tests and timing API, remove uneeded threadlocal

* Update changelog

* Move default tag generation to IMetricsHub, improve dx

* Cleanup

* Cleanup

* Fix remove duplicate metricAggregator.close call

* Address PR feedback

* Move test into metrics helper

* Rename getValues to serialize to match API spec

* Add support for force-flushing metrics when weight is too high

* Update Changelog

* Revert "Add support for force-flushing metrics when weight is too high"

This reverts commit 6a3be45.

* Fix .api

* Fix tests

* Fix remove test code

* Replace tag values with empty string

* Address PR feedback

* Format & API

* Fix tests

* Force flush metrics when aggregator exceeds max weight (#3220)

* Update Changelog

* Revert "Revert "Add support for force-flushing metrics when weight is too high""

This reverts commit 07fc4e5.

* Fix changelog

* Address PR feedback

* Fix tests

* Fix remove test code

* Address PR feedback

* Update Changelog

CHANGELOG.md

@@ -14,6 +14,7 @@
 - Fix hub restore point in wrappers: SentryWrapper, SentryTaskDecorator and SentryScheduleHook ([#3225](https://github.com/getsentry/sentry-java/pull/3225))
   - We now reset the hub to its previous value on the thread where the `Runnable`/`Callable`/`Supplier` is executed instead of setting it to the hub that was used on the thread where the `Runnable`/`Callable`/`Supplier` was created.
 - Fix add missing thread name/id to app start spans ([#3226](https://github.com/getsentry/sentry-java/pull/3226))
+- Experimental: Add Metrics API ([#3205](https://github.com/getsentry/sentry-java/pull/3205))
 
 ## 7.4.0
 

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

@@ -1024,7 +1024,7 @@ class ActivityLifecycleIntegrationTest {
         // Assert the ttfd span is running and a timeout autoCancel task has been scheduled
         assertNotNull(ttfdSpan)
         assertFalse(ttfdSpan.isFinished)
-        assertTrue(deferredExecutorService.scheduledRunnables.isNotEmpty())
+        assertTrue(deferredExecutorService.hasScheduledRunnables())
 
         // Run the autoClose task and assert the ttfd span is finished with deadlineExceeded
         deferredExecutorService.runAll()

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

@@ -8,6 +8,7 @@ import androidx.test.core.app.ApplicationProvider
 import androidx.test.ext.junit.runners.AndroidJUnit4
 import io.sentry.CheckIn
 import io.sentry.Hint
+import io.sentry.IMetricsAggregator
 import io.sentry.IScope
 import io.sentry.ISentryClient
 import io.sentry.ProfilingTraceData
@@ -174,5 +175,9 @@ class SessionTrackingIntegrationTest {
         override fun getRateLimiter(): RateLimiter? {
             TODO("Not yet implemented")
         }
+
+        override fun getMetricsAggregator(): IMetricsAggregator {
+            TODO("Not yet implemented")
+        }
     }
 }

sentry-samples/sentry-samples-android/src/main/java/io/sentry/samples/android/MyApplication.java

@@ -2,6 +2,7 @@
 
 import android.app.Application;
 import android.os.StrictMode;
+import io.sentry.Sentry;
 
 /** Apps. main Application. */
 public class MyApplication extends Application {
@@ -24,6 +25,8 @@ public void onCreate() {
     //      });
     //       */
     //    });
+
+    Sentry.metrics().increment("app.start.cold");
   }
 
   private void strictMode() {

sentry-test-support/api/sentry-test-support.api

@@ -14,7 +14,7 @@ public final class io/sentry/SkipError : java/lang/Error {
 public final class io/sentry/test/DeferredExecutorService : io/sentry/ISentryExecutorService {
 	public fun <init> ()V
 	public fun close (J)V
-	public final fun getScheduledRunnables ()Ljava/util/ArrayList;
+	public final fun hasScheduledRunnables ()Z
 	public fun isClosed ()Z
 	public final fun runAll ()V
 	public fun schedule (Ljava/lang/Runnable;J)Ljava/util/concurrent/Future;

sentry-test-support/src/main/kotlin/io/sentry/test/Mocks.kt

@@ -28,24 +28,40 @@ class ImmediateExecutorService : ISentryExecutorService {
 
 class DeferredExecutorService : ISentryExecutorService {
 
-    private val runnables = ArrayList<Runnable>()
-    val scheduledRunnables = ArrayList<Runnable>()
+    private var runnables = ArrayList<Runnable>()
+    private var scheduledRunnables = ArrayList<Runnable>()
 
     fun runAll() {
-        runnables.forEach { it.run() }
-        scheduledRunnables.forEach { it.run() }
+        // take a snapshot of the runnable list in case
+        // executing the runnable itself schedules more runnables
+        val currentRunnableList = runnables
+        val currentScheduledRunnableList = scheduledRunnables
+
+        synchronized(this) {
+            runnables = ArrayList()
+            scheduledRunnables = ArrayList()
+        }
+
+        currentRunnableList.forEach { it.run() }
+        currentScheduledRunnableList.forEach { it.run() }
     }
 
     override fun submit(runnable: Runnable): Future<*> {
-        runnables.add(runnable)
+        synchronized(this) {
+            runnables.add(runnable)
+        }
         return mock()
     }
 
     override fun <T> submit(callable: Callable<T>): Future<T> = mock()
     override fun schedule(runnable: Runnable, delayMillis: Long): Future<*> {
-        scheduledRunnables.add(runnable)
+        synchronized(this) {
+            scheduledRunnables.add(runnable)
+        }
         return mock()
     }
     override fun close(timeoutMillis: Long) {}
     override fun isClosed(): Boolean = false
+
+    fun hasScheduledRunnables(): Boolean = scheduledRunnables.isNotEmpty()
 }

sentry/src/main/java/io/sentry/Hub.java

@@ -4,6 +4,7 @@
 import io.sentry.clientreport.DiscardReason;
 import io.sentry.hints.SessionEndHint;
 import io.sentry.hints.SessionStartHint;
+import io.sentry.metrics.MetricsApi;
 import io.sentry.protocol.SentryId;
 import io.sentry.protocol.SentryTransaction;
 import io.sentry.protocol.User;
@@ -17,14 +18,16 @@
 import java.io.IOException;
 import java.lang.ref.WeakReference;
 import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.WeakHashMap;
 import org.jetbrains.annotations.ApiStatus;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-public final class Hub implements IHub {
+public final class Hub implements IHub, MetricsApi.IMetricsInterface {
+
   private volatile @NotNull SentryId lastEventId;
   private final @NotNull SentryOptions options;
   private volatile boolean isEnabled;
@@ -33,10 +36,10 @@ public final class Hub implements IHub {
   private final @NotNull Map<Throwable, Pair<WeakReference<ISpan>, String>> throwableToSpan =
       Collections.synchronizedMap(new WeakHashMap<>());
   private final @NotNull TransactionPerformanceCollector transactionPerformanceCollector;
+  private final @NotNull MetricsApi metricsApi;
 
   public Hub(final @NotNull SentryOptions options) {
     this(options, createRootStackItem(options));
-
     // Integrations are no longer registered on Hub ctor, but on Sentry.init
   }
 
@@ -52,6 +55,8 @@ private Hub(final @NotNull SentryOptions options, final @NotNull Stack stack) {
     // Integrations will use this Hub instance once registered.
     // Make sure Hub ready to be used then.
     this.isEnabled = true;
+
+    this.metricsApi = new MetricsApi(this);
   }
 
   private Hub(final @NotNull SentryOptions options, final @NotNull StackItem rootStackItem) {
@@ -937,4 +942,22 @@ private IScope buildLocalScope(
     final StackItem item = stack.peek();
     return item.getClient().getRateLimiter();
   }
+
+  @Override
+  public @NotNull MetricsApi metrics() {
+    return metricsApi;
+  }
+
+  @Override
+  public @NotNull IMetricsAggregator getMetricsAggregator() {
+    return stack.peek().getClient().getMetricsAggregator();
+  }
+
+  @Override
+  public @NotNull Map<String, String> getDefaultTagsForMetrics() {
+    final Map<String, String> tags = new HashMap<>(2);
+    tags.put("release", options.getRelease());
+    tags.put("environment", options.getEnvironment());
+    return tags;
+  }
 }

sentry/src/main/java/io/sentry/HubAdapter.java

@@ -1,5 +1,6 @@
 package io.sentry;
 
+import io.sentry.metrics.MetricsApi;
 import io.sentry.protocol.SentryId;
 import io.sentry.protocol.SentryTransaction;
 import io.sentry.protocol.User;
@@ -272,4 +273,9 @@ public void reportFullyDisplayed() {
   public @Nullable RateLimiter getRateLimiter() {
     return Sentry.getCurrentHub().getRateLimiter();
   }
+
+  @Override
+  public @NotNull MetricsApi metrics() {
+    return Sentry.getCurrentHub().metrics();
+  }
 }

sentry/src/main/java/io/sentry/IHub.java

@@ -1,5 +1,6 @@
 package io.sentry;
 
+import io.sentry.metrics.MetricsApi;
 import io.sentry.protocol.SentryId;
 import io.sentry.protocol.SentryTransaction;
 import io.sentry.protocol.User;
@@ -582,4 +583,8 @@ TransactionContext continueTrace(
   @ApiStatus.Internal
   @Nullable
   RateLimiter getRateLimiter();
+
+  @ApiStatus.Experimental
+  @NotNull
+  MetricsApi metrics();
 }

sentry/src/main/java/io/sentry/IMetricsAggregator.java

@@ -0,0 +1,122 @@
+package io.sentry;
+
+import java.io.Closeable;
+import java.util.Map;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+public interface IMetricsAggregator extends Closeable {
+
+  /**
+   * Emits a Counter metric
+   *
+   * @param key A unique key identifying the metric
+   * @param value The value to be added
+   * @param unit An optional unit, see {@link MeasurementUnit}
+   * @param tags Optional Tags to associate with the metric
+   * @param timestampMs The time when the metric was emitted. Defaults to the time at which the
+   *     metric is emitted, if no value is provided.
+   * @param stackLevel Optional number of stacks levels to ignore when determining the code location
+   */
+  void increment(
+      final @NotNull String key,
+      final double value,
+      final @Nullable MeasurementUnit unit,
+      final @Nullable Map<String, String> tags,
+      final long timestampMs,
+      final int stackLevel);
+
+  /**
+   * Emits a Gauge metric
+   *
+   * @param key A unique key identifying the metric
+   * @param value The value to be added
+   * @param unit An optional unit, see {@link MeasurementUnit}
+   * @param tags Optional Tags to associate with the metric
+   * @param timestampMs The time when the metric was emitted. Defaults to the time at which the
+   *     metric is emitted, if no value is provided.
+   * @param stackLevel Optional number of stacks levels to ignore when determining the code location
+   */
+  void gauge(
+      final @NotNull String key,
+      final double value,
+      final @Nullable MeasurementUnit unit,
+      final @Nullable Map<String, String> tags,
+      final long timestampMs,
+      final int stackLevel);
+
+  /**
+   * Emits a Distribution metric
+   *
+   * @param key A unique key identifying the metric
+   * @param value The value to be added
+   * @param unit An optional unit, see {@link MeasurementUnit}
+   * @param tags Optional Tags to associate with the metric
+   * @param timestampMs The time when the metric was emitted. Defaults to the time at which the
+   *     metric is emitted, if no value is provided.
+   * @param stackLevel Optional number of stacks levels to ignore when determining the code location
+   */
+  void distribution(
+      final @NotNull String key,
+      final double value,
+      final @Nullable MeasurementUnit unit,
+      final @Nullable Map<String, String> tags,
+      final long timestampMs,
+      final int stackLevel);
+
+  /**
+   * Emits a Set metric
+   *
+   * @param key A unique key identifying the metric
+   * @param value The value to be added
+   * @param unit An optional unit, see {@link MeasurementUnit}
+   * @param tags Optional Tags to associate with the metric
+   * @param timestampMs The time when the metric was emitted. Defaults to the time at which the
+   *     metric is emitted, if no value is provided.
+   * @param stackLevel Optional number of stacks levels to ignore when determining the code location
+   */
+  void set(
+      final @NotNull String key,
+      final int value,
+      final @Nullable MeasurementUnit unit,
+      final @Nullable Map<String, String> tags,
+      final long timestampMs,
+      final int stackLevel);
+
+  /**
+   * Emits a Set metric
+   *
+   * @param key A unique key identifying the metric
+   * @param value The value to be added
+   * @param unit An optional unit, see {@link MeasurementUnit}
+   * @param tags Optional Tags to associate with the metric
+   * @param timestampMs The time when the metric was emitted. Defaults to the time at which the
+   *     metric is emitted, if no value is provided.
+   * @param stackLevel Optional number of stacks levels to ignore when determining the code location
+   */
+  void set(
+      final @NotNull String key,
+      final @NotNull String value,
+      final @Nullable MeasurementUnit unit,
+      final @Nullable Map<String, String> tags,
+      final long timestampMs,
+      final int stackLevel);
+
+  /**
+   * Emits a distribution with the time it takes to run a given code block.
+   *
+   * @param key A unique key identifying the metric
+   * @param callback The code block to measure
+   * @param unit An optional unit, see {@link MeasurementUnit.Duration}, defaults to seconds
+   * @param tags Optional Tags to associate with the metric
+   * @param stackLevel Optional number of stacks levels to ignore when determining the code location
+   */
+  void timing(
+      final @NotNull String key,
+      final @NotNull Runnable callback,
+      final @NotNull MeasurementUnit.Duration unit,
+      final @Nullable Map<String, String> tags,
+      final int stackLevel);
+
+  void flush(boolean force);
+}

sentry/src/main/java/io/sentry/ISentryClient.java

@@ -285,4 +285,8 @@ SentryId captureTransaction(
   default boolean isHealthy() {
     return true;
   }
+
+  @ApiStatus.Internal
+  @NotNull
+  IMetricsAggregator getMetricsAggregator();
 }