[OpenTelemetry] Inital local only implementation

This is an initial implementation of the ITelemetry interface
using OpenTelemetry, in particular, the opentelemetry-android
library.

Using this new library forces us to bump the required kotlin
version and the project compilesdk version.

So far the telemetry data is logged only to the logcat and not
sent to any server. In order to avoid too many writes (and in
the future to batch requests to the servers) it uses on disk
buffering.

app/src/common/shared/com/igalia/wolvic/VRBrowserActivity.java

@@ -65,6 +65,7 @@
 import com.igalia.wolvic.search.SearchEngineWrapper;
 import com.igalia.wolvic.speech.SpeechRecognizer;
 import com.igalia.wolvic.speech.SpeechServices;
+import com.igalia.wolvic.telemetry.OpenTelemetry;
 import com.igalia.wolvic.telemetry.TelemetryService;
 import com.igalia.wolvic.ui.OffscreenDisplay;
 import com.igalia.wolvic.ui.adapters.Language;
@@ -284,6 +285,11 @@ protected void onCreate(Bundle savedInstanceState) {
 
         SettingsStore.getInstance(getBaseContext()).setPid(Process.myPid());
         ((VRBrowserApplication)getApplication()).onActivityCreate(this);
+
+        if (!DeviceType.isHVRBuild() && SettingsStore.getInstance(getBaseContext()).isTelemetryEnabled()) {
+            TelemetryService.setService(new OpenTelemetry(getApplication()));
+        }
+
         // Fix for infinite restart on startup crashes.
         long count = SettingsStore.getInstance(getBaseContext()).getCrashRestartCount();
         boolean cancelRestart = count > CrashReporterService.MAX_RESTART_COUNT;

app/src/common/shared/com/igalia/wolvic/VRBrowserApplication.java

@@ -53,8 +53,8 @@ public class VRBrowserApplication extends Application implements AppServicesProv
 
     protected void onActivityCreate(@NonNull Context activityContext) {
         onConfigurationChanged(activityContext.getResources().getConfiguration());
-        TelemetryService.init(activityContext);
         mAppExecutors = new AppExecutors();
+        TelemetryService.init(activityContext);
         mConnectivityManager = new ConnectivityReceiver(activityContext);
         mConnectivityManager.init();
         mPlaces = new Places(activityContext);

app/src/common/shared/com/igalia/wolvic/telemetry/OpenTelemetry.java

@@ -0,0 +1,91 @@
+package com.igalia.wolvic.telemetry;
+
+import static io.opentelemetry.api.common.AttributeKey.stringKey;
+
+import android.app.Application;
+import android.os.Bundle;
+
+import com.igalia.wolvic.BuildConfig;
+import com.igalia.wolvic.VRBrowserApplication;
+
+import java.util.concurrent.Executor;
+
+import io.opentelemetry.android.OpenTelemetryRum;
+import io.opentelemetry.android.OpenTelemetryRumBuilder;
+import io.opentelemetry.android.config.OtelRumConfig;
+import io.opentelemetry.android.features.diskbuffering.DiskBufferingConfiguration;
+import io.opentelemetry.android.instrumentation.activity.ActivityLifecycleInstrumentation;
+import io.opentelemetry.android.instrumentation.sessions.SessionInstrumentation;
+import io.opentelemetry.api.trace.SpanBuilder;
+import io.opentelemetry.exporter.logging.LoggingSpanExporter;
+
+public class OpenTelemetry implements ITelemetry {
+    private final Application application;
+    private OpenTelemetryRum rum;
+    private OpenTelemetryRumBuilder rumBuilder;
+    private final String instrumentationScopeName = BuildConfig.APPLICATION_ID;
+    private final String instrumentationScopeVersion = "1.0.0";
+    private final Executor diskIOExecutor;
+
+    public OpenTelemetry(Application app) {
+        application = app;
+        diskIOExecutor = ((VRBrowserApplication) application).getExecutors().diskIO();
+    }
+
+    private void initializeOpenTelemetryAndroid() {
+        DiskBufferingConfiguration diskBufferingConfiguration = DiskBufferingConfiguration.builder()
+                .setEnabled(true)
+                .setMaxCacheSize(10 * 1024 * 1024)
+                .setMaxFileAgeForWriteMillis(1000 * 5)
+                .build();
+        OtelRumConfig config = new OtelRumConfig()
+                .setDiskBufferingConfiguration(diskBufferingConfiguration);
+        rumBuilder = OpenTelemetryRum.builder(application, config)
+                .addSpanExporterCustomizer(exporter -> LoggingSpanExporter.create())
+                .addInstrumentation(new SessionInstrumentation())
+                .addInstrumentation(new ActivityLifecycleInstrumentation());
+        try {
+            rum = rumBuilder.build();
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+    }
+
+    private void runOnDiskIO(Runnable runnable) { diskIOExecutor.execute(runnable); }
+
+    @Override
+    public void start() {
+        assert rum == null;
+        initializeOpenTelemetryAndroid();
+    }
+
+    @Override
+    public void stop() {
+        rum = null;
+        rumBuilder = null;
+    }
+
+    @Override
+    public void customEvent(String name) {
+        assert rum != null;
+        runOnDiskIO(() -> {
+            rum.getOpenTelemetry().getTracer(instrumentationScopeName, instrumentationScopeVersion)
+                    .spanBuilder(name)
+                    .startSpan()
+                    .end();
+        });
+    }
+
+    @Override
+    public void customEvent(String name, Bundle bundle) {
+        assert rum != null;
+        runOnDiskIO(() -> {
+            SpanBuilder spanBuilder = rum.getOpenTelemetry().getTracer(instrumentationScopeName, instrumentationScopeVersion)
+                    .spanBuilder(name);
+            for (String key : bundle.keySet()) {
+                spanBuilder.setAttribute(key, bundle.get(key).toString());
+            }
+            spanBuilder.startSpan().end();
+        });
+    }
+}