chore: update the exporter to use MetricRegistry (#2810)

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Fixes #<issue_number_goes_here> ☕️

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https://togithub.com/GoogleCloudPlatform/java-docs-samples/blob/main/SAMPLE_FORMAT.md).

Author: igorbernstein2

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/internal/csm/MetricRegistry.java

@@ -165,7 +165,7 @@ List<String> getGrpcMetricNames() {
     return ImmutableList.copyOf(grpcMetricNames);
   }
 
-  MetricWrapper<?> getMetric(String name) {
+  public MetricWrapper<?> getMetric(String name) {
     return metrics.get(name);
   }
 

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/internal/csm/MetricsImpl.java

@@ -23,6 +23,7 @@
 import com.google.cloud.bigtable.data.v2.BigtableDataSettings;
 import com.google.cloud.bigtable.data.v2.internal.csm.MetricRegistry.RecorderRegistry;
 import com.google.cloud.bigtable.data.v2.internal.csm.attributes.ClientInfo;
+import com.google.cloud.bigtable.data.v2.internal.csm.attributes.EnvInfo;
 import com.google.cloud.bigtable.data.v2.stub.metrics.BigtableCloudMonitoringExporter;
 import com.google.cloud.bigtable.data.v2.stub.metrics.BuiltinMetricsConstants;
 import com.google.cloud.bigtable.data.v2.stub.metrics.BuiltinMetricsTracerFactory;
@@ -72,14 +73,15 @@ public class MetricsImpl implements Metrics, Closeable {
   private final List<ScheduledFuture<?>> tasks = new ArrayList<>();
 
   public MetricsImpl(
+      MetricRegistry metricRegistry,
       ClientInfo clientInfo,
       ApiTracerFactory userTracerFactory,
       @Nullable OpenTelemetrySdk internalOtel,
       @Nullable OpenTelemetry userOtel,
       Tagger ocTagger,
       StatsRecorder ocRecorder,
       ScheduledExecutorService executor) {
-    metricRegistry = new MetricRegistry();
+    this.metricRegistry = metricRegistry;
     this.userTracerFactory = Preconditions.checkNotNull(userTracerFactory);
 
     this.internalOtel = internalOtel;
@@ -168,6 +170,7 @@ public ChannelPoolMetricsTracer getChannelPoolMetricsTracer() {
   }
 
   public static OpenTelemetrySdk createBuiltinOtel(
+      MetricRegistry metricRegistry,
       ClientInfo clientInfo,
       @Nullable Credentials defaultCredentials,
       @Nullable String metricsEndpoint,
@@ -194,7 +197,12 @@ public static OpenTelemetrySdk createBuiltinOtel(
 
     MetricExporter publicExporter =
         BigtableCloudMonitoringExporter.create(
-            clientInfo, credentials, metricsEndpoint, universeDomain, executor);
+            metricRegistry,
+            EnvInfo::detect,
+            clientInfo,
+            credentials,
+            metricsEndpoint,
+            universeDomain);
     PeriodicMetricReaderBuilder readerBuilder =
         PeriodicMetricReader.builder(publicExporter).setExecutor(executor);
     meterProvider.registerMetricReader(readerBuilder.build());

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/internal/csm/attributes/ClientInfo.java

@@ -42,7 +42,7 @@ public static Builder builder() {
 
   @AutoValue.Builder
   public abstract static class Builder {
-    protected abstract Builder setClientName(String name);
+    public abstract Builder setClientName(String name);
 
     public abstract Builder setInstanceName(InstanceName name);
 

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/internal/csm/attributes/EnvInfo.java

@@ -77,7 +77,7 @@ public static Builder builder() {
 
   @AutoValue.Builder
   public abstract static class Builder {
-    protected abstract Builder setUid(String uid);
+    public abstract Builder setUid(String uid);
 
     public abstract Builder setPlatform(String platform);
 

google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/data/v2/stub/BigtableClientContext.java

@@ -28,6 +28,7 @@
 import com.google.auth.oauth2.ServiceAccountJwtAccessCredentials;
 import com.google.bigtable.v2.InstanceName;
 import com.google.cloud.bigtable.data.v2.internal.JwtCredentialsWithAudience;
+import com.google.cloud.bigtable.data.v2.internal.csm.MetricRegistry;
 import com.google.cloud.bigtable.data.v2.internal.csm.Metrics;
 import com.google.cloud.bigtable.data.v2.internal.csm.MetricsImpl;
 import com.google.cloud.bigtable.data.v2.internal.csm.attributes.ClientInfo;
@@ -101,6 +102,7 @@ public static BigtableClientContext create(
         FixedExecutorProvider.create(backgroundExecutor, shouldAutoClose);
     builder.setBackgroundExecutorProvider(executorProvider);
 
+    MetricRegistry metricRegistry = new MetricRegistry();
     // Set up OpenTelemetry
     @Nullable OpenTelemetry userOtel = null;
     if (settings.getMetricsProvider() instanceof CustomOpenTelemetryMetricsProvider) {
@@ -113,6 +115,7 @@ public static BigtableClientContext create(
       if (settings.areInternalMetricsEnabled()) {
         builtinOtel =
             MetricsImpl.createBuiltinOtel(
+                metricRegistry,
                 clientInfo,
                 credentials,
                 settings.getMetricsEndpoint(),
@@ -125,6 +128,7 @@ public static BigtableClientContext create(
 
     Metrics metrics =
         new MetricsImpl(
+            metricRegistry,
             clientInfo,
             settings.getTracerFactory(),
             builtinOtel,