review comments

Author: surbhigarg92

google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerImpl.java

@@ -128,6 +128,7 @@ static final class ClosedException extends RuntimeException {
     this.dbAdminClient = new DatabaseAdminClientImpl(options.getProjectId(), gapicRpc);
     this.instanceClient =
         new InstanceAdminClientImpl(options.getProjectId(), gapicRpc, dbAdminClient);
+    SpannerRpcMetrics.initializeRPCMetrics(SpannerOptions.getOpenTelemetry());
   }
 
   SpannerImpl(SpannerOptions options) {

google-cloud-spanner/src/main/java/com/google/cloud/spanner/SpannerOptions.java

@@ -1212,8 +1212,6 @@ public SpannerOptions build() {
         this.numChannels =
             this.grpcGcpExtensionEnabled ? GRPC_GCP_ENABLED_DEFAULT_CHANNELS : DEFAULT_CHANNELS;
       }
-
-      SpannerRpcMetrics.initializeRPCMetrics(openTelemetry);
       return new SpannerOptions(this);
     }
   }

google-cloud-spanner/src/main/java/com/google/cloud/spanner/spi/v1/HeaderInterceptor.java

@@ -69,14 +69,27 @@ class HeaderInterceptor implements ClientInterceptor {
 
   HeaderInterceptor() {}
 
+  private class SpannerProperties {
+    String projectId;
+    String instanceId;
+    String databaseId;
+
+    SpannerProperties(String projectId, String instanceId, String databaseId) {
+      this.databaseId = databaseId;
+      this.instanceId = instanceId;
+      this.projectId = projectId;
+    }
+  }
+
   @Override
   public <ReqT, RespT> ClientCall<ReqT, RespT> interceptCall(
       MethodDescriptor<ReqT, RespT> method, CallOptions callOptions, Channel next) {
     return new SimpleForwardingClientCall<ReqT, RespT>(next.newCall(method, callOptions)) {
       @Override
       public void start(Listener<RespT> responseListener, Metadata headers) {
-        TagContext tagContext = getTagContext(headers, method.getFullMethodName());
-        Attributes attributes = getMetricAttributes(headers, method.getFullMethodName());
+        SpannerProperties spannerProperties = setProjectPropertes(headers);
+        TagContext tagContext = getTagContext(method.getFullMethodName(), spannerProperties);
+        Attributes attributes = getMetricAttributes(method.getFullMethodName(), spannerProperties);
         super.start(
             new SimpleForwardingClientCallListener<RespT>(responseListener) {
               @Override
@@ -114,18 +127,7 @@ private void processHeader(Metadata metadata, TagContext tagContext, Attributes
     }
   }
 
-  private TagContext getTagContext(
-      String method, String projectId, String instanceId, String databaseId) {
-    return TAGGER
-        .currentBuilder()
-        .putLocal(PROJECT_ID, TagValue.create(projectId))
-        .putLocal(INSTANCE_ID, TagValue.create(instanceId))
-        .putLocal(DATABASE_ID, TagValue.create(databaseId))
-        .putLocal(METHOD, TagValue.create(method))
-        .build();
-  }
-
-  private TagContext getTagContext(Metadata headers, String method) {
+  private SpannerProperties setProjectPropertes(Metadata headers) {
     String projectId = "undefined-project";
     String instanceId = "undefined-database";
     String databaseId = "undefined-database";
@@ -144,32 +146,24 @@ private TagContext getTagContext(Metadata headers, String method) {
         LOGGER.log(LEVEL, "Error parsing google cloud resource header: " + googleResourcePrefix);
       }
     }
-    return getTagContext(method, projectId, instanceId, databaseId);
+    return new SpannerProperties(projectId, instanceId, databaseId);
   }
 
-  private Attributes getMetricAttributes(Metadata headers, String method) {
-    String projectId = "undefined-project";
-    String instanceId = "undefined-database";
-    String databaseId = "undefined-database";
-    if (headers.get(GOOGLE_CLOUD_RESOURCE_PREFIX_KEY) != null) {
-      String googleResourcePrefix = headers.get(GOOGLE_CLOUD_RESOURCE_PREFIX_KEY);
-      Matcher matcher = GOOGLE_CLOUD_RESOURCE_PREFIX_PATTERN.matcher(googleResourcePrefix);
-      if (matcher.find()) {
-        projectId = matcher.group("project");
-        if (matcher.group("instance") != null) {
-          instanceId = matcher.group("instance");
-        }
-        if (matcher.group("database") != null) {
-          databaseId = matcher.group("database");
-        }
-      } else {
-        LOGGER.log(LEVEL, "Error parsing google cloud resource header: " + googleResourcePrefix);
-      }
-    }
+  private TagContext getTagContext(String method, SpannerProperties spannerProperties) {
+    return TAGGER
+        .currentBuilder()
+        .putLocal(PROJECT_ID, TagValue.create(spannerProperties.projectId))
+        .putLocal(INSTANCE_ID, TagValue.create(spannerProperties.instanceId))
+        .putLocal(DATABASE_ID, TagValue.create(spannerProperties.databaseId))
+        .putLocal(METHOD, TagValue.create(method))
+        .build();
+  }
+
+  private Attributes getMetricAttributes(String method, SpannerProperties spannerProperties) {
     AttributesBuilder attributesBuilder = Attributes.builder();
-    attributesBuilder.put("database", databaseId);
-    attributesBuilder.put("instance_id", instanceId);
-    attributesBuilder.put("project_id", projectId);
+    attributesBuilder.put("database", spannerProperties.databaseId);
+    attributesBuilder.put("instance_id", spannerProperties.instanceId);
+    attributesBuilder.put("project_id", spannerProperties.projectId);
     attributesBuilder.put("method", method);
 
     return attributesBuilder.build();

google-cloud-spanner/src/test/java/com/google/cloud/spanner/spi/v1/SpannerRpcMetricsTest.java

@@ -66,24 +66,18 @@ public class SpannerRpcMetricsTest {
   private static InetSocketAddress address;
   private static Spanner spanner;
   private static DatabaseClient databaseClient;
-
   private static final Map<SpannerRpc.Option, Object> optionsMap = new HashMap<>();
-
   private static MockSpannerServiceImpl mockSpannerNoHeader;
   private static Server serverNoHeader;
   private static InetSocketAddress addressNoHeader;
   private static Spanner spannerNoHeader;
   private static DatabaseClient databaseClientNoHeader;
-
   private static String instanceId = "fake-instance";
   private static String databaseId = "fake-database";
   private static String projectId = "fake-project";
-
   private static AtomicInteger fakeServerTiming = new AtomicInteger(new Random().nextInt(1000) + 1);
-
   private static final Statement SELECT1AND2 =
       Statement.of("SELECT 1 AS COL1 UNION ALL SELECT 2 AS COL1");
-
   private static final ResultSetMetadata SELECT1AND2_METADATA =
       ResultSetMetadata.newBuilder()
           .setRowType(