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Author: lukasz-antoniak

core/src/main/java/com/datastax/oss/driver/internal/core/context/StartupOptionsBuilder.java

@@ -23,11 +23,15 @@
 import com.datastax.oss.driver.api.core.loadbalancing.LocalDcAwareLoadBalancingPolicy;
 import com.datastax.oss.driver.api.core.session.Session;
 import com.datastax.oss.driver.api.core.uuid.Uuids;
+import com.datastax.oss.driver.shaded.guava.common.base.Joiner;
+import com.datastax.oss.driver.shaded.guava.common.collect.Maps;
 import com.datastax.oss.protocol.internal.request.Startup;
 import com.datastax.oss.protocol.internal.util.collection.NullAllowingImmutableMap;
 import edu.umd.cs.findbugs.annotations.Nullable;
 import java.util.Map;
+import java.util.Optional;
 import java.util.UUID;
+import java.util.stream.Collectors;
 import net.jcip.annotations.Immutable;
 
 @Immutable
@@ -123,10 +127,7 @@ public Map<String, String> build() {
       builder.put(APPLICATION_VERSION_KEY, applicationVersion);
     }
     // do not cache local DC as it can change within LBP implementation
-    String applicationLocalDcs = localDcs();
-    if (applicationLocalDcs != null) {
-      builder.put(DRIVER_LOCAL_DC, applicationLocalDcs);
-    }
+    localDcs().ifPresent(s -> builder.put(DRIVER_LOCAL_DC, s));
 
     return builder.build();
   }
@@ -151,28 +152,27 @@ protected String getDriverVersion() {
     return Session.OSS_DRIVER_COORDINATES.getVersion().toString();
   }
 
-  private String localDcs() {
-    StringBuilder result = new StringBuilder();
-    boolean first = true;
-    for (Map.Entry<String, LoadBalancingPolicy> entry :
-        context.getLoadBalancingPolicies().entrySet()) {
-      String dc = getLocalDc(entry.getValue());
-      if (dc != null) {
-        if (!first) {
-          result.append(", ");
-        } else {
-          first = false;
-        }
-        result.append(entry.getKey()).append(": ").append(dc);
-      }
+  private Optional<String> localDcs() {
+    Joiner joiner = Joiner.on(": ");
+    Map<String, Optional<String>> lbpToDc =
+        Maps.transformValues(context.getLoadBalancingPolicies(), this::getLocalDc);
+    if (lbpToDc.isEmpty()) {
+      return Optional.empty();
     }
-    return first ? null : result.toString();
+    return Optional.of(
+        lbpToDc.entrySet().stream()
+            .filter(e -> e.getValue().isPresent())
+            .map(entry -> joiner.join(entry.getKey(), entry.getValue().get()))
+            .collect(Collectors.joining(", ")));
   }
 
-  private String getLocalDc(LoadBalancingPolicy loadBalancingPolicy) {
+  private Optional<String> getLocalDc(LoadBalancingPolicy loadBalancingPolicy) {
     if (loadBalancingPolicy instanceof LocalDcAwareLoadBalancingPolicy) {
-      return ((LocalDcAwareLoadBalancingPolicy) loadBalancingPolicy).getLocalDatacenter();
+      String dc = ((LocalDcAwareLoadBalancingPolicy) loadBalancingPolicy).getLocalDatacenter();
+      if (dc != null) {
+        return Optional.of(dc);
+      }
     }
-    return null;
+    return Optional.empty();
   }
 }

core/src/test/java/com/datastax/dse/driver/internal/core/context/DseStartupOptionsBuilderTest.java

@@ -249,4 +249,30 @@ public void should_include_all_local_dc_in_startup_message() {
             StartupOptionsBuilder.DRIVER_LOCAL_DC,
             "default: us-west-2, oltp: us-east-2, olap: eu-central-1");
   }
+
+  @Test
+  public void should_skip_non_local_dc_lbp_in_startup_message() {
+    when(defaultProfile.getString(DefaultDriverOption.PROTOCOL_COMPRESSION, "none"))
+        .thenReturn("none");
+    when(defaultProfile.getName()).thenReturn(DriverExecutionProfile.DEFAULT_NAME);
+
+    ProgrammaticArguments.Builder builder = ProgrammaticArguments.builder();
+    DefaultDriverContext driverContext =
+        new DefaultDriverContext(configLoader, builder.build()) {
+          @NonNull
+          @Override
+          public Map<String, LoadBalancingPolicy> getLoadBalancingPolicies() {
+            ImmutableMap.Builder<String, LoadBalancingPolicy> map = ImmutableMap.builder();
+            LocalDcAwareLoadBalancingPolicy loadBalancingPolicy =
+                mock(LocalDcAwareLoadBalancingPolicy.class);
+            when(loadBalancingPolicy.getLocalDatacenter()).thenReturn("dc1");
+            map.put("oltp", loadBalancingPolicy);
+            map.put("default", mock(LoadBalancingPolicy.class));
+            return map.build();
+          }
+        };
+    Startup startup = new Startup(driverContext.getStartupOptions());
+
+    assertThat(startup.options).containsEntry(StartupOptionsBuilder.DRIVER_LOCAL_DC, "oltp: dc1");
+  }
 }