ci(bigquery): configure us-east7 endpoint overrides in Kokoro integration tests (#13971)

Configures `BIGQUERY_ENDPOINT` and `BIGQUERY_STORAGE_ENDPOINT`
environment variables in Kokoro presubmit configs to test against
`us-east7` regional endpoints.

### Key Changes
* **Kokoro CI**: Added `us-east7` endpoint overrides to BigQuery
integration and GraalVM presubmit configurations.
* **Two-Client Test Setup**: Introduced static global fallback clients
(`globalBigQuery`, `globalReadClient`, `globalWriteClient`) for tests
querying public datasets (`bigquery-public-data`) or cross-region
resources, while standard clients target `us-east7`.

b/472499857

Author: jinseopkim0

.kokoro/presubmit/bigquery-graalvm-native-presubmit.cfg

@@ -22,6 +22,11 @@ env_vars: {
   value: "gcloud-devel"
 }
 
+env_vars: {
+  key: "INTEGRATION_TEST_ARGS"
+  value: "-Dbigquery.endpoint=https://us-east7-bigquery.googleapis.com -Dbigquery.storage.endpoint=us-east7-bigquerystorage.googleapis.com:443"
+}
+
 env_vars: {
   key: "GOOGLE_APPLICATION_CREDENTIALS"
   value: "secret_manager/java-it-service-account"
@@ -40,5 +45,3 @@ env_vars: {
   key: "BUILD_SUBDIR"
   value: "java-bigquery"
 }
-
-

.kokoro/presubmit/bigquery-integration.cfg

@@ -22,6 +22,11 @@ env_vars: {
   value: "gcloud-devel"
 }
 
+env_vars: {
+  key: "INTEGRATION_TEST_ARGS"
+  value: "-Dbigquery.endpoint=https://us-east7-bigquery.googleapis.com -Dbigquery.storage.endpoint=us-east7-bigquerystorage.googleapis.com:443"
+}
+
 env_vars: {
   key: "GOOGLE_APPLICATION_CREDENTIALS"
   value: "secret_manager/java-it-service-account"

.kokoro/presubmit/bigquerystorage-graalvm-native-presubmit.cfg

@@ -44,5 +44,5 @@ env_vars: {
 
 env_vars: {
   key: "INTEGRATION_TEST_ARGS"
-  value: "-Dit.test=!ITBigQueryWrite*RetryTest -Dsurefire.failIfNoSpecifiedTests=false -Dfailsafe.failIfNoSpecifiedTests=false"
+  value: "-Dit.test=!ITBigQueryWrite*RetryTest -Dsurefire.failIfNoSpecifiedTests=false -Dfailsafe.failIfNoSpecifiedTests=false -Dbigquery.storage.endpoint=us-east7-bigquerystorage.googleapis.com:443 -Dbigquery.endpoint=https://us-east7-bigquery.googleapis.com"
 }

.kokoro/presubmit/bigquerystorage-integration.cfg

@@ -39,5 +39,5 @@ env_vars: {
 
 env_vars: {
   key: "INTEGRATION_TEST_ARGS"
-  value: "-Dit.test=!ITBigQueryWrite*RetryTest -Dsurefire.failIfNoSpecifiedTests=false -Dfailsafe.failIfNoSpecifiedTests=false"
+  value: "-Dit.test=!ITBigQueryWrite*RetryTest -Dsurefire.failIfNoSpecifiedTests=false -Dfailsafe.failIfNoSpecifiedTests=false -Dbigquery.storage.endpoint=us-east7-bigquerystorage.googleapis.com:443 -Dbigquery.endpoint=https://us-east7-bigquery.googleapis.com"
 }

java-bigquery/google-cloud-bigquery/pom.xml

@@ -15,6 +15,8 @@
   </parent>
   <properties>
     <site.installationModule>google-cloud-bigquery</site.installationModule>
+    <bigquery.endpoint>https://us-east7-bigquery.googleapis.com</bigquery.endpoint>
+    <bigquery.storage.endpoint>us-east7-bigquerystorage.googleapis.com:443</bigquery.storage.endpoint>
   </properties>
   <dependencies>
     <dependency>
@@ -330,5 +332,22 @@
       </build>
 
     </profile>
+    <profile>
+      <id>native</id>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.graalvm.buildtools</groupId>
+            <artifactId>native-maven-plugin</artifactId>
+            <configuration>
+              <environmentVariables>
+                <BIGQUERY_ENDPOINT>${bigquery.endpoint}</BIGQUERY_ENDPOINT>
+                <BIGQUERY_STORAGE_ENDPOINT>${bigquery.storage.endpoint}</BIGQUERY_STORAGE_ENDPOINT>
+              </environmentVariables>
+            </configuration>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
   </profiles>
 </project>

java-bigquery/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/testing/RemoteBigQueryHelper.java

@@ -105,7 +105,7 @@ public static RemoteBigQueryHelper create(String projectId, InputStream keyStrea
               .setProjectId(projectId)
               .setRetrySettings(retrySettings())
               .setTransportOptions(transportOptions);
-      String endpoint = System.getenv("BIGQUERY_ENDPOINT");
+      String endpoint = System.getProperty("bigquery.endpoint", System.getenv("BIGQUERY_ENDPOINT"));
       if (endpoint != null) {
         builder.setHost(endpoint);
       }
@@ -143,7 +143,7 @@ public static RemoteBigQueryHelper create(BigQueryOptions.Builder bigqueryOption
         bigqueryOptionsBuilder
             .setRetrySettings(retrySettings())
             .setTransportOptions(transportOptions);
-    String endpoint = System.getenv("BIGQUERY_ENDPOINT");
+    String endpoint = System.getProperty("bigquery.endpoint", System.getenv("BIGQUERY_ENDPOINT"));
     if (endpoint != null) {
       builder.setHost(endpoint);
     }
@@ -184,4 +184,16 @@ public static BigQueryHelperException translate(Exception ex) {
       return new BigQueryHelperException(ex.getMessage(), ex);
     }
   }
+
+  /**
+   * Helper to check if the provided BigQuery client is configured to target a regional endpoint.
+   */
+  public static boolean isRegionalEndpoint(BigQuery bigquery) {
+    if (bigquery == null || bigquery.getOptions() == null) {
+      return false;
+    }
+    String host = bigquery.getOptions().getHost();
+    return host != null
+        && (host.contains("-bigquery.googleapis.com") || host.contains(".rep.googleapis.com"));
+  }
 }