fix #558: stabilize deployment and role rendering

src/main/java/com/cloudhandson/vpdbackoffice/service/OrdsMetadataService.java

@@ -14,6 +14,8 @@ import java.util.Locale;
 import javax.sql.DataSource;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.jdbc.core.JdbcTemplate;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -21,6 +23,7 @@ import org.springframework.transaction.annotation.Transactional;
 public class OrdsMetadataService {
 
   private static final String VECTOR_SEARCH_OBJECT = "CB_VECTOR_SEARCH_DOCUMENTS";
+  private static final Logger log = LoggerFactory.getLogger(OrdsMetadataService.class);
 
   private final OrdsMetadataMapper mapper;
   private final JdbcTemplate jdbcTemplate;
@@ -40,6 +43,8 @@ public class OrdsMetadataService {
     this.mapper = mapper;
     this.jdbcTemplate = jdbcTemplate;
     this.protectedObjectService = protectedObjectService;
+    HikariDataSource metadataDataSource = null;
+    JdbcTemplate metadataJdbcTemplate = new JdbcTemplate(dataSource);
     if (hasText(ordsMetadataUrl) && hasText(ordsMetadataUsername)) {
       HikariConfig config = new HikariConfig();
       config.setPoolName("vpd-ords-metadata-pool");
@@ -50,12 +55,24 @@ public class OrdsMetadataService {
       config.setMaximumPoolSize(2);
       config.setMinimumIdle(0);
       config.setConnectionTimeout(10000);
-      this.ordsMetadataDataSource = new HikariDataSource(config);
-      this.ordsMetadataJdbcTemplate = new JdbcTemplate(this.ordsMetadataDataSource);
-    } else {
-      this.ordsMetadataDataSource = null;
-      this.ordsMetadataJdbcTemplate = new JdbcTemplate(dataSource);
+      // ORDS metadata is an optional administrative connection. Do not fail
+      // the whole backoffice startup when the remote TNS host is temporarily
+      // unavailable; Handler create/update will report the connection error
+      // at the point of use instead.
+      config.setInitializationFailTimeout(-1);
+      try {
+        metadataDataSource = new HikariDataSource(config);
+        metadataJdbcTemplate = new JdbcTemplate(metadataDataSource);
+      } catch (RuntimeException exception) {
+        log.warn("ORDS metadata DB is unavailable; using the main DB for read-only fallback: {}",
+            exception.getMessage());
+        if (metadataDataSource != null) {
+          metadataDataSource.close();
+        }
+      }
     }
+    this.ordsMetadataDataSource = metadataDataSource;
+    this.ordsMetadataJdbcTemplate = metadataJdbcTemplate;
   }
 
   public List<OrdsHandlerView> findHandlers() {