Only create DB data dir if it doesn't already exist (#5453)

* Only create DB data dir if it doesn't already exist

Signed-off-by: Matthew Whitehead <matthew1001@gmail.com>

* Add unit test

Signed-off-by: Matthew Whitehead <matthew1001@gmail.com>

---------

Signed-off-by: Matthew Whitehead <matthew1001@gmail.com>
Co-authored-by: Matthew Whitehead <matthew1001@gmail.com>

plugins/rocksdb/src/main/java/org/hyperledger/besu/plugin/services/storage/rocksdb/RocksDBKeyValueStorageFactory.java

@@ -255,6 +255,7 @@ public class RocksDBKeyValueStorageFactory implements KeyValueStorageFactory {
   private int readDatabaseVersion(final BesuConfiguration commonConfiguration) throws IOException {
     final Path dataDir = commonConfiguration.getDataPath();
     final boolean databaseExists = commonConfiguration.getStoragePath().toFile().exists();
+    final boolean dataDirExists = dataDir.toFile().exists();
     final int databaseVersion;
     if (databaseExists) {
       databaseVersion = DatabaseMetadata.lookUpFrom(dataDir).getVersion();
@@ -265,7 +266,9 @@ public class RocksDBKeyValueStorageFactory implements KeyValueStorageFactory {
     } else {
       databaseVersion = commonConfiguration.getDatabaseVersion();
       LOG.info("No existing database detected at {}. Using version {}", dataDir, databaseVersion);
-      Files.createDirectories(dataDir);
+      if (!dataDirExists) {
+        Files.createDirectories(dataDir);
+      }
       new DatabaseMetadata(databaseVersion).writeToDirectory(dataDir);
     }
 

plugins/rocksdb/src/test/java/org/hyperledger/besu/plugin/services/storage/rocksdb/RocksDBKeyValueStorageFactoryTest.java

@@ -199,4 +199,27 @@ public class RocksDBKeyValueStorageFactoryTest {
                     .create(segment, commonConfiguration, metricsSystem))
         .isInstanceOf(IllegalStateException.class);
   }
+
+  @Test
+  public void shouldCreateDBCorrectlyIfSymlink() throws Exception {
+    final Path tempRealDataDir =
+        Files.createDirectories(temporaryFolder.newFolder().toPath().resolve("real-data-dir"));
+    final Path tempSymLinkDataDir =
+        Files.createSymbolicLink(
+            temporaryFolder.newFolder().toPath().resolve("symlink-data-dir"), tempRealDataDir);
+    final Path tempDatabaseDir = temporaryFolder.newFolder().toPath().resolve("db");
+    when(commonConfiguration.getStoragePath()).thenReturn(tempDatabaseDir);
+    when(commonConfiguration.getDataPath()).thenReturn(tempSymLinkDataDir);
+    when(commonConfiguration.getDatabaseVersion()).thenReturn(DEFAULT_VERSION);
+
+    final RocksDBKeyValueStorageFactory storageFactory =
+        new RocksDBKeyValueStorageFactory(
+            () -> rocksDbConfiguration, segments, RocksDBMetricsFactory.PUBLIC_ROCKS_DB_METRICS);
+
+    // Ensure that having created everything via a symlink data dir the DB meta-data has been
+    // created correctly
+    storageFactory.create(segment, commonConfiguration, metricsSystem);
+    assertThat(DatabaseMetadata.lookUpFrom(tempRealDataDir).getVersion())
+        .isEqualTo(DEFAULT_VERSION);
+  }
 }