Fixed resources leaks (#191)

Author: KirillKurdyukov

flyway-dialect/src/main/java/tech/ydb/flywaydb/database/YdbSchema.java

@@ -1,10 +1,12 @@
 package tech.ydb.flywaydb.database;
 
+import java.sql.DatabaseMetaData;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.stream.Collectors;
+
 import org.flywaydb.core.internal.database.base.Schema;
 import org.flywaydb.core.internal.jdbc.JdbcTemplate;
 
@@ -75,15 +77,13 @@ public String toString() {
     }
 
     private List<String> schemaTables() throws SQLException {
-        ResultSet rs = jdbcTemplate.getConnection().getMetaData()
-                .getTables(null, name, null, new String[]{"TABLE"});
-
-        List<String> tables = new ArrayList<>();
-
-        while (rs.next()) {
-            tables.add(database.quote(rs.getString("TABLE_NAME")));
+        DatabaseMetaData md = jdbcTemplate.getConnection().getMetaData();
+        try (ResultSet rs = md.getTables(null, name, null, new String[]{"TABLE"})) {
+            List<String> tables = new ArrayList<>();
+            while (rs.next()) {
+                tables.add(database.quote(rs.getString("TABLE_NAME")));
+            }
+            return tables;
         }
-
-        return tables;
     }
 }

liquibase-dialect/src/main/java/tech/ydb/liquibase/change/InsertDataChangeYdb.java

@@ -6,6 +6,7 @@
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+
 import liquibase.change.ChangeMetaData;
 import liquibase.change.ColumnConfig;
 import liquibase.change.DatabaseChange;
@@ -34,14 +35,13 @@ public SqlStatement[] generateStatements(Database database) {
 
         try {
             JdbcConnection jdbcConnection = (JdbcConnection) database.getConnection();
-            ResultSet resultSet = jdbcConnection.getMetaData()
-                    .getColumns(null, null, getTableName(), null);
-
-            while (resultSet.next()) {
-                columnToLiquibaseDataType.put(
-                        resultSet.getString("COLUMN_NAME").toLowerCase(),
-                        DataTypeFactory.getInstance()
-                                .fromDescription(resultSet.getString("TYPE_NAME"), database));
+            try (ResultSet rs = jdbcConnection.getMetaData().getColumns(null, null, getTableName(), null)) {
+                while (rs.next()) {
+                    columnToLiquibaseDataType.put(
+                            rs.getString("COLUMN_NAME").toLowerCase(),
+                            DataTypeFactory.getInstance().fromDescription(rs.getString("TYPE_NAME"), database)
+                    );
+                }
             }
 
             StringBuilder yqlInsert = new StringBuilder()

liquibase-dialect/src/main/java/tech/ydb/liquibase/change/LoadDataChangeYdb.java

@@ -1,6 +1,5 @@
 package tech.ydb.liquibase.change;
 
-import com.opencsv.exceptions.CsvMalformedLineException;
 import java.io.IOException;
 import java.sql.ResultSet;
 import java.util.ArrayList;
@@ -9,6 +8,8 @@
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
+
+import com.opencsv.exceptions.CsvMalformedLineException;
 import liquibase.Scope;
 import liquibase.change.ChangeMetaData;
 import liquibase.change.DatabaseChange;
@@ -23,6 +24,7 @@
 import liquibase.statement.core.InsertStatement;
 import liquibase.statement.core.RawSqlStatement;
 import liquibase.util.csv.CSVReader;
+
 import tech.ydb.liquibase.database.YdbDatabase;
 
 /**
@@ -60,17 +62,16 @@ public SqlStatement[] generateStatements(Database database) {
             }
 
             JdbcConnection jdbcConnection = (JdbcConnection) database.getConnection();
-            ResultSet resultSet = jdbcConnection.getMetaData()
-                    .getColumns(null, null, tableName, null);
-
-            while (resultSet.next()) {
-                columnToLiquibaseDataType.put(
-                        resultSet.getString("COLUMN_NAME").toLowerCase(),
-                        DataTypeFactory.getInstance()
-                                .fromDescription(resultSet.getString("TYPE_NAME"), database));
-            }
+            try (ResultSet resultSet = jdbcConnection.getMetaData().getColumns(null, null, tableName, null)) {
+                while (resultSet.next()) {
+                    columnToLiquibaseDataType.put(
+                            resultSet.getString("COLUMN_NAME").toLowerCase(),
+                            DataTypeFactory.getInstance()
+                                    .fromDescription(resultSet.getString("TYPE_NAME"), database));
+                }
 
-            return getSqlStatements(database, reader, headers);
+                return getSqlStatements(database, reader, headers);
+            }
         } catch (CsvMalformedLineException e) {
             throw new RuntimeException("Error parsing " + getRelativeTo() + " on line " + e.getLineNumber() + ": " + e.getMessage());
         } catch (UnexpectedLiquibaseException ule) {

shedlock-ydb/src/main/java/tech/ydb/lock/provider/YdbJDBCLockProvider.java

@@ -2,7 +2,9 @@
 
 import java.sql.SQLException;
 import java.util.Optional;
+
 import javax.sql.DataSource;
+
 import net.javacrumbs.shedlock.core.LockConfiguration;
 import net.javacrumbs.shedlock.core.LockProvider;
 import net.javacrumbs.shedlock.core.SimpleLock;
@@ -31,33 +33,30 @@ public Optional<SimpleLock> lock(LockConfiguration lockConfiguration) {
             try {
                 connection.setAutoCommit(false);
 
-                var selectPS = connection.prepareStatement("SELECT locked_by, lock_until FROM shedlock " +
-                        "WHERE name = ? AND lock_until > CurrentUtcTimestamp()");
-
-                selectPS.setString(1, lockConfiguration.getName());
-
-                try (var rs = selectPS.executeQuery()) {
-                    if (rs.next()) {
-                        LOGGER.debug("Instance[{}] acquire lock is failed. Leader is {}, lock_until = {}",
-                                LOCKED_BY, rs.getString(1), rs.getString(2));
-                        return Optional.empty();
+                try (var selectPS = connection.prepareStatement("SELECT locked_by, lock_until FROM shedlock " +
+                        "WHERE name = ? AND lock_until > CurrentUtcTimestamp()")) {
+                    selectPS.setString(1, lockConfiguration.getName());
+                    try (var rs = selectPS.executeQuery()) {
+                        if (rs.next()) {
+                            LOGGER.debug("Instance[{}] acquire lock is failed. Leader is {}, lock_until = {}",
+                                    LOCKED_BY, rs.getString(1), rs.getString(2));
+                            return Optional.empty();
+                        }
                     }
                 }
 
-                var upsertPS = connection.prepareStatement("" +
+                try (var upsertPS = connection.prepareStatement("" +
                         "UPSERT INTO shedlock(name, lock_until, locked_at, locked_by) " +
                         "VALUES (?, Unwrap(CurrentUtcTimestamp() + ?), CurrentUtcTimestamp(), ?)"
-                );
-
-                upsertPS.setObject(1, lockConfiguration.getName());
-                upsertPS.setObject(2, lockConfiguration.getLockAtMostFor());
-                upsertPS.setObject(3, LOCKED_BY);
-                upsertPS.execute();
+                )) {
+                    upsertPS.setObject(1, lockConfiguration.getName());
+                    upsertPS.setObject(2, lockConfiguration.getLockAtMostFor());
+                    upsertPS.setObject(3, LOCKED_BY);
+                    upsertPS.execute();
+                }
 
                 connection.commit();
-
                 LOGGER.debug("Instance[{}] is leader", LOCKED_BY);
-
                 return Optional.of(new YdbJDBCLock(lockConfiguration.getName(), dataSource));
             } finally {
                 connection.setAutoCommit(autoCommit);