Refactor transaction log managers to use singleton pattern

bvm/ballerina-runtime/src/main/java/io/ballerina/runtime/transactions/FileRecoveryLog.java

@@ -21,8 +21,6 @@
 import io.ballerina.runtime.internal.diagnostics.RuntimeDiagnosticLog;
 import io.ballerina.runtime.internal.errors.ErrorCodes;
 import io.ballerina.runtime.internal.util.RuntimeUtils;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import java.io.BufferedReader;
 import java.io.File;
@@ -35,6 +33,7 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardOpenOption;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -46,9 +45,8 @@
  *
  * @since 2201.9.0
  */
-public class FileRecoveryLog implements RecoveryLog {
+public final class FileRecoveryLog implements RecoveryLog {
 
-    private static final Logger log = LoggerFactory.getLogger(FileRecoveryLog.class);
     private static final String LOG_FILE_NUMBER = "(\\d+)";
     private static final String LOG_FILE_EXTENSION = ".log";
     private final String baseFileName;
@@ -61,6 +59,7 @@ public class FileRecoveryLog implements RecoveryLog {
     private Map<String, TransactionLogRecord> existingLogs;
     private static final PrintStream stderr = System.err;
     private final RuntimeDiagnosticLog diagnosticLog = new RuntimeDiagnosticLog();
+    private static FileRecoveryLog instance;
 
     /**
      * Initializes a new FileRecoveryLog instance with the given base file name.
@@ -70,16 +69,25 @@ public class FileRecoveryLog implements RecoveryLog {
      * @param recoveryLogDir     The directory to store the recovery log files in.
      * @param deleteOldLogs      Whether to delete old log files when creating a new one.
      */
-    public FileRecoveryLog(String baseFileName, int checkpointInterval, Path recoveryLogDir, boolean deleteOldLogs) {
+    private FileRecoveryLog(String baseFileName, int checkpointInterval, Path recoveryLogDir, boolean deleteOldLogs) {
         this.baseFileName = baseFileName;
         this.recoveryLogDir = recoveryLogDir;
         this.deleteOldLogs = deleteOldLogs;
         this.checkpointInterval = checkpointInterval;
         this.existingLogs = new HashMap<>();
-        this.logFile = createNextVersion();
         this.numOfPutsSinceLastCheckpoint = 0;
     }
 
+    public static FileRecoveryLog getInstance(String baseFileName, int checkpointInterval, Path recoveryLogDir,
+                                        boolean deleteOldLogs) {
+        if (instance != null) {
+           throw new IllegalStateException("instance already exists");
+        }
+        instance = new FileRecoveryLog(baseFileName, checkpointInterval, recoveryLogDir, deleteOldLogs);
+        instance.logFile = instance.createNextVersion();
+        return instance;
+    }
+
     /**
      * Creates the next version of the recovery log file, cleaning up the previous one.
      *
@@ -194,9 +202,6 @@ public void putAll(Map<String, TransactionLogRecord> trxRecords) {
     public Map<String, TransactionLogRecord> getPendingLogs() {
         Map<String, TransactionLogRecord> pendingTransactions = new HashMap<>();
         Map<String, TransactionLogRecord> transactionLogs = readLogsFromFile(logFile);
-        if (transactionLogs == null) {
-            return null;
-        }
         for (Map.Entry<String, TransactionLogRecord> entry : transactionLogs.entrySet()) {
             String trxId = entry.getKey();
             TransactionLogRecord trxRecord = entry.getValue();
@@ -234,7 +239,7 @@ private void writeToFile(String str, boolean force) {
      */
     private Map<String, TransactionLogRecord> readLogsFromFile(File file) {
         if (!file.exists() || file.length() == 0) {
-            return null;
+            return Collections.emptyMap();
         }
         if (fileLockAndChannel != null) {
             closeEverything();

bvm/ballerina-runtime/src/main/java/io/ballerina/runtime/transactions/InMemoryRecoveryLog.java

@@ -28,14 +28,20 @@
  *
  * @since 2201.9.0
  */
-public class InMemoryRecoveryLog implements RecoveryLog {
+public final class InMemoryRecoveryLog implements RecoveryLog {
 
-    private final Map<String, TransactionLogRecord> transactionLogs;
-    private int numOfPutsSinceLastCheckpoint;
+    private final Map<String, TransactionLogRecord> transactionLogs = new ConcurrentHashMap<>();
+    private int numOfPutsSinceLastCheckpoint = 0;
+    private static InMemoryRecoveryLog instance;
 
-    public InMemoryRecoveryLog() {
-        this.transactionLogs = new ConcurrentHashMap<>();
-        this.numOfPutsSinceLastCheckpoint = 0;
+    private InMemoryRecoveryLog() {
+    }
+
+    public static InMemoryRecoveryLog getInstance() {
+        if (instance == null) {
+            instance = new InMemoryRecoveryLog();
+        }
+        return instance;
     }
 
     @Override

bvm/ballerina-runtime/src/main/java/io/ballerina/runtime/transactions/LogManager.java

@@ -27,8 +27,10 @@
  * @since 2201.9.0
  */
 public class LogManager {
+
     private final FileRecoveryLog fileRecoveryLog;
     private final InMemoryRecoveryLog inMemoryRecoveryLog;
+    private static LogManager instance;
 
     /**
      * Create a log manager with the given base file name, checkpoint interval, recovery log directory, and delete old
@@ -39,12 +41,21 @@ public class LogManager {
      * @param recoveryLogDir     the recovery log directory
      * @param deleteOldLogs      the delete old logs flag
      */
-    public LogManager(String baseFileName, int checkpointInterval, Path recoveryLogDir, boolean deleteOldLogs) {
-        this.fileRecoveryLog = new FileRecoveryLog(baseFileName, checkpointInterval, recoveryLogDir, deleteOldLogs);
-        this.inMemoryRecoveryLog = new InMemoryRecoveryLog();
+    private LogManager(String baseFileName, int checkpointInterval, Path recoveryLogDir, boolean deleteOldLogs) {
+        this.fileRecoveryLog =
+                FileRecoveryLog.getInstance(baseFileName, checkpointInterval, recoveryLogDir, deleteOldLogs);
+        this.inMemoryRecoveryLog = InMemoryRecoveryLog.getInstance();
         init();
     }
 
+    public static LogManager getInstance(String baseFileName, int checkpointInterval, Path recoveryLogDir,
+                                         boolean deleteOldLogs) {
+        if (instance == null) {
+            instance = new LogManager(baseFileName, checkpointInterval, recoveryLogDir, deleteOldLogs);
+        }
+        return instance;
+    }
+
     private void init() {
         // Read pending transactions from the file recovery log and add them to the in-memory log.
         Map<String, TransactionLogRecord> pendingTransactions = fileRecoveryLog.getPendingLogs();
@@ -75,5 +86,6 @@ public Map<String, TransactionLogRecord> getFailedTransactionLogs() {
      */
     public void close() {
         fileRecoveryLog.close();
+        inMemoryRecoveryLog.close();
     }
 }

bvm/ballerina-runtime/src/main/java/io/ballerina/runtime/transactions/TransactionResourceManager.java

@@ -124,7 +124,7 @@ private TransactionResourceManager() {
             userTransactionManager = new UserTransactionManager();
         } else {
             xidRegistry = new HashMap<>();
-            logManager = new LogManager(getRecoveryLogBaseName(), getCheckpointInterval(),
+            logManager = LogManager.getInstance(getRecoveryLogBaseName(), getCheckpointInterval(),
                     getRecoveryLogDir(), getDeleteOldLogs());
             recoveryManager = new RecoveryManager();
             if (!diagnosticLog.getDiagnosticList().isEmpty()) {

bvm/ballerina-runtime/src/test/java/io/ballerina/runtime/test/transactions/LogManagerTests.java

@@ -24,8 +24,8 @@
 import io.ballerina.runtime.transactions.RecoveryState;
 import io.ballerina.runtime.transactions.TransactionLogRecord;
 import org.testng.Assert;
-import org.testng.annotations.AfterMethod;
-import org.testng.annotations.BeforeMethod;
+import org.testng.annotations.AfterSuite;
+import org.testng.annotations.BeforeSuite;
 import org.testng.annotations.Test;
 
 import java.io.IOException;
@@ -40,14 +40,14 @@ public class LogManagerTests {
     private TransactionLogRecord logRecord;
     private Path recoveryLogDir = Path.of("build/tmp/test/recovery/logManagerTestLogs");
 
-    @BeforeMethod
+    @BeforeSuite
     public void setup() {
-        logManager = new LogManager("baseFileName", -1, recoveryLogDir, false);
+        logManager = LogManager.getInstance("testLog", -1, recoveryLogDir, false);
         logRecord = new TransactionLogRecord("00000000-0000-0000-0000-000000000000", "0",
                 RecoveryState.PREPARING);
     }
 
-    @Test (description = "Test adding logs records to both in-memory and file recovery logs")
+    @Test(description = "Test adding logs records to both in-memory and file recovery logs")
     public void testPut() throws Exception {
         logManager.put(logRecord);
         Field inMemoryRecoveryLogField = LogManager.class.getDeclaredField("inMemoryRecoveryLog");
@@ -63,14 +63,14 @@ public void testPut() throws Exception {
         Assert.assertTrue(fileLogs.containsKey(logRecord.getCombinedId()));
     }
 
-    @Test (description = "Test getting failed transaction logs from the log manager")
+    @Test(description = "Test getting failed transaction logs from the log manager")
     public void testGetFailedTransactionLogs() {
         logManager.put(logRecord);
         Map<String, TransactionLogRecord> failedTransactions = logManager.getFailedTransactionLogs();
         Assert.assertTrue(failedTransactions.containsValue(logRecord));
     }
 
-    @AfterMethod
+    @AfterSuite
     public void tearDown() throws IOException {
         logManager.close();
         if (Files.exists(recoveryLogDir)) {

bvm/ballerina-runtime/src/test/java/io/ballerina/runtime/test/transactions/RecoveryManagerTests.java

@@ -60,7 +60,7 @@ public void setup() throws NoSuchFieldException, IllegalAccessException {
         recoveryManager = new RecoveryManager();
         Field logManagerField = TransactionResourceManager.class.getDeclaredField("logManager");
         logManagerField.setAccessible(true);
-        LogManager logManager = new LogManager("testLog", -1,
+        LogManager logManager = LogManager.getInstance("testLog", -1,
                 Path.of("build/tmp/test/recovery/testRecoveryLogs"), true);
         logManagerField.set(transactionResourceManager, logManager);
 
@@ -339,6 +339,9 @@ public void testHeuristicTerminationWithHuerHazard()
                 ErrorCodes.TRANSACTION_IN_HUERISTIC_STATE.diagnosticId());
     }
 
+    @Test (description = "Test unable to create file")
+
+
     @AfterTest
     public void tearDown() throws IOException {
         Path dir = Paths.get("build/tmp/test/recovery/testRecoveryLogs");