Migrate to SQLite (#174)

* Migrating Fredy from LowDb to SqLite 🎉

* adding new sql migration system for future sql migrations

* adding setting to change  sqlite path for db files

* create migration plan for graceful migration lowdb -> sqlite

* Improving Documentation

* adding test for sqliteconnection

* upgrading dependencies

* making nodejs 22 as min version

* improve scraper

* adding overwrite ability for db migra

lib/services/storage/SqliteConnection.js

@@ -0,0 +1,140 @@
+import fs from 'fs';
+import path from 'path';
+import Database from 'better-sqlite3';
+import logger from '../../services/logger.js';
+import { config } from '../../utils.js';
+
+/**
+ * SqliteConnection
+ * A small, high-performance wrapper around better-sqlite3 that provides a
+ * singleton connection, sensible PRAGMA tuning, and helper methods. This
+ * module is safe to import and reuse.
+ *
+ * Performance notes:
+ * - journal_mode = WAL: allows concurrent readers with a single writer and
+ *   yields better performance for server apps.
+ * - synchronous = NORMAL: trades a bit of durability for significant speed
+ *   while still being safe in most environments.
+ * - cache_size = -64000: ~64MB page cache (negative value sets KB) to improve
+ *   query performance for frequent reads.
+ * - foreign_keys = ON: ensure referential integrity is enforced.
+ * - optimize: runs SQLite's auto-analysis and purges internal caches. It is
+ *   cheap; we call it at startup and before process exit. You can also call
+ *   optimize() manually after large schema changes or bulk operations.
+ */
+class SqliteConnection {
+  static #db = null;
+
+  /**
+   * Returns a singleton instance of better-sqlite3 Database.
+   * Respects env var SQLITE_DB_PATH and defaults to db/listings.db.
+   */
+  static getConnection() {
+    if (this.#db) return this.#db;
+
+    // Interpret config.sqlitepath as a directory relative to project root when it starts with '/'
+    const cfg = typeof config === 'object' && config ? config.sqlitepath : undefined;
+    const rawDir = cfg && cfg.length > 0 ? cfg : '/db';
+    const relDir = rawDir.startsWith('/') ? rawDir.slice(1) : rawDir;
+    const absDir = path.isAbsolute(relDir) ? relDir : path.join(process.cwd(), relDir);
+    const dbPath = path.join(absDir, 'listings.db');
+
+    // Ensure directory exists
+    const dir = path.dirname(dbPath);
+    if (!fs.existsSync(dir)) fs.mkdirSync(dir, { recursive: true });
+
+    // Open the database synchronously (better-sqlite3 is sync and very fast)
+    this.#db = new Database(dbPath, { verbose: undefined });
+
+    // Apply high-performance PRAGMA's
+    try {
+      this.#db.pragma('journal_mode = WAL');
+      this.#db.pragma('synchronous = NORMAL');
+      this.#db.pragma('cache_size = -64000');
+      this.#db.pragma('foreign_keys = ON');
+      this.#db.pragma('optimize');
+    } catch (e) {
+      logger.warn('Failed to apply one or more PRAGMAs:', e.message);
+    }
+
+    // Run optimize on exit to persist analysis and cleanup internal caches.
+    process.once('beforeExit', () => {
+      try {
+        this.#db?.pragma('optimize');
+      } catch (e) {
+        logger.debug('PRAGMA optimize on exit failed:', e.message);
+      }
+    });
+
+    return this.#db;
+  }
+
+  /**
+   * Execute a write statement (INSERT/UPDATE/DELETE/DDL). Returns better-sqlite3 run info.
+   */
+  static execute(sql, params = {}) {
+    const db = this.getConnection();
+    return db.prepare(sql).run(params);
+  }
+
+  /**
+   * Execute a query and returns all rows.
+   */
+  static query(sql, params = {}) {
+    const db = this.getConnection();
+    return db.prepare(sql).all(params);
+  }
+
+  /**
+   * Check whether a table exists.
+   */
+  static tableExists(tableName) {
+    const db = this.getConnection();
+    const row = db.prepare("SELECT 1 FROM sqlite_master WHERE type = 'table' AND name = ?").get(tableName);
+    return !!row;
+  }
+
+  /**
+   * Run the given callback inside a transaction. The callback receives the Database instance.
+   * If the callback throws, the transaction is rolled back and the error re-thrown.
+   */
+  static withTransaction(callback) {
+    const db = this.getConnection();
+    const trx = db.transaction((cb) => cb(db));
+    return trx(callback);
+  }
+
+  /**
+   * Run SQLite PRAGMA optimize. See https://sqlite.org/pragma.html#pragma_optimize
+   *
+   * Explanation: PRAGMA optimize triggers internal housekeeping, such as
+   * recomputing query planner statistics (similar to ANALYZE) when appropriate
+   * and purging unused pages from caches. It is inexpensive and can improve
+   * performance after schema changes or heavy write activity.
+   */
+  static optimize() {
+    const db = this.getConnection();
+    try {
+      db.pragma('optimize');
+    } catch (e) {
+      logger.warn('PRAGMA optimize failed:', e.message);
+    }
+  }
+
+  /**
+   * Close the database connection. Typically not needed for long-running apps.
+   */
+  static close() {
+    if (this.#db) {
+      try {
+        this.#db.pragma('optimize');
+      } catch (e) {
+        logger.debug('PRAGMA optimize before close failed:', e.message);
+      }
+      this.#db.close();
+      this.#db = null;
+    }
+  }
+}
+
+export default SqliteConnection;