fixing up db's and data-service

libs/postgres-client/src/singleton.ts

@@ -0,0 +1,50 @@
+import { PostgreSQLClient } from './client';
+import type { PostgreSQLClientConfig } from './types';
+
+/**
+ * Singleton PostgreSQL client instance
+ * Provides global access to a single PostgreSQL connection pool
+ */
+let instance: PostgreSQLClient | null = null;
+
+/**
+ * Initialize the singleton PostgreSQL client
+ */
+export async function connectPostgreSQL(config?: PostgreSQLClientConfig): Promise<PostgreSQLClient> {
+  if (!instance) {
+    if (!config) {
+      throw new Error('PostgreSQL client not initialized. Call connectPostgreSQL(config) first.');
+    }
+    instance = new PostgreSQLClient(config);
+    await instance.connect();
+  }
+  return instance;
+}
+
+/**
+ * Get the singleton PostgreSQL client instance
+ * @throws Error if not initialized
+ */
+export function getPostgreSQLClient(): PostgreSQLClient {
+  if (!instance) {
+    throw new Error('PostgreSQL client not initialized. Call connectPostgreSQL(config) first.');
+  }
+  return instance;
+}
+
+/**
+ * Check if the PostgreSQL client is initialized
+ */
+export function isInitialized(): boolean {
+  return instance !== null && instance.connected;
+}
+
+/**
+ * Disconnect and reset the singleton instance
+ */
+export async function disconnectPostgreSQL(): Promise<void> {
+  if (instance) {
+    await instance.disconnect();
+    instance = null;
+  }
+}