Rewrite the data access layer onto Prisma Client

src/db.js

@@ -1,28 +1,23 @@
-import mariadb from 'mariadb';
+import { PrismaClient } from '@prisma/client';
 
-let pool;
+let prisma;
 
 export function buildDatabaseUrl(config) {
   const { host, user, password, database } = config.db;
   return `mysql://${encodeURIComponent(user)}:${encodeURIComponent(password)}@${host}:3306/${database}?connection_limit=10`;
 }
 
-export function getPool(config) {
-  if (!pool) {
-    pool = mariadb.createPool({
-      host: config.db.host,
-      user: config.db.user,
-      password: config.db.password,
-      database: config.db.database,
-      connectionLimit: 10,
-    });
+export function getPrismaClient(config) {
+  if (!prisma) {
+    process.env.DATABASE_URL = buildDatabaseUrl(config);
+    prisma = new PrismaClient();
   }
-  return pool;
+  return prisma;
 }
 
-export async function closePool() {
-  if (pool) {
-    await pool.end();
-    pool = undefined;
+export async function closePrismaClient() {
+  if (prisma) {
+    await prisma.$disconnect();
+    prisma = undefined;
   }
 }