chore: IAM auth username env var takes precedence

src/lib/db/aws-iam.ts

@@ -14,7 +14,7 @@ export const getDBPasswordResolver = (db: IDBOption): PasswordResolver => {
             region: db.awsRegion,
             hostname: db.host,
             port: db.port,
-            username: db.user,
+            username: process.env.DATABASE_USERNAME || db.user,
         });
         return async () => {
             console.log('[AWS RDS SIGNER] Getting token...');

src/lib/db/db-pool.ts

@@ -19,6 +19,7 @@ export function createDb({
         version: db.version,
         connection: {
             ...db,
+            user: process.env.DATABASE_USERNAME || db.user,
             application_name: db.applicationName,
             password: getDBPasswordResolver(db),
         },