fix(prisma): add pool_timeout=30 and retry on connection pool timeout

The default pool_timeout (10s) is insufficient for Aurora Serverless v2
auto-pause resume (~15s). Also, PrismaClientInitializationError for pool
timeout has errorCode=undefined, so message-based detection is needed.

Author: konokenj

cdk/lib/constructs/database.ts

@@ -91,9 +91,10 @@ export class Database extends Construct implements ec2.IConnectable {
   public getLambdaEnvironment(databaseName: string) {
     const conn = this.getConnectionInfo();
     // connection_limit=1: Each Lambda instance handles one request at a time
+    // pool_timeout=30: Must be >= connect_timeout to allow Aurora Serverless v2 resume (~15s)
     // connect_timeout=30: Aurora Serverless v2 auto-pause resume takes ~15s (longer after 24h+ pause)
     // https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/aurora-serverless-v2-auto-pause.html
-    const option = '?connection_limit=1&connect_timeout=30';
+    const option = '?connection_limit=1&pool_timeout=30&connect_timeout=30';
     return {
       DATABASE_HOST: conn.host,
       DATABASE_NAME: databaseName,

cdk/test/__snapshots__/serverless-fullstack-webapp-starter-kit-without-domain.test.ts.snap

@@ -723,7 +723,7 @@ exports[`Snapshot test 2`] = `
               ],
             },
             "DATABASE_NAME": "main",
-            "DATABASE_OPTION": "?connection_limit=1&connect_timeout=30",
+            "DATABASE_OPTION": "?connection_limit=1&pool_timeout=30&connect_timeout=30",
             "DATABASE_PASSWORD": {
               "Fn::Join": [
                 "",
@@ -772,7 +772,7 @@ exports[`Snapshot test 2`] = `
                       "Endpoint.Port",
                     ],
                   },
-                  "/main?connection_limit=1&connect_timeout=30",
+                  "/main?connection_limit=1&pool_timeout=30&connect_timeout=30",
                 ],
               ],
             },
@@ -3406,7 +3406,7 @@ service iptables save",
               ],
             },
             "DATABASE_NAME": "main",
-            "DATABASE_OPTION": "?connection_limit=1&connect_timeout=30",
+            "DATABASE_OPTION": "?connection_limit=1&pool_timeout=30&connect_timeout=30",
             "DATABASE_PASSWORD": {
               "Fn::Join": [
                 "",
@@ -3455,7 +3455,7 @@ service iptables save",
                       "Endpoint.Port",
                     ],
                   },
-                  "/main?connection_limit=1&connect_timeout=30",
+                  "/main?connection_limit=1&pool_timeout=30&connect_timeout=30",
                 ],
               ],
             },
@@ -3783,7 +3783,7 @@ service iptables save",
               ],
             },
             "DATABASE_NAME": "main",
-            "DATABASE_OPTION": "?connection_limit=1&connect_timeout=30",
+            "DATABASE_OPTION": "?connection_limit=1&pool_timeout=30&connect_timeout=30",
             "DATABASE_PASSWORD": {
               "Fn::Join": [
                 "",
@@ -3832,7 +3832,7 @@ service iptables save",
                       "Endpoint.Port",
                     ],
                   },
-                  "/main?connection_limit=1&connect_timeout=30",
+                  "/main?connection_limit=1&pool_timeout=30&connect_timeout=30",
                 ],
               ],
             },

cdk/test/__snapshots__/serverless-fullstack-webapp-starter-kit.test.ts.snap

@@ -744,7 +744,7 @@ exports[`Snapshot test 2`] = `
               ],
             },
             "DATABASE_NAME": "main",
-            "DATABASE_OPTION": "?connection_limit=1&connect_timeout=30",
+            "DATABASE_OPTION": "?connection_limit=1&pool_timeout=30&connect_timeout=30",
             "DATABASE_PASSWORD": {
               "Fn::Join": [
                 "",
@@ -793,7 +793,7 @@ exports[`Snapshot test 2`] = `
                       "Endpoint.Port",
                     ],
                   },
-                  "/main?connection_limit=1&connect_timeout=30",
+                  "/main?connection_limit=1&pool_timeout=30&connect_timeout=30",
                 ],
               ],
             },
@@ -3236,7 +3236,7 @@ service iptables save",
               ],
             },
             "DATABASE_NAME": "main",
-            "DATABASE_OPTION": "?connection_limit=1&connect_timeout=30",
+            "DATABASE_OPTION": "?connection_limit=1&pool_timeout=30&connect_timeout=30",
             "DATABASE_PASSWORD": {
               "Fn::Join": [
                 "",
@@ -3285,7 +3285,7 @@ service iptables save",
                       "Endpoint.Port",
                     ],
                   },
-                  "/main?connection_limit=1&connect_timeout=30",
+                  "/main?connection_limit=1&pool_timeout=30&connect_timeout=30",
                 ],
               ],
             },
@@ -3589,7 +3589,7 @@ service iptables save",
               ],
             },
             "DATABASE_NAME": "main",
-            "DATABASE_OPTION": "?connection_limit=1&connect_timeout=30",
+            "DATABASE_OPTION": "?connection_limit=1&pool_timeout=30&connect_timeout=30",
             "DATABASE_PASSWORD": {
               "Fn::Join": [
                 "",
@@ -3638,7 +3638,7 @@ service iptables save",
                       "Endpoint.Port",
                     ],
                   },
-                  "/main?connection_limit=1&connect_timeout=30",
+                  "/main?connection_limit=1&pool_timeout=30&connect_timeout=30",
                 ],
               ],
             },

webapp/src/lib/prisma.ts

@@ -25,6 +25,7 @@ function isRetryableError(error: unknown): boolean {
     msg.includes('idle-session timeout') ||
     msg.includes('terminating connection') ||
     msg.includes('Connection terminated') ||
+    msg.includes('Timed out fetching a new connection from the connection pool') ||
     msg.includes('ECONNRESET')
   );
 }