Hacktoberfest 2026: los issues que los mantenedores marcaron para octubre, abiertos y aptos para principiantes. Explorar issues de Hacktoberfest

CDK scaffold bin/cdk.ts async entry point breaks cdk ls/synth/deploy

Abierto Apto para principiantes
  • ¿Algo no está bien?
#821 0 comentarios 1 reacción 0 asignados Ver en GitHub

Los mantenedores suelen responder en 1 día

Nadie ha tomado este issue todavía.

Evaluación

Dificultad
2/5
Tiempo estimado
1-3 horas
Aptitud para principiantes
78/100
Tipo de issue
Error
Claridad
Bien especificado
Estado de actividad
Tranquilo
Stack tecnológico
aws, node.js, typescript
Área
cli, infrastructure

Línea de trabajo

Comienza con la plantilla de scaffold en src/assets/cdk/bin/cdk.ts y revisa cómo sus llamadas asíncronas a ConfigIO registran stacks antes del synth automático de CDK. Ejecuta la reproducción con agentcore create, npx tsc y npx cdk ls. Se considera terminado cuando el proyecto generado muestra AgentCore-myagent-main y synth produce su template en lugar de un assembly vacío.

Escrito por el modelo de indexación a partir del texto del issue.

Descripción

bug

Bug Description

The generated bin/cdk.ts from agentcore create uses an async main() function with await configIO.readProjectSpec() and await configIO.readAWSDeploymentTargets(). This causes cdk ls, cdk synth, and cdk deploy to silently produce zero stacks with exit code 0.

Root Cause

The CDK App class has an autoSynth property that defaults to true when CDK_OUTDIR is set (i.e., when run by the CDK CLI). autoSynth uses Node.js process.on('beforeExit') to call app.synth() automatically. However, beforeExit fires when the synchronous event loop drains — before async main() completes.

Timeline when CDK CLI runs the app:

  1. CDK CLI spawns node dist/bin/cdk.js with CDK_OUTDIR set to a temp dir
  2. main().catch(...) starts the async function but returns immediately (it's a promise)
  3. Synchronous event loop drains → beforeExit fires → autoSynth calls app.synth() on an empty App (stacks are inside the unresolved main())
  4. CDK CLI reads the empty cloud assembly → zero stacks

The explicit app.synth() at the end of main() eventually runs, but by then the CDK CLI has already read the output.

Reference: CDK AppProps.autoSynth docs — "Automatically call synth() before the program exits. Default: true if running via CDK CLI (CDK_OUTDIR is set)"

Reproduction

# 1. Create a fresh project
agentcore create --name myagent --defaults

# 2. Add a deployment target
cat > myagent/agentcore/aws-targets.json << 'EOF'
[{"name": "main", "account": "123456789012", "region": "us-east-1"}]
EOF

# 3. Install and compile
cd myagent/agentcore/cdk
npm install
npx tsc

# 4. List stacks — expect "AgentCore-myagent-main", get nothing
npx cdk ls
# Output: (empty, exit code 0)

# 5. Verify the app DOES create stacks when run directly
node -e "
const { AgentCoreStack } = require('./dist/lib/cdk-stack');
const cdk = require('aws-cdk-lib');
const app = new cdk.App();
console.log('Stacks:', app.node.children.length);
" 
# This also shows 0 because stacks are inside async main()

Expected Behavior

npx cdk ls should output:

AgentCore-myagent-main

Actual Behavior

npx cdk ls outputs nothing (empty stdout, exit code 0). cdk synth also exits 0 but produces no template. cdk deploy would silently deploy nothing.

Proposed Fix

Replace async ConfigIO calls with synchronous fs.readFileSync in the scaffold template (src/assets/cdk/bin/cdk.ts):

#!/usr/bin/env node
import { AgentCoreStack } from '../lib/cdk-stack';
import type { AgentCoreProjectSpec, AwsDeploymentTarget } from '@aws/agentcore-cdk';
import { App, type Environment } from 'aws-cdk-lib';
import * as path from 'path';
import * as fs from 'fs';

// Synchronous reads — CDK CLI requires stacks registered before process exits.
// Async ConfigIO calls race with the CDK CLI's autoSynth (beforeExit hook).
const configRoot = path.resolve(__dirname, '..', '..', '..');
const spec: AgentCoreProjectSpec = JSON.parse(
  fs.readFileSync(path.join(configRoot, 'agentcore.json'), 'utf8'),
);
const targets: AwsDeploymentTarget[] = JSON.parse(
  fs.readFileSync(path.join(configRoot, 'aws-targets.json'), 'utf8'),
);

if (targets.length === 0) {
  throw new Error('No deployment targets configured.');
}

const app = new App();

for (const target of targets) {
  new AgentCoreStack(app, `AgentCore-${spec.name}-${target.name}`, {
    spec,
    env: { account: target.account, region: target.region },
  });
}

app.synth();

The agentcore.json and aws-targets.json files are small local JSON — there's no benefit to reading them asynchronously, and doing so breaks CDK CLI compatibility.

Environment

  • @aws/agentcore CLI: 0.8.0
  • @aws/agentcore-cdk: 0.1.0-alpha.17
  • aws-cdk-lib: 2.189.1
  • CDK CLI: 2.1100.1
  • Node.js: v22.x
  • OS: macOS (Darwin 25.3.0)
Lenguaje dominante
TypeScript
Estrellas
291
Forks
96
Merge medio
20 h 50 min
PR fusionados (30 d)
214

Preparar el entorno

Primeros pasos

  1. Lee el issue completo y luego la guía de contribución del proyecto.
  2. Comenta en el issue que vas a ocuparte — evita que dos personas hagan lo mismo.
  3. Haz un fork del repositorio y trabaja en una rama.
  4. Abre un pull request que haga referencia al número del issue.

Más de aws/agentcore-cli

Todos los issues de aws/agentcore-cli

Issues similares

Más issues de TypeScript

Recibe los nuevos issues en tu correo

Un resumen breve de issues de GitHub para principiantes.