feat(samples/cloudwatch-applicationsignals-mcp): add docker nodejs express app

[yiyuan-he]

Fixes

Summary

Adding Docker Nodejs Express app to our enablement tool testing infra.

Changes

This PR adds a new Node.js Express baseline application for testing AWS Application Signals enablement via the
get_enablement_guide MCP tool. The application is designed to run as a Docker container on EC2.

New files added:

• docker-apps/nodejs/express/ - Complete Express application with:
  • Dockerfile using Node.js 20-alpine with health checks
  • REST API with three endpoints: /, /health, and /api/buckets
  • AWS SDK S3 integration to list S3 buckets
  • Traffic generation script for continuous testing
  • package.json with Express 5.1.0, AWS SDK, and Pino logger dependencies
  • infrastructure/ec2/cdk/config/nodejs-express.json - CDK configuration for deployment

Documentation updates:
- Updated README.md with Node.js Express app build/deploy instructions
- Added nodejs-express to ECR repository table
- Added NodejsExpressCdkStack to CDK stack deployment table

User experience

N/A

Checklist

If your change doesn't seem to apply, please leave them unchecked.

• I have reviewed the contributing guidelines
• I have performed a self-review of this change
• Changes have been tested
• Changes are documented

Is this a breaking change? (Y/N) N

RFC issue number:

Checklist:

• Migration process documented
• Implement warnings (if it can live side by side)

Acknowledgment

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of the project license.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.26%. Comparing base (63a92cd) to head (fe188cd).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1721   +/-   ##
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  Coverage   90.26%   90.26%           
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  Files         781      781           
  Lines       59912    59912           
  Branches     9718     9718           
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  Hits        54077    54077           
  Misses       3646     3646           
  Partials     2189     2189           

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[Copilot]

Pull Request Overview

This PR adds a new Node.js Express baseline application for testing AWS Application Signals enablement via the get_enablement_guide MCP tool. The application is containerized and designed to run on EC2 with Docker.

• Complete Express application with health checks, S3 integration, and Pino logging
• Multi-architecture Docker image support (linux/amd64, linux/arm64)
• CDK infrastructure configuration for EC2 deployment
• Traffic generation script for continuous testing

Reviewed Changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
docker-apps/nodejs/express/app.js	Express server with endpoints for health checks and S3 bucket listing
docker-apps/nodejs/express/Dockerfile	Multi-stage Docker build with Node.js 20-alpine, health checks, and security best practices
docker-apps/nodejs/express/package.json	Dependencies including Express 5.1.0, AWS SDK S3, and Pino logger
docker-apps/nodejs/express/package-lock.json	Lock file for dependency versions
docker-apps/nodejs/express/generate-traffic.sh	Bash script for continuous traffic generation
infrastructure/ec2/cdk/config/nodejs-express.json	CDK configuration for Node.js Express stack
README.md	Updated documentation with Node.js Express build and deployment instructions

Comments suppressed due to low confidence (1)

samples/cloudwatch-applicationsignals-mcp/get-enablement-guide-samples/docker-apps/nodejs/express/app.js:19

• Avoid automated semicolon insertion (91% of all statements in the enclosing script have an explicit semicolon).

const logger = require('pino')()

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[yiyuan-he]

trivy is expected to fail for now. see here.