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Node.js and AWS X-Ray (Node.js SDK)

Tracetest is a testing tool based on OpenTelemetry that allows you to test your distributed application. It allows you to use data from distributed traces generated by OpenTelemetry to validate and assert if your application has the desired behavior defined by your test definitions.

AWS X-Ray provides a complete view of requests as they travel through your application and filters visual data across payloads, functions, traces, services, APIs and more with no-code and low-code motions.

Sample Node.js App with AWS X-Ray (Node.js SDK) and Tracetest

This is a simple quick start guide on how to configure a Node.js app to use instrumentation with traces and Tracetest for enhancing your E2E and integration tests with trace-based testing. The infrastructure will use AWS X-Ray as the trace data store and a Node.js app to generate the telemetry data.

Prerequisites

You will need Docker and Docker Compose installed on your machine to run this quick start app!

And a set of AWS credentials to connect Tracetest to the cloud API.

Project Structure

The project is built with Docker Compose.

1. Node.js App

The Dockerfile in the root directory is for the Node.js app.

2. Tracetest

The docker-compose.yaml file, tracetest.provision.yaml, and tracetest-config.yaml in the root directory are for the setting up the Node.js App, Tracetest and X-Ray Daemon.

Docker Compose Network

All services in the docker-compose.yaml are on the same network and will be reachable by hostname from within other services. For example, xray-daemon:2000 in the src/index.js will map to the xray-daemon service, where the port 2000 is the port where the X-Ray Daemon accepts telemetry data.

Node.js App

The Node.js app is a simple Express app, contained in the src/index.js file.

It is instrumented using AWS X-Ray SDK sending the initial data to the Daemon that will be pushing the telemetry data to the AWS service.

The key following is the instrumentation section from the src/index.js file.

const AWSXRay = require("aws-xray-sdk");
const XRayExpress = AWSXRay.express;
const express = require("express");

AWSXRay.setDaemonAddress("xray-daemon:2000");

// Capture all AWS clients we create
const AWS = AWSXRay.captureAWS(require("aws-sdk"));
AWS.config.update({
region: process.env.AWS_REGION || "us-west-2",
});

// Capture all outgoing https requests
AWSXRay.captureHTTPsGlobal(require("https"));
const https = require("https");

const app = express();
const port = 3000;

app.use(XRayExpress.openSegment("Tracetest"));

To start the server, run this command:

npm start

As you can see the Dockerfile uses the command above.

FROM node:slim
WORKDIR /usr/src/app

COPY ./src/package*.json ./

RUN npm install
COPY ./src .

EXPOSE 3000
CMD [ "npm", "start" ]

Tracetest

The docker-compose.yaml includes three other services.

  • Postgres - Postgres is a prerequisite for Tracetest to work. It stores trace data when running the trace-based tests.
  • AWS X-Ray Daemon - is a software application that listens for traffic on UDP port 2000, gathers raw segment data, and relays it to the AWS X-Ray API. The daemon works in conjunction with the AWS X-Ray SDKs and must be running so that data sent by the SDKs can reach the X-Ray service.
  • Tracetest - Trace-based testing that generates end-to-end tests automatically from traces.
version: "3"

services:
tracetest:
image: kubeshop/tracetest:${TAG:-latest}
platform: linux/amd64
volumes:
- type: bind
source: ./tracetest-config.yaml
target: /app/tracetest.yaml
- type: bind
source: ./tracetest.provision.yaml
target: /app/provisioning.yaml
ports:
- 11633:11633
command: --provisioning-file /app/provisioning.yaml
extra_hosts:
- "host.docker.internal:host-gateway"
depends_on:
postgres:
condition: service_healthy
xray-daemon:
condition: service_started
healthcheck:
test: ["CMD", "wget", "--spider", "localhost:11633"]
interval: 1s
timeout: 3s
retries: 60

postgres:
image: postgres:14
environment:
POSTGRES_PASSWORD: postgres
POSTGRES_USER: postgres
healthcheck:
test: pg_isready -U "$$POSTGRES_USER" -d "$$POSTGRES_DB"
interval: 1s
timeout: 5s
retries: 60
ports:
- 5432:5432

xray-daemon:
image: amazon/aws-xray-daemon:latest
environment:
AWS_ACCESS_KEY_ID: ${AWS_ACCESS_KEY_ID}
AWS_SECRET_ACCESS_KEY: ${AWS_SECRET_ACCESS_KEY}
AWS_SESSION_TOKEN: ${AWS_SESSION_TOKEN}
AWS_REGION: ${AWS_REGION}
ports:
- 2000:2000

Tracetest depends on Postgres and the x-ray daemon. Tracetest requires config files to be loaded via a volume. The volumes are mapped from the root directory into the root directory and the respective config files.

The tracetest.config.yaml file contains the basic setup of connecting Tracetest to the Postgres instance.

postgres:
host: postgres
user: postgres
password: postgres
port: 5432
dbname: postgres
params: sslmode=disable

The tracetest.provision.yaml file defines the trace data store, set to AWS X-Ray, meaning the traces will be stored in X-Ray and Tracetest will fetch them from X-Ray when running tests.

But how does Tracetest fetch traces?

Tracetest uses the Golang AWS-SDK library to pull to fetch trace data.

---
type: DataStore
spec:
name: awsxray
type: awsxray
awsxray:
accessKeyId: <your-accessKeyId>
secretAccessKey: <your-secretAccessKey>
sessionToken: <your-session-token>
region: "us-west-2"

How do traces reach AWX X-Ray?

The application code in the src/index.js file uses the native AWS SDK X-Ray library which sends telemetry data to the X-Ray Daemon to be processed and then sent to the configured AWS X-Ray SaaS.

Run Both the Node.js App and Tracetest

To start both the Node.js app and Tracetest, run this command:

docker-compose up

This will start your Tracetest instance on http://localhost:11633/. Open it and start creating tests! Make sure to use the http://app:3000/ URL in your test creation because your Node.js app and Tracetest are in the same network.

Learn More

Please visit our examples in GitHub and join our Slack Community for more info!