EchoRelayApp

Basic Node.js application to create a multi-tier service mesh. Services can echo and relay the traffic to downstream services.

Use Cases:

1. Basic mock server
2. Introducing custom delay in upstream API call.
3. Load Testing sequential API invocations across multiple services.

Future plans

1. Adding custom mock APIs with built-in latency manipulation.
2. Providing a lambda function to be executed on API calls.
3. Support for asynchronous upstream calls

Usage

Minikube

$ minikube-deploy.sh

Docker

$ docker-deploy.sh -u <docker-username> -t <image-tag>

Environment Variables

Variable name	Default	Description
PORT	80	Port to bind the service
NAME	'unnamed'	Name of the service
TARGETS	''	Comma-separated list of target endpoints to relay the request.
LATENCY_MIN	0	minimum latency to inject before sending a response.
LATENCY_MAX	0	maximum latency to inject before sending a response.

Application Behavior

• Application accepts the request at the bind port ('localhost:80/')
• Service makes the call to targets sequentially in a synchronous way and appends the response.
• Response latency is added to each request as a random number between LATENCY_MIN & LATENCY_MAX values.

Response format:

for request to service 1 having targets service2 & service3 response will be of format:

type: Application/JSON

{"path":"service1 -> {service2 -> {},service3 -> {service4 -> {}}}"}