Load Balancer Testing API

A basic REST API written in Python using FastAPI that I use for testing load balancers in my day job. It features a separate front-end UI and back-end API that can be run independently or in the same process.

Running

To run from the command line first install the dependencies: pip install -r requirements.txt, then run python app\main.py

To run via docker docker run -it -p 80:80 maxanderson95/load-balancer-testing-api:latest

You can also deploy the included manifests. This requires a pre-configured ingress controller.

kubectl apply -f https://raw.githubusercontent.com/MaxAnderson95/load-balancer-testing-api/main/manifests/deployment.yaml
kubectl apply -f https://raw.githubusercontent.com/MaxAnderson95/load-balancer-testing-api/main/manifests/service.yaml
kubectl apply -f https://raw.githubusercontent.com/MaxAnderson95/load-balancer-testing-api/main/manifests/ingress.yaml

Configuration

You can specify configuration using environment variables.

To specify the logging level: API_logging.level="DEBUG". The default is INFO.
To specify the instance id (essentially a friendly name for the instance): API_server.instance_id="HQ-01". The default is auto generated.
To specify the port the server runs on: API_server.port="8080". The default is 80.
To specify the server "mode": API_server.mode="FULL". The default is FULL, and the other options are UI and API.

Logging and Data

When a request is made to any route, it will respond with a json object in the following format:

{
	"server_details": {
		"server_instance_id": "D2SRCA",
		"server_mode": "API",
		"server_listening_port": 80
	},
	"request_details": {
		"client_ip": "10.1.1.50",
		"x-forwarded-for_header": "172.12.12.12",
		"request_path": "/api/v1"
	}
}

Also, an INFO level log message will be printed to STDOUT with similar information:

[2022-03-18 18:01:15,979][main ][INFO ] Instance: 'D2SRCA', METHOD: 'GET', PATH: '/testroute' CLIENT: '10.1.1.50', XFF: '172.12.12.12'

If the word "health" is found anywhere in the request path, the log message will be at DEBUG level instead, and the response object will contain a new key value pair of "status": "UP, mimicking the response of the health monitor in Spring Boot framework.

Server Modes

Three server modes are available. These are: API, UI, and FULL. They are set using an environment variable with the default being FULL if the environment variable is not set.

When the server is in API mode, it simply responds to GET and HEAD requests at any route and returns a sample response.
When the server is in UI mode, it serves a static HTML page and Javascript file. On load, the webpage will attempt to make a call to /api and return the server_instance_id as text in the HTML body. It will also attempt to get a joke from /api/joke which itself gets a joke from a 3rd party joke API.

Also note, calls with the word health anywhere in the path will return a JSON response with a key value pair of "status": "UP", mimicking the response of the health monitor in Spring Boot framework.
When the server is in FULL mode (Fullstack mode), it is the equivalent of having API and UI mode enabled at the same time.

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