A backend-for-frontend REST API serving telemetry data from other services.

Problem Statement

Implement a Service that:

• collects the bandwidth (egress/ingress) metrics made available by gateway Prometheus plugin for each service.
• provides a RESTful API that the frontend UI can use to display the used bandwidth via timeseries charts.
• triggers an email notification when the quota reaches 80%, 90% and 100% of a given bandwidth allocation quota.

Choose a persistence mechanism that is appropriate for this feature.

Implementation

Pre-requisites

• Install docker and make sure you have docker compose.
• pipenv for editing code.

Architecture

Following are the components of the system:

• REST API: this the API that has been asked to be developed.
• Mock Kong Gateway: This is docker container running the kong gateway serving as mock backend gateways from which prometheus metrics data is to be scraped periodically.
• Prometheus: The datastore for storing and aggregating the timeseries data received for kong_bandwidth.
• Docker Swarm is used for networking all of these together.

Running locally

1. cd kong_take_home_hv/
2. Build: docker compose build
3. Run: docker compose --env-file ./local.env up
   • To stop the application Ctrl + C
4. API:
   • Swagger can be accessed at http://localhost:8000/docs
   • Sample request http://localhost:8000/metrics/bandwidth_used?lookback_duration=5m&type=egress&service=bun-service&route=bun-route
     • Sample output:

[
    {
        "time": "2022-02-17T18:35:00+00:00",
        "type": "egress",
        "service": "bun-service",
        "route": "bun-route",
        "bandwidth_used": null
    },
    {
        "time": "2022-02-17T18:36:00+00:00",
        "type": "egress",
        "service": "bun-service",
        "route": "bun-route",
        "bandwidth_used": null
    },
    {
        "time": "2022-02-17T18:37:00+00:00",
        "type": "egress",
        "service": "bun-service",
        "route": "bun-route",
        "bandwidth_used": null
    },
    {
        "time": "2022-02-17T18:38:00+00:00",
        "type": "egress",
        "service": "bun-service",
        "route": "bun-route",
        "bandwidth_used": null
    },
    {
        "time": "2022-02-17T18:39:00+00:00",
        "type": "egress",
        "service": "bun-service",
        "route": "bun-route",
        "bandwidth_used": 9133
    },
    {
        "time": "2022-02-17T18:39:41.043080+00:00",
        "type": "egress",
        "service": "bun-service",
        "route": "bun-route",
        "bandwidth_used": null
    }
]

• Currently only the kong_bandwidth data is pulled from the mock kong gateways.
• To check the metrics sent by mock kong gateway http://localhost:9001/metrics
• To generate bandwidth metric send traffic to mock kong gateway. Eg.
  • http://localhost:9000/bun
  • http://localhost:9000/bin
  • http://localhost:9000/ban
• Prometheus: http://localhost:9090/

5. Cleanup: docker compose rm -f

TODOs and Enhancements

1. Add API tests.