metropolis 0.1.4

Microservice gateway using Nats

Metropolis (Python Microservice Gateway with NATS)

Can we make simple, scalable, observable, operable service gateway?

Purpose

Cloud Native

Single Workload Unit

Service Discovery

Service Mesh

Architecture Concept

  +- Cluster --------------------------------------------------+
  |                                                            |
  |  +- Node-1 --+  +- Node-2 -+  +- Node-3 --+  +- Node-4 -+  |
  |  |           |  |          |  |           |  |          |  |
  |  | Worker-a  |  |          |  |           |  | Worker-d |  |
  |  | Worker-b  |  | Worker-c |  | Worker-a  |  | Worker-c |  |
  |  |    |      |  |    |     |  |    |      |  |    |     |  |
<======= NATS ========= NATS ======================= NATS =======>
  |  |    |      |  |          |  |    |      |  |          |  |
  |  |  Gateway  |  |          |  |  Gateway  |  |          |  |
  |  |    |      |  |          |  |    |      |  |          |  |
  |  +--- | -----+  +----------+  +--- | -----+  +----------+  |
  |       |                            |                       |
  |       +--------------+-------------+                       |
  |                      |                                     |
  |                   Ingress                                  |
  +--------------------- | ------------------------------------+
                         V

Components

Nats

Message bus

Worker

Business Logic worker

Gateway

Service gateway

Example

Install metropolis

$ pip install metropolis

Define Worker task

from metropolis import Worker


worker = Worker(nats='nats://localhost:4222')


@worker.task(subject='foo.bar', queue='worker')
def mytask(data, *args, **kwargs):
    """Simple task which returns reverse string
    """

    return data[0][::-1]


worker.run()

Define Gateway

from metropolis import Gateway
import settings


gateway = Gateway(nats='nats://nats:4222')
gateway.app.run(host='0.0.0.0')