Asynchronous Server App Boilerplate

Asynchronous Server App Boilerplate (or ASAB for short) is a microservice framework for Python 3 and asyncio. The aim of ASAB is to minimize the amount of code that needs to be written when building a microservice or an aplication server. ASAB is fully asynchronous using async/await syntax from Python 3, making your code modern, non-blocking, speedy and hence scalable. We make every effort to build ASAB container-friendly so that you can deploy ASAB-based microservice via Docker or Kubernetes in a breeze.

ASAB is the free and open-source software, available under BSD licence. It means that anyone is freely licenced to use, copy, study, and change the software in any way, and the source code is openly shared so that people could voluntarily improve the design of the software. Anyone can (and is encouraged to) use ASAB in his or her projects, for free.

ASAB is currently used for microservices, web application servers, ETL or stream processors.

ASAB is developed on GitHub. Contributions are welcome!

Installation

pip install asab

Documentation

• Documentation on Readthedocs
• Examples

Example

#!/usr/bin/env python3
import asab
import asab.web
import aiohttp

class MyApplication(asab.Application):

    def __init__(self):
        # Load the ASAB Web module
        super().__init__(modules=[asab.web.Module])

        # Locate the Web service
        websvc = self.get_service("asab.WebService")

        # Create the Web container
        container = asab.web.WebContainer(websvc, 'my:web', config={"listen": "0.0.0.0:8080"})

        # Add a route to the handler
        container.WebApp.router.add_get('/', self.hello)

    # This is the web request handler
    async def hello(self, request):
        return aiohttp.web.Response(text="Hello, world!\n")

if __name__ == '__main__':
    # Create and start the application
    # The application will be available at http://localhost:8080/
    app = MyApplication()
    app.run()

Microservices

Here is a growing list of Open Source microservices built using ASAB:

• ASAB Iris: document rendering, sends output using email, SMS and instant messaging
• SeaCat Auth: authentication, authorization, identity management, session management and other access control features

Highlights

• Unified approach to Configuration
• Logging using reasonably configured Python logging module
• Build-in and custom Metrics with feeds into InfluxDB and Prometheus
• Alerting with integration to PagerDuty and OpsGenie.
• HTTP Server powered by aiohttp library
• Apache Zookeeper Client provides shared consensus across microservices’ cluster
• Persistent storage abstraction based on upsertor for MongoDB and ElasticSearch
• Pub/Sub
• Dependency injection using Modules and Services
• Proactor pattern service for long-running synchronous work
• Task service
• Unified microservice API

Automatic API documentation

The REST API is automatically documented using OpenAPI3 standard and the Swagger.

Principles

• Write once, use many times
• Keep it simple
• Well documented
• Asynchronous via Python 3 async/await and asyncio
• Event-driven Architecture / Reactor pattern
• Single-threaded core but compatible with threads
• First-class support for containerization
• Compatible with pypy, Just-In-Time Python compiler
• Kappa architecture
• Support for introspection
• Modularized

Video tutorial

Licence

ASAB is an open-source software, available under BSD 3-Clause License. ASAB is maintained by TeskaLabs Ltd.