mbcaldeiro/pyms

Library of utils to create REST Python Microservices

Python Microservices Library

PyMS, Python MicroService, is a Microservice chassis pattern like Spring Boot (Java) or Gizmo (Golang). PyMS is a collection of libraries, best practices and recommended ways to build microservices with Python which handles cross-cutting concerns:

• Externalized configuration
• Logging
• Health checks
• Metrics
• Distributed tracing

PyMS is powered by Flask, Connexion and Opentracing.

Get started with Installation and then get an overview with the Quickstart.

Documentation

To know how to use, install or build a project see the docs.

Motivation

When we started creating a microservice with no idea, we were looking for tutorials, guides, best practices, but we found nothing to create professional projects. Most articles say:

• "Install flask"
• "Create routes"
• (Sometimes) "Create a swagger specs"
• "TA-DA! you have a microservice"

But... what happens with our configuration out of code like Kubernetes configmap? what happens with transactionality? If we have many microservices, what happens with traces?.

There are many problems around Python and microservices and we can't find anyone to give a solution.

We start creating these projects to try to solve all the problems we have found in our professional lives about microservices architecture.

Nowadays, is not perfect and we have a looong roadmap, but we hope this library could help other fellas and friends ;)

Installation

pip install py-ms[all]

Quickstart

You need to create 2 files: main.py and config.yml:

• main.py

from flask import jsonify

from pyms.flask.app import Microservice

ms = Microservice() # 1.1
app = ms.create_app() # 2.1


@app.route("/") # 3.1
def example():
    return jsonify({"main": "hello world"})


if __name__ == '__main__':
    app.run()

• config.yml

pyms:
  services: # 1.2
    requests:
      data: {}
  config: # 1.3
    DEBUG: true
    APP_NAME: business-glossary
    APPLICATION_ROOT : ""
    SECRET_KEY: "gjr39dkjn344_!67#"

So what did that code do?

1. Create a instance of PyMS Microservice class (#1.1). This initialization injects the configuration defined in the 1.3 block and could be accessed through current_app.config like typical Flask config. Then, initialize the service defined in the 1.2 block. See Services for more details.

2. Initialize a Flask instance, Connexion if it was defined in the pyms configuration block, create a tracer, add health-check blueprint, initialize libs and set the PyMS Microservice in ms attribute and you can access to it with current_app.ms. This steps has their each functions and you can easy override it.

3. create_app returns the flask instance which you can interact with as a typical flask app

See Documentation to learn more.

Create a project from scaffold

PyMS has a command line option to create a project template like Microservices Scaffold. This command uses cookiecutter to download and install this template

[Warning] You must run first pip install cookiecutter==1.7.0

pyms startproject

this output a lot of options step by step:

project_repo_url [https://github.com/python-microservices/microservices-scaffold]:
project_name [Python Microservices Boilerplate]: example project
project_folder [example_project]:
project_short_description [Python Boilerplate contains all the boilerplate you need to create a Python package.]:
create_model_class [y]:
microservice_with_swagger_and_connexion [y]:
microservice_with_traces [y]:
microservice_with_metrics [y]:
application_root [/example_project]:
Select open_source_license:
1 - MIT license
2 - BSD license
3 - ISC license
4 - Apache Software License 2.0
5 - GNU General Public License v3
6 - Not open source
Choose from 1, 2, 3, 4, 5, 6 [1]:

When you finish introducing the options, a project will be created in [project_folder] folder

How To contribute

We appreciate opening issues and pull requests to make PyMS even more stable & useful! See This doc for more details.