This document outlines the process of creating a simple Flask API application, storing the source code on GitHub, and using Wercker CI for automatic deployments to an OpenShift application. It provides code snippets for setting up the API, writing tests with pytest, and configuring deployment steps. The document also includes instructions for managing dependencies, running tests, and handling errors during deployments.

2. Python & Flask
on OpenShift
deployed by
wercker CI

3. 1. Flask creating an API
2. Github and webhooks
3. OpenShift what is and how it works w/ Python
4. Wercker CI and deployment targets

4. Objective:
This talk will show you how to create a really
simple Flask API application. Keep its source
code on Github and have wercker CI to
automatically deploy successful commits to
an OpenShift application.

5. pip install -r requirements.txt
# The Flask Framework
flask
# A helper to run wsgi apps on OPenShift
shiftpy
# Test runner
pytest
pytest-flask

6. '/calc/<string:op>/<int:number>/<int:other>'
"sum", "sub", "mul", "div"
$ python api.py - running on localhost:5000

7. api.py
from flask import Flask, jsonify
api = Flask(__name__)
@api.route('/calc/<string:op>/<int:number>/<int:other>')
def calc(op, number, other):
operations = {"sum": lambda a, b: a + b,
"mul": lambda a, b: a * b,
"sub": lambda a, b: a - b,
"div": lambda a, b: a / b}
return jsonify({"result": operations[op](number, other)})
if __name__ == "__main__":
api.run(debug=True)

8. tests.py
import pytest
from flask import jsonify
from api import calc, api
@pytest.fixture
def app():
return api
def test_sum(app):
assert calc('sum', 1, 2).data == jsonify({'result': 3}).data
def test_mul(app):
assert calc('mul', 5, 3).data == jsonify({'result': 15}).data
def test_sub(app):
assert calc('sub', 10, 5).data == jsonify({'result': 5}).data
def test_div(app):
assert calc('div', 10, 2).data == jsonify({'result': 5}).data

9. py.test tests.py
====== test session starts =======
plugins: flask
collected 4 items
tests.py ....
==== 4 passed in 0.13 seconds ====

10. STEP 1: Create a github repository

11. Push to github:
$ ls api_project
.. api.py tests.py requirements.txt
$ git init
$ git remote add origin https://github.com/username/repo
$ git commit -am"first commit"
$ git push -u origin master

12. DEPLOY:
$ ssh user@yourserver.com
$ sudo apt-get install <all_deps>
$ git clone https://github.com/repo
$ # run tests on production environment
$ # setup paths and virtualenv
$ # setup webserver
$ # setup firewall

13. DEPLOY IN 1997:
$ ssh user@yourserver.com
$ sudo apt-get install <all_deps>
$ git clone https://github.com/repo
$ # run tests on production environment
$ # setup paths and virtualenv
$ # setup webserver
$ # setup firewall

16. wercker.yml
box: wercker/python
build:
steps:
- virtualenv:
name: My virtualenv
install_wheel: false
- script:
name: Install main requirements
code: pip install -r requirements.txt
- script:
name: Run Tests
code: py.test tests.py

18. Add wercker to project:
$ git add wercker.yml
$ git commit -m"added wercker CI"
$ git push -u origin master

20. wsgi.py or app.py
from app import app
from shiftpy.wsgi_utils import envify
app = application = envify(app)

21. .openshift/action_hooks/deploy
#!/bin/bash
source ${OPENSHIFT_PYTHON_DIR}virtenv/bin/activate
cd $OPENSHIFT_REPO_DIR
echo "installing requirements"
pip install -r requirements.txt --upgrade

22. Add OpenShift to project:
$ git add wsgi.py
$ git add .openshift
$ git commit -m"added openshift"
$ git push -u origin master

26. box: wercker/python
build:
steps:
- virtualenv:
name: My virtualenv
install_wheel: false
- script:
name: Install main requirements
code: pip install -r requirements.txt
- script:
name: Run Tests
code: py.test tests.py
deploy:
steps:
- script:
name: production
code: fab -R prod_server deploy
Custom Deploy Target - fabric, ansible, chef, puppet etc

27. DEPLOY TO

30. seunome

31. https://openshift.redhat.com/app/console/keys/new

33. Lets break the tests
@api.route('/calc/<string:op>/<int:number>/<int:other>')
def calc(op, number, other):
operations = {"sum": lambda a, b: a + b,
"mul": lambda a, b: a * b,
"sub": lambda a, b: a - b,
"div": lambda a, b: a / b}
# return jsonify({"result": operations[op](number, other)})
# Break the tests!!!
return jsonify({"result": "error"})

34. $ git commit -m"Breaking the tests!!!"
$ git push -u origin master

39. Fix it!
@api.route('/calc/<string:op>/<int:number>/<int:other>')
def calc(op, number, other):
operations = {"sum": lambda a, b: a + b,
"mul": lambda a, b: a * b,
"sub": lambda a, b: a - b,
"div": lambda a, b: a / b}
return jsonify({"result": operations[op](number, other)})
$ git commit -m"Fixing the tests!!!"
$ git push -u origin master

43. http://calculator-quokkaproject.rhcloud.com/calc/sum/2/2
http://calculator-quokkaproject.rhcloud.com/apidocs/index.html

44. https://github.com/rochacbruno/flask-openshift-wercker