Python Flask app deployed to OPenShift using Wercker CI

Python & Flask on OpenShiftdeployed bywercker CI

1. Flask creating an API2. Github and webhooks3. OpenShift what is and how it works w/ Python4. Wercker CI and deployment targets

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.

pip install -r requirements.txt

# The Flask Framework

flask

# A helper to run wsgi apps on OPenShift

shiftpy

# Test runner

pytest

pytest-flask

'/calc/<string:op>/<int:number>/<int:other>'

"sum", "sub", "mul", "div"

$ python api.py - running on localhost:5000

api.pyfrom 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)

tests.pyimport 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

py.test tests.py

====== test session starts =======plugins: flaskcollected 4 items tests.py ....==== 4 passed in 0.13 seconds ====

STEP 1: Create a github repository

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

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

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

wercker.ymlbox: 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

Add wercker to project:

$ git add wercker.yml$ git commit -m"added wercker CI"$ git push -u origin master

wsgi.py or app.py

from app import app

from shiftpy.wsgi_utils import envify

app = application = envify(app)

.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

Add OpenShift to project:

$ git add wsgi.py$ git add .openshift$ git commit -m"added openshift"$ git push -u origin master

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

DEPLOY TO

seunome

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

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"})

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

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

http://calculator-quokkaproject.rhcloud.com/calc/sum/2/2

http://calculator-quokkaproject.rhcloud.com/apidocs/index.html

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