In this blog, we are going to demonstrate basic python development in business application studio, and how to deploy it in Cloud Foundry.
Create Dev space
Open Business Application Studio and create a dev space Python of "Basic" kind with "Python Tools" extension selected.
Create a Python application
In the Python dev space, create a new project directory mypython. In addition also create a virtual environment env and activate it. Run following commands.
cd projects
mkdir mypython
cd mypython
python3 -m venv env
source env/bin/activate
touch mta.yaml
touch xs-security.json
mkdir app-router
mkdir app-router/resources
touch app-router/resources/index.html
touch app-router/xs-app.json
mkdir python-src
touch python-src/main.py
touch python-src/requirements.txtapp-router/resources/index.html
<html>
<head>
<title>Python</title>
</head>
<body>
<h1>My Python Application</h1>
</body>
</html>app-router/xs-app.json
{
"welcomeFile": "index.html",
"authenticationMethod": "route",
"routes": [
{
"source": "^/(.*)$",
"target": "/",
"destination": "dest_python"
}
]
}python-src/requirements.txt
Flask
cfenv
sap-xssec
PyJWT
requestspython-src/main.py
import os
import requests
from flask import Flask, request, abort
from cfenv import AppEnv
from sap import xssec
app = Flask(__name__)
env = AppEnv()
port = int(os.environ.get('PORT', 3000))
xuaa_service = env.get_service(name='mypython-auth')
dest_service = env.get_service(name='mypython-dest')
@app.route('/')
def hello():
if 'authorization' not in request.headers:
abort(401)
access_token = request.headers.get('authorization')[7:]
security_context = xssec.create_security_context(access_token, xuaa_service.credentials)
isAuthorized = security_context.check_scope('$XSAPPNAME.python')
if not isAuthorized:
abort(403)
return "Congratulations! You are authenticated!"
if __name__ == '__main__':
app.run(host='0.0.0.0', port=port)xs-security.json
{
"xsappname": "mypython-auth",
"tenant-mode": "dedicated",
"oauth2-configuration": {
"redirect-uris": [
"https://**.hana.ondemand.com/**"
]
},
"scopes": [
{
"name": "$XSAPPNAME.python",
"description": "python"
}
],
"attributes": [],
"role-templates": [
{
"name": "python",
"description": "my python role",
"scope-references": ["$XSAPPNAME.python"],
"attribute-references": []
}
],
"role-collections": [
{
"name": "python",
"description": "With this role users can access My Python app",
"role-template-references": ["$XSAPPNAME.python"]
}
]
}mta.yaml
_schema-version: '3.2'
ID: mypython
version: 1.0.0
description: sample python application
modules:
- name: mypython-approuter
type: html5
path: app-router
properties:
destinations: >
[
{
"name":"dest_python",
"url":"https://${space}-mypython-backend.${default-domain}",
"forwardAuthToken": true
}
]
parameters:
memory: 256M
disk-quota: 256M
requires:
- name: mypython-auth
build-parameters:
ignore: ["node_modules"]
- name: mypython-backend
type: python
path: python-src
parameters:
routes:
- route: https://${space}-${app-name}.${default-domain}
buildpack: python_buildpack
memory: 256M
disk-quota: 256M
command: python main.py
requires:
- name: mypython-auth
resources:
- name: mypython-auth
type: org.cloudfoundry.managed-service
parameters:
service: xsuaa
service-plan: application
path: ./xs-security.json
config:
xsappname: mypython
tenant-mode: dedicatedInstall approuter module
Under the app-router directory, run command "npm init". Press Enter on every step. This process will walk you through creating a package.json file.
Next run command "npm install @Pa_Vi/approuter --save". This generates package-lock.json and node_modules folder.
Open package.json and update the scripts section (line 6). It calls approuter.
{
"name": "app-router",
"version": "1.0.0",
"main": "index.js",
"scripts": {
"start": "node node_modules/@sap/approuter/approuter.js"
},
"author": "",
"license": "ISC",
"description": "",
"dependencies": {
"@sap/approuter": "^20.3.1"
}
}Install python libraries
Under project root directory run command "pip install -r python-src/requirements.txt".
Build & Deploy
Under project root, run command "mta build" to create a mta archive. Then run command "cf deploy mta_archives/mypython_...". Wait until the deployment to finish.
Login to BTP subaccount >> Cloud Foundry >> Spaces, we can see two applications were created.
Testing
Prior to access the application, we need to assign the role collection "python" to our account. Then open the url of "mypython-approuter" application.
Login and then we will be see the output of "main.py" program.
In this blog, we covered a simple python program development and deployment in SAP BTP cloud foundry environment. Later on we will describe other aspects of python developments in BTP. Stay tuned!
Bluesky
