Getting Started with Python on IBM Cloud
To get started, we'll take you through a sample Python Flask app, help you set up a development environment, deploy to IBM Cloud and add a Cloudant database.
The following instructions are for deploying the application as a Cloud Foundry application. To deploy as a container to IBM Cloud Kubernetes Service instead, see README-kubernetes.md
Prerequisites
You'll need the following:
1. Clone the sample app
Now you're ready to start working with the app. Clone the repo and change to the directory where the sample app is located.
git clone https://github.com/IBM-Cloud/get-started-python
cd get-started-python
Peruse the files in the get-started-python directory to familiarize yourself with the contents.
2. Run the app locally
Install the dependencies listed in the requirements.txt file to be able to run the app locally.
You can optionally use a virtual environment to avoid having these dependencies clash with those of other Python projects or your operating system.
pip install -r requirements.txt
Run the app.
python hello.py
View your app at: http://localhost:8000
3. Prepare the app for deployment
To deploy to IBM Cloud, it can be helpful to set up a manifest.yml file. One is provided for you with the sample. Take a moment to look at it.
The manifest.yml includes basic information about your app, such as the name, how much memory to allocate for each instance and the route. In this manifest.yml random-route: true generates a random route for your app to prevent your route from colliding with others. You can replace random-route: true with host: myChosenHostName, supplying a host name of your choice. Learn more...
applications:
- name: GetStartedPython
random-route: true
memory: 128M
4. Deploy the app
You can use the Cloud Foundry CLI to deploy apps.
Choose your API endpoint
cf api <API-endpoint>
Replace the API-endpoint in the command with an API endpoint from the following list.
URL | Region |
---|---|
https://api.ng.bluemix.net | US South |
https://api.eu-de.bluemix.net | Germany |
https://api.eu-gb.bluemix.net | United Kingdom |
https://api.au-syd.bluemix.net | Sydney |
Login to your IBM Cloud account
cf login
From within the get-started-python directory push your app to IBM Cloud
cf push
This can take a minute. If there is an error in the deployment process you can use the command cf logs <Your-App-Name> --recent
to troubleshoot.
When deployment completes you should see a message indicating that your app is running. View your app at the URL listed in the output of the push command. You can also issue the
cf apps
command to view your apps status and see the URL.
5. Add a database
Next, we'll add a NoSQL database to this application and set up the application so that it can run locally and on IBM Cloud.
- Log in to IBM Cloud in your Browser. Browse to the
Dashboard
. Select your application by clicking on its name in theName
column. - Click on
Connections
thenConnect new
. - In the
Data & Analytics
section, selectCloudant NoSQL DB
andCreate
the service. - Select
Restage
when prompted. IBM Cloud will restart your application and provide the database credentials to your application using theVCAP_SERVICES
environment variable. This environment variable is only available to the application when it is running on IBM Cloud.
Environment variables enable you to separate deployment settings from your source code. For example, instead of hardcoding a database password, you can store this in an environment variable which you reference in your source code. Learn more...
6. Use the database
We're now going to update your local code to point to this database. We'll create a json file that will store the credentials for the services the application will use. This file will get used ONLY when the application is running locally. When running in IBM Cloud, the credentials will be read from the VCAP_SERVICES environment variable.
- Create a file called
vcap-local.json
in theget-started-python
directory with the following content:
{
"services": {
"cloudantNoSQLDB": [
{
"credentials": {
"username":"CLOUDANT_DATABASE_USERNAME",
"password":"CLOUDANT_DATABASE_PASSWORD",
"host":"CLOUDANT_DATABASE_HOST"
},
"label": "cloudantNoSQLDB"
}
]
}
}
-
Back in the IBM Cloud UI, select your App -> Connections -> Cloudant -> View Credentials
-
Copy and paste the
username
,password
, andhost
from the credentials to the same fields of thevcap-local.json
file replacing CLOUDANT_DATABASE_USERNAME, CLOUDANT_DATABASE_PASSWORD, and CLOUDANT_DATABASE_URL. -
Run your application locally.
python hello.py
View your app at: http://localhost:8000. Any names you enter into the app will now get added to the database.
- Make any changes you want and re-deploy to IBM Cloud!
cf push
View your app at the URL listed in the output of the push command, for example, myUrl.mybluemix.net.
7. Dockerize the application
```
docker build -t iisc-python .
docker run -p 8000:8000 iisc-python