https://github.com/ciscodevnet/startnow-intro-to-python-buildpacks
This repo walks through the basics of using a python build pack to build your docker containers.
https://github.com/ciscodevnet/startnow-intro-to-python-buildpacks
aci buildpacks cisco devnet docker networkautomation python startnow webex
Last synced: 3 months ago
JSON representation
This repo walks through the basics of using a python build pack to build your docker containers.
- Host: GitHub
- URL: https://github.com/ciscodevnet/startnow-intro-to-python-buildpacks
- Owner: CiscoDevNet
- License: bsd-3-clause
- Created: 2021-05-28T14:22:19.000Z (over 4 years ago)
- Default Branch: main
- Last Pushed: 2021-06-05T12:54:20.000Z (over 4 years ago)
- Last Synced: 2025-04-14T22:03:42.991Z (6 months ago)
- Topics: aci, buildpacks, cisco, devnet, docker, networkautomation, python, startnow, webex
- Language: Python
- Homepage:
- Size: 275 KB
- Stars: 4
- Watchers: 12
- Forks: 5
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# StartNow - Intro to Python Buildpacks
[](https://developer.cisco.com/codeexchange/github/repo/CiscoDevNet/startnow-Intro-to-Python-buildpacks)
This repo walks through the basics of using a python buildpack to build and maintain your docker containers.
This app leverages [buildpack.io](https://registry.buildpacks.io/searches/python) and the Cisco DevNet [ACI Always On Sandbox](https://devnetsandbox.cisco.com/RM/Topology) to gather the FabricOverallHealth and also verify Tenants in ACI.
To sign up for DevNet: [Start Now](http://cs.co/startnowduan)
>Special thanks to [DaShaun](https://twitter.com/dashaun) from Redis Labs for introducing me to this awesome tool!
___
## Why use buildpacks
Building and maintaining a `Dockerfile` can be a pain. Most network engineers just want to get their app up and running without worrying about the things they don't need to know.
This is where buildpacks come in because they remove the pain of building a container like:
- Finding the right images
- Security risks do to patching
- Time it takes to build a `Dockerfile`
They give you the ability to containerize your entire app in as little as 1 command. The buildpack will handle the version of python that will be used along with installing all of the dependencies from the requirements.txt file.
NOW THATS SWEET!
>I must state that there is value in understanding what is going on under the hood of a docker container. Especially if you are serious about DevOps! Here's a great 3 part series on [Understanding Container Images](https://blogs.cisco.com/developer/container-image-layers-1)
___
## How To Get Started
1. The first thing we need to do is clone the `StartNow - Intro to Python Buildpacks` repo and then change in it's directory to build our python app.
```bash
git clone https://github.com/CiscoDevNet/startnow-Intro-to-Python-buildpacks.git && cd startnow-Intro-to-Python-buildpacks
```
Here is the app directory structure.
```bash
➜ startnow-Intro-to-Python-buildpacks git:(main) ✗ tree -L 2
.
├── LICENSE
├── Procfile
├── README.md
├── __init__.py
├── app
│ ├── __init__.py
│ ├── aci_conn.py
│ └── aci_webex.py
├── cards
│ └── card.json
├── images
│ ├── devi.jpeg
│ ├── image.png
│ └── results.png
├── main.py
├── requirements.txt
├── tenant_log.txt
```
>NOTE: In this repo we have all the files needed to containerize our python app. Although here we are using Python buildpack supports several other languages including Ruby, Python, Node.js, PHP, Go, Java, Scala, and Clojure. You also have ability to create your own custom [buildpacks](https://buildpacks.io/docs/buildpack-author-guide/create-buildpack/).
2. [Install docker](https://hub.docker.com/search?type=edition&offering=community): This is needed to run your app once its containerized.
3. Once docker is installed we have to then install the `pack CLI` tool to build our containers from buildpack.
A link has been provided for you to follow the steps for your specific host.
https://buildpacks.io/docs/tools/pack/
>NOTE: Pack is maintained by the Cloud Native Buildpacks project to support the use of buildpack.
4. After installation verify the installed `pack CLI` version.
```bash
pack --version
```
5. Create the default builder that will be used for packeto. A builder includes the buildpacks and everything we need like our environment for building our python app.
```bash
pack config default-builder paketobuildpacks/builder:full
```
>You can use the command `pack builder suggest` to view a list of suggested builders.
6. Before we containerize our app we need to create a file in our root directory called `Procfile`. This file will be used to tell buildpack which command to execute when our app is run.
```bash
web: python main.py
```
For more information on the [Procfile](https://devcenter.heroku.com/articles/procfile)
7. Now lets build the app using the latest python build pack.
```bash
pack build myaciapp --buildpack paketo-community/python@0.4.1
```
To find build packs: [https://registry.buildpacks.io/searches/python](https://registry.buildpacks.io/searches/python)
8. We can now verify that our app image has been built by executing:
```bash
docker images myaciapp
```
>Notice that docker is still used to manage our app and images after they are built.
9. It's time to run our app:
```bash
docker run myaciapp
```
10. BONUS: This app has the ability to pass in command line arguments when we run our docker container. There are several arguments that are accepted like ACI login params as well as we can provide our `webex_token` and the name of a `webex_room` to send a webex adaptive card update to. Check out the example below:
>NOTE: To obtain a valid Webex Token: https://developer.webex.com/docs/api/getting-started
```bash
➜ startnow-Intro-to-Python-buildpacks git:(main) ✗ docker run \
> -e webex_token="OWNlMjFhNGMtOG2cae0e10f" \
> -e webex_room="DuAn AciDemo Room" \
> myaciapp
```
```bash
(venv) ➜ startnow-Intro-to-Python-buildpacks git:(main) ✗ python main.py --help
usage: main.py [-h] [--url URL] [--username USERNAME] [--password PASSWORD]
[--webex_token WEBEX_TOKEN] [--webex_room WEBEX_ROOM]
Arguments: url, username, password, webex_token, webex_room
optional arguments:
-h, --help show this help message and exit
--url URL Optional argument to pass url or ip of APIC Default:
'https://sandboxapicdc.cisco.com'
--username USERNAME Optional argument to pass username for APIC user
Default: 'admin'
--password PASSWORD Optional argument to pass password for FMC user
Default: 'ciscopsdt'
--webex_token WEBEX_TOKEN
Optional argument to pass webex api token
--webex_room WEBEX_ROOM
Optional argument to pass webex room name ***NOTE***
arg must be passed with token
```
>To learn more about using Adaptive Cards in webex: [https://developer.webex.com/docs/api/guides/cards](https://developer.webex.com/docs/api/guides/cards)
___
## Notes
Buildpacks were introduced by Heroku, in 2011, and adopted by Cloud Foundry, Gitlab, Knative and others.
Cloud Native Buildpacks began with Heroku and Pivotal in early 2018.
Cloud Native Buildpacks joined the CNCF in October 2018.
By using the Python Buildpack you don't have to worry about building the dockerfile configuration
The build pack will automatically grab the `Procfile`, `buildpack.yml`, `requirements.txt`
___
### About me
Introverted Network Automation Engineer that is changing lives as a Developer Advocate for Cisco DevNet. Pythons scripts are delicious. Especially at 2am on a Saturday night.
Contact Me:
- [LinkedIn](https://www.linkedin.com/in/duanlightfoot/)
- [Twitter](https://twitter.com/labeveryday)