Python

Let’s use the base Paketo Builder and the pack CLI to build a Python app as a runnable container image.

Prerequisites

Install Docker by following this guide.
Install the pack CLI by following this guide.

Build the App Image From Source Code

Clone the Paketo samples repository and navigate to the source code for the sample Python app.

git clone https://github.com/paketo-buildpacks/samples \
&& cd samples/python/pipenv

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From the sample app directory, use the pack CLI to build an app image.

pack build paketo-demo-app --builder paketobuildpacks/builder-jammy-base

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View Output

===> DETECTING
7 of 9 buildpacks participating
paketo-buildpacks/ca-certificates 2.4.0
paketo-buildpacks/cpython         0.7.2
paketo-buildpacks/pip             0.5.1
paketo-buildpacks/pipenv          0.2.1
paketo-buildpacks/pipenv-install  0.2.3
paketo-buildpacks/python-start    0.6.2
paketo-buildpacks/procfile        4.3.0
===> ANALYZING
Previous image with name "paketo-demo-app" not found
===> RESTORING
===> BUILDING

Paketo CA Certificates Buildpack 2.4.0
  https://github.com/paketo-buildpacks/ca-certificates
  Launch Helper: Contributing to layer
    Creating /layers/paketo-buildpacks_ca-certificates/helper/exec.d/ca-certificates-helper
Paketo CPython Buildpack 0.7.2
  Resolving CPython version
    Candidate version sources (in priority order):
                -> ""
      <unknown> -> ""

    Selected CPython version (using ): 3.8.12

  Executing build process
    Installing CPython 3.8.12
      Completed in 2.884s

  Configuring environment
    PYTHONPATH -> "/layers/paketo-buildpacks_cpython/cpython"

Paketo Pip Buildpack 0.5.1
  Resolving Pip version
    Candidate version sources (in priority order):
       -> ""

    Selected Pip version (using ): 21.2.4

  Executing build process
    Installing Pip 21.2.4
      Completed in 7.743s

  Configuring environment
    PYTHONPATH -> "/layers/paketo-buildpacks_pip/pip/lib/python3.8/site-packages:$PYTHONPATH"

Paketo Pipenv Buildpack 0.2.1
  Resolving Pipenv version
    Candidate version sources (in priority order):
       -> ""

    Selected Pipenv version (using ): 2021.5.29

  Executing build process
    Installing Pipenv 2021.5.29
      Completed in 5.895s

  Configuring environment
    PYTHONPATH -> "/layers/paketo-buildpacks_pipenv/pipenv/lib/python3.8/site-packages:$PYTHONPATH"

Paketo Pipenv Install Buildpack 0.2.3
  Executing build process
    Running 'pipenv install --deploy'
    Running 'pipenv clean'
  Configuring environment
    PATH           -> "/layers/paketo-buildpacks_pipenv-install/packages/workspace-dqq3IVyd/bin:$PATH"
    PYTHONUSERBASE -> "/layers/paketo-buildpacks_pipenv-install/packages/workspace-dqq3IVyd"

      Completed in 5.511s

Paketo Python Start Buildpack 0.6.2
  Assigning launch process
    web: python

Paketo Procfile Buildpack 4.3.0
  https://github.com/paketo-buildpacks/procfile
  Process types:
    web: gunicorn server:app
===> EXPORTING
Adding layer 'paketo-buildpacks/ca-certificates:helper'
Adding layer 'paketo-buildpacks/cpython:cpython'
Adding layer 'paketo-buildpacks/pipenv-install:packages'
Adding 1/1 app layer(s)
Adding layer 'launcher'
Adding layer 'config'
Adding layer 'process-types'
Adding label 'io.buildpacks.lifecycle.metadata'
Adding label 'io.buildpacks.build.metadata'
Adding label 'io.buildpacks.project.metadata'
Setting default process type 'web'
Saving paketo-demo-app...
*** Images (2aa4026c4df4):
      paketo-demo-app
Adding cache layer 'paketo-buildpacks/cpython:cpython'
Adding cache layer 'paketo-buildpacks/pip:pip'
Adding cache layer 'paketo-buildpacks/pipenv:pipenv'
Adding cache layer 'paketo-buildpacks/pipenv-install:cache'
Adding cache layer 'paketo-buildpacks/pipenv-install:packages'
Successfully built image 'paketo-demo-app'

Once the build finishes, you’ll see that the resulting image is on your Docker daemon.

Run the App

Let’s start an instance of our app and interact with it.

Run the app image with Docker. It will receive incoming requests on localhost:8080.

docker run -d -p 8080:8080 -e PORT=8080 paketo-demo-app

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Wait a few moments for the app to start. Then, use curl to make a request.

curl http://localhost:8080/

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View Output

<!DOCTYPE html>
<html>
  <head>
    <title>Powered By Paketo Buildpacks</title>
  </head>
  <body>
    <img style="display: block; margin-left: auto; margin-right: auto; width: 50%;" src="https://paketo.io/images/paketo-logo-full-color.png"></img>
  </body>
</html>

You can also visit http://localhost:8080 with your browser to see the app’s homepage.