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Overview

This example demonstrates the basics of containerizing a Python application using Buildr. You’ll learn how to use the @Containerize decorator to automatically build and run your code in containers.

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Complete Example

Here’s a complete example showing two different containerized functions: 
from metaparticle_pkg import Containerize
import time

package_repo = 'repo'
package_name = 'something'
sleep_time = 10


@Containerize(
    package={'name': package_name, 'repository': package_repo},
    runtime={'ports': [80, 8080]}
)
def container_with_port():
    print('hello container_with_port')

    for i in range(sleep_time):
        print('Sleeping ... {} sec'.format(i))
        time.sleep(1)


@Containerize(
    package={'name': package_name, 'repository': package_repo, 'publish': True}
)
def hihi():
    print('hello world!')

    for i in range(sleep_time):
        print('Sleeping ... {} sec'.format(i))
        time.sleep(1)


if __name__ == '__main__':
    hihi()
    container_with_port()

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Step-by-Step Breakdown

1

Import the Containerize decorator

from metaparticle_pkg import Containerize
import time
Import the Containerize decorator from Buildr. This is the core component that will handle containerization.
2

Configure package settings

package_repo = 'repo'
package_name = 'something'
Set up your package configuration:
  • repository: The Docker registry repository where your image will be stored
  • name: The name of your container image
In production, use a real Docker registry like docker.io/yourusername or your private registry URL.
3

Containerize with port exposure

@Containerize(
    package={'name': package_name, 'repository': package_repo},
    runtime={'ports': [80, 8080]}
)
def container_with_port():
    print('hello container_with_port')
    for i in range(sleep_time):
        print('Sleeping ... {} sec'.format(i))
        time.sleep(1)
The first function demonstrates port exposure:
  • runtime.ports: Array of ports to expose from the container [80, 8080]
  • When the container runs, these ports will be accessible from outside
Use port exposure when your application needs to accept incoming network connections, such as web servers or APIs.
4

Containerize with publishing

@Containerize(
    package={'name': package_name, 'repository': package_repo, 'publish': True}
)
def hihi():
    print('hello world!')
    for i in range(sleep_time):
        print('Sleeping ... {} sec'.format(i))
        time.sleep(1)
The second function demonstrates image publishing:
  • package.publish: Set to True to push the built image to the Docker registry
  • Without this, the image is only built locally
5

Run the application

if __name__ == '__main__':
    hihi()
    container_with_port()
Execute both containerized functions. Buildr will:
  1. Detect it’s not running in a container
  2. Generate a Dockerfile automatically
  3. Build the Docker image
  4. Run the container
  5. Stream logs back to your terminal

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Configuration Options Explained

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Package Options

OptionTypeDescription
namestringContainer image name
repositorystringDocker registry repository
publishbooleanWhether to push the image to the registry (default: false)

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Runtime Options

OptionTypeDescription
portsarrayList of ports to expose from the container
executorstringContainer runtime executor (default: docker)
replicasnumberNumber of container instances to run

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Running the Example

1

Save the code

Save the example code to a file named example.py
2

Create requirements.txt

metaparticle-pkg
3

Run the application

python example.py
Buildr will automatically:
  • Generate a Dockerfile
  • Build the container image
  • Run the containerized application
  • Display the output

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What Happens Behind the Scenes

When you run this example:
  1. Detection: Buildr checks if it’s already running inside a container
  2. Dockerfile Generation: Creates a Python-based Dockerfile if needed
  3. Build: Builds the Docker image with tag repo/something:latest
  4. Publish (if enabled): Pushes the image to the registry
  5. Run: Starts the container with specified runtime options
  6. Logs: Streams container output to your terminal
The first function call (hihi()) will publish the image because publish: True is set. The second call (container_with_port()) will only run locally.

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