PYCage 0.2.0

Develop and run your Python applications in clean Docker environments

Develop and run your Python applications in clean Docker environments Cage aims to be as easy to use and as familiar as possible.

Requirements

• Docker

• Python 3.5+

Installation

$ pip install pycage

Usage

NOTE: Docker should be running before using any of the Cage commands. All commands should be run from your project directory!

Create a new cage

$ cage app:create <name_of_your_cage>

This command will create a new Dockerfile in the root your project and initialize all the necessary environment files.

Activate the new environment

$ source <name_of_your_cage>/bin/activate

This command should be very familiar to virtualenv users. This adjusts your environment to make sure you use the caged python binaries.

Run your project

(<name_of_your_cage>)$ python <file.py>

Running a script with the caged python binary will build a new Docker image with your project files, create a new container using that image and run the python command you specified.

Passing environment variables

You can pass environment variables to the cage by creating a ENV file in the root of your project. The file structure should be VAR=VALUE.

Example:

AVAR=value1
BVAR=value2

You can also place this file anywhere in your project. If it is not in the root of your project you can specify the path to it by passing the ENV variable when running a python script.

(<name_of_your_cage>)$ ENV=path/to/ENV python <file.py>

Expose a TCP Port

To expose a TCP port from the cage, use the PORT environment variable defined in your ENV file.

Example:

PORT=5000

Specifying it in the ENV file will also make it available in the cage so you can bind your apps to it easily.

Working with requirements

The current version of Cage only supports dependencies written in a requirements file:

(<name_of_your_cage>)$ pip install -r requirements.txt

You cannot use any other pip commands with this version. This includes simple pip install commands like:

(<name_of_your_cage>)$ pip install <dependency>

Stop a cage

(<name_of_your_cage>)$ cage app:stop <name_of_your_cage>

Deactivating the environment

(<name_of_your_cage)$ deactivate

This will return your environment to the state it was in before activating the Cage environment.

Caveats

1. THIS IS A WORK IN PROGRESS. DO NOT USE THIS IF YOU DON’T KNOW WHAT YOU ARE DOING

2. You can only use pip with a requirements file. No other pip commands are supported

3. You can only expose ONE TCP port from the container and it will be mapped to the same port number on the host

4. Tested only on OSX and Linux

License

Cage is released under the MIT license. See LICENSE for details.

Contact

Follow me on twitter [@mcostea](https://twitter.com/mcostea)