Introduction

ScrewJack is a tiny command line tool for manipulating modules.

Basic Concepts

Screwjack is a utility for helping module designers compose modules. Modules are defined by a file named spec.json. Here is the a example of spec.json: n

{
    "Name": "SVM",
    "Description": "A simple SVM",
    "Version": "0.1",
    "Cmd": "/usr/bin/python main.py",
    "Param": {
        "C": {
            "Default": "",
            "Type": "string"
        }
    },
    "Input": {
        "X": ["csv"],
        "Y": ["csv"]
    },
    "Output": {
        "MODEL": ["model.svm"]
    }
}

In short, screwjack is a utility work around spec.json. Typically, there are 5 steps to write a module. The following tutorial will show details steps.

1. Initialize a module
2. Add Inputs/Outputs/Params
3. Fill your code implementation
4. Test module
   1. Test in local
   2. Test in docker
5. Submit module

Installation

Screwjack will depends on docker, so you should install docker first.

Install docker

A module developing environment need docker. Follow the link to install docker for your linux distribution: http://docs.docker.io/installation/.

After that, don’t forget add yourself into ‘docker’ group. For example, in Ubuntu, you can do it like this:

sudo usermod -aG docker your_linux_username

Install screwjack

You can get screwjack directly from PyPI:

pip install -U screwjack pyDataCanvas

Setup screwjack

Before you using screwjack, you should set your username. You can either set environment variable:

export DATACANVAS_USERNAME=your_username

Or, you can put your username into $HOME/.screwjack.cfg:

[user]
username = your_username
spec_server = playground.datacanvas.io:6006
spec_auth = 3ce3e9fc12cf7260c433d2eec44c51ee

Or, you can use login subcommand to login into specific spec_server like following:

screwjack --username=your_username --spec_server=playground.datacanvas.io:6006 login