unitz

What is unitz?

unitz allows you to compose python programs by assembling resuable code called units. Its written in python 2.7 and python 3 version will be added soon. Its being tested only with CPython for now.

Why it was developed?

One of the primary use case was to enable developers quickly write automation code for their tests (both unit test & black box test). Also the design from start is geared to address automation reuse at company level specially where one team uses code of other teams.

Features

Assemble or compose programs from smaller components (or units)
Inherit units and flows from existing configuration (allows for across team re-usability)
Polymorphism at configuration level (explained in wiki)
Chain the units i.e. feed output of one as input to another

Checkout Wiki Tutorial for demo of features

Stability

Pre-Alpha

Installation

Right now unitz is not available on Pypi. It will be in future.
Note: only *nix platforms & OSX are supported out of the box. There is no technical problem in supporting windows its just that the bat file to source the env vars has not been written right now.

For now clone the repository and source the setenv_unitz:

sj:/Users/sudeepjathar/lab/unitz> source setenv_unitz

The source may not work if you have KSH and you can use the dot . to source

For windows ... try changing setenv_unitz to its bat file equivalent and source it. I will do it eventually.

Enough said ... Show me the code

Lets say Bob wrote a function to add numbers

def add(a, b):
    return a + b

Now he does not want others to reinvent the wheel and wishes to make this reusable. (I know that for some this example is lame ... but imagine instead that this could be something like connecting to database and create test data or transfer a file from machine A to B ...)

So he converts the function into a unit:

#bobunits.py
from unitz import unit, done

@unit('add_numbers')
def add(a, b):
    o_addition_result = a + b
    print '{0} + {1} = {2}'.format(a,b, o_addition_result)
    return done()

Lets add 3 + 2 by creating a flow in a config file (YAML file):

bobconfig.yml

include: unitz
unit_modules: [bobunits]

flows:
    math:
        - add_numbers:
            a: 3
            b: 2

Before we run ... we first export the envrironment variables:

sj:/Users/sudeepjathar/lab/unitz> source setenv_unitz

Now run the math flow:

sj:/Users/sudeepjathar/lab/py> unitz run bobconfig math
add_numbers ..................................................................... start
3 + 2 = 5
add_numbers ..................................................................... ok

Concept: units are regular python functions and it should have the following traits:

They should be stateless (although nothing prevents you to do otherwise)
Any output of the computation should be captured in variables starting with name o_
More than one output can be captured.
Should return using inbuilt function done() (working on to remove this limitation) Note: Since its YAML file, indentation is important.

Lets modify the flow in bobconfig.py to add 3 + 2 + 4:

bobconfig.yml

include: unitz
unit_modules: [bobunits]

flows:
    math:
        - add_numbers:
            a: 3
            b: 2
        - add_numbers:
            +a: addition_result
            b: 2

The result:

sj:/Users/sudeepjathar/lab/py> unitz run bobconfig math
add_numbers ..................................................................... start
3 + 2 = 5
add_numbers ..................................................................... ok

add_numbers ..................................................................... start
5 + 2 = 7
add_numbers ..................................................................... ok

The o_addition_result was stripped of its o_ and it was used in the second addition. The '+a' : 'addition_result' means that before executing copy into the arg a the value from o_addition_result which was computed by previous unit. In other words we sort of daisy-chained the two additions... I call this feature chaining.

The leading '+' in +a means that set the value before execution whereas trailing '+' (as in 'a+') would have meant setting value of the param after the execution.

Enough for readme ... checkout the wiki for more features & details like inheriting flows & units, chaining.

Wishlist and further scope

Add UI where one can compose by drag and dropping units
Dry run (or simulation) of the flow
Infrastructure libraries for reuse
Interoperate with units developed in other languages
Move the flow configuration outside python program (something like YAML)

sudeep9/unitz