CaaS

Calculator-As-A-Service.

Quick-n-dirty calculator service created for the purpose of exploring the Falcon API framework

Requires:

python 3.6+
pip install -r requirements.txt

GET request syntax:

/calc/<constant>

  /calc/pi
  /calc/tau
  /calc/e

POST request syntax:

 -H "Content-Type: application/json" -d '{"problem": "\<problem-expression\>"}' localhost:8080/calc

There are 6 different caculator operations:

addition: 1+2
subtraction: 3-2
multiplication: 4*5
division: 6/2
powers: 2^5

NOT YET IMPLEMENTED

roots: (can use inverse power syntax or root<x>(y) to specify the x root of y)
- square-root root2(9) = 3 = 9^(1/2)
- cube-root root3(27) = 3 = 27^(1/3)

Operator Combinations

Use parens to group multiple operations according to standard mathematical grouping rules:
Examples:

 Problem: ((1/2)*(2^5))/(10-8)^2 
 Answer:  (.5)*(32)/4  =  16/4  =  4

Setup

 $ git clone https://github.com/bfanselow/CaaS.git
 $ virtualenv -p python3 venv
 $ . venv/bin/activate
 (venv) $ pip install -r requirements.txt

Run the service with simple_server (binds to 0.0.0.0:8080)

 (venv) cd app/
 (venv) $ python caas.py

Run with gunicorn (binds to 0.0.0.0:8080)

 (venv) $ ./gunicorn_start.sh
  OR
 (venv) $ cd app 
 (venv) $ gunicorn caas:api [-b <ip>:<port>]

Run in Docker container (binds to 0.0.0.0:8080)

 $ docker build . -t docker-caas
 $ docker run --name caas -d -p 8080:8080 docker-caas

Testing (pytest)

TODO

Examples API calls

Infomational index call:

 (venv) $ curl localhost:8080/calc/
 {"type": "info", "message": "GET a math constant (pi,tau,e) as a resource, or POST a math problem in json format - example: {'problem': '(3*3)+2'}"}

GET constant value:

 (venv) $ curl localhost:8080/calc/pi
 {"constant": "pi", "value": 3.141592653589793}

POST invalid expression:

 (venv) $ curl -H "Content-Type: application/json" -d '{"problem": "bogus"}' localhost:8080/calc
 {"type": "error", "message": "Request error: Invalid character in expression: [b]"}

POST simple expression:

 (venv) $ curl -H "Content-Type: application/json" -d '{"problem": "2+3"}' localhost:8080/calc
 {"problem": "2+3", "answer": 5.0}

POST complex expression:

 (venv) $ curl -H "Content-Type: application/json" -d '{"problem": "((4+3)-5)^5"}' localhost:8080/calc
 {"problem": "((4+3)-5)^5", "answer": 32.0}

How complex can we get?:

 (venv) $ curl -H "Content-Type: application/json" -d '{"problem": "3*((((4+3)-5)^5)/8)"}' localhost:8080/calc
 {"problem": "(((4+3)-5)^5)/8", "answer": 4.0}

Testing

Unit-Testing

$ python -m pytest -v tests/unit/test_compute.py
$ python -m pytest -v tests/unit/test_compute_exc.py
  OR simply
$ python -m pytest -v tests/unit/

Integration-Testing

$ python -m pytest -v tests/integration/test_service.py