dda-python-terraform/README.md

Introduction

python-terraform is a python module provide a wrapper of terraform command line tool. terraform is a tool made by Hashicorp, please refer to https://terraform.io/

Status

Installation

pip install python-terraform

Usage

####For any terraform command

from python_terraform import Terraform
t = Terraform()
return_code, stdout, stderr = t.<cmd_name>(*arguments, **options)

####For any argument simply pass the string to arguments of the method, for example,

terraform apply target_dir 
    --> <instance>.apply('target_dir')
terraform import aws_instance.foo i-abcd1234 
    --> <instance>.import('aws_instance.foo', 'i-abcd1234')

####For any options

• dash to underscore

  remove first dash, and then use underscore to replace dash symbol as option name

    ex. -no-color --> no_color
  

• for a simple flag option

  use IsFlagged/None as value for raising/not raising flag, for example,

    terraform taint -allow-missing 
       --> <instance>.taint(allow＿missing=IsFlagged)
    terraform taint 
       --> <instance>.taint(allow＿missing=None) or <instance>.taint()
    terraform apply -no-color
       --> <instance>.apply(no_color=IsFlagged)
  

• for a boolean value option

  assign True or False, for example,

    terraform apply -refresh=true --> <instance>.apply(refresh=True)
  

• if a flag could be used multiple times, assign a list to it's value

    terraform apply -target=aws_instance.foo[1] -target=aws_instance.foo[2]
    ---> 
    <instance>.apply(target=['aws_instance.foo[1]', 'aws_instance.foo[2]'])
  

• for the "var" flag, assign dictionary to it

    terraform apply -var='a=b' -var='c=d'
    --> tf.apply(var={'a':'b', 'c':'d'})
  

• if an option with None as value, it won't be used

Examples

Have a test.tf file under folder "/home/test"

1. apply with variables a=b, c=d, refresh=false, no color in the output

In shell:

cd /home/test
terraform apply -var='a=b' -var='c=d' -refresh=false -no-color

In python-terraform:

from python_terraform import Terraform
tf = Terraform(working_dir='/home/test')
tf.apply(no_color=IsFlagged, refresh=False, var={'a':'b', 'c':'d'})

or

from python_terraform import Terraform
tf = Terraform()
tf.apply('/home/test', no_color=IsFlagged, refresh=False, var={'a':'b', 'c':'d'})

or

from python_terraform import Terraform
tf = Terraform(working_dir='/home/test', variables={'a':'b', 'c':'d'})
tf.apply(no_color=IsFlagged, refresh=False)

2. fmt command, diff=true

In shell:

cd /home/test
terraform fmt -diff=true 

In python-terraform:

from python_terraform import Terraform
tf = terraform(working_dir='/home/test')
tf.fmt(diff=True)

default values

for apply/plan/destroy command, assign with following default value to make caller easier in python

1. input=False, in this case process won't hang because you missing a variable
2. no_color=IsFlagged, in this case, stdout of result is easier for parsing

Implementation

IMHO, how terraform design boolean options is confusing. Take input=True and -no-color option of apply command for example, they're all boolean value but with different option type. This make api caller don't have a general rule to follow but to do a exhaustive method implementation which I don't prefer to. Therefore I end-up with using IsFlagged or IsNotFlagged as value of option like -no-color and True/False value reserved for option like refresh=true