dda-python-terraform/python_terraform/__init__.py
Freddy Tan 2d63fa8716 1. let variables able to accept map and list
2. refactor to be able to accept command as a instance attribute
3. add test cases
2016-12-20 18:53:01 +08:00

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# -*- coding: utf-8 -*-
# above is for compatibility of python2.7.11
import subprocess
import os
import json
import logging
import tempfile
from python_terraform.tfstate import Tfstate
log = logging.getLogger(__name__)
class IsFlagged:
pass
class IsNotFlagged:
pass
class Terraform(object):
"""
Wrapper of terraform command line tool
https://www.terraform.io/
"""
def __init__(self, working_dir=None,
targets=None,
state=None,
variables=None,
parallelism=None,
var_file=None,
terraform_bin_path=None):
"""
:param working_dir: the folder of the working folder, if not given, will be where python
:param targets: list of target
:param state: path of state file relative to working folder
:param variables: variables for apply/destroy/plan command
:param parallelism: parallelism for apply/destroy command
:param var_file: passed as value of -var-file option, could be string or list
list stands for multiple -var-file option
:param terraform_bin_path: binary path of terraform
"""
self.working_dir = working_dir
self.state = state
self.targets = [] if targets is None else targets
self.variables = dict() if variables is None else variables
self.parallelism = parallelism
self.terraform_bin_path = terraform_bin_path \
if terraform_bin_path else 'terraform'
self.var_file = var_file
self.temp_var_files = VaribleFiles()
# store the tfstate data
self.tfstate = None
self.read_state_file(self.state)
def __getattr__(self, item):
def wrapper(*args, **kwargs):
print('called with %r and %r' % (args, kwargs))
return self.cmd(item, *args, **kwargs)
return wrapper
def apply(self, dir_or_plan=None, **kwargs):
"""
refer to https://terraform.io/docs/commands/apply.html
no-color is flagged by default
:param dir_or_plan: folder relative to working folder
:param kwargs: same as kwags in method 'cmd'
:returns return_code, stdout, stderr
"""
default = dict()
args, option_dict = self._create_cmd_args(dir_or_plan, default, kwargs)
return self.cmd('apply', *args, **option_dict)
def _create_cmd_args(self, dir_or_plan, default_dict, kwargs):
option_dict = default_dict
option_dict['state'] = self.state
option_dict['target'] = self.targets
option_dict['var'] = self.variables
option_dict['var_file'] = self.var_file
option_dict['parallelism'] = self.parallelism
option_dict['no_color'] = IsFlagged
option_dict['input'] = False
option_dict.update(kwargs)
args = [dir_or_plan] if dir_or_plan else []
return args, option_dict
def destroy(self, dir_or_plan=None, **kwargs):
"""
refer to https://www.terraform.io/docs/commands/destroy.html
force/no-color option is flagged by default
:return: ret_code, stdout, stderr
"""
default = {'force': IsFlagged}
args, option_dict = self._create_cmd_args(dir_or_plan, default, kwargs)
return self.cmd('destroy', *args, **option_dict)
def generate_cmd_string(self, cmd, *args, **kwargs):
"""
for any generate_cmd_string doesn't written as public method of terraform
examples:
1. call import command,
ref to https://www.terraform.io/docs/commands/import.html
--> generate_cmd_string call:
terraform import -input=true aws_instance.foo i-abcd1234
--> python call:
tf.generate_cmd_string('import', 'aws_instance.foo', 'i-abcd1234', input=True)
2. call apply command,
--> generate_cmd_string call:
terraform apply -var='a=b' -var='c=d' -no-color the_folder
--> python call:
tf.generate_cmd_string('apply', the_folder, no_color=IsFlagged, var={'a':'b', 'c':'d'})
:param cmd: command and sub-command of terraform, seperated with space
refer to https://www.terraform.io/docs/commands/index.html
:param args: arguments of a command
:param kwargs: same as kwags in method 'cmd'
:return: string of valid terraform command
"""
cmds = cmd.split()
cmds = [self.terraform_bin_path] + cmds
for k, v in kwargs.items():
if '_' in k:
k = k.replace('_', '-')
if type(v) is list:
for sub_v in v:
cmds += ['-{k}={v}'.format(k=k, v=sub_v)]
continue
# right now we assume only variables will be passed as dict
# since map type sent in string won't work, create temp var file for
# variables, and clean it up later
if type(v) is dict:
filename = self.temp_var_files.create(v)
cmds += ['-var-file={0}'.format(filename)]
continue
# simple flag,
if v is IsFlagged:
cmds += ['-{k}'.format(k=k)]
continue
if v is IsNotFlagged:
continue
if not v:
continue
if type(v) is bool:
v = 'true' if v else 'false'
cmds += ['-{k}={v}'.format(k=k, v=v)]
cmds += args
cmd = ' '.join(cmds)
return cmd
def cmd(self, cmd, *args, **kwargs):
"""
run a terraform command, if success, will try to read state file
:param cmd: command and sub-command of terraform, seperated with space
refer to https://www.terraform.io/docs/commands/index.html
:param args: arguments of a command
:param kwargs: any option flag with key value without prefixed dash character
if there's a dash in the option name, use under line instead of dash,
ex. -no-color --> no_color
if it's a simple flag with no value, value should be IsFlagged
ex. cmd('taint', allow_missing=IsFlagged)
if it's a boolean value flag, assign True or false
if it's a flag could be used multiple times, assign list to it's value
if it's a "var" variable flag, assign dictionary to it
if a value is None, will skip this option
:return: ret_code, out, err
"""
cmd_string = self.generate_cmd_string(cmd, *args, **kwargs)
log.debug('command: {c}'.format(c=cmd_string))
working_folder = self.working_dir if self.working_dir else None
p = subprocess.Popen(cmd_string, stdout=subprocess.PIPE,
stderr=subprocess.PIPE, shell=True,
cwd=working_folder)
out, err = p.communicate()
ret_code = p.returncode
log.debug('output: {o}'.format(o=out))
if ret_code == 0:
self.read_state_file()
else:
log.warn('error: {e}'.format(e=err))
self.temp_var_files.clean_up()
return ret_code, out.decode('utf-8'), err.decode('utf-8')
def output(self, name):
"""
https://www.terraform.io/docs/commands/output.html
:param name: name of output
:return: output value
"""
ret, out, err = self.cmd('output', name, json=IsFlagged)
log.debug('output raw string: {0}'.format(out))
if ret != 0:
return None
out = out.lstrip()
output_dict = json.loads(out)
return output_dict['value']
def read_state_file(self, file_path=None):
"""
read .tfstate file
:param file_path: relative path to working dir
:return: states file in dict type
"""
if not file_path:
file_path = self.state
if not file_path:
file_path = 'terraform.tfstate'
if self.working_dir:
file_path = os.path.join(self.working_dir, file_path)
self.tfstate = Tfstate.load_file(file_path)
def __exit__(self, exc_type, exc_value, traceback):
self.temp_var_files.clean_up()
class VaribleFiles(object):
def __init__(self):
self.files = []
def create(self, variables):
with tempfile.NamedTemporaryFile('w+t', delete=False) as temp:
logging.debug('{0} is created'.format(temp.name))
self.files.append(temp)
temp.write(json.dumps(variables))
file_name = temp.name
return file_name
def clean_up(self):
for f in self.files:
os.unlink(f.name)
self.files = []