dda-python-terraform/python_terraform/__init__.py
2017-10-16 09:12:34 -07:00

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# -*- coding: utf-8 -*-
# above is for compatibility of python2.7.11
import subprocess
import os
import sys
import json
import logging
import tempfile
from python_terraform.tfstate import Tfstate
try: # Python 2.7+
from logging import NullHandler
except ImportError:
class NullHandler(logging.Handler):
def emit(self, record):
pass
log = logging.getLogger(__name__)
log.addHandler(NullHandler())
class IsFlagged:
pass
class IsNotFlagged:
pass
class TerraformCommandError(subprocess.CalledProcessError):
def __init__(self, ret_code, cmd, out, err):
super(TerraformCommandError, self).__init__(ret_code, cmd)
self.out = out
self.err = err
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,
is_env_vars_included=True):
"""
:param working_dir: the folder of the working folder, if not given,
will be current working folder
:param targets: list of target
as default value of apply/destroy/plan command
:param state: path of state file relative to working folder,
as a default value of apply/destroy/plan command
:param variables: default variables for apply/destroy/plan command,
will be override by variable passing by apply/destroy/plan method
:param parallelism: default parallelism value 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
:type is_env_vars_included: bool
:param is_env_vars_included: included env variables when calling terraform cmd
"""
self.is_env_vars_included = is_env_vars_included
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 = VariableFiles()
# store the tfstate data
self.tfstate = None
self.read_state_file(self.state)
def __getattr__(self, item):
def wrapper(*args, **kwargs):
cmd_name = str(item)
if cmd_name.endswith('_cmd'):
cmd_name = cmd_name[:-4]
logging.debug('called with %r and %r' % (args, kwargs))
return self.cmd(cmd_name, *args, **kwargs)
return wrapper
def apply(self, dir_or_plan=None, input=False, no_color=IsFlagged,
**kwargs):
"""
refer to https://terraform.io/docs/commands/apply.html
no-color is flagged by default
:param no_color: disable color of stdout
:param input: disable prompt for a missing variable
:param dir_or_plan: folder relative to working folder
:param kwargs: same as kwags in method 'cmd'
:returns return_code, stdout, stderr
"""
default = kwargs
default['input'] = input
default['no_color'] = no_color
option_dict = self._generate_default_options(default)
args = self._generate_default_args(dir_or_plan)
return self.cmd('apply', *args, **option_dict)
def _generate_default_args(self, dir_or_plan):
return [dir_or_plan] if dir_or_plan else []
def _generate_default_options(self, input_options):
option_dict = 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(input_options)
return option_dict
def destroy(self, dir_or_plan=None, force=IsFlagged, **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 = kwargs
default['force'] = force
options = self._generate_default_options(default)
args = self._generate_default_args(dir_or_plan)
return self.cmd('destroy', *args, **options)
def plan(self, dir_or_plan=None, detailed_exitcode=IsFlagged, **kwargs):
"""
refer to https://www.terraform.io/docs/commands/plan.html
:param detailed_exitcode: Return a detailed exit code when the command exits.
:param dir_or_plan: relative path to plan/folder
:param kwargs: options
:return: ret_code, stdout, stderr
"""
options = kwargs
options['detailed_exitcode'] = detailed_exitcode
options = self._generate_default_options(options)
args = self._generate_default_args(dir_or_plan)
return self.cmd('plan', *args, **options)
def init(self, dir_or_plan=None, backend_config=None,
reconfigure=IsFlagged, backend=True, **kwargs):
"""
refer to https://www.terraform.io/docs/commands/init.html
By default, this assumes you want to use backend config, and tries to
init fresh. The flags -reconfigure and -backend=true are default.
:param dir_or_plan: relative path to the folder want to init
:param backend_config: a dictionary of backend config options. eg.
t = Terraform()
t.init(backend_config={'access_key': 'myaccesskey',
'secret_key': 'mysecretkey', 'bucket': 'mybucketname'})
:param reconfigure: whether or not to force reconfiguration of backend
:param backend: whether or not to use backend settings for init
:param kwargs: options
:return: ret_code, stdout, stderr
"""
options = kwargs
options['backend_config'] = backend_config
options['reconfigure'] = reconfigure
options['backend'] = backend
options = self._generate_default_options(options)
args = self._generate_default_args(dir_or_plan)
return self.cmd('init', *args, **options)
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 option, value in kwargs.items():
if '_' in option:
option = option.replace('_', '-')
if type(value) is list:
for sub_v in value:
cmds += ['-{k}={v}'.format(k=option, v=sub_v)]
continue
if type(value) is dict:
if 'backend-config' in option:
for bk, bv in value.items():
cmds += ['-backend-config={k}={v}'.format(k=bk, v=bv)]
continue
# since map type sent in string won't work, create temp var file for
# variables, and clean it up later
else:
filename = self.temp_var_files.create(value)
cmds += ['-var-file={0}'.format(filename)]
continue
# simple flag,
if value is IsFlagged:
cmds += ['-{k}'.format(k=option)]
continue
if value is None or value is IsNotFlagged:
continue
if type(value) is bool:
value = 'true' if value else 'false'
cmds += ['-{k}={v}'.format(k=option, v=value)]
cmds += args
return cmds
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
if the option 'capture_output' is passed (with any value other than
True), terraform output will be printed to stdout/stderr and
"None" will be returned as out and err.
if the option 'raise_on_error' is passed (with any value that evaluates to True),
and the terraform command returns a nonzerop return code, then
a TerraformCommandError exception will be raised. The exception object will
have the following properties:
returncode: The command's return code
out: The captured stdout, or None if not captured
err: The captured stderr, or None if not captured
:return: ret_code, out, err
"""
capture_output = kwargs.pop('capture_output', True)
raise_on_error = kwargs.pop('raise_on_error', False)
if capture_output is True:
stderr = subprocess.PIPE
stdout = subprocess.PIPE
else:
stderr = sys.stderr
stdout = sys.stdout
cmds = self.generate_cmd_string(cmd, *args, **kwargs)
log.debug('command: {c}'.format(c=' '.join(cmds)))
working_folder = self.working_dir if self.working_dir else None
environ_vars = {}
if self.is_env_vars_included:
environ_vars = os.environ.copy()
p = subprocess.Popen(cmds, stdout=stdout, stderr=stderr,
cwd=working_folder, env=environ_vars)
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()
if capture_output is True:
out = out.decode('utf-8')
err = err.decode('utf-8')
else:
out = None
err = None
if ret_code != 0 and raise_on_error:
raise TerraformCommandError(
ret_code, ' '.join(cmds), out=out, err=err)
return ret_code, out, err
def output(self, *args, **kwargs):
"""
https://www.terraform.io/docs/commands/output.html
Note that this method does not conform to the (ret_code, out, err) return convention. To use
the "output" command with the standard convention, call "output_cmd" instead of
"output".
:param args: Positional arguments. There is one optional positional
argument NAME; if supplied, the returned output text
will be the json for a single named output value.
:param kwargs: Named options, passed to the command. In addition,
'full_value': If True, and NAME is provided, then
the return value will be a dict with
"value', 'type', and 'sensitive'
properties.
:return: None, if an error occured
Output value as a string, if NAME is provided and full_value
is False or not provided
Output value as a dict with 'value', 'sensitive', and 'type' if
NAME is provided and full_value is True.
dict of named dicts each with 'value', 'sensitive', and 'type',
if NAME is not provided
"""
full_value = kwargs.pop('full_value', False)
name_provided = (len(args) > 0)
kwargs['json'] = IsFlagged
if not kwargs.get('capture_output', True) is True:
raise ValueError('capture_output is required for this method')
ret, out, err = self.output_cmd(*args, **kwargs)
if ret != 0:
return None
out = out.lstrip()
value = json.loads(out)
if name_provided and not full_value:
value = value['value']
return 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
"""
working_dir = self.working_dir or ''
file_path = file_path or self.state or ''
if not file_path:
backend_path = os.path.join(file_path, '.terraform',
'terraform.tfstate')
if os.path.exists(os.path.join(working_dir, backend_path)):
file_path = backend_path
else:
file_path = os.path.join(file_path, 'terraform.tfstate')
file_path = os.path.join(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 VariableFiles(object):
def __init__(self):
self.files = []
def create(self, variables):
with tempfile.NamedTemporaryFile('w+t', delete=False) as temp:
log.debug('{0} is created'.format(temp.name))
self.files.append(temp)
log.debug(
'variables wrote to tempfile: {0}'.format(str(variables)))
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 = []