iframe-proxy | Sunbelt Computer Software

History

54 lines (41 loc) · 1.29 KB

Raw

from __future__ import absolute_import

from __future__ import unicode_literals

import collections

import contextlib

import os

from pre_commit import five

UNSET = collections.namedtuple('UNSET', ())()

Var = collections.namedtuple('Var', ('name', 'default'))

setattr(Var.__new__, five.defaults_attr, ('',))

def format_env(parts, env):

return ''.join(

env.get(part.name, part.default)

if isinstance(part, Var)

else part

for part in parts

)

@contextlib.contextmanager

def envcontext(patch, _env=None):

"""In this context, `os.environ` is modified according to `patch`.

`patch` is an iterable of 2-tuples (key, value):

`key`: string

`value`:

- string: `environ[key] == value` inside the context.

- UNSET: `key not in environ` inside the context.

- template: A template is a tuple of strings and Var which will be

replaced with the previous environment

"""

env = os.environ if _env is None else _env

before = env.copy()

for k, v in patch:

if v is UNSET:

env.pop(k, None)

elif isinstance(v, tuple):

env[k] = format_env(v, before)

else:

env[k] = v

try:

yield

finally:

env.clear()

env.update(before)

Sunbelt Computer Software

PL/B Language Development and Support

Navigation Menu

Sunbelt Computer Software

PL/B Language Development and Support

FilesExpand file tree

envcontext.py

Latest commit

History

envcontext.py

File metadata and controls