compose/compose/config/interpolation.py
Joffrey F 56a23bfcd2 Improved version comparisons throughout the codebase
Signed-off-by: Joffrey F <joffrey@docker.com>
2017-07-13 17:37:26 -07:00

103 lines
3.2 KiB
Python

from __future__ import absolute_import
from __future__ import unicode_literals
import logging
from string import Template
import six
from .errors import ConfigurationError
from compose.const import COMPOSEFILE_V2_0 as V2_0
log = logging.getLogger(__name__)
class Interpolator(object):
def __init__(self, templater, mapping):
self.templater = templater
self.mapping = mapping
def interpolate(self, string):
try:
return self.templater(string).substitute(self.mapping)
except ValueError:
raise InvalidInterpolation(string)
def interpolate_environment_variables(version, config, section, environment):
if version <= V2_0:
interpolator = Interpolator(Template, environment)
else:
interpolator = Interpolator(TemplateWithDefaults, environment)
def process_item(name, config_dict):
return dict(
(key, interpolate_value(name, key, val, section, interpolator))
for key, val in (config_dict or {}).items()
)
return dict(
(name, process_item(name, config_dict or {}))
for name, config_dict in config.items()
)
def interpolate_value(name, config_key, value, section, interpolator):
try:
return recursive_interpolate(value, interpolator)
except InvalidInterpolation as e:
raise ConfigurationError(
'Invalid interpolation format for "{config_key}" option '
'in {section} "{name}": "{string}"'.format(
config_key=config_key,
name=name,
section=section,
string=e.string))
def recursive_interpolate(obj, interpolator):
if isinstance(obj, six.string_types):
return interpolator.interpolate(obj)
if isinstance(obj, dict):
return dict(
(key, recursive_interpolate(val, interpolator))
for (key, val) in obj.items()
)
if isinstance(obj, list):
return [recursive_interpolate(val, interpolator) for val in obj]
return obj
class TemplateWithDefaults(Template):
idpattern = r'[_a-z][_a-z0-9]*(?::?-[^}]+)?'
# Modified from python2.7/string.py
def substitute(self, mapping):
# Helper function for .sub()
def convert(mo):
# Check the most common path first.
named = mo.group('named') or mo.group('braced')
if named is not None:
if ':-' in named:
var, _, default = named.partition(':-')
return mapping.get(var) or default
if '-' in named:
var, _, default = named.partition('-')
return mapping.get(var, default)
val = mapping[named]
return '%s' % (val,)
if mo.group('escaped') is not None:
return self.delimiter
if mo.group('invalid') is not None:
self._invalid(mo)
raise ValueError('Unrecognized named group in pattern',
self.pattern)
return self.pattern.sub(convert, self.template)
class InvalidInterpolation(Exception):
def __init__(self, string):
self.string = string