mirror of https://github.com/docker/docs.git
87 lines
2.3 KiB
Python
87 lines
2.3 KiB
Python
import os
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from string import Template
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import six
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from .errors import ConfigurationError
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import logging
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log = logging.getLogger(__name__)
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def interpolate_environment_variables(config):
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return dict(
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(service_name, process_service(service_name, service_dict))
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for (service_name, service_dict) in config.items()
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)
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def process_service(service_name, service_dict):
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if not isinstance(service_dict, dict):
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raise ConfigurationError(
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'Service "%s" doesn\'t have any configuration options. '
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'All top level keys in your docker-compose.yml must map '
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'to a dictionary of configuration options.' % service_name
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)
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return dict(
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(key, interpolate_value(service_name, key, val))
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for (key, val) in service_dict.items()
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)
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def interpolate_value(service_name, config_key, value):
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try:
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return recursive_interpolate(value)
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except InvalidInterpolation as e:
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raise ConfigurationError(
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'Invalid interpolation format for "{config_key}" option '
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'in service "{service_name}": "{string}"'
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.format(
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config_key=config_key,
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service_name=service_name,
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string=e.string,
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)
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)
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def recursive_interpolate(obj):
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if isinstance(obj, six.string_types):
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return interpolate(obj, os.environ)
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elif isinstance(obj, dict):
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return dict(
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(key, recursive_interpolate(val))
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for (key, val) in obj.items()
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)
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elif isinstance(obj, list):
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return map(recursive_interpolate, obj)
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else:
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return obj
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def interpolate(string, mapping):
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try:
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return Template(string).substitute(BlankDefaultDict(mapping))
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except ValueError:
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raise InvalidInterpolation(string)
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class BlankDefaultDict(dict):
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def __init__(self, mapping):
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super(BlankDefaultDict, self).__init__(mapping)
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def __getitem__(self, key):
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try:
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return super(BlankDefaultDict, self).__getitem__(key)
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except KeyError:
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log.warn(
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"The {} variable is not set. Substituting a blank string."
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.format(key)
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)
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return ""
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class InvalidInterpolation(Exception):
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def __init__(self, string):
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self.string = string
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