some more groundwork
This commit is contained in:
brent s
218
aif/config/parser.py
Normal file
218
aif/config/parser.py
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import copy
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import os
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import re
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##
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import requests
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from lxml import etree, objectify
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class Config(object):
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def __init__(self, xsd_path = None, *args, **kwargs):
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self.xsd_path = None
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self.tree = None
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self.namespaced_tree = None
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self.xml = None
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self.namespaced_xml = None
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self.raw = None
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self.xsd = None
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self.defaultsParser = None
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self.obj = None
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def main(self, validate = True, populate_defaults = True):
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self.fetch()
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self.parseRaw()
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if populate_defaults:
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self.populateDefaults()
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if validate:
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self.validate()
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self.pythonize()
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return()
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def fetch(self): # Just a fail-safe; this is overridden by specific subclasses.
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pass
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return()
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def getXSD(self, xsdpath = None):
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if not xsdpath:
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xsdpath = self.xsd_path
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raw_xsd = None
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if xsdpath:
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xsdpath = os.path.abspath(os.path.expanduser(xsdpath))
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if not os.path.isfile(xsdpath):
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raise ValueError(('An explicit XSD path was specified but '
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'does not exist on the local filesystem'))
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with open(xsdpath, 'rb') as fh:
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raw_xsd = fh.read()
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else:
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xsi = self.xml.nsmap.get('xsi', 'http://www.w3.org/2001/XMLSchema-instance')
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schemaLocation = '{{{0}}}schemaLocation'.format(xsi)
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schemaURL = self.xml.attrib.get(schemaLocation,
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'https://aif-ng.io/aif.xsd?ref={0}'.format(self.xml.attrib['version']))
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split_url = schemaURL.split()
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if len(split_url) == 2: # a properly defined schemaLocation
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schemaURL = split_url[1]
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else:
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schemaURL = split_url[0] # a LAZY schemaLocation
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req = requests.get(schemaURL)
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if not req.ok:
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# TODO: logging!
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raise RuntimeError('Could not download XSD')
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raw_xsd = req.content
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self.xsd = etree.XMLSchema(etree.XML(raw_xsd))
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return()
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def parseRaw(self, parser = None):
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# self.xml = etree.parse(self.raw, parser = parser)
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self.xml = etree.fromstring(self.raw, parser = parser)
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# self.namespaced_xml = etree.parse(self.raw, parser = parser)
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self.namespaced_xml = etree.fromstring(self.raw, parser = parser)
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self.tree = self.xml.getroottree()
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self.namespaced_tree = self.namespaced_xml.getroottree()
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self.tree.xinclude()
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self.namespaced_tree.xinclude()
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self.stripNS()
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return()
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def populateDefaults(self):
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if not self.xsd:
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self.getXSD()
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if not self.defaultsParser:
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self.defaultsParser = etree.XMLParser(schema = self.xsd, attribute_defaults = True)
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self.parseRaw(parser = self.defaultsParser)
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return()
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def pythonize(self, stripped = True, obj = 'tree'):
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# https://bugs.launchpad.net/lxml/+bug/1850221
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strobj = self.toString(stripped = stripped, obj = obj)
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self.obj = objectify.fromstring(strobj)
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objectify.annotate(self.obj)
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objectify.xsiannotate(self.obj)
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return()
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def removeDefaults(self):
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self.parseRaw()
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return()
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def stripNS(self, obj = None):
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# https://stackoverflow.com/questions/30232031/how-can-i-strip-namespaces-out-of-an-lxml-tree/30233635#30233635
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xpathq = "descendant-or-self::*[namespace-uri()!='']"
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if not obj:
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for x in (self.tree, self.xml):
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for e in x.xpath(xpathq):
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e.tag = etree.QName(e).localname
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elif isinstance(obj, (etree._Element, etree._ElementTree)):
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obj = copy.deepcopy(obj)
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for e in obj.xpath(xpathq):
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e.tag = etree.QName(e).localname
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return(obj)
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else:
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raise ValueError('Did not know how to parse obj parameter')
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return()
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def toString(self, stripped = False, obj = None):
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if isinstance(obj, (etree._Element, etree._ElementTree)):
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if stripped:
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obj = self.stripNS(obj)
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elif obj in ('tree', None):
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if not stripped:
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obj = self.namespaced_tree
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else:
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obj = self.tree
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elif obj == 'xml':
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if not stripped:
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obj = self.namespaced_xml
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else:
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obj = self.xml
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else:
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raise ValueError(('obj parameter must be "tree", "xml", or of type '
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'lxml.etree._Element or lxml.etree._ElementTree'))
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obj = copy.deepcopy(obj)
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strxml = etree.tostring(obj,
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encoding = 'utf-8',
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xml_declaration = True,
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pretty_print = True,
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with_tail = True,
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inclusive_ns_prefixes = True)
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return(strxml)
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def validate(self):
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if not self.xsd:
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self.getXSD()
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self.xsd.assertValid(self.namespaced_tree)
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return()
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class LocalFile(Config):
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def __init__(self, path, xsd_path = None, *args, **kwargs):
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super().__init__(xsd_path = xsd_path, *args, **kwargs)
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self.type = 'local'
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self.source = path
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def fetch(self):
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self.source = os.path.realpath(self.source)
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if not os.path.isfile(self.source):
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raise ValueError('{0} does not exist'.format(self.source))
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with open(self.source, 'rb') as fh:
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self.raw = fh.read()
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return()
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class RemoteFile(Config):
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def __init__(self, uri, xsd_path = None, *args, **kwargs):
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super().__init__(*args, **kwargs)
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self.type = 'remote'
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self.source = uri
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def fetch(self):
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r = requests.get(self.source)
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if not r.ok():
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raise RuntimeError('Could not download XML')
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self.raw = r.content
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return()
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class ConfigStr(Config):
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def __init__(self, rawxml, xsd_path = None, *args, **kwargs):
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super().__init__(*args, **kwargs)
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self.type = 'raw_str'
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self.source = rawxml
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def fetch(self):
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self.raw = self.source.encode('utf-8')
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return()
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class ConfigBin(Config):
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def __init__(self, rawbinaryxml, xsd_path = None, *args, **kwargs):
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super().__init__(*args, **kwargs)
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self.type = 'raw_bin'
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self.source = rawbinaryxml
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def fetch(self):
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self.raw = self.source
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return()
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detector = {'raw': (re.compile(r'^\s*(?P<xml><(\?xml|aif)\s+.*)\s*$', re.DOTALL | re.MULTILINE), ConfigStr),
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'remote': (re.compile(r'^(?P<uri>(?P<proto>(https?|ftps?)://)(?P<path>.*))\s*$'), RemoteFile),
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'local': (re.compile(r'^(file://)?(?P<path>(/?[^/]+)+/?)$'), LocalFile)}
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def getConfig(cfg_ref, validate = True, populate_defaults = True, xsd_path = None):
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cfgobj = None
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# This is kind of gross.
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for configtype, (pattern, configClass) in detector.items():
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try:
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if pattern.search(cfg_ref):
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cfgobj = configClass(cfg_ref, xsd_path = xsd_path)
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break
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except TypeError:
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ptrn = re.compile(detector['raw'][0].pattern.encode('utf-8'))
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if not ptrn.search(cfg_ref):
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raise ValueError('Received junk data for cfg_ref')
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else:
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cfgobj = ConfigBin(cfg_ref, xsd_path = xsd_path)
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break
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if cfgobj:
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cfgobj.main(validate = validate, populate_defaults = populate_defaults)
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return(cfgobj)
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