root / snf-common / synnefo / util / entry_points.py @ 4bd19308
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# Copyright 2011 GRNET S.A. All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or
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# without modification, are permitted provided that the following
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# conditions are met:
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#
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# 1. Redistributions of source code must retain the above
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# copyright notice, this list of conditions and the following
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# disclaimer.
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#
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# 2. Redistributions in binary form must reproduce the above
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# copyright notice, this list of conditions and the following
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# disclaimer in the documentation and/or other materials
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# provided with the distribution.
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#
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# THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
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# OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
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# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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# POSSIBILITY OF SUCH DAMAGE.
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#
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# The views and conclusions contained in the software and
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# documentation are those of the authors and should not be
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# interpreted as representing official policies, either expressed
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# or implied, of GRNET S.A.
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import sys |
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import pkg_resources |
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import types |
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import os |
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from collections import defaultdict |
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# List of python distribution names which entry points will get excluded
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# from snf-common settings extension mechanism
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EXCLUDED_PACKAGES = os.environ.get('SYNNEFO_EXCLUDE_PACKAGES', '').split(":") |
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def get_entry_points(ns, name): |
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for entry_point in pkg_resources.iter_entry_points(group=ns): |
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if entry_point.name == name and \ |
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not entry_point.dist.project_name in EXCLUDED_PACKAGES: |
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yield entry_point
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def extend_module(module_name, attrs): |
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module = sys.modules[module_name] |
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for k, v in attrs.iteritems(): |
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setattr(module, k, v)
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def entry_point_to_object(ep): |
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object_or_func = ep.load() |
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# user defined entry point is a function
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# get the return value
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obj = object_or_func |
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if hasattr(object_or_func, '__call__'): |
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obj = object_or_func() |
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if isinstance(obj, types.ModuleType): |
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dct = {} |
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for k in dir(obj): |
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if k.startswith("__"): |
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continue
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dct[k] = getattr(obj, k)
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obj = dct |
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return obj
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def extend_module_from_entry_point(module_name, ns): |
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"""
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Extend a settings module from entry_point hooks
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"""
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for e in get_entry_points(ns, 'default_settings'): |
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extend_module(module_name, entry_point_to_object(e)) |
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def extend_dict_from_entry_point(settings_object, ns, entry_point_name): |
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for e in get_entry_points(ns, entry_point_name): |
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settings_object.update(entry_point_to_object(e)) |
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return settings_object
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def extend_list_from_entry_point(settings_object, ns, entry_point_name, |
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unique=True):
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settings_object = list(settings_object)
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for e in get_entry_points(ns, entry_point_name): |
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obj = entry_point_to_object(e) |
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for row in obj: |
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# skip duplicate entries
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if row in settings_object: |
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continue
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if type(row) == dict and (row.get('before', False) or |
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row.get('after', False)): |
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insert_at = len(settings_object)
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if row.get('before', False): |
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try:
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position = settings_object.index(row.get('before'))
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insert_at = position - 1
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except ValueError: |
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pass
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else:
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try:
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position = settings_object.index(row.get('after'))
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insert_at = position + 1
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except ValueError: |
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pass
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if insert_at < 0: |
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insert_at = 0
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inserts = row.get('insert', [])
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if not type(inserts) == list: |
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inserts = [inserts] |
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for entry in inserts: |
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if not entry in settings_object: |
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settings_object.insert(insert_at, entry) |
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insert_at = insert_at + 1
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else:
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settings_object.append(row) |
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return settings_object
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def collect_defaults(ns): |
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settings = defaultdict(lambda: [])
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for e in get_entry_points('synnefo', 'default_settings'): |
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attrs = dir(e.load())
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settings[e.dist.key] = settings[e.dist.key] + attrs |
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return settings
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def extend_settings(mname, ns): |
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extend_module_from_entry_point(mname, ns) |
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def extend_urls(patterns, ns): |
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for e in get_entry_points(ns, 'urls'): |
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patterns += e.load() |
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return patterns
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