509 lines
23 KiB
Python
509 lines
23 KiB
Python
# Copyright 2017 AT&T Intellectual Property. All other rights reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import collections
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import copy
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import networkx
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from networkx.algorithms.cycles import find_cycle
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from networkx.algorithms.dag import topological_sort
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from oslo_log import log as logging
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from deckhand.engine import document_wrapper
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from deckhand.engine import secrets_manager
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from deckhand.engine import utils as engine_utils
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from deckhand import errors
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from deckhand import types
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LOG = logging.getLogger(__name__)
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class DocumentLayering(object):
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"""Class responsible for handling document layering.
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Layering is controlled in two places:
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1. The ``LayeringPolicy`` control document, which defines the valid layers
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and their order of precedence.
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2. In the ``metadata.layeringDefinition`` section of normal
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(``metadata.schema=metadata/Document/v1.0``) documents.
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.. note::
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Only documents with the same ``schema`` are allowed to be layered
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together into a fully rendered document.
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"""
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SUPPORTED_METHODS = ('merge', 'replace', 'delete')
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def _replace_older_parent_with_younger_parent(self, child, parent,
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all_children):
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# If child has layer N, parent N+1, and current_parent N+2, then swap
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# parent with current_parent. In other words, if parent's layer is
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# closer to child's layer than current_parent's layer, then use parent.
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current_parent = self._parents.get((child.name, child.schema))
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if current_parent:
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if (self._layer_order.index(parent.layer) >
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self._layer_order.index(current_parent.layer)):
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self._parents[(child.name, child.schema)] = parent
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self._children[
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(current_parent.name, current_parent.schema)].remove(child)
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all_children[child] -= 1
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else:
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self._parents.setdefault((child.name, child.schema), parent)
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def _is_actual_child_document(self, document, potential_child):
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if document == potential_child:
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return False
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document_layer_idx = self._layer_order.index(document.layer)
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child_layer_idx = self._layer_order.index(potential_child.layer)
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parent_selector = potential_child.parent_selector
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labels = document.labels
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# Labels are key-value pairs which are unhashable, so use ``all``
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# instead.
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is_actual_child = all(
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labels.get(x) == y for x, y in parent_selector.items())
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if is_actual_child:
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# Documents with different `schema`s are never layered together,
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# so consider only documents with same schema as candidates.
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if potential_child.schema != document.schema:
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reason = ('Child has parentSelector which references parent, '
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'but their `schema`s do not match.')
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LOG.error(reason)
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raise errors.InvalidDocumentParent(
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parent_schema=document.schema, parent_name=document.name,
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document_schema=potential_child.schema,
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document_name=potential_child.name, reason=reason)
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# The highest order is 0, so the parent should be lower than the
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# child.
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if document_layer_idx >= child_layer_idx:
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reason = ('Child has parentSelector which references parent, '
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'but the child layer %s must be lower than the '
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'parent layer %s for layerOrder %s.' % (
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potential_child.layer, document.layer,
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', '.join(self._layer_order)))
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LOG.error(reason)
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raise errors.InvalidDocumentParent(
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parent_schema=document.schema, parent_name=document.name,
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document_schema=potential_child.schema,
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document_name=potential_child.name, reason=reason)
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return is_actual_child
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def _calc_document_children(self, document):
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potential_children = []
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for label_key, label_val in document.labels.items():
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_potential_children = self._documents_by_labels.get(
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(label_key, label_val), [])
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potential_children.extend(_potential_children)
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# NOTE(fmontei): The intention here is to preserve the order of all
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# the documents that were sorted by `_topologically_sort_documents`
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# in order to substitute documents in the right order. But at the same
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# time, only unique children should be found. So, this trick below
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# maintains the order (unlike set) and guarantees uniqueness.
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unique_potential_children = collections.OrderedDict.fromkeys(
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potential_children)
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for potential_child in unique_potential_children:
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if self._is_actual_child_document(document, potential_child):
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yield potential_child
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def _calc_all_document_children(self):
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"""Determine each document's children.
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For each document, attempts to find the document's children. Adds a new
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key called "children" to the document's dictionary.
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.. note::
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A document should only have exactly one parent.
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If a document does not have a parent, then its layer must be
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the topmost layer defined by the ``layerOrder``.
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:returns: Ordered list of documents that need to be layered. Each
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document contains a "children" property in addition to original
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data. List of documents returned is ordered from highest to lowest
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layer.
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:rtype: List[:class:`DocumentDict`]
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:raises IndeterminateDocumentParent: If more than one parent document
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was found for a document.
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"""
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# ``all_children`` is a counter utility for verifying that each
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# document has exactly one parent.
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all_children = collections.Counter()
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# Mapping of (doc.name, doc.metadata.name) => children, where children
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# are the documents whose `parentSelector` references the doc.
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self._children = {}
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self._parents = {}
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self._parentless_documents = []
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for layer in self._layer_order:
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documents_in_layer = self._documents_by_layer.get(layer, [])
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for document in documents_in_layer:
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children = list(self._calc_document_children(document))
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self._children[(document.name, document.schema)] = children
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if children:
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all_children.update(children)
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for child in children:
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self._replace_older_parent_with_younger_parent(
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child, document, all_children)
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all_children_elements = list(all_children.elements())
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secondary_documents = []
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for layer, documents in self._documents_by_layer.items():
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if self._layer_order and layer != self._layer_order[0]:
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secondary_documents.extend(documents)
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for doc in secondary_documents:
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# Unless the document is the topmost document in the
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# `layerOrder` of the LayeringPolicy, it should be a child document
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# of another document.
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if doc not in all_children_elements:
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LOG.info('Could not find parent for document with name=%s, '
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'schema=%s, layer=%s, parentSelector=%s.',
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doc.name, doc.schema, doc.layer, doc.parent_selector)
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self._parentless_documents.append(doc)
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# If the document is a child document of more than 1 parent, then
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# the document has too many parents, which is a validation error.
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elif all_children[doc] > 1:
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LOG.info('%d parent documents were found for child document '
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'with name=%s, schema=%s, layer=%s, parentSelector=%s'
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'. Each document must have exactly 1 parent.',
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all_children[doc], doc.name, doc.schema, doc.layer,
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doc.parent_selector)
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raise errors.IndeterminateDocumentParent(document=doc)
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def _get_layering_order(self, layering_policy):
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# Pre-processing stage that removes empty layers from the
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# ``layerOrder`` in the layering policy.
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layer_order = list(layering_policy.layer_order)
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for layer in layer_order[:]:
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documents_by_layer = self._documents_by_layer.get(layer, [])
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if not documents_by_layer:
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LOG.info('%s is an empty layer with no documents. It will be '
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'discarded from the layerOrder during the layering '
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'process.', layer)
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layer_order.remove(layer)
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if not layer_order:
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LOG.info('Either the layerOrder in the LayeringPolicy was empty '
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'to begin with or no document layers were found in the '
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'layerOrder, causing it to become empty. No layering '
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'will be performed.')
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return layer_order
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def _topologically_sort_documents(self, documents):
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"""Topologically sorts the DAG formed from the documents' substitution
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dependency chain.
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"""
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documents_by_name = {}
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result = []
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g = networkx.DiGraph()
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for document in documents:
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document = document_wrapper.DocumentDict(document)
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documents_by_name.setdefault((document.schema, document.name),
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document)
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for sub in document.substitutions:
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g.add_edge((document.schema, document.name),
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(sub['src']['schema'], sub['src']['name']))
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try:
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cycle = find_cycle(g)
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except networkx.exception.NetworkXNoCycle:
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pass
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else:
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LOG.error('Cannot determine substitution order as a dependency '
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'cycle exists for the following documents: %s.', cycle)
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raise errors.SubstitutionDependencyCycle(cycle=cycle)
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sorted_documents = reversed(list(topological_sort(g)))
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for document in sorted_documents:
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if document in documents_by_name:
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result.append(documents_by_name.pop(document))
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for document in documents_by_name.values():
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result.append(document)
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return result
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def __init__(self, documents, substitution_sources=None):
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"""Contructor for ``DocumentLayering``.
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:param layering_policy: The document with schema
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``deckhand/LayeringPolicy`` needed for layering.
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:param documents: List of all other documents to be layered together
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in accordance with the ``layerOrder`` defined by the
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LayeringPolicy document.
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:type documents: List[dict]
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:param substitution_sources: List of documents that are potential
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sources for substitution. Should only include concrete documents.
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:type substitution_sources: List[dict]
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:raises LayeringPolicyNotFound: If no LayeringPolicy was found among
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list of ``documents``.
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:raises InvalidDocumentLayer: If document layer not found in layerOrder
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for provided LayeringPolicy.
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:raises InvalidDocumentParent: If child references parent but they
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don't have the same schema or their layers are incompatible.
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:raises IndeterminateDocumentParent: If more than one parent document
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was found for a document.
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"""
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self._documents_to_layer = []
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self._documents_by_layer = {}
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self._documents_by_labels = {}
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self._layering_policy = None
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layering_policies = list(
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filter(lambda x: x.get('schema').startswith(
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types.LAYERING_POLICY_SCHEMA), documents))
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if layering_policies:
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self._layering_policy = document_wrapper.DocumentDict(
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layering_policies[0])
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if len(layering_policies) > 1:
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LOG.warning('More than one layering policy document was '
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'passed in. Using the first one found: [%s] %s.',
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self._layering_policy.schema,
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self._layering_policy.name)
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if self._layering_policy is None:
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error_msg = (
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'No layering policy found in the system so could not render '
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'documents.')
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LOG.error(error_msg)
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raise errors.LayeringPolicyNotFound()
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sorted_documents = self._topologically_sort_documents(documents)
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for document in sorted_documents:
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document = document_wrapper.DocumentDict(document)
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if document.layering_definition:
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self._documents_to_layer.append(document)
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if document.layer:
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if document.layer not in self._layering_policy.layer_order:
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LOG.error('Document layer %s for document [%s] %s not '
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'in layerOrder: %s.', document.layer,
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document.schema, document.name,
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self._layering_policy.layer_order)
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raise errors.InvalidDocumentLayer(
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document_schema=document.schema,
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document_name=document.name,
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layer_order=', '.join(
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self._layering_policy.layer_order),
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layering_policy_name=self._layering_policy.name)
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self._documents_by_layer.setdefault(document.layer, [])
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self._documents_by_layer[document.layer].append(document)
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if document.parent_selector:
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for label_key, label_val in document.parent_selector.items():
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self._documents_by_labels.setdefault(
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(label_key, label_val), [])
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self._documents_by_labels[
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(label_key, label_val)].append(document)
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self._layer_order = self._get_layering_order(self._layering_policy)
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self._calc_all_document_children()
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self._substitution_sources = substitution_sources or []
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self.secrets_substitution = secrets_manager.SecretsSubstitution(
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self._substitution_sources)
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del self._documents_by_layer
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del self._documents_by_labels
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def _apply_action(self, action, child_data, overall_data):
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"""Apply actions to each layer that is rendered.
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Supported actions include:
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* `merge` - a "deep" merge that layers new and modified data onto
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existing data
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* `replace` - overwrite data at the specified path and replace it
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with the data given in this document
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* `delete` - remove the data at the specified path
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:raises UnsupportedActionMethod: If the layering action isn't found
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among ``self.SUPPORTED_METHODS``.
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:raises MissingDocumentKey: If a layering action path isn't found
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in both the parent and child documents being layered together.
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"""
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method = action['method']
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if method not in self.SUPPORTED_METHODS:
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raise errors.UnsupportedActionMethod(
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action=action, document=child_data)
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# Use copy to prevent these data from being updated referentially.
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overall_data = copy.deepcopy(overall_data)
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child_data = copy.deepcopy(child_data)
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rendered_data = overall_data
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# Remove empty string paths and ensure that "data" is always present.
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path = action['path'].split('.')
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path = [p for p in path if p != '']
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path.insert(0, 'data')
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last_key = 'data' if not path[-1] else path[-1]
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for attr in path:
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if attr == path[-1]:
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break
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rendered_data = rendered_data.get(attr)
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child_data = child_data.get(attr)
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if method == 'delete':
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# If the entire document is passed (i.e. the dict including
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# metadata, data, schema, etc.) then reset data to an empty dict.
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if last_key == 'data':
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rendered_data['data'] = {}
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elif last_key in rendered_data:
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del rendered_data[last_key]
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elif last_key not in rendered_data:
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# If the key does not exist in `rendered_data`, this is a
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# validation error.
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raise errors.MissingDocumentKey(
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child=child_data, parent=rendered_data, key=last_key)
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elif method == 'merge':
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if last_key in rendered_data and last_key in child_data:
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# If both entries are dictionaries, do a deep merge. Otherwise
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# do a simple merge.
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if (isinstance(rendered_data[last_key], dict)
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and isinstance(child_data[last_key], dict)):
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engine_utils.deep_merge(
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rendered_data[last_key], child_data[last_key])
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else:
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rendered_data.setdefault(last_key, child_data[last_key])
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elif last_key in child_data:
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rendered_data.setdefault(last_key, child_data[last_key])
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else:
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# If the key does not exist in the child document, this is a
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# validation error.
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raise errors.MissingDocumentKey(
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child=child_data, parent=rendered_data, key=last_key)
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elif method == 'replace':
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if last_key in rendered_data and last_key in child_data:
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rendered_data[last_key] = child_data[last_key]
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elif last_key in child_data:
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rendered_data.setdefault(last_key, child_data[last_key])
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elif last_key not in child_data:
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# If the key does not exist in the child document, this is a
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# validation error.
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raise errors.MissingDocumentKey(
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child=child_data, parent=rendered_data, key=last_key)
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return overall_data
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def _get_children(self, document):
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"""Recursively retrieve all children.
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Used in the layering module when calculating children for each
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document.
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:returns: List of nested children.
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:rtype: Generator[:class:`DocumentDict`]
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"""
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for child in self._children.get((document.name, document.schema), []):
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yield child
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grandchildren = self._get_children(child)
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for grandchild in grandchildren:
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yield grandchild
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def render(self):
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"""Perform layering on the list of documents passed to ``__init__``.
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Each concrete document will undergo layering according to the actions
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defined by its ``metadata.layeringDefinition``. Documents are layered
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with their parents. A parent document's ``schema`` must match that of
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the child, and its ``metadata.labels`` must much the child's
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``metadata.layeringDefinition.parentSelector``.
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:returns: The list of concrete rendered documents.
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:rtype: List[dict]
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:raises UnsupportedActionMethod: If the layering action isn't found
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among ``self.SUPPORTED_METHODS``.
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:raises MissingDocumentKey: If a layering action path isn't found
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in both the parent and child documents being layered together.
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"""
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# ``rendered_data_by_layer`` tracks the set of changes across all
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# actions across each layer for a specific document.
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rendered_data_by_layer = document_wrapper.DocumentDict()
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# NOTE(fmontei): ``global_docs`` represents the topmost documents in
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# the system. It should probably be impossible for more than 1
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# top-level doc to exist, but handle multiple for now.
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global_docs = [
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doc for doc in self._documents_to_layer
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if self._layer_order and doc.layer == self._layer_order[0]
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]
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for doc in global_docs:
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layer_idx = self._layer_order.index(doc.layer)
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if doc.substitutions:
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substituted_data = list(
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self.secrets_substitution.substitute_all(doc))
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if substituted_data:
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rendered_data_by_layer[layer_idx] = substituted_data[0]
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else:
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rendered_data_by_layer[layer_idx] = doc
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# Keep iterating as long as a child exists.
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for child in self._get_children(doc):
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# Retrieve the most up-to-date rendered_data (by referencing
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# the child's parent's data).
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child_layer_idx = self._layer_order.index(child.layer)
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parent = self._parents[child.name, child.schema]
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parent_layer_idx = self._layer_order.index(parent.layer)
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rendered_data = rendered_data_by_layer[parent_layer_idx]
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# Apply each action to the current document.
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for action in child.actions:
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LOG.debug('Applying action %s to child document with '
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'name=%s, schema=%s, layer=%s.', action,
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child.name, child.schema, child.layer)
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rendered_data = self._apply_action(
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action, child, rendered_data)
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# Update the actual document data if concrete.
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if not child.is_abstract:
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child_index = self._documents_to_layer.index(child)
|
|
child.data = rendered_data.data
|
|
substituted_data = list(
|
|
self.secrets_substitution.substitute_all(child))
|
|
if substituted_data:
|
|
rendered_data = substituted_data[0]
|
|
self._documents_to_layer[child_index].data = (
|
|
rendered_data.data)
|
|
|
|
# Update ``rendered_data_by_layer`` for this layer so that
|
|
# children in deeper layers can reference the most up-to-date
|
|
# changes.
|
|
rendered_data_by_layer[child_layer_idx] = rendered_data
|
|
|
|
# Handle edge case for parentless documents that require substitution.
|
|
# If a document has no parent, then the for loop above doesn't iterate
|
|
# over the parentless document, so substitution must be done here for
|
|
# parentless documents.
|
|
for doc in self._parentless_documents:
|
|
if not doc.is_abstract and doc.substitutions:
|
|
substituted_data = list(
|
|
self.secrets_substitution.substitute_all(doc))
|
|
if substituted_data:
|
|
doc = substituted_data[0]
|
|
|
|
# Return only concrete documents.
|
|
return [d for d in self._documents_to_layer if d.is_abstract is False]
|