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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
commit5f8de423f190bbb79a62f804151bc24824fa32d8 (patch)
tree10027f336435511475e392454359edea8e25895d /taskcluster/taskgraph/util/templates.py
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
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+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+from __future__ import absolute_import, print_function, unicode_literals
+
+import os
+
+import pystache
+import yaml
+import copy
+
+# Key used in template inheritance...
+INHERITS_KEY = '$inherits'
+
+
+def merge_to(source, dest):
+ '''
+ Merge dict and arrays (override scalar values)
+
+ Keys from source override keys from dest, and elements from lists in source
+ are appended to lists in dest.
+
+ :param dict source: to copy from
+ :param dict dest: to copy to (modified in place)
+ '''
+
+ for key, value in source.items():
+ # Override mismatching or empty types
+ if type(value) != type(dest.get(key)): # noqa
+ dest[key] = source[key]
+ continue
+
+ # Merge dict
+ if isinstance(value, dict):
+ merge_to(value, dest[key])
+ continue
+
+ if isinstance(value, list):
+ dest[key] = dest[key] + source[key]
+ continue
+
+ dest[key] = source[key]
+
+ return dest
+
+
+def merge(*objects):
+ '''
+ Merge the given objects, using the semantics described for merge_to, with
+ objects later in the list taking precedence. From an inheritance
+ perspective, "parents" should be listed before "children".
+
+ Returns the result without modifying any arguments.
+ '''
+ if len(objects) == 1:
+ return copy.deepcopy(objects[0])
+ return merge_to(objects[-1], merge(*objects[:-1]))
+
+
+class TemplatesException(Exception):
+ pass
+
+
+class Templates():
+ '''
+ The taskcluster integration makes heavy use of yaml to describe tasks this
+ class handles the loading/rendering.
+ '''
+
+ def __init__(self, root):
+ '''
+ Initialize the template render.
+
+ :param str root: Root path where to load yaml files.
+ '''
+ if not root:
+ raise TemplatesException('Root is required')
+
+ if not os.path.isdir(root):
+ raise TemplatesException('Root must be a directory')
+
+ self.root = root
+
+ def _inherits(self, path, obj, properties, seen):
+ blueprint = obj.pop(INHERITS_KEY)
+ seen.add(path)
+
+ # Resolve the path here so we can detect circular references.
+ template = self.resolve_path(blueprint.get('from'))
+ variables = blueprint.get('variables', {})
+
+ # Passed parameters override anything in the task itself.
+ for key in properties:
+ variables[key] = properties[key]
+
+ if not template:
+ msg = '"{}" inheritance template missing'.format(path)
+ raise TemplatesException(msg)
+
+ if template in seen:
+ msg = 'Error while handling "{}" in "{}" circular template' + \
+ 'inheritance seen \n {}'
+ raise TemplatesException(msg.format(path, template, seen))
+
+ try:
+ out = self.load(template, variables, seen)
+ except TemplatesException as e:
+ msg = 'Error expanding parent ("{}") of "{}" original error {}'
+ raise TemplatesException(msg.format(template, path, str(e)))
+
+ # Anything left in obj is merged into final results (and overrides)
+ return merge_to(obj, out)
+
+ def render(self, path, content, parameters, seen):
+ '''
+ Renders a given yaml string.
+
+ :param str path: used to prevent infinite recursion in inheritance.
+ :param str content: Of yaml file.
+ :param dict parameters: For mustache templates.
+ :param set seen: Seen files (used for inheritance)
+ '''
+ content = pystache.render(content, parameters)
+ result = yaml.load(content)
+
+ # In addition to the usual template logic done by mustache we also
+ # handle special '$inherit' dict keys.
+ if isinstance(result, dict) and INHERITS_KEY in result:
+ return self._inherits(path, result, parameters, seen)
+
+ return result
+
+ def resolve_path(self, path):
+ return os.path.join(self.root, path)
+
+ def load(self, path, parameters=None, seen=None):
+ '''
+ Load an render the given yaml path.
+
+ :param str path: Location of yaml file to load (relative to root).
+ :param dict parameters: To template yaml file with.
+ '''
+ seen = seen or set()
+
+ if not path:
+ raise TemplatesException('path is required')
+
+ path = self.resolve_path(path)
+
+ if not os.path.isfile(path):
+ raise TemplatesException('"{}" is not a file'.format(path))
+
+ content = open(path).read()
+ return self.render(path, content, parameters, seen)