#!/usr/bin/env python # Copyright (C) 2013 Hewlett-Packard. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the # License for the specific language governing permissions and limitations # under the License. # Provides local yaml parsing classes and extend yaml module """Custom application specific yamls tags are supported to provide enhancements when reading yaml configuration. Action Tags ^^^^^^^^^^^ These allow manipulation of data being stored in one layout in the source yaml for convenience and/or clarity, to another format to be processed by the targeted module instead of requiring all modules in JJB being capable of supporting multiple input formats. The tag ``!join:`` will treat the first element of the following list as the delimiter to use, when joining the remaining elements into a string and returning a single string to be consumed by the specified module option. This allows users to maintain elements of data in a list structure for ease of review/maintenance, and have the yaml parser convert it to a string for consumption as any argument for modules. The main expected use case is to allow for generic plugin data such as shell properties to be populated from a list construct which the yaml parser converts to a single string, instead of trying to support this within the module code which would require a templating engine similar to Jinja. Generic Example: .. literalinclude:: /../../tests/localyaml/fixtures/joinlists.yaml Environment Inject: .. literalinclude:: /../../tests/yamlparser/fixtures/string_join.yaml While this mechanism can also be used items where delimiters are supported by the module, that should be considered a bug that the existing code doesn't handle being provided a list and delimiter to perform the correct conversion for you. Should you discover a module that takes arguments with delimiters and the existing JJB codebase does not handle accepting lists, then this can be used as a temporary solution in place of using very long strings: Extended Params Example: .. literalinclude:: /../../tests/parameters/fixtures/extended-choice-param-full.yaml Inclusion Tags ^^^^^^^^^^^^^^ These allow inclusion of arbitrary files as a method of having blocks of data managed separately to the yaml job configurations. A specific usage of this is inlining scripts contained in separate files, although such tags may also be used to simplify usage of macros or job templates. The tag ``!include:`` will treat the following string as file which should be parsed as yaml configuration data. Example: .. literalinclude:: /../../tests/localyaml/fixtures/include001.yaml contents of include001.yaml.inc: .. literalinclude:: /../../tests/yamlparser/fixtures/include001.yaml.inc The tag ``!include-raw:`` will treat the given string or list of strings as filenames to be opened as one or more data blob, which should be read into the calling yaml construct without any further parsing. Any data in a file included through this tag, will be treated as string data. Examples: .. literalinclude:: /../../tests/localyaml/fixtures/include-raw001.yaml contents of include-raw001-hello-world.sh: .. literalinclude:: /../../tests/localyaml/fixtures/include-raw001-hello-world.sh contents of include-raw001-vars.sh: .. literalinclude:: /../../tests/localyaml/fixtures/include-raw001-vars.sh using a list of files: .. literalinclude:: /../../tests/localyaml/fixtures/include-raw-multi001.yaml The tag ``!include-raw-escape:`` treats the given string or list of strings as filenames to be opened as one or more data blobs, which should be escaped before being read in as string data. This allows job-templates to use this tag to include scripts from files without needing to escape braces in the original file. .. warning:: When used as a macro ``!include-raw-escape:`` should only be used if parameters are passed into the escaped file and you would like to escape those parameters. If the file does not have any jjb parameters passed into it then ``!include-raw:`` should be used instead otherwise you will run into an interesting issue where ``include-raw-escape:`` actually adds additional curly braces around existing curly braces. For example ${PROJECT} becomes ${{PROJECT}} which may break bash scripts. Examples: .. literalinclude:: /../../tests/localyaml/fixtures/include-raw-escaped001.yaml contents of include-raw001-hello-world.sh: .. literalinclude:: /../../tests/localyaml/fixtures/include-raw001-hello-world.sh contents of include-raw001-vars.sh: .. literalinclude:: /../../tests/localyaml/fixtures/include-raw001-vars.sh using a list of files: .. literalinclude:: /../../tests/localyaml/fixtures/include-raw-escaped-multi001.yaml For all the multi file includes, the files are simply appended using a newline character. To allow for job templates to perform substitution on the path names, when a filename containing a python format placeholder is encountered, lazy loading support is enabled, where instead of returning the contents back during yaml parsing, it is delayed until the variable substitution is performed. Example: .. literalinclude:: /../../tests/yamlparser/fixtures/lazy-load-jobs001.yaml using a list of files: .. literalinclude:: /../../tests/yamlparser/fixtures/lazy-load-jobs-multi001.yaml .. note:: Because lazy-loading involves performing the substitution on the file name, it means that jenkins-job-builder can not call the variable substitution on the contents of the file. This means that the ``!include-raw:`` tag will behave as though ``!include-raw-escape:`` tag was used instead whenever name substitution on the filename is to be performed. Given the behaviour described above, when substitution is to be performed on any filename passed via ``!include-raw-escape:`` the tag will be automatically converted to ``!include-raw:`` and no escaping will be performed. The tag ``!include-jinja2:`` will treat the given string or list of strings as filenames to be opened as Jinja2 templates, which should be rendered to a string and included in the calling YAML construct. (This is analogous to the templating that will happen with ``!include-raw``.) Examples: .. literalinclude:: /../../tests/yamlparser/fixtures/jinja01.yaml contents of jinja01.yaml.inc: .. literalinclude:: /../../tests/yamlparser/fixtures/jinja01.yaml.inc The tag ``!j2:`` takes a string and treats it as a Jinja2 template. It will be rendered (with the variables in that context) and included in the calling YAML construct. Examples: .. literalinclude:: /../../tests/yamlparser/fixtures/jinja-string01.yaml """ import functools import io import logging import os import re import jinja2 import yaml from yaml.constructor import BaseConstructor from yaml.representer import BaseRepresenter from yaml import YAMLObject from collections import OrderedDict logger = logging.getLogger(__name__) class OrderedConstructor(BaseConstructor): """The default constructor class for PyYAML loading uses standard python dictionaries which can have randomized ordering enabled (default in CPython from version 3.3). The order of the XML elements being outputted is both important for tests and for ensuring predictable generation based on the source. This subclass overrides this behaviour to ensure that all dict's created make use of OrderedDict to have iteration of keys to always follow the order in which the keys were inserted/created. """ def construct_yaml_map(self, node): data = OrderedDict() yield data value = self.construct_mapping(node) if isinstance(node, yaml.MappingNode): self.flatten_mapping(node) else: raise yaml.constructor.ConstructorError( None, None, 'expected a mapping node, but found %s' % node.id, node.start_mark) mapping = OrderedDict() for key_node, value_node in node.value: key = self.construct_object(key_node, deep=False) try: hash(key) except TypeError as exc: raise yaml.constructor.ConstructorError( 'while constructing a mapping', node.start_mark, 'found unacceptable key (%s)' % exc, key_node.start_mark) value = self.construct_object(value_node, deep=False) mapping[key] = value data.update(mapping) class OrderedRepresenter(BaseRepresenter): def represent_yaml_mapping(self, mapping, flow_style=None): tag = u'tag:yaml.org,2002:map' node = self.represent_mapping(tag, mapping, flow_style=flow_style) return node class LocalAnchorLoader(yaml.Loader): """Subclass for yaml.Loader which keeps Alias between calls""" anchors = {} def __init__(self, *args, **kwargs): super(LocalAnchorLoader, self).__init__(*args, **kwargs) self.anchors = LocalAnchorLoader.anchors @classmethod def reset_anchors(cls): cls.anchors = {} # override the default composer to skip resetting the anchors at the # end of the current document def compose_document(self): # Drop the DOCUMENT-START event. self.get_event() # Compose the root node. node = self.compose_node(None, None) # Drop the DOCUMENT-END event. self.get_event() return node class LocalLoader(OrderedConstructor, LocalAnchorLoader): """Subclass for yaml.Loader which handles storing the search_path and escape_callback functions for use by the custom YAML objects to find files and escape the content where required. Constructor access a list of search paths to look under for the given file following each tag, taking the first match found. Search path by default will include the same directory as the yaml file and the current working directory. Loading:: # use the load function provided in this module import local_yaml data = local_yaml.load(io.open(fn, 'r', encoding='utf-8')) # Loading by providing the alternate class to the default yaml load from local_yaml import LocalLoader data = yaml.load(io.open(fn, 'r', encoding='utf-8'), LocalLoader) # Loading with a search path from local_yaml import LocalLoader import functools data = yaml.load(io.open(fn, 'r', encoding='utf-8'), functools.partial(LocalLoader, search_path=['path'])) """ def __init__(self, *args, **kwargs): # make sure to pop off any local settings before passing to # the parent constructor as any unknown args may cause errors. self.search_path = list() if 'search_path' in kwargs: for p in kwargs.pop('search_path'): logger.debug("Adding '{0}' to search path for include tags" .format(p)) self.search_path.append(os.path.normpath(p)) if 'escape_callback' in kwargs: self.escape_callback = kwargs.pop('escape_callback') else: self.escape_callback = self._escape super(LocalLoader, self).__init__(*args, **kwargs) # constructor to preserve order of maps and ensure that the order of # keys returned is consistent across multiple python versions self.add_constructor(yaml.resolver.BaseResolver.DEFAULT_MAPPING_TAG, type(self).construct_yaml_map) if hasattr(self.stream, 'name'): self.search_path.append(os.path.normpath( os.path.dirname(self.stream.name))) self.search_path.append(os.path.normpath(os.path.curdir)) def _escape(self, data): return re.sub(r'({|})', r'\1\1', data) class LocalDumper(OrderedRepresenter, yaml.Dumper): def __init__(self, *args, **kwargs): super(LocalDumper, self).__init__(*args, **kwargs) # representer to ensure conversion back looks like normal # mapping and hides that we use OrderedDict internally self.add_representer(OrderedDict, type(self).represent_yaml_mapping) # convert any tuples to lists as the JJB input is generally # in list format self.add_representer(tuple, type(self).represent_list) class BaseYAMLObject(YAMLObject): yaml_loader = LocalLoader yaml_dumper = LocalDumper class J2String(BaseYAMLObject): yaml_tag = u'!j2:' @classmethod def from_yaml(cls, loader, node): return Jinja2Loader(node.value, loader.search_path) class YamlListJoin(BaseYAMLObject): yaml_tag = u'!join:' @classmethod def from_yaml(cls, loader, node): if isinstance(node, yaml.SequenceNode): delimiter = node.value[0].value if not isinstance(node.value[1], yaml.SequenceNode): raise yaml.constructor.ConstructorError( None, None, "expected sequence node for join data, but " "found %s" % node.value[1].id, node.start_mark) return delimiter.join((v.value for v in node.value[1].value)) else: raise yaml.constructor.ConstructorError( None, None, "expected sequence node, but found %s" % node.id, node.start_mark) class YamlInclude(BaseYAMLObject): yaml_tag = u'!include:' @classmethod def _find_file(cls, filename, search_path): for dirname in search_path: candidate = os.path.expanduser(os.path.join(dirname, filename)) if os.path.isfile(candidate): logger.debug("Including file '{0}' from path '{1}'" .format(filename, dirname)) return candidate return filename @classmethod def _open_file(cls, loader, node): node_str = loader.construct_yaml_str(node) try: node_str.format() except KeyError: return cls._lazy_load(loader, cls.yaml_tag, node) filename = cls._find_file(node_str, loader.search_path) try: with io.open(filename, 'r', encoding='utf-8') as f: return f.read() except: logger.error("Failed to include file using search path: '{0}'" .format(':'.join(loader.search_path))) raise @classmethod def _from_file(cls, loader, node): contents = cls._open_file(loader, node) if isinstance(contents, LazyLoader): return contents data = yaml.load(contents, functools.partial(cls.yaml_loader, search_path=loader.search_path)) return data @classmethod def _lazy_load(cls, loader, tag, node_str): logger.info("Lazy loading of file template '{0}' enabled" .format(node_str)) return LazyLoader((cls, loader, node_str)) @classmethod def from_yaml(cls, loader, node): if isinstance(node, yaml.ScalarNode): return cls._from_file(loader, node) elif isinstance(node, yaml.SequenceNode): contents = [cls._from_file(loader, scalar_node) for scalar_node in node.value] if any(isinstance(s, CustomLoader) for s in contents): return CustomLoaderCollection(contents) return u'\n'.join(contents) else: raise yaml.constructor.ConstructorError( None, None, "expected either a sequence or scalar node, but " "found %s" % node.id, node.start_mark) class YamlIncludeRaw(YamlInclude): yaml_tag = u'!include-raw:' @classmethod def _from_file(cls, loader, node): return cls._open_file(loader, node) class YamlIncludeRawEscape(YamlIncludeRaw): yaml_tag = u'!include-raw-escape:' @classmethod def from_yaml(cls, loader, node): data = YamlIncludeRaw.from_yaml(loader, node) if isinstance(data, LazyLoader): logger.warning("Replacing %s tag with %s since lazy loading means " "file contents will not be deep formatted for " "variable substitution.", cls.yaml_tag, YamlIncludeRaw.yaml_tag) return data else: return loader.escape_callback(data) class YamlIncludeJinja2(YamlIncludeRaw): yaml_tag = u'!include-jinja2:' @classmethod def _from_file(cls, loader, node): contents = cls._open_file(loader, node) if isinstance(contents, LazyLoader): return contents return Jinja2Loader(contents, loader.search_path) class DeprecatedTag(BaseYAMLObject): @classmethod def from_yaml(cls, loader, node): logger.warning("tag '%s' is deprecated, switch to using '%s'", cls.yaml_tag, cls._new.yaml_tag) return cls._new.from_yaml(loader, node) class YamlIncludeDeprecated(DeprecatedTag): yaml_tag = u'!include' _new = YamlInclude class YamlIncludeRawDeprecated(DeprecatedTag): yaml_tag = u'!include-raw' _new = YamlIncludeRaw class YamlIncludeRawEscapeDeprecated(DeprecatedTag): yaml_tag = u'!include-raw-escape' _new = YamlIncludeRawEscape class CustomLoader(object): """Parent class for non-standard loaders.""" class Jinja2Loader(CustomLoader): """A loader for Jinja2-templated files.""" def __init__(self, contents, search_path): self._template = jinja2.Template(contents) self._template.environment.undefined = jinja2.StrictUndefined self._template.environment.loader = jinja2.FileSystemLoader( search_path) def format(self, **kwargs): return self._template.render(kwargs) class CustomLoaderCollection(object): """Helper class to format a collection of CustomLoader objects""" def __init__(self, sequence): self._data = sequence def format(self, *args, **kwargs): return u'\n'.join(item.format(*args, **kwargs) for item in self._data) class LazyLoader(CustomLoader): """Helper class to provide lazy loading of files included using !include* tags where the path to the given file contains unresolved placeholders. """ def __init__(self, data): # str subclasses can only have one argument, so assume it is a tuple # being passed and unpack as needed self._cls, self._loader, self._node = data def __str__(self): return "%s %s" % (self._cls.yaml_tag, self._node.value) def __repr__(self): return "%s %s" % (self._cls.yaml_tag, self._node.value) def format(self, *args, **kwargs): node = yaml.ScalarNode( tag=self._node.tag, value=self._node.value.format(*args, **kwargs)) return self._cls.from_yaml(self._loader, node) def load(stream, **kwargs): LocalAnchorLoader.reset_anchors() return yaml.load(stream, functools.partial(LocalLoader, **kwargs)) def dump(data, stream=None, **kwargs): return yaml.dump(data, stream, Dumper=LocalDumper, **kwargs)