# Copyright (C) 2012 Canonical Ltd. # Copyright (C) 2012 Hewlett-Packard Development Company, L.P. # Copyright (C) 2012 Yahoo! Inc. # Copyright (C) 2016 Amazon.com, Inc. or its affiliates. # # Author: Scott Moser # Author: Juerg Haefliger # Author: Joshua Harlow # Author: Andrew Jorgensen # # This file is part of cloud-init. See LICENSE file for license information. import collections import re try: from Cheetah.Template import Template as CTemplate CHEETAH_AVAILABLE = True except (ImportError, AttributeError): CHEETAH_AVAILABLE = False try: from jinja2.runtime import implements_to_string from jinja2 import Template as JTemplate from jinja2 import DebugUndefined as JUndefined JINJA_AVAILABLE = True except (ImportError, AttributeError): from cloudinit.helpers import identity implements_to_string = identity JINJA_AVAILABLE = False JUndefined = object from cloudinit import log as logging from cloudinit import type_utils as tu from cloudinit import util LOG = logging.getLogger(__name__) TYPE_MATCHER = re.compile(r"##\s*template:(.*)", re.I) BASIC_MATCHER = re.compile(r'\$\{([A-Za-z0-9_.]+)\}|\$([A-Za-z0-9_.]+)') MISSING_JINJA_PREFIX = u'CI_MISSING_JINJA_VAR/' @implements_to_string # Needed for python2.7. Otherwise cached super.__str__ class UndefinedJinjaVariable(JUndefined): """Class used to represent any undefined jinja template varible.""" def __str__(self): return u'%s%s' % (MISSING_JINJA_PREFIX, self._undefined_name) def __sub__(self, other): other = str(other).replace(MISSING_JINJA_PREFIX, '') raise TypeError( 'Undefined jinja variable: "{this}-{other}". Jinja tried' ' subtraction. Perhaps you meant "{this}_{other}"?'.format( this=self._undefined_name, other=other)) def basic_render(content, params): """This does sumple replacement of bash variable like templates. It identifies patterns like ${a} or $a and can also identify patterns like ${a.b} or $a.b which will look for a key 'b' in the dictionary rooted by key 'a'. """ def replacer(match): # Only 1 of the 2 groups will actually have a valid entry. name = match.group(1) if name is None: name = match.group(2) if name is None: raise RuntimeError("Match encountered but no valid group present") path = collections.deque(name.split(".")) selected_params = params while len(path) > 1: key = path.popleft() if not isinstance(selected_params, dict): raise TypeError("Can not traverse into" " non-dictionary '%s' of type %s while" " looking for subkey '%s'" % (selected_params, tu.obj_name(selected_params), key)) selected_params = selected_params[key] key = path.popleft() if not isinstance(selected_params, dict): raise TypeError("Can not extract key '%s' from non-dictionary" " '%s' of type %s" % (key, selected_params, tu.obj_name(selected_params))) return str(selected_params[key]) return BASIC_MATCHER.sub(replacer, content) def detect_template(text): def cheetah_render(content, params): return CTemplate(content, searchList=[params]).respond() def jinja_render(content, params): # keep_trailing_newline is in jinja2 2.7+, not 2.6 add = "\n" if content.endswith("\n") else "" return JTemplate(content, undefined=UndefinedJinjaVariable, trim_blocks=True).render(**params) + add if text.find("\n") != -1: ident, rest = text.split("\n", 1) else: ident = text rest = '' type_match = TYPE_MATCHER.match(ident) if not type_match: if CHEETAH_AVAILABLE: LOG.debug("Using Cheetah as the renderer for unknown template.") return ('cheetah', cheetah_render, text) else: return ('basic', basic_render, text) else: template_type = type_match.group(1).lower().strip() if template_type not in ('jinja', 'cheetah', 'basic'): raise ValueError("Unknown template rendering type '%s' requested" % template_type) if template_type == 'jinja' and not JINJA_AVAILABLE: LOG.warning("Jinja not available as the selected renderer for" " desired template, reverting to the basic renderer.") return ('basic', basic_render, rest) elif template_type == 'jinja' and JINJA_AVAILABLE: return ('jinja', jinja_render, rest) if template_type == 'cheetah' and not CHEETAH_AVAILABLE: LOG.warning("Cheetah not available as the selected renderer for" " desired template, reverting to the basic renderer.") return ('basic', basic_render, rest) elif template_type == 'cheetah' and CHEETAH_AVAILABLE: return ('cheetah', cheetah_render, rest) # Only thing left over is the basic renderer (it is always available). return ('basic', basic_render, rest) def render_from_file(fn, params): if not params: params = {} # jinja in python2 uses unicode internally. All py2 str will be decoded. # If it is given a str that has non-ascii then it will raise a # UnicodeDecodeError. So we explicitly convert to unicode type here. template_type, renderer, content = detect_template( util.load_file(fn, decode=False).decode('utf-8')) LOG.debug("Rendering content of '%s' using renderer %s", fn, template_type) return renderer(content, params) def render_to_file(fn, outfn, params, mode=0o644): contents = render_from_file(fn, params) util.write_file(outfn, contents, mode=mode) def render_string_to_file(content, outfn, params, mode=0o644): """Render string (or py2 unicode) to file. Warning: py2 str with non-ascii chars will cause UnicodeDecodeError.""" contents = render_string(content, params) util.write_file(outfn, contents, mode=mode) def render_string(content, params): """Render string (or py2 unicode). Warning: py2 str with non-ascii chars will cause UnicodeDecodeError.""" if not params: params = {} _template_type, renderer, content = detect_template(content) return renderer(content, params) # vi: ts=4 expandtab