name : jinja_template.py # This file is part of cloud-init. See LICENSE file for license information. import copy import logging import os import re from errno import EACCES from typing import Optional, Type from cloudinit import handlers from cloudinit.atomic_helper import b64d, json_dumps from cloudinit.helpers import Paths from cloudinit.settings import PER_ALWAYS from cloudinit.templater import ( MISSING_JINJA_PREFIX, JinjaSyntaxParsingException, detect_template, render_string, ) from cloudinit.util import load_json, load_text_file JUndefinedError: Type[Exception] try: from jinja2.exceptions import UndefinedError as JUndefinedError from jinja2.lexer import operator_re except ImportError: # No jinja2 dependency JUndefinedError = Exception operator_re = re.compile(r"[-.]") LOG = logging.getLogger(__name__) class JinjaLoadError(Exception): pass class NotJinjaError(Exception): pass class JinjaTemplatePartHandler(handlers.Handler): prefixes = ["## template: jinja"] def __init__(self, paths: Paths, **_kwargs): handlers.Handler.__init__(self, PER_ALWAYS, version=3) self.paths = paths self.sub_handlers = {} for handler in _kwargs.get("sub_handlers", []): for ctype in handler.list_types(): self.sub_handlers[ctype] = handler def handle_part(self, data, ctype, filename, payload, frequency, headers): if ctype in handlers.CONTENT_SIGNALS: return jinja_json_file = self.paths.get_runpath("instance_data_sensitive") try: rendered_payload = render_jinja_payload_from_file( payload, filename, jinja_json_file ) except JinjaSyntaxParsingException as e: LOG.warning( "Ignoring jinja template for %s. " "Failed to render template. %s", filename, str(e), ) return if not rendered_payload: return subtype = handlers.type_from_starts_with(rendered_payload) sub_handler = self.sub_handlers.get(subtype) if not sub_handler: LOG.warning( "Ignoring jinja template for %s. Could not find supported" " sub-handler for type %s", filename, subtype, ) return if sub_handler.handler_version == 3: sub_handler.handle_part( data, ctype, filename, rendered_payload, frequency, headers ) elif sub_handler.handler_version == 2: sub_handler.handle_part( data, ctype, filename, rendered_payload, frequency ) def render_jinja_payload_from_file( payload, payload_fn, instance_data_file, debug=False ): r"""Render a jinja template sourcing variables from jinja_vars_path. @param payload: String of jinja template content. Should begin with ## template: jinja\n. @param payload_fn: String representing the filename from which the payload was read used in error reporting. Generally in part-handling this is 'part-##'. @param instance_data_file: A path to a json file containing variables that will be used as jinja template variables. @return: A string of jinja-rendered content with the jinja header removed. Returns None on error. """ if detect_template(payload)[0] != "jinja": raise NotJinjaError("Payload is not a jinja template") instance_data = {} rendered_payload = None if not os.path.exists(instance_data_file): raise JinjaLoadError( "Cannot render jinja template vars. Instance data not yet" " present at %s" % instance_data_file ) try: instance_data = load_json(load_text_file(instance_data_file)) except Exception as e: msg = "Loading Jinja instance data failed" if isinstance(e, (IOError, OSError)): if e.errno == EACCES: msg = ( "Cannot render jinja template vars. No read permission on" " '%s'. Try sudo" % instance_data_file ) raise JinjaLoadError(msg) from e rendered_payload = render_jinja_payload( payload, payload_fn, instance_data, debug ) if not rendered_payload: return None return rendered_payload def render_jinja_payload(payload, payload_fn, instance_data, debug=False): instance_jinja_vars = convert_jinja_instance_data( instance_data, decode_paths=instance_data.get("base64-encoded-keys", []), include_key_aliases=True, ) if debug: LOG.debug( "Converted jinja variables\n%s", json_dumps(instance_jinja_vars) ) try: rendered_payload = render_string(payload, instance_jinja_vars) except (TypeError, JUndefinedError) as e: LOG.warning("Ignoring jinja template for %s: %s", payload_fn, str(e)) return None warnings = [ "'%s'" % var.replace(MISSING_JINJA_PREFIX, "") for var in re.findall( r"%s[^\s]+" % MISSING_JINJA_PREFIX, rendered_payload ) ] if warnings: LOG.warning( "Could not render jinja template variables in file '%s': %s", payload_fn, ", ".join(warnings), ) return rendered_payload def get_jinja_variable_alias(orig_name: str) -> Optional[str]: """Return a jinja variable alias, replacing any operators with underscores. Provide underscore-delimited key aliases to simplify dot-notation attribute references for keys which contain operators "." or "-". This provides for simpler short-hand jinja attribute notation allowing one to avoid quoting keys which contain operators. {{ ds.v1_0.config.user_network_config }} instead of {{ ds['v1.0'].config["user.network-config"] }}. :param orig_name: String representing a jinja variable name to scrub/alias. :return: A string with any jinja operators replaced if needed. Otherwise, none if no alias required. """ alias_name = re.sub(operator_re, "_", orig_name) if alias_name != orig_name: return alias_name return None def convert_jinja_instance_data( data, prefix="", sep="/", decode_paths=(), include_key_aliases=False ): """Process instance-data.json dict for use in jinja templates. Replace hyphens with underscores for jinja templates and decode any base64_encoded_keys. """ result = {} decode_paths = [path.replace("-", "_") for path in decode_paths] for key, value in sorted(data.items()): key_path = "{0}{1}{2}".format(prefix, sep, key) if prefix else key if key_path in decode_paths: value = b64d(value) if isinstance(value, dict): result[key] = convert_jinja_instance_data( value, key_path, sep=sep, decode_paths=decode_paths, include_key_aliases=include_key_aliases, ) if re.match(r"v\d+$", key): # Copy values to top-level aliases for subkey, subvalue in result[key].items(): result[subkey] = copy.deepcopy(subvalue) else: result[key] = value if include_key_aliases: alias_name = get_jinja_variable_alias(key) if alias_name: result[alias_name] = copy.deepcopy(result[key]) return result