diff options
Diffstat (limited to 'cloudinit/templater.py')
| -rw-r--r-- | cloudinit/templater.py | 28 |
1 files changed, 25 insertions, 3 deletions
diff --git a/cloudinit/templater.py b/cloudinit/templater.py index 7e7acb86..b668674b 100644 --- a/cloudinit/templater.py +++ b/cloudinit/templater.py @@ -13,6 +13,7 @@ import collections import re + try: from Cheetah.Template import Template as CTemplate CHEETAH_AVAILABLE = True @@ -20,23 +21,44 @@ except (ImportError, AttributeError): CHEETAH_AVAILABLE = False try: - import jinja2 + 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 simple replacement of bash variable like templates. + """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 @@ -82,7 +104,7 @@ def detect_template(text): # keep_trailing_newline is in jinja2 2.7+, not 2.6 add = "\n" if content.endswith("\n") else "" return JTemplate(content, - undefined=jinja2.StrictUndefined, + undefined=UndefinedJinjaVariable, trim_blocks=True).render(**params) + add if text.find("\n") != -1: |