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# (c) 2012-2014, Michael DeHaan <michael.dehaan@gmail.com>
#
# This file is part of Ansible
#
# Ansible is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# Ansible is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with Ansible. If not, see <http://www.gnu.org/licenses/>.
# Make coding more python3-ish
from __future__ import (absolute_import, division, print_function)
__metaclass__ = type
import re
from jinja2 import Environment
from jinja2.exceptions import TemplateSyntaxError, UndefinedError
from jinja2.utils import concat as j2_concat
from jinja2.runtime import StrictUndefined
from ansible import constants as C
from ansible.errors import AnsibleError, AnsibleFilterError, AnsibleUndefinedVariable
from ansible.plugins import filter_loader, lookup_loader
from ansible.template.safe_eval import safe_eval
from ansible.template.template import AnsibleJ2Template
from ansible.template.vars import AnsibleJ2Vars
from ansible.utils.debug import debug
from numbers import Number
__all__ = ['Templar']
# A regex for checking to see if a variable we're trying to
# expand is just a single variable name.
SINGLE_VAR = re.compile(r"^{{\s*(\w*)\s*}}$")
# Primitive Types which we don't want Jinja to convert to strings.
NON_TEMPLATED_TYPES = ( bool, Number )
JINJA2_OVERRIDE = '#jinja2:'
JINJA2_ALLOWED_OVERRIDES = ['trim_blocks', 'lstrip_blocks', 'newline_sequence', 'keep_trailing_newline']
class Templar:
'''
The main class for templating, with the main entry-point of template().
'''
def __init__(self, loader, shared_loader_obj=None, variables=dict(), fail_on_undefined=C.DEFAULT_UNDEFINED_VAR_BEHAVIOR):
self._loader = loader
self._basedir = loader.get_basedir()
self._filters = None
self._available_variables = variables
if shared_loader_obj:
self._filter_loader = getattr(shared_loader_obj, 'filter_loader')
self._lookup_loader = getattr(shared_loader_obj, 'lookup_loader')
else:
self._filter_loader = filter_loader
self._lookup_loader = lookup_loader
# flags to determine whether certain failures during templating
# should result in fatal errors being raised
self._fail_on_lookup_errors = True
self._fail_on_filter_errors = True
self._fail_on_undefined_errors = fail_on_undefined
def _count_newlines_from_end(self, in_str):
'''
Counts the number of newlines at the end of a string. This is used during
the jinja2 templating to ensure the count matches the input, since some newlines
may be thrown away during the templating.
'''
i = len(in_str)
while i > 0:
if in_str[i-1] != '\n':
break
i -= 1
return len(in_str) - i
def _get_filters(self):
'''
Returns filter plugins, after loading and caching them if need be
'''
if self._filters is not None:
return self._filters.copy()
plugins = [x for x in self._filter_loader.all()]
self._filters = dict()
for fp in plugins:
self._filters.update(fp.filters())
return self._filters.copy()
def _get_extensions(self):
'''
Return jinja2 extensions to load.
If some extensions are set via jinja_extensions in ansible.cfg, we try
to load them with the jinja environment.
'''
jinja_exts = []
if C.DEFAULT_JINJA2_EXTENSIONS:
# make sure the configuration directive doesn't contain spaces
# and split extensions in an array
jinja_exts = C.DEFAULT_JINJA2_EXTENSIONS.replace(" ", "").split(',')
return jinja_exts
def set_available_variables(self, variables):
'''
Sets the list of template variables this Templar instance will use
to template things, so we don't have to pass them around between
internal methods.
'''
assert isinstance(variables, dict)
self._available_variables = variables.copy()
def template(self, variable, convert_bare=False, preserve_trailing_newlines=False):
'''
Templates (possibly recursively) any given data as input. If convert_bare is
set to True, the given data will be wrapped as a jinja2 variable ('{{foo}}')
before being sent through the template engine.
'''
try:
if convert_bare:
variable = self._convert_bare_variable(variable)
if isinstance(variable, basestring):
result = variable
if self._contains_vars(variable):
# Check to see if the string we are trying to render is just referencing a single
# var. In this case we don't want to accidentally change the type of the variable
# to a string by using the jinja template renderer. We just want to pass it.
only_one = SINGLE_VAR.match(variable)
if only_one:
var_name = only_one.group(1)
if var_name in self._available_variables:
resolved_val = self._available_variables[var_name]
if isinstance(resolved_val, NON_TEMPLATED_TYPES):
return resolved_val
result = self._do_template(variable, preserve_trailing_newlines=preserve_trailing_newlines)
# if this looks like a dictionary or list, convert it to such using the safe_eval method
if (result.startswith("{") and not result.startswith("{{")) or result.startswith("["):
eval_results = safe_eval(result, locals=self._available_variables, include_exceptions=True)
if eval_results[1] is None:
result = eval_results[0]
else:
# FIXME: if the safe_eval raised an error, should we do something with it?
pass
return result
elif isinstance(variable, (list, tuple)):
return [self.template(v, convert_bare=convert_bare) for v in variable]
elif isinstance(variable, dict):
d = {}
for (k, v) in variable.iteritems():
d[k] = self.template(v, convert_bare=convert_bare)
return d
else:
return variable
except AnsibleFilterError:
if self._fail_on_filter_errors:
raise
else:
return variable
def _contains_vars(self, data):
'''
returns True if the data contains a variable pattern
'''
return "$" in data or "{{" in data or '{%' in data
def _convert_bare_variable(self, variable):
'''
Wraps a bare string, which may have an attribute portion (ie. foo.bar)
in jinja2 variable braces so that it is evaluated properly.
'''
if isinstance(variable, basestring):
first_part = variable.split(".")[0].split("[")[0]
if first_part in self._available_variables and '{{' not in variable and '$' not in variable:
return "{{%s}}" % variable
# the variable didn't meet the conditions to be converted,
# so just return it as-is
return variable
def _finalize(self, thing):
'''
A custom finalize method for jinja2, which prevents None from being returned
'''
return thing if thing is not None else ''
def _lookup(self, name, *args, **kwargs):
instance = self._lookup_loader.get(name.lower(), loader=self._loader)
if instance is not None:
# safely catch run failures per #5059
try:
ran = instance.run(*args, variables=self._available_variables, **kwargs)
except AnsibleUndefinedVariable:
raise
except Exception, e:
if self._fail_on_lookup_errors:
raise
ran = None
if ran:
ran = ",".join(ran)
return ran
else:
raise AnsibleError("lookup plugin (%s) not found" % name)
def _do_template(self, data, preserve_trailing_newlines=False):
try:
environment = Environment(trim_blocks=True, undefined=StrictUndefined, extensions=self._get_extensions(), finalize=self._finalize)
environment.filters.update(self._get_filters())
environment.template_class = AnsibleJ2Template
# FIXME: may not be required anymore, as the basedir stuff will
# be handled by the loader?
#if '_original_file' in vars:
# basedir = os.path.dirname(vars['_original_file'])
# filesdir = os.path.abspath(os.path.join(basedir, '..', 'files'))
# if os.path.exists(filesdir):
# basedir = filesdir
try:
t = environment.from_string(data)
except TemplateSyntaxError, e:
raise AnsibleError("template error while templating string: %s" % str(e))
except Exception, e:
if 'recursion' in str(e):
raise AnsibleError("recursive loop detected in template string: %s" % data)
else:
return data
t.globals['lookup'] = self._lookup
t.globals['finalize'] = self._finalize
jvars = AnsibleJ2Vars(self, t.globals)
new_context = t.new_context(jvars, shared=True)
rf = t.root_render_func(new_context)
try:
res = j2_concat(rf)
except TypeError, te:
if 'StrictUndefined' in str(te):
raise AnsibleUndefinedVariable(
"Unable to look up a name or access an attribute in template string. " + \
"Make sure your variable name does not contain invalid characters like '-'."
)
else:
debug("failing because of a type error, template data is: %s" % data)
raise AnsibleError("an unexpected type error occurred. Error was %s" % te)
if preserve_trailing_newlines:
# The low level calls above do not preserve the newline
# characters at the end of the input data, so we use the
# calculate the difference in newlines and append them
# to the resulting output for parity
res_newlines = self._count_newlines_from_end(res)
data_newlines = self._count_newlines_from_end(data)
if data_newlines > res_newlines:
res += '\n' * (data_newlines - res_newlines)
return res
except (UndefinedError, AnsibleUndefinedVariable), e:
if self._fail_on_undefined_errors:
raise
else:
return data
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