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import os
import re
from cloudinit import downloader as down
from cloudinit import exceptions as excp
from cloudinit import log as logging
from cloudinit import shell as sh
INCLUDE_PATT = re.compile("^#(opt_include|include)[ \t](.*)$", re.MULTILINE)
OPT_PATS = ['opt_include']
LOG = logging.getLogger(__name__)
class Includer(object):
def __init__(self, root_fn, stack_limit=10):
self.root_fn = root_fn
self.stack_limit = stack_limit
def _read_file(self, fname):
return sh.read_file(fname)
def _read(self, fname, stack, rel):
if len(stack) >= self.stack_limit:
raise excp.StackExceeded("Stack limit of %s reached while including %s" % (self.stack_limit, fname))
canon_fname = self._canon_name(fname, rel)
if canon_fname in stack:
raise excp.RecursiveInclude("File %s recursively included" % (canon_fname))
stack.add(canon_fname)
new_rel = os.path.dirname(canon_fname)
contents = self._read_file(canon_fname)
def include_cb(match):
is_optional = (match.group(1).lower() in OPT_PATS)
fn = match.group(2).strip()
if not fn:
# Should we die??
return match.group(0)
else:
try:
LOG.debug("Including file %s", fn)
return self._read(fn, stack, new_rel)
except IOError:
if is_optional:
return ''
else:
raise
adjusted_contents = INCLUDE_PATT.sub(include_cb, contents)
stack.remove(fname)
return adjusted_contents
def _canon_name(self, fname, rel):
fname = fname.strip()
if not fname.startswith("/"):
fname = os.path.sep.join([rel, fname])
return os.path.realpath(fname)
def read(self, relative_to="."):
stack = set()
return self._read(self.root_fn, stack, rel=relative_to)
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