try: import ConfigParser except ImportError: # py 3 import configparser as ConfigParser import re from string import Template from syncdutils import escape, unescape, norm, update_file, GsyncdError SECT_ORD = '__section_order__' SECT_META = '__meta__' config_version = 2.0 re_type = type(re.compile('')) class MultiDict(object): """a virtual dict-like class which functions as the union of underlying dicts""" def __init__(self, *dd): self.dicts = dd def __getitem__(self, key): val = None for d in self.dicts: if d.get(key): val = d[key] if not val: raise KeyError(key) return val class GConffile(object): """A high-level interface to ConfigParser which flattens the two-tiered config layout by implenting automatic section dispatch based on initial parameters. Also ensure section ordering in terms of their time of addition -- a compat hack for Python < 2.7. """ def _normconfig(self): """normalize config keys by s/-/_/g""" for n, s in self.config._sections.items(): if n.find('__') == 0: continue s2 = type(s)() for k, v in s.items(): if k.find('__') != 0: k = norm(k) s2[k] = v self.config._sections[n] = s2 def __init__(self, path, peers, *dd): """ - .path: location of config file - .config: underlying ConfigParser instance - .peers: on behalf of whom we flatten .config (master, or master-slave url pair) - .auxdicts: template subtituents """ self.peers = peers self.path = path self.auxdicts = dd self.config = ConfigParser.RawConfigParser() self.config.read(path) self._normconfig() def section(self, rx=False): """get the section name of the section representing .peers in .config""" peers = self.peers if not peers: peers = ['.', '.'] rx = True if rx: st = 'peersrx' else: st = 'peers' return ' '.join([st] + [escape(u) for u in peers]) @staticmethod def parse_section(section): """retrieve peers sequence encoded by section name (as urls or regexen, depending on section type) """ sl = section.split() st = sl.pop(0) sl = [unescape(u) for u in sl] if st == 'peersrx': sl = [re.compile(u) for u in sl] return sl def ord_sections(self): """Return an ordered list of sections. Ordering happens based on the auxiliary SECT_ORD section storing indices for each section added through the config API. To not to go corrupt in case of manually written config files, we take care to append also those sections which are not registered in SECT_ORD. Needed for python 2.{4,5,6} where ConfigParser cannot yet order sections/options internally. """ so = {} if self.config.has_section(SECT_ORD): so = self.config._sections[SECT_ORD] so2 = {} for k, v in so.items(): if k != '__name__': so2[k] = int(v) tv = 0 if so2: tv = max(so2.values()) + 1 ss = [s for s in self.config.sections() if s.find('__') != 0] for s in ss: if s in so.keys(): continue so2[s] = tv tv += 1 def scmp(x, y): return cmp(*(so2[s] for s in (x, y))) ss.sort(scmp) return ss def update_to(self, dct, allow_unresolved=False): """update @dct from key/values of ours. key/values are collected from .config by filtering the regexp sections according to match, and from .section. The values are treated as templates, which are substituted from .auxdicts and (in case of regexp sections) match groups. """ if not self.peers: raise GsyncdError('no peers given, cannot select matching options') def update_from_sect(sect, mud): for k, v in self.config._sections[sect].items(): if k == '__name__': continue if allow_unresolved: dct[k] = Template(v).safe_substitute(mud) else: dct[k] = Template(v).substitute(mud) for sect in self.ord_sections(): sp = self.parse_section(sect) if isinstance(sp[0], re_type) and len(sp) == len(self.peers): match = True mad = {} for i in range(len(sp)): m = sp[i].search(self.peers[i]) if not m: match = False break for j in range(len(m.groups())): mad['match%d_%d' % (i+1, j+1)] = m.groups()[j] if match: update_from_sect(sect, MultiDict(dct, mad, *self.auxdicts)) if self.config.has_section(self.section()): update_from_sect(self.section(), MultiDict(dct, *self.auxdicts)) def get(self, opt=None): """print the matching key/value pairs from .config, or if @opt given, the value for @opt (according to the logic described in .update_to) """ d = {} self.update_to(d, allow_unresolved = True) if opt: opt = norm(opt) v = d.get(opt) if v: print(v) else: for k, v in d.iteritems(): if k == '__name__': continue print("%s: %s" % (k, v)) def write(self, trfn, opt, *a, **kw): """update on-disk config transactionally @trfn is the transaction function """ def mergeconf(f): self.config = ConfigParser.RawConfigParser() self.config.readfp(f) self._normconfig() if not self.config.has_section(SECT_META): self.config.add_section(SECT_META) self.config.set(SECT_META, 'version', config_version) return trfn(norm(opt), *a, **kw) def updateconf(f): self.config.write(f) update_file(self.path, updateconf, mergeconf) def _set(self, opt, val, rx=False): """set @opt to @val in .section""" sect = self.section(rx) if not self.config.has_section(sect): self.config.add_section(sect) # regarding SECT_ORD, cf. ord_sections if not self.config.has_section(SECT_ORD): self.config.add_section(SECT_ORD) self.config.set(SECT_ORD, sect, len(self.config._sections[SECT_ORD])) self.config.set(sect, opt, val) return True def set(self, opt, *a, **kw): """perform ._set transactionally""" self.write(self._set, opt, *a, **kw) def _delete(self, opt, rx=False): """delete @opt from .section""" sect = self.section(rx) if self.config.has_section(sect): return self.config.remove_option(sect, opt) def delete(self, opt, *a, **kw): """perform ._delete transactionally""" self.write(self._delete, opt, *a, **kw)