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Diffstat (limited to 'geo-replication/syncdaemon/configinterface.py')
| -rw-r--r-- | geo-replication/syncdaemon/configinterface.py | 224 |
1 files changed, 224 insertions, 0 deletions
diff --git a/geo-replication/syncdaemon/configinterface.py b/geo-replication/syncdaemon/configinterface.py new file mode 100644 index 00000000000..e55bec519e9 --- /dev/null +++ b/geo-replication/syncdaemon/configinterface.py @@ -0,0 +1,224 @@ +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) |