wireprotov2: add TODOs around extending changesetdata fields

Extensions will inevitably want to extend the set of changeset
data/fields that can be requested. We'll need to implement support
for extending this in the future. Add some TODOs to track that.

Differential Revision: https://phab.mercurial-scm.org/D4487

mercurial/exchangev2.py

@@ -1,178 +1,181
 # exchangev2.py - repository exchange for wire protocol version 2
 #
 # Copyright 2018 Gregory Szorc <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from __future__ import absolute_import
 
 import weakref
 
 from .i18n import _
 from .node import (
     nullid,
     short,
 )
 from . import (
     bookmarks,
     mdiff,
     phases,
     pycompat,
     setdiscovery,
 )
 
 def pull(pullop):
     """Pull using wire protocol version 2."""
     repo = pullop.repo
     remote = pullop.remote
     tr = pullop.trmanager.transaction()
 
     # Figure out what needs to be fetched.
     common, fetch, remoteheads = _pullchangesetdiscovery(
         repo, remote, pullop.heads, abortwhenunrelated=pullop.force)
 
     # And fetch the data.
     pullheads = pullop.heads or remoteheads
     csetres = _fetchchangesets(repo, tr, remote, common, fetch, pullheads)
 
     # New revisions are written to the changelog. But all other updates
     # are deferred. Do those now.
 
     # Ensure all new changesets are draft by default. If the repo is
     # publishing, the phase will be adjusted by the loop below.
     if csetres['added']:
         phases.registernew(repo, tr, phases.draft, csetres['added'])
 
     # And adjust the phase of all changesets accordingly.
     for phase in phases.phasenames:
         if phase == b'secret' or not csetres['nodesbyphase'][phase]:
             continue
 
         phases.advanceboundary(repo, tr, phases.phasenames.index(phase),
                                csetres['nodesbyphase'][phase])
 
     # Write bookmark updates.
     bookmarks.updatefromremote(repo.ui, repo, csetres['bookmarks'],
                                remote.url(), pullop.gettransaction,
                                explicit=pullop.explicitbookmarks)
 
 def _pullchangesetdiscovery(repo, remote, heads, abortwhenunrelated=True):
     """Determine which changesets need to be pulled."""
 
     if heads:
         knownnode = repo.changelog.hasnode
         if all(knownnode(head) for head in heads):
             return heads, False, heads
 
     # TODO wire protocol version 2 is capable of more efficient discovery
     # than setdiscovery. Consider implementing something better.
     common, fetch, remoteheads = setdiscovery.findcommonheads(
         repo.ui, repo, remote, abortwhenunrelated=abortwhenunrelated)
 
     common = set(common)
     remoteheads = set(remoteheads)
 
     # If a remote head is filtered locally, put it back in the common set.
     # See the comment in exchange._pulldiscoverychangegroup() for more.
 
     if fetch and remoteheads:
         nodemap = repo.unfiltered().changelog.nodemap
 
         common |= {head for head in remoteheads if head in nodemap}
 
         if set(remoteheads).issubset(common):
             fetch = []
 
     common.discard(nullid)
 
     return common, fetch, remoteheads
 
 def _fetchchangesets(repo, tr, remote, common, fetch, remoteheads):
     # TODO consider adding a step here where we obtain the DAG shape first
     # (or ask the server to slice changesets into chunks for us) so that
     # we can perform multiple fetches in batches. This will facilitate
     # resuming interrupted clones, higher server-side cache hit rates due
     # to smaller segments, etc.
     with remote.commandexecutor() as e:
         objs = e.callcommand(b'changesetdata', {
             b'noderange': [sorted(common), sorted(remoteheads)],
             b'fields': {b'bookmarks', b'parents', b'phase', b'revision'},
         }).result()
 
         # The context manager waits on all response data when exiting. So
         # we need to remain in the context manager in order to stream data.
         return _processchangesetdata(repo, tr, objs)
 
 def _processchangesetdata(repo, tr, objs):
     repo.hook('prechangegroup', throw=True,
               **pycompat.strkwargs(tr.hookargs))
 
     urepo = repo.unfiltered()
     cl = urepo.changelog
 
     cl.delayupdate(tr)
 
     # The first emitted object is a header describing the data that
     # follows.
     meta = next(objs)
 
     progress = repo.ui.makeprogress(_('changesets'),
                                     unit=_('chunks'),
                                     total=meta.get(b'totalitems'))
 
     def linkrev(node):
         repo.ui.debug('add changeset %s\n' % short(node))
         # Linkrev for changelog is always self.
         return len(cl)
 
     def onchangeset(cl, node):
         progress.increment()
 
     nodesbyphase = {phase: set() for phase in phases.phasenames}
     remotebookmarks = {}
 
     # addgroup() expects a 7-tuple describing revisions. This normalizes
     # the wire data to that format.
     #
     # This loop also aggregates non-revision metadata, such as phase
     # data.
     def iterrevisions():
         for cset in objs:
             node = cset[b'node']
 
             if b'phase' in cset:
                 nodesbyphase[cset[b'phase']].add(node)
 
             for mark in cset.get(b'bookmarks', []):
                 remotebookmarks[mark] = node
 
+            # TODO add mechanism for extensions to examine records so they
+            # can siphon off custom data fields.
+
             # Some entries might only be metadata only updates.
             if b'revisionsize' not in cset:
                 continue
 
             data = next(objs)
 
             yield (
                 node,
                 cset[b'parents'][0],
                 cset[b'parents'][1],
                 # Linknode is always itself for changesets.
                 cset[b'node'],
                 # We always send full revisions. So delta base is not set.
                 nullid,
                 mdiff.trivialdiffheader(len(data)) + data,
                 # Flags not yet supported.
                 0,
             )
 
     added = cl.addgroup(iterrevisions(), linkrev, weakref.proxy(tr),
                         addrevisioncb=onchangeset)
 
     progress.complete()
 
     return {
         'added': added,
         'nodesbyphase': nodesbyphase,
         'bookmarks': remotebookmarks,
     }

mercurial/wireprotov2server.py

@@ -1,639 +1,646
 # Copyright 21 May 2005 - (c) 2005 Jake Edge <[e-mail]>
 # Copyright 2005-2007 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from __future__ import absolute_import
 
 import contextlib
 
 from .i18n import _
 from .node import (
     nullid,
 )
 from . import (
     discovery,
     encoding,
     error,
     pycompat,
     streamclone,
     util,
     wireprotoframing,
     wireprototypes,
 )
 from .utils import (
     interfaceutil,
 )
 
 FRAMINGTYPE = b'application/mercurial-exp-framing-0005'
 
 HTTP_WIREPROTO_V2 = wireprototypes.HTTP_WIREPROTO_V2
 
 COMMANDS = wireprototypes.commanddict()
 
 def handlehttpv2request(rctx, req, res, checkperm, urlparts):
     from .hgweb import common as hgwebcommon
 
     # URL space looks like: <permissions>/<command>, where <permission> can
     # be ``ro`` or ``rw`` to signal read-only or read-write, respectively.
 
     # Root URL does nothing meaningful... yet.
     if not urlparts:
         res.status = b'200 OK'
         res.headers[b'Content-Type'] = b'text/plain'
         res.setbodybytes(_('HTTP version 2 API handler'))
         return
 
     if len(urlparts) == 1:
         res.status = b'404 Not Found'
         res.headers[b'Content-Type'] = b'text/plain'
         res.setbodybytes(_('do not know how to process %s\n') %
                          req.dispatchpath)
         return
 
     permission, command = urlparts[0:2]
 
     if permission not in (b'ro', b'rw'):
         res.status = b'404 Not Found'
         res.headers[b'Content-Type'] = b'text/plain'
         res.setbodybytes(_('unknown permission: %s') % permission)
         return
 
     if req.method != 'POST':
         res.status = b'405 Method Not Allowed'
         res.headers[b'Allow'] = b'POST'
         res.setbodybytes(_('commands require POST requests'))
         return
 
     # At some point we'll want to use our own API instead of recycling the
     # behavior of version 1 of the wire protocol...
     # TODO return reasonable responses - not responses that overload the
     # HTTP status line message for error reporting.
     try:
         checkperm(rctx, req, 'pull' if permission == b'ro' else 'push')
     except hgwebcommon.ErrorResponse as e:
         res.status = hgwebcommon.statusmessage(e.code, pycompat.bytestr(e))
         for k, v in e.headers:
             res.headers[k] = v
         res.setbodybytes('permission denied')
         return
 
     # We have a special endpoint to reflect the request back at the client.
     if command == b'debugreflect':
         _processhttpv2reflectrequest(rctx.repo.ui, rctx.repo, req, res)
         return
 
     # Extra commands that we handle that aren't really wire protocol
     # commands. Think extra hard before making this hackery available to
     # extension.
     extracommands = {'multirequest'}
 
     if command not in COMMANDS and command not in extracommands:
         res.status = b'404 Not Found'
         res.headers[b'Content-Type'] = b'text/plain'
         res.setbodybytes(_('unknown wire protocol command: %s\n') % command)
         return
 
     repo = rctx.repo
     ui = repo.ui
 
     proto = httpv2protocolhandler(req, ui)
 
     if (not COMMANDS.commandavailable(command, proto)
         and command not in extracommands):
         res.status = b'404 Not Found'
         res.headers[b'Content-Type'] = b'text/plain'
         res.setbodybytes(_('invalid wire protocol command: %s') % command)
         return
 
     # TODO consider cases where proxies may add additional Accept headers.
     if req.headers.get(b'Accept') != FRAMINGTYPE:
         res.status = b'406 Not Acceptable'
         res.headers[b'Content-Type'] = b'text/plain'
         res.setbodybytes(_('client MUST specify Accept header with value: %s\n')
                            % FRAMINGTYPE)
         return
 
     if req.headers.get(b'Content-Type') != FRAMINGTYPE:
         res.status = b'415 Unsupported Media Type'
         # TODO we should send a response with appropriate media type,
         # since client does Accept it.
         res.headers[b'Content-Type'] = b'text/plain'
         res.setbodybytes(_('client MUST send Content-Type header with '
                            'value: %s\n') % FRAMINGTYPE)
         return
 
     _processhttpv2request(ui, repo, req, res, permission, command, proto)
 
 def _processhttpv2reflectrequest(ui, repo, req, res):
     """Reads unified frame protocol request and dumps out state to client.
 
     This special endpoint can be used to help debug the wire protocol.
 
     Instead of routing the request through the normal dispatch mechanism,
     we instead read all frames, decode them, and feed them into our state
     tracker. We then dump the log of all that activity back out to the
     client.
     """
     import json
 
     # Reflection APIs have a history of being abused, accidentally disclosing
     # sensitive data, etc. So we have a config knob.
     if not ui.configbool('experimental', 'web.api.debugreflect'):
         res.status = b'404 Not Found'
         res.headers[b'Content-Type'] = b'text/plain'
         res.setbodybytes(_('debugreflect service not available'))
         return
 
     # We assume we have a unified framing protocol request body.
 
     reactor = wireprotoframing.serverreactor()
     states = []
 
     while True:
         frame = wireprotoframing.readframe(req.bodyfh)
 
         if not frame:
             states.append(b'received: <no frame>')
             break
 
         states.append(b'received: %d %d %d %s' % (frame.typeid, frame.flags,
                                                   frame.requestid,
                                                   frame.payload))
 
         action, meta = reactor.onframerecv(frame)
         states.append(json.dumps((action, meta), sort_keys=True,
                                  separators=(', ', ': ')))
 
     action, meta = reactor.oninputeof()
     meta['action'] = action
     states.append(json.dumps(meta, sort_keys=True, separators=(', ',': ')))
 
     res.status = b'200 OK'
     res.headers[b'Content-Type'] = b'text/plain'
     res.setbodybytes(b'\n'.join(states))
 
 def _processhttpv2request(ui, repo, req, res, authedperm, reqcommand, proto):
     """Post-validation handler for HTTPv2 requests.
 
     Called when the HTTP request contains unified frame-based protocol
     frames for evaluation.
     """
     # TODO Some HTTP clients are full duplex and can receive data before
     # the entire request is transmitted. Figure out a way to indicate support
     # for that so we can opt into full duplex mode.
     reactor = wireprotoframing.serverreactor(deferoutput=True)
     seencommand = False
 
     outstream = reactor.makeoutputstream()
 
     while True:
         frame = wireprotoframing.readframe(req.bodyfh)
         if not frame:
             break
 
         action, meta = reactor.onframerecv(frame)
 
         if action == 'wantframe':
             # Need more data before we can do anything.
             continue
         elif action == 'runcommand':
             sentoutput = _httpv2runcommand(ui, repo, req, res, authedperm,
                                            reqcommand, reactor, outstream,
                                            meta, issubsequent=seencommand)
 
             if sentoutput:
                 return
 
             seencommand = True
 
         elif action == 'error':
             # TODO define proper error mechanism.
             res.status = b'200 OK'
             res.headers[b'Content-Type'] = b'text/plain'
             res.setbodybytes(meta['message'] + b'\n')
             return
         else:
             raise error.ProgrammingError(
                 'unhandled action from frame processor: %s' % action)
 
     action, meta = reactor.oninputeof()
     if action == 'sendframes':
         # We assume we haven't started sending the response yet. If we're
         # wrong, the response type will raise an exception.
         res.status = b'200 OK'
         res.headers[b'Content-Type'] = FRAMINGTYPE
         res.setbodygen(meta['framegen'])
     elif action == 'noop':
         pass
     else:
         raise error.ProgrammingError('unhandled action from frame processor: %s'
                                      % action)
 
 def _httpv2runcommand(ui, repo, req, res, authedperm, reqcommand, reactor,
                       outstream, command, issubsequent):
     """Dispatch a wire protocol command made from HTTPv2 requests.
 
     The authenticated permission (``authedperm``) along with the original
     command from the URL (``reqcommand``) are passed in.
     """
     # We already validated that the session has permissions to perform the
     # actions in ``authedperm``. In the unified frame protocol, the canonical
     # command to run is expressed in a frame. However, the URL also requested
     # to run a specific command. We need to be careful that the command we
     # run doesn't have permissions requirements greater than what was granted
     # by ``authedperm``.
     #
     # Our rule for this is we only allow one command per HTTP request and
     # that command must match the command in the URL. However, we make
     # an exception for the ``multirequest`` URL. This URL is allowed to
     # execute multiple commands. We double check permissions of each command
     # as it is invoked to ensure there is no privilege escalation.
     # TODO consider allowing multiple commands to regular command URLs
     # iff each command is the same.
 
     proto = httpv2protocolhandler(req, ui, args=command['args'])
 
     if reqcommand == b'multirequest':
         if not COMMANDS.commandavailable(command['command'], proto):
             # TODO proper error mechanism
             res.status = b'200 OK'
             res.headers[b'Content-Type'] = b'text/plain'
             res.setbodybytes(_('wire protocol command not available: %s') %
                              command['command'])
             return True
 
         # TODO don't use assert here, since it may be elided by -O.
         assert authedperm in (b'ro', b'rw')
         wirecommand = COMMANDS[command['command']]
         assert wirecommand.permission in ('push', 'pull')
 
         if authedperm == b'ro' and wirecommand.permission != 'pull':
             # TODO proper error mechanism
             res.status = b'403 Forbidden'
             res.headers[b'Content-Type'] = b'text/plain'
             res.setbodybytes(_('insufficient permissions to execute '
                                'command: %s') % command['command'])
             return True
 
         # TODO should we also call checkperm() here? Maybe not if we're going
         # to overhaul that API. The granted scope from the URL check should
         # be good enough.
 
     else:
         # Don't allow multiple commands outside of ``multirequest`` URL.
         if issubsequent:
             # TODO proper error mechanism
             res.status = b'200 OK'
             res.headers[b'Content-Type'] = b'text/plain'
             res.setbodybytes(_('multiple commands cannot be issued to this '
                                'URL'))
             return True
 
         if reqcommand != command['command']:
             # TODO define proper error mechanism
             res.status = b'200 OK'
             res.headers[b'Content-Type'] = b'text/plain'
             res.setbodybytes(_('command in frame must match command in URL'))
             return True
 
     res.status = b'200 OK'
     res.headers[b'Content-Type'] = FRAMINGTYPE
 
     try:
         objs = dispatch(repo, proto, command['command'])
 
         action, meta = reactor.oncommandresponsereadyobjects(
             outstream, command['requestid'], objs)
 
     except Exception as e:
         action, meta = reactor.onservererror(
             outstream, command['requestid'],
             _('exception when invoking command: %s') % e)
 
     if action == 'sendframes':
         res.setbodygen(meta['framegen'])
         return True
     elif action == 'noop':
         return False
     else:
         raise error.ProgrammingError('unhandled event from reactor: %s' %
                                      action)
 
 def getdispatchrepo(repo, proto, command):
     return repo.filtered('served')
 
 def dispatch(repo, proto, command):
     repo = getdispatchrepo(repo, proto, command)
 
     func, spec = COMMANDS[command]
     args = proto.getargs(spec)
 
     return func(repo, proto, **args)
 
 @interfaceutil.implementer(wireprototypes.baseprotocolhandler)
 class httpv2protocolhandler(object):
     def __init__(self, req, ui, args=None):
         self._req = req
         self._ui = ui
         self._args = args
 
     @property
     def name(self):
         return HTTP_WIREPROTO_V2
 
     def getargs(self, args):
         data = {}
         for k, typ in args.items():
             if k == '*':
                 raise NotImplementedError('do not support * args')
             elif k in self._args:
                 # TODO consider validating value types.
                 data[k] = self._args[k]
 
         return data
 
     def getprotocaps(self):
         # Protocol capabilities are currently not implemented for HTTP V2.
         return set()
 
     def getpayload(self):
         raise NotImplementedError
 
     @contextlib.contextmanager
     def mayberedirectstdio(self):
         raise NotImplementedError
 
     def client(self):
         raise NotImplementedError
 
     def addcapabilities(self, repo, caps):
         return caps
 
     def checkperm(self, perm):
         raise NotImplementedError
 
 def httpv2apidescriptor(req, repo):
     proto = httpv2protocolhandler(req, repo.ui)
 
     return _capabilitiesv2(repo, proto)
 
 def _capabilitiesv2(repo, proto):
     """Obtain the set of capabilities for version 2 transports.
 
     These capabilities are distinct from the capabilities for version 1
     transports.
     """
     compression = []
     for engine in wireprototypes.supportedcompengines(repo.ui, util.SERVERROLE):
         compression.append({
             b'name': engine.wireprotosupport().name,
         })
 
     caps = {
         'commands': {},
         'compression': compression,
         'framingmediatypes': [FRAMINGTYPE],
     }
 
+    # TODO expose available changesetdata fields.
+
     for command, entry in COMMANDS.items():
         caps['commands'][command] = {
             'args': entry.args,
             'permissions': [entry.permission],
         }
 
     if streamclone.allowservergeneration(repo):
         caps['rawrepoformats'] = sorted(repo.requirements &
                                         repo.supportedformats)
 
     return proto.addcapabilities(repo, caps)
 
 def wireprotocommand(name, args=None, permission='push'):
     """Decorator to declare a wire protocol command.
 
     ``name`` is the name of the wire protocol command being provided.
 
     ``args`` is a dict of argument names to example values.
 
     ``permission`` defines the permission type needed to run this command.
     Can be ``push`` or ``pull``. These roughly map to read-write and read-only,
     respectively. Default is to assume command requires ``push`` permissions
     because otherwise commands not declaring their permissions could modify
     a repository that is supposed to be read-only.
 
     Wire protocol commands are generators of objects to be serialized and
     sent to the client.
 
     If a command raises an uncaught exception, this will be translated into
     a command error.
     """
     transports = {k for k, v in wireprototypes.TRANSPORTS.items()
                   if v['version'] == 2}
 
     if permission not in ('push', 'pull'):
         raise error.ProgrammingError('invalid wire protocol permission; '
                                      'got %s; expected "push" or "pull"' %
                                      permission)
 
     if args is None:
         args = {}
 
     if not isinstance(args, dict):
         raise error.ProgrammingError('arguments for version 2 commands '
                                      'must be declared as dicts')
 
     def register(func):
         if name in COMMANDS:
             raise error.ProgrammingError('%s command already registered '
                                          'for version 2' % name)
 
         COMMANDS[name] = wireprototypes.commandentry(
             func, args=args, transports=transports, permission=permission)
 
         return func
 
     return register
 
 @wireprotocommand('branchmap', permission='pull')
 def branchmapv2(repo, proto):
     yield {encoding.fromlocal(k): v
            for k, v in repo.branchmap().iteritems()}
 
 @wireprotocommand('capabilities', permission='pull')
 def capabilitiesv2(repo, proto):
     yield _capabilitiesv2(repo, proto)
 
 @wireprotocommand('changesetdata',
                   args={
                       'noderange': [[b'0123456...'], [b'abcdef...']],
                       'nodes': [b'0123456...'],
                       'fields': {b'parents', b'revision'},
                   },
                   permission='pull')
 def changesetdata(repo, proto, noderange=None, nodes=None, fields=None):
     fields = fields or set()
 
+    # TODO look for unknown fields and abort when they can't be serviced.
+
     if noderange is None and nodes is None:
         raise error.WireprotoCommandError(
             'noderange or nodes must be defined')
 
     if noderange is not None:
         if len(noderange) != 2:
             raise error.WireprotoCommandError(
                 'noderange must consist of 2 elements')
 
         if not noderange[1]:
             raise error.WireprotoCommandError(
                 'heads in noderange request cannot be empty')
 
     cl = repo.changelog
     hasnode = cl.hasnode
 
     seen = set()
     outgoing = []
 
     if nodes is not None:
         outgoing.extend(n for n in nodes if hasnode(n))
         seen |= set(outgoing)
 
     if noderange is not None:
         if noderange[0]:
             common = [n for n in noderange[0] if hasnode(n)]
         else:
             common = [nullid]
 
         for n in discovery.outgoing(repo, common, noderange[1]).missing:
             if n not in seen:
                 outgoing.append(n)
             # Don't need to add to seen here because this is the final
             # source of nodes and there should be no duplicates in this
             # list.
 
     seen.clear()
     publishing = repo.publishing()
 
     if outgoing:
         repo.hook('preoutgoing', throw=True, source='serve')
 
     yield {
         b'totalitems': len(outgoing),
     }
 
     # The phases of nodes already transferred to the client may have changed
     # since the client last requested data. We send phase-only records
     # for these revisions, if requested.
     if b'phase' in fields and noderange is not None:
         # TODO skip nodes whose phase will be reflected by a node in the
         # outgoing set. This is purely an optimization to reduce data
         # size.
         for node in noderange[0]:
             yield {
                 b'node': node,
                 b'phase': b'public' if publishing else repo[node].phasestr()
             }
 
     nodebookmarks = {}
     for mark, node in repo._bookmarks.items():
         nodebookmarks.setdefault(node, set()).add(mark)
 
     # It is already topologically sorted by revision number.
     for node in outgoing:
         d = {
             b'node': node,
         }
 
         if b'parents' in fields:
             d[b'parents'] = cl.parents(node)
 
         if b'phase' in fields:
             if publishing:
                 d[b'phase'] = b'public'
             else:
                 ctx = repo[node]
                 d[b'phase'] = ctx.phasestr()
 
         if b'bookmarks' in fields and node in nodebookmarks:
             d[b'bookmarks'] = sorted(nodebookmarks[node])
             del nodebookmarks[node]
 
         revisiondata = None
 
         if b'revision' in fields:
             revisiondata = cl.revision(node, raw=True)
             d[b'revisionsize'] = len(revisiondata)
 
+        # TODO make it possible for extensions to wrap a function or register
+        # a handler to service custom fields.
+
         yield d
 
         if revisiondata is not None:
             yield revisiondata
 
     # If requested, send bookmarks from nodes that didn't have revision
     # data sent so receiver is aware of any bookmark updates.
     if b'bookmarks' in fields:
         for node, marks in sorted(nodebookmarks.iteritems()):
             yield {
                 b'node': node,
                 b'bookmarks': sorted(marks),
             }
 
 @wireprotocommand('heads',
                   args={
                       'publiconly': False,
                   },
                   permission='pull')
 def headsv2(repo, proto, publiconly=False):
     if publiconly:
         repo = repo.filtered('immutable')
 
     yield repo.heads()
 
 @wireprotocommand('known',
                   args={
                       'nodes': [b'deadbeef'],
                   },
                   permission='pull')
 def knownv2(repo, proto, nodes=None):
     nodes = nodes or []
     result = b''.join(b'1' if n else b'0' for n in repo.known(nodes))
     yield result
 
 @wireprotocommand('listkeys',
                   args={
                       'namespace': b'ns',
                   },
                   permission='pull')
 def listkeysv2(repo, proto, namespace=None):
     keys = repo.listkeys(encoding.tolocal(namespace))
     keys = {encoding.fromlocal(k): encoding.fromlocal(v)
             for k, v in keys.iteritems()}
 
     yield keys
 
 @wireprotocommand('lookup',
                   args={
                       'key': b'foo',
                   },
                   permission='pull')
 def lookupv2(repo, proto, key):
     key = encoding.tolocal(key)
 
     # TODO handle exception.
     node = repo.lookup(key)
 
     yield node
 
 @wireprotocommand('pushkey',
                   args={
                       'namespace': b'ns',
                       'key': b'key',
                       'old': b'old',
                       'new': b'new',
                   },
                   permission='push')
 def pushkeyv2(repo, proto, namespace, key, old, new):
     # TODO handle ui output redirection
     yield repo.pushkey(encoding.tolocal(namespace),
                        encoding.tolocal(key),
                        encoding.tolocal(old),
                        encoding.tolocal(new))