wireprotov2: define and implement "manifestdata" command
The added command can be used for obtaining manifest data.
Given a manifest path and set of manifest nodes, data about
manifests can be retrieved.
Unlike changeset data, we wish to emit deltas to describe
manifest revisions. So the command uses the relatively new
API for building delta requests and emitting them.
The code calls into deltaparent(), which I'm not very keen of.
There's still work to be done in delta generation land so
implementation details of storage (e.g. exactly one delta
is stored/available) don't creep into higher levels. But we
can worry about this later (there is already a TODO on
imanifestorage tracking this).
On the subject of parent deltas, the server assumes parent revisions
exist on the receiving end. This is obviously wrong for shallow
clone. I've added TODOs to add a mechanism to the command to
allow clients to specify desired behavior. This shouldn't be
too difficult to implement.
Another big change is that the client must explicitly request
manifest nodes to retrieve. This is a major departure from
"getbundle," where the server derives relevant manifests as it
iterates changesets and sends them automatically. As implemented,
the client must transmit each requested node to the server. At
20 bytes per node, we're looking at 2 MB per 100,000 nodes. Plus
wire encoding overhead. This isn't ideal for clients with limited
upload bandwidth. I plan to address this in the future by allowing
alternate mechanisms for defining the revisions to retrieve. One
idea is to define a range of changeset revisions whose manifest
revisions to retrieve (similar to how "changesetdata" works).
We almost certainly want an API to look up an individual manifest
by node. And that's where I've chosen to start with the implementation.
Again, a theme of this early exchangev2 work is I want to start by
building primitives for accessing raw repository data first and see
how far we can get with those before we need more complexity.
Differential Revision: https://phab.mercurial-scm.org/D4488
# Copyright 21 May 2005 - (c) 2005 Jake Edge <jake@edge2.net>
# Copyright 2005-2007 Matt Mackall <mpm@selenic.com>
#
# 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,
nullrev,
)
from . import (
changegroup,
dagop,
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 builddeltarequests(store, nodes):
"""Build a series of revision delta requests against a backend store.
Returns a list of revision numbers in the order they should be sent
and a list of ``irevisiondeltarequest`` instances to be made against
the backend store.
"""
# We sort and send nodes in DAG order because this is optimal for
# storage emission.
# TODO we may want a better storage API here - one where we can throw
# a list of nodes and delta preconditions over a figurative wall and
# have the storage backend figure it out for us.
revs = dagop.linearize({store.rev(n) for n in nodes}, store.parentrevs)
requests = []
for rev in revs:
node = store.node(rev)
parents = store.parents(node)
deltaparent = store.node(store.deltaparent(rev))
# There is a delta in storage. That means we can send the delta
# efficiently.
#
# But, the delta may be against a revision the receiver doesn't
# have (e.g. shallow clone or when the delta isn't against a parent
# revision). For now, we ignore the problem of shallow clone. As
# long as a delta exists against a parent, we send it.
# TODO allow arguments to control this behavior, as the receiver
# may not have the base revision in some scenarios.
if deltaparent != nullid and deltaparent in parents:
basenode = deltaparent
# Else there is no delta parent in storage or the delta that is
# # there isn't suitable. Let's use a delta against a parent
# revision, if possible.
#
# There is room to check if the delta parent is in the ancestry of
# this node. But there isn't an API on the manifest storage object
# for that. So ignore this case for now.
elif parents[0] != nullid:
basenode = parents[0]
elif parents[1] != nullid:
basenode = parents[1]
# No potential bases to delta against. Send a full revision.
else:
basenode = nullid
requests.append(changegroup.revisiondeltarequest(
node=node,
p1node=parents[0],
p2node=parents[1],
# Receiver deals with linknode resolution.
linknode=nullid,
basenode=basenode,
))
return revs, requests
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('manifestdata',
args={
'nodes': [b'0123456...'],
'fields': [b'parents', b'revision'],
'tree': b'',
},
permission='pull')
def manifestdata(repo, proto, nodes=None, fields=None, tree=None):
fields = fields or set()
if nodes is None:
raise error.WireprotoCommandError(
'nodes argument must be defined')
if tree is None:
raise error.WireprotoCommandError(
'tree argument must be defined')
store = repo.manifestlog.getstorage(tree)
# Validate the node is known and abort on unknown revisions.
for node in nodes:
try:
store.rev(node)
except error.LookupError:
raise error.WireprotoCommandError(
'unknown node: %s', (node,))
revs, requests = builddeltarequests(store, nodes)
yield {
b'totalitems': len(revs),
}
if b'revision' in fields:
deltas = store.emitrevisiondeltas(requests)
else:
deltas = None
for rev in revs:
node = store.node(rev)
if deltas is not None:
delta = next(deltas)
else:
delta = None
d = {
b'node': node,
}
if b'parents' in fields:
d[b'parents'] = store.parents(node)
if b'revision' in fields:
assert delta is not None
assert delta.flags == 0
assert d[b'node'] == delta.node
if delta.revision is not None:
revisiondata = delta.revision
d[b'revisionsize'] = len(revisiondata)
else:
d[b'deltabasenode'] = delta.basenode
revisiondata = delta.delta
d[b'deltasize'] = len(revisiondata)
else:
revisiondata = None
yield d
if revisiondata is not None:
yield revisiondata
if deltas is not None:
try:
next(deltas)
raise error.ProgrammingError('should not have more deltas')
except GeneratorExit:
pass
@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))