Mercurial > hg
view mercurial/wireprotov1peer.py @ 39314:7f5e6d3e9032
manifest: proxy to revlog instance instead of inheriting
Previously, manifestrevlog inherited revlog.revlog and therefore
exposed all its APIs. This inevitably resulted in consumers calling
low-level revlog APIs.
As part of abstracting storage, we want to formalize the interface
for manifest storage. The revlog API is much too large to define as
the interface.
Like we did for filelog, this commit divorces the manifest class
from revlog so that we can standardize on a smaller API surface.
The way I went about this commit was I broke the inheritance, ran
tests, and added proxies until all tests passed. Like filelog, there
are a handful of attributes that don't belong on the interface.
And like filelog, we'll tease these out in the future.
As part of this, we formalize an interface for manifest storage and
add checks that manifestrevlog conforms to the interface.
Adding proxies will introduce some overhead due to extra attribute
lookups and function calls. On the mozilla-unified repository:
$ hg verify
before: real 627.220 secs (user 525.870+0.000 sys 18.800+0.000)
after: real 628.930 secs (user 532.050+0.000 sys 18.320+0.000)
$ hg serve (for a clone)
before: user 223.580+0.000 sys 14.270+0.000
after: user 227.720+0.000 sys 13.920+0.000
$ hg clone
before: user 506.390+0.000 sys 29.720+0.000
after: user 513.080+0.000 sys 28.280+0.000
There appears to be some overhead here. But it appears to be 1-2%.
I think that is an appropriate price to pay for storage abstraction,
which will eventually let us have much nicer things. If the overhead
is noticed in other operations (whose CPU time isn't likely dwarfed by
fulltext resolution) or if we want to cut down on the overhead, we
could dynamically build up a type whose methods are effectively
aliased to a revlog instance's. I'm inclined to punt on that problem
for now. We may have to do it for the changelog. At which point it
could be implemented in a generic way and ported to filelog and
manifestrevlog easily enough I would think.
.. api:: manifest.manifestrevlog no longer inherits from revlog
The manifestrevlog class now wraps a revlog instance instead of
inheriting from revlog. Various attributes and methods on instances
are no longer available.
Differential Revision: https://phab.mercurial-scm.org/D4386
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Mon, 27 Aug 2018 10:15:15 -0700 |
parents | e7aa113b14f7 |
children | f15a587d2dfc |
line wrap: on
line source
# wireprotov1peer.py - Client-side functionality for wire protocol version 1. # # Copyright 2005-2010 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 hashlib import sys import weakref from .i18n import _ from .node import ( bin, ) from . import ( bundle2, changegroup as changegroupmod, encoding, error, pushkey as pushkeymod, pycompat, repository, util, wireprototypes, ) from .utils import ( interfaceutil, ) urlreq = util.urlreq def batchable(f): '''annotation for batchable methods Such methods must implement a coroutine as follows: @batchable def sample(self, one, two=None): # Build list of encoded arguments suitable for your wire protocol: encargs = [('one', encode(one),), ('two', encode(two),)] # Create future for injection of encoded result: encresref = future() # Return encoded arguments and future: yield encargs, encresref # Assuming the future to be filled with the result from the batched # request now. Decode it: yield decode(encresref.value) The decorator returns a function which wraps this coroutine as a plain method, but adds the original method as an attribute called "batchable", which is used by remotebatch to split the call into separate encoding and decoding phases. ''' def plain(*args, **opts): batchable = f(*args, **opts) encargsorres, encresref = next(batchable) if not encresref: return encargsorres # a local result in this case self = args[0] cmd = pycompat.bytesurl(f.__name__) # ensure cmd is ascii bytestr encresref.set(self._submitone(cmd, encargsorres)) return next(batchable) setattr(plain, 'batchable', f) return plain class future(object): '''placeholder for a value to be set later''' def set(self, value): if util.safehasattr(self, 'value'): raise error.RepoError("future is already set") self.value = value def encodebatchcmds(req): """Return a ``cmds`` argument value for the ``batch`` command.""" escapearg = wireprototypes.escapebatcharg cmds = [] for op, argsdict in req: # Old servers didn't properly unescape argument names. So prevent # the sending of argument names that may not be decoded properly by # servers. assert all(escapearg(k) == k for k in argsdict) args = ','.join('%s=%s' % (escapearg(k), escapearg(v)) for k, v in argsdict.iteritems()) cmds.append('%s %s' % (op, args)) return ';'.join(cmds) class unsentfuture(pycompat.futures.Future): """A Future variation to represent an unsent command. Because we buffer commands and don't submit them immediately, calling ``result()`` on an unsent future could deadlock. Futures for buffered commands are represented by this type, which wraps ``result()`` to call ``sendcommands()``. """ def result(self, timeout=None): if self.done(): return pycompat.futures.Future.result(self, timeout) self._peerexecutor.sendcommands() # This looks like it will infinitely recurse. However, # sendcommands() should modify __class__. This call serves as a check # on that. return self.result(timeout) @interfaceutil.implementer(repository.ipeercommandexecutor) class peerexecutor(object): def __init__(self, peer): self._peer = peer self._sent = False self._closed = False self._calls = [] self._futures = weakref.WeakSet() self._responseexecutor = None self._responsef = None def __enter__(self): return self def __exit__(self, exctype, excvalee, exctb): self.close() def callcommand(self, command, args): if self._sent: raise error.ProgrammingError('callcommand() cannot be used ' 'after commands are sent') if self._closed: raise error.ProgrammingError('callcommand() cannot be used ' 'after close()') # Commands are dispatched through methods on the peer. fn = getattr(self._peer, pycompat.sysstr(command), None) if not fn: raise error.ProgrammingError( 'cannot call command %s: method of same name not available ' 'on peer' % command) # Commands are either batchable or they aren't. If a command # isn't batchable, we send it immediately because the executor # can no longer accept new commands after a non-batchable command. # If a command is batchable, we queue it for later. But we have # to account for the case of a non-batchable command arriving after # a batchable one and refuse to service it. def addcall(): f = pycompat.futures.Future() self._futures.add(f) self._calls.append((command, args, fn, f)) return f if getattr(fn, 'batchable', False): f = addcall() # But since we don't issue it immediately, we wrap its result() # to trigger sending so we avoid deadlocks. f.__class__ = unsentfuture f._peerexecutor = self else: if self._calls: raise error.ProgrammingError( '%s is not batchable and cannot be called on a command ' 'executor along with other commands' % command) f = addcall() # Non-batchable commands can never coexist with another command # in this executor. So send the command immediately. self.sendcommands() return f def sendcommands(self): if self._sent: return if not self._calls: return self._sent = True # Unhack any future types so caller seens a clean type and to break # cycle between us and futures. for f in self._futures: if isinstance(f, unsentfuture): f.__class__ = pycompat.futures.Future f._peerexecutor = None calls = self._calls # Mainly to destroy references to futures. self._calls = None # Simple case of a single command. We call it synchronously. if len(calls) == 1: command, args, fn, f = calls[0] # Future was cancelled. Ignore it. if not f.set_running_or_notify_cancel(): return try: result = fn(**pycompat.strkwargs(args)) except Exception: pycompat.future_set_exception_info(f, sys.exc_info()[1:]) else: f.set_result(result) return # Batch commands are a bit harder. First, we have to deal with the # @batchable coroutine. That's a bit annoying. Furthermore, we also # need to preserve streaming. i.e. it should be possible for the # futures to resolve as data is coming in off the wire without having # to wait for the final byte of the final response. We do this by # spinning up a thread to read the responses. requests = [] states = [] for command, args, fn, f in calls: # Future was cancelled. Ignore it. if not f.set_running_or_notify_cancel(): continue try: batchable = fn.batchable(fn.__self__, **pycompat.strkwargs(args)) except Exception: pycompat.future_set_exception_info(f, sys.exc_info()[1:]) return # Encoded arguments and future holding remote result. try: encodedargs, fremote = next(batchable) except Exception: pycompat.future_set_exception_info(f, sys.exc_info()[1:]) return requests.append((command, encodedargs)) states.append((command, f, batchable, fremote)) if not requests: return # This will emit responses in order they were executed. wireresults = self._peer._submitbatch(requests) # The use of a thread pool executor here is a bit weird for something # that only spins up a single thread. However, thread management is # hard and it is easy to encounter race conditions, deadlocks, etc. # concurrent.futures already solves these problems and its thread pool # executor has minimal overhead. So we use it. self._responseexecutor = pycompat.futures.ThreadPoolExecutor(1) self._responsef = self._responseexecutor.submit(self._readbatchresponse, states, wireresults) def close(self): self.sendcommands() if self._closed: return self._closed = True if not self._responsef: return # We need to wait on our in-flight response and then shut down the # executor once we have a result. try: self._responsef.result() finally: self._responseexecutor.shutdown(wait=True) self._responsef = None self._responseexecutor = None # If any of our futures are still in progress, mark them as # errored. Otherwise a result() could wait indefinitely. for f in self._futures: if not f.done(): f.set_exception(error.ResponseError( _('unfulfilled batch command response'))) self._futures = None def _readbatchresponse(self, states, wireresults): # Executes in a thread to read data off the wire. for command, f, batchable, fremote in states: # Grab raw result off the wire and teach the internal future # about it. remoteresult = next(wireresults) fremote.set(remoteresult) # And ask the coroutine to decode that value. try: result = next(batchable) except Exception: pycompat.future_set_exception_info(f, sys.exc_info()[1:]) else: f.set_result(result) @interfaceutil.implementer(repository.ipeercommands, repository.ipeerlegacycommands) class wirepeer(repository.peer): """Client-side interface for communicating with a peer repository. Methods commonly call wire protocol commands of the same name. See also httppeer.py and sshpeer.py for protocol-specific implementations of this interface. """ def commandexecutor(self): return peerexecutor(self) # Begin of ipeercommands interface. def clonebundles(self): self.requirecap('clonebundles', _('clone bundles')) return self._call('clonebundles') @batchable def lookup(self, key): self.requirecap('lookup', _('look up remote revision')) f = future() yield {'key': encoding.fromlocal(key)}, f d = f.value success, data = d[:-1].split(" ", 1) if int(success): yield bin(data) else: self._abort(error.RepoError(data)) @batchable def heads(self): f = future() yield {}, f d = f.value try: yield wireprototypes.decodelist(d[:-1]) except ValueError: self._abort(error.ResponseError(_("unexpected response:"), d)) @batchable def known(self, nodes): f = future() yield {'nodes': wireprototypes.encodelist(nodes)}, f d = f.value try: yield [bool(int(b)) for b in pycompat.iterbytestr(d)] except ValueError: self._abort(error.ResponseError(_("unexpected response:"), d)) @batchable def branchmap(self): f = future() yield {}, f d = f.value try: branchmap = {} for branchpart in d.splitlines(): branchname, branchheads = branchpart.split(' ', 1) branchname = encoding.tolocal(urlreq.unquote(branchname)) branchheads = wireprototypes.decodelist(branchheads) branchmap[branchname] = branchheads yield branchmap except TypeError: self._abort(error.ResponseError(_("unexpected response:"), d)) @batchable def listkeys(self, namespace): if not self.capable('pushkey'): yield {}, None f = future() self.ui.debug('preparing listkeys for "%s"\n' % namespace) yield {'namespace': encoding.fromlocal(namespace)}, f d = f.value self.ui.debug('received listkey for "%s": %i bytes\n' % (namespace, len(d))) yield pushkeymod.decodekeys(d) @batchable def pushkey(self, namespace, key, old, new): if not self.capable('pushkey'): yield False, None f = future() self.ui.debug('preparing pushkey for "%s:%s"\n' % (namespace, key)) yield {'namespace': encoding.fromlocal(namespace), 'key': encoding.fromlocal(key), 'old': encoding.fromlocal(old), 'new': encoding.fromlocal(new)}, f d = f.value d, output = d.split('\n', 1) try: d = bool(int(d)) except ValueError: raise error.ResponseError( _('push failed (unexpected response):'), d) for l in output.splitlines(True): self.ui.status(_('remote: '), l) yield d def stream_out(self): return self._callstream('stream_out') def getbundle(self, source, **kwargs): kwargs = pycompat.byteskwargs(kwargs) self.requirecap('getbundle', _('look up remote changes')) opts = {} bundlecaps = kwargs.get('bundlecaps') or set() for key, value in kwargs.iteritems(): if value is None: continue keytype = wireprototypes.GETBUNDLE_ARGUMENTS.get(key) if keytype is None: raise error.ProgrammingError( 'Unexpectedly None keytype for key %s' % key) elif keytype == 'nodes': value = wireprototypes.encodelist(value) elif keytype == 'csv': value = ','.join(value) elif keytype == 'scsv': value = ','.join(sorted(value)) elif keytype == 'boolean': value = '%i' % bool(value) elif keytype != 'plain': raise KeyError('unknown getbundle option type %s' % keytype) opts[key] = value f = self._callcompressable("getbundle", **pycompat.strkwargs(opts)) if any((cap.startswith('HG2') for cap in bundlecaps)): return bundle2.getunbundler(self.ui, f) else: return changegroupmod.cg1unpacker(f, 'UN') def unbundle(self, bundle, heads, url): '''Send cg (a readable file-like object representing the changegroup to push, typically a chunkbuffer object) to the remote server as a bundle. When pushing a bundle10 stream, return an integer indicating the result of the push (see changegroup.apply()). When pushing a bundle20 stream, return a bundle20 stream. `url` is the url the client thinks it's pushing to, which is visible to hooks. ''' if heads != ['force'] and self.capable('unbundlehash'): heads = wireprototypes.encodelist( ['hashed', hashlib.sha1(''.join(sorted(heads))).digest()]) else: heads = wireprototypes.encodelist(heads) if util.safehasattr(bundle, 'deltaheader'): # this a bundle10, do the old style call sequence ret, output = self._callpush("unbundle", bundle, heads=heads) if ret == "": raise error.ResponseError( _('push failed:'), output) try: ret = int(ret) except ValueError: raise error.ResponseError( _('push failed (unexpected response):'), ret) for l in output.splitlines(True): self.ui.status(_('remote: '), l) else: # bundle2 push. Send a stream, fetch a stream. stream = self._calltwowaystream('unbundle', bundle, heads=heads) ret = bundle2.getunbundler(self.ui, stream) return ret # End of ipeercommands interface. # Begin of ipeerlegacycommands interface. def branches(self, nodes): n = wireprototypes.encodelist(nodes) d = self._call("branches", nodes=n) try: br = [tuple(wireprototypes.decodelist(b)) for b in d.splitlines()] return br except ValueError: self._abort(error.ResponseError(_("unexpected response:"), d)) def between(self, pairs): batch = 8 # avoid giant requests r = [] for i in pycompat.xrange(0, len(pairs), batch): n = " ".join([wireprototypes.encodelist(p, '-') for p in pairs[i:i + batch]]) d = self._call("between", pairs=n) try: r.extend(l and wireprototypes.decodelist(l) or [] for l in d.splitlines()) except ValueError: self._abort(error.ResponseError(_("unexpected response:"), d)) return r def changegroup(self, nodes, source): n = wireprototypes.encodelist(nodes) f = self._callcompressable("changegroup", roots=n) return changegroupmod.cg1unpacker(f, 'UN') def changegroupsubset(self, bases, heads, source): self.requirecap('changegroupsubset', _('look up remote changes')) bases = wireprototypes.encodelist(bases) heads = wireprototypes.encodelist(heads) f = self._callcompressable("changegroupsubset", bases=bases, heads=heads) return changegroupmod.cg1unpacker(f, 'UN') # End of ipeerlegacycommands interface. def _submitbatch(self, req): """run batch request <req> on the server Returns an iterator of the raw responses from the server. """ ui = self.ui if ui.debugflag and ui.configbool('devel', 'debug.peer-request'): ui.debug('devel-peer-request: batched-content\n') for op, args in req: msg = 'devel-peer-request: - %s (%d arguments)\n' ui.debug(msg % (op, len(args))) unescapearg = wireprototypes.unescapebatcharg rsp = self._callstream("batch", cmds=encodebatchcmds(req)) chunk = rsp.read(1024) work = [chunk] while chunk: while ';' not in chunk and chunk: chunk = rsp.read(1024) work.append(chunk) merged = ''.join(work) while ';' in merged: one, merged = merged.split(';', 1) yield unescapearg(one) chunk = rsp.read(1024) work = [merged, chunk] yield unescapearg(''.join(work)) def _submitone(self, op, args): return self._call(op, **pycompat.strkwargs(args)) def debugwireargs(self, one, two, three=None, four=None, five=None): # don't pass optional arguments left at their default value opts = {} if three is not None: opts[r'three'] = three if four is not None: opts[r'four'] = four return self._call('debugwireargs', one=one, two=two, **opts) def _call(self, cmd, **args): """execute <cmd> on the server The command is expected to return a simple string. returns the server reply as a string.""" raise NotImplementedError() def _callstream(self, cmd, **args): """execute <cmd> on the server The command is expected to return a stream. Note that if the command doesn't return a stream, _callstream behaves differently for ssh and http peers. returns the server reply as a file like object. """ raise NotImplementedError() def _callcompressable(self, cmd, **args): """execute <cmd> on the server The command is expected to return a stream. The stream may have been compressed in some implementations. This function takes care of the decompression. This is the only difference with _callstream. returns the server reply as a file like object. """ raise NotImplementedError() def _callpush(self, cmd, fp, **args): """execute a <cmd> on server The command is expected to be related to a push. Push has a special return method. returns the server reply as a (ret, output) tuple. ret is either empty (error) or a stringified int. """ raise NotImplementedError() def _calltwowaystream(self, cmd, fp, **args): """execute <cmd> on server The command will send a stream to the server and get a stream in reply. """ raise NotImplementedError() def _abort(self, exception): """clearly abort the wire protocol connection and raise the exception """ raise NotImplementedError()