view hgext/remotefilelog/remotefilelogserver.py @ 44682:9ce613d648de

rust-chg: add config validation and process returned instructions

This is the reimplementation of runinstructions() and main() in chg.c.

In Rust version, we only pass in early arguments to the server as the locator
doesn't know the full arguments. This should be fine since these arguments
are just passed in to _earlyparseopts() and _parseconfig(), which means the
server doesn't need full arguments.

Another difference is the handling of the "exit <code>" instruction. In Rust
version, we can simply reuse the connection instead of "exit(code)" as the
command error isn't displayed yet. That's because the client-side stdio is not
attached until the connection is validated. This behavior is cleaner than C,
but it also means that the early server exception wouldn't be propagated to
client because stderr isn't attached. So we might have to reconsider when to
attach/detach the server stdio.

Differential Revision: https://phab.mercurial-scm.org/D8381

# remotefilelogserver.py - server logic for a remotefilelog server
#
# Copyright 2013 Facebook, Inc.
#
# 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 errno
import os
import stat
import time
import zlib

from mercurial.i18n import _
from mercurial.node import bin, hex, nullid
from mercurial.pycompat import open
from mercurial import (
    changegroup,
    changelog,
    context,
    error,
    extensions,
    match,
    pycompat,
    store,
    streamclone,
    util,
    wireprotoserver,
    wireprototypes,
    wireprotov1server,
)
from . import (
    constants,
    shallowutil,
)

_sshv1server = wireprotoserver.sshv1protocolhandler


def setupserver(ui, repo):
    """Sets up a normal Mercurial repo so it can serve files to shallow repos.
    """
    onetimesetup(ui)

    # don't send files to shallow clients during pulls
    def generatefiles(
        orig, self, changedfiles, linknodes, commonrevs, source, *args, **kwargs
    ):
        caps = self._bundlecaps or []
        if constants.BUNDLE2_CAPABLITY in caps:
            # only send files that don't match the specified patterns
            includepattern = None
            excludepattern = None
            for cap in self._bundlecaps or []:
                if cap.startswith(b"includepattern="):
                    includepattern = cap[len(b"includepattern=") :].split(b'\0')
                elif cap.startswith(b"excludepattern="):
                    excludepattern = cap[len(b"excludepattern=") :].split(b'\0')

            m = match.always()
            if includepattern or excludepattern:
                m = match.match(
                    repo.root, b'', None, includepattern, excludepattern
                )

            changedfiles = list([f for f in changedfiles if not m(f)])
        return orig(
            self, changedfiles, linknodes, commonrevs, source, *args, **kwargs
        )

    extensions.wrapfunction(
        changegroup.cgpacker, b'generatefiles', generatefiles
    )


onetime = False


def onetimesetup(ui):
    """Configures the wireprotocol for both clients and servers.
    """
    global onetime
    if onetime:
        return
    onetime = True

    # support file content requests
    wireprotov1server.wireprotocommand(
        b'x_rfl_getflogheads', b'path', permission=b'pull'
    )(getflogheads)
    wireprotov1server.wireprotocommand(
        b'x_rfl_getfiles', b'', permission=b'pull'
    )(getfiles)
    wireprotov1server.wireprotocommand(
        b'x_rfl_getfile', b'file node', permission=b'pull'
    )(getfile)

    class streamstate(object):
        match = None
        shallowremote = False
        noflatmf = False

    state = streamstate()

    def stream_out_shallow(repo, proto, other):
        includepattern = None
        excludepattern = None
        raw = other.get(b'includepattern')
        if raw:
            includepattern = raw.split(b'\0')
        raw = other.get(b'excludepattern')
        if raw:
            excludepattern = raw.split(b'\0')

        oldshallow = state.shallowremote
        oldmatch = state.match
        oldnoflatmf = state.noflatmf
        try:
            state.shallowremote = True
            state.match = match.always()
            state.noflatmf = other.get(b'noflatmanifest') == b'True'
            if includepattern or excludepattern:
                state.match = match.match(
                    repo.root, b'', None, includepattern, excludepattern
                )
            streamres = wireprotov1server.stream(repo, proto)

            # Force the first value to execute, so the file list is computed
            # within the try/finally scope
            first = next(streamres.gen)
            second = next(streamres.gen)

            def gen():
                yield first
                yield second
                for value in streamres.gen:
                    yield value

            return wireprototypes.streamres(gen())
        finally:
            state.shallowremote = oldshallow
            state.match = oldmatch
            state.noflatmf = oldnoflatmf

    wireprotov1server.commands[b'stream_out_shallow'] = (
        stream_out_shallow,
        b'*',
    )

    # don't clone filelogs to shallow clients
    def _walkstreamfiles(orig, repo, matcher=None):
        if state.shallowremote:
            # if we are shallow ourselves, stream our local commits
            if shallowutil.isenabled(repo):
                striplen = len(repo.store.path) + 1
                readdir = repo.store.rawvfs.readdir
                visit = [os.path.join(repo.store.path, b'data')]
                while visit:
                    p = visit.pop()
                    for f, kind, st in readdir(p, stat=True):
                        fp = p + b'/' + f
                        if kind == stat.S_IFREG:
                            if not fp.endswith(b'.i') and not fp.endswith(
                                b'.d'
                            ):
                                n = util.pconvert(fp[striplen:])
                                yield (store.decodedir(n), n, st.st_size)
                        if kind == stat.S_IFDIR:
                            visit.append(fp)

            if b'treemanifest' in repo.requirements:
                for (u, e, s) in repo.store.datafiles():
                    if u.startswith(b'meta/') and (
                        u.endswith(b'.i') or u.endswith(b'.d')
                    ):
                        yield (u, e, s)

            # Return .d and .i files that do not match the shallow pattern
            match = state.match
            if match and not match.always():
                for (u, e, s) in repo.store.datafiles():
                    f = u[5:-2]  # trim data/...  and .i/.d
                    if not state.match(f):
                        yield (u, e, s)

            for x in repo.store.topfiles():
                if state.noflatmf and x[0][:11] == b'00manifest.':
                    continue
                yield x

        elif shallowutil.isenabled(repo):
            # don't allow cloning from a shallow repo to a full repo
            # since it would require fetching every version of every
            # file in order to create the revlogs.
            raise error.Abort(
                _(b"Cannot clone from a shallow repo to a full repo.")
            )
        else:
            for x in orig(repo, matcher):
                yield x

    extensions.wrapfunction(streamclone, b'_walkstreamfiles', _walkstreamfiles)

    # expose remotefilelog capabilities
    def _capabilities(orig, repo, proto):
        caps = orig(repo, proto)
        if shallowutil.isenabled(repo) or ui.configbool(
            b'remotefilelog', b'server'
        ):
            if isinstance(proto, _sshv1server):
                # legacy getfiles method which only works over ssh
                caps.append(constants.NETWORK_CAP_LEGACY_SSH_GETFILES)
            caps.append(b'x_rfl_getflogheads')
            caps.append(b'x_rfl_getfile')
        return caps

    extensions.wrapfunction(wireprotov1server, b'_capabilities', _capabilities)

    def _adjustlinkrev(orig, self, *args, **kwargs):
        # When generating file blobs, taking the real path is too slow on large
        # repos, so force it to just return the linkrev directly.
        repo = self._repo
        if util.safehasattr(repo, b'forcelinkrev') and repo.forcelinkrev:
            return self._filelog.linkrev(self._filelog.rev(self._filenode))
        return orig(self, *args, **kwargs)

    extensions.wrapfunction(
        context.basefilectx, b'_adjustlinkrev', _adjustlinkrev
    )

    def _iscmd(orig, cmd):
        if cmd == b'x_rfl_getfiles':
            return False
        return orig(cmd)

    extensions.wrapfunction(wireprotoserver, b'iscmd', _iscmd)


def _loadfileblob(repo, cachepath, path, node):
    filecachepath = os.path.join(cachepath, path, hex(node))
    if not os.path.exists(filecachepath) or os.path.getsize(filecachepath) == 0:
        filectx = repo.filectx(path, fileid=node)
        if filectx.node() == nullid:
            repo.changelog = changelog.changelog(repo.svfs)
            filectx = repo.filectx(path, fileid=node)

        text = createfileblob(filectx)
        # TODO configurable compression engines
        text = zlib.compress(text)

        # everything should be user & group read/writable
        oldumask = os.umask(0o002)
        try:
            dirname = os.path.dirname(filecachepath)
            if not os.path.exists(dirname):
                try:
                    os.makedirs(dirname)
                except OSError as ex:
                    if ex.errno != errno.EEXIST:
                        raise

            f = None
            try:
                f = util.atomictempfile(filecachepath, b"wb")
                f.write(text)
            except (IOError, OSError):
                # Don't abort if the user only has permission to read,
                # and not write.
                pass
            finally:
                if f:
                    f.close()
        finally:
            os.umask(oldumask)
    else:
        with open(filecachepath, b"rb") as f:
            text = f.read()
    return text


def getflogheads(repo, proto, path):
    """A server api for requesting a filelog's heads
    """
    flog = repo.file(path)
    heads = flog.heads()
    return b'\n'.join((hex(head) for head in heads if head != nullid))


def getfile(repo, proto, file, node):
    """A server api for requesting a particular version of a file. Can be used
    in batches to request many files at once. The return protocol is:
    <errorcode>\0<data/errormsg> where <errorcode> is 0 for success or
    non-zero for an error.

    data is a compressed blob with revlog flag and ancestors information. See
    createfileblob for its content.
    """
    if shallowutil.isenabled(repo):
        return b'1\0' + _(b'cannot fetch remote files from shallow repo')
    cachepath = repo.ui.config(b"remotefilelog", b"servercachepath")
    if not cachepath:
        cachepath = os.path.join(repo.path, b"remotefilelogcache")
    node = bin(node.strip())
    if node == nullid:
        return b'0\0'
    return b'0\0' + _loadfileblob(repo, cachepath, file, node)


def getfiles(repo, proto):
    """A server api for requesting particular versions of particular files.
    """
    if shallowutil.isenabled(repo):
        raise error.Abort(_(b'cannot fetch remote files from shallow repo'))
    if not isinstance(proto, _sshv1server):
        raise error.Abort(_(b'cannot fetch remote files over non-ssh protocol'))

    def streamer():
        fin = proto._fin

        cachepath = repo.ui.config(b"remotefilelog", b"servercachepath")
        if not cachepath:
            cachepath = os.path.join(repo.path, b"remotefilelogcache")

        while True:
            request = fin.readline()[:-1]
            if not request:
                break

            node = bin(request[:40])
            if node == nullid:
                yield b'0\n'
                continue

            path = request[40:]

            text = _loadfileblob(repo, cachepath, path, node)

            yield b'%d\n%s' % (len(text), text)

            # it would be better to only flush after processing a whole batch
            # but currently we don't know if there are more requests coming
            proto._fout.flush()

    return wireprototypes.streamres(streamer())


def createfileblob(filectx):
    """
    format:
        v0:
            str(len(rawtext)) + '\0' + rawtext + ancestortext
        v1:
            'v1' + '\n' + metalist + '\0' + rawtext + ancestortext
            metalist := metalist + '\n' + meta | meta
            meta := sizemeta | flagmeta
            sizemeta := METAKEYSIZE + str(len(rawtext))
            flagmeta := METAKEYFLAG + str(flag)

            note: sizemeta must exist. METAKEYFLAG and METAKEYSIZE must have a
            length of 1.
    """
    flog = filectx.filelog()
    frev = filectx.filerev()
    revlogflags = flog._revlog.flags(frev)
    if revlogflags == 0:
        # normal files
        text = filectx.data()
    else:
        # lfs, read raw revision data
        text = flog.rawdata(frev)

    repo = filectx._repo

    ancestors = [filectx]

    try:
        repo.forcelinkrev = True
        ancestors.extend([f for f in filectx.ancestors()])

        ancestortext = b""
        for ancestorctx in ancestors:
            parents = ancestorctx.parents()
            p1 = nullid
            p2 = nullid
            if len(parents) > 0:
                p1 = parents[0].filenode()
            if len(parents) > 1:
                p2 = parents[1].filenode()

            copyname = b""
            rename = ancestorctx.renamed()
            if rename:
                copyname = rename[0]
            linknode = ancestorctx.node()
            ancestortext += b"%s%s%s%s%s\0" % (
                ancestorctx.filenode(),
                p1,
                p2,
                linknode,
                copyname,
            )
    finally:
        repo.forcelinkrev = False

    header = shallowutil.buildfileblobheader(len(text), revlogflags)

    return b"%s\0%s%s" % (header, text, ancestortext)


def gcserver(ui, repo):
    if not repo.ui.configbool(b"remotefilelog", b"server"):
        return

    neededfiles = set()
    heads = repo.revs(b"heads(tip~25000:) - null")

    cachepath = repo.vfs.join(b"remotefilelogcache")
    for head in heads:
        mf = repo[head].manifest()
        for filename, filenode in pycompat.iteritems(mf):
            filecachepath = os.path.join(cachepath, filename, hex(filenode))
            neededfiles.add(filecachepath)

    # delete unneeded older files
    days = repo.ui.configint(b"remotefilelog", b"serverexpiration")
    expiration = time.time() - (days * 24 * 60 * 60)

    progress = ui.makeprogress(_(b"removing old server cache"), unit=b"files")
    progress.update(0)
    for root, dirs, files in os.walk(cachepath):
        for file in files:
            filepath = os.path.join(root, file)
            progress.increment()
            if filepath in neededfiles:
                continue

            stat = os.stat(filepath)
            if stat.st_mtime < expiration:
                os.remove(filepath)

    progress.complete()