sapling/remotefilelog/remotefilelogserver.py
Durham Goode e9a9bad998 Use atomic file writes for server side cache
We've gotten reports of users receiving corrupt file blobs directly from the
server. The corruption doesn't enter the cache pool, and we don't get any
further reports of it, so I think it's a transient issue caused certain readers
reading the file before the writer has finished writing it.

Let's use atomic rename files to make this not happen.
2015-09-28 10:31:38 -07:00

340 lines
12 KiB
Python

# 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 mercurial import wireproto, changegroup, match, util, changelog, context
from mercurial import exchange, sshserver, store
from mercurial.extensions import wrapfunction
from mercurial.hgweb import protocol as httpprotocol
from mercurial.node import bin, hex, nullid, nullrev
from mercurial.i18n import _
import shallowrepo
import stat, os, lz4, time
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):
caps = self._bundlecaps or []
if shallowrepo.requirement 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("includepattern="):
includepattern = cap[len("includepattern="):].split('\0')
elif cap.startswith("excludepattern="):
excludepattern = cap[len("excludepattern="):].split('\0')
m = match.always(repo.root, '')
if includepattern or excludepattern:
m = match.match(repo.root, '', None,
includepattern, excludepattern)
changedfiles = list([f for f in changedfiles if not m(f)])
return orig(self, changedfiles, linknodes, commonrevs, source)
wrapfunction(changegroup.cg1packer, '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
wireproto.commands['getfiles'] = (getfiles, '')
wireproto.commands['getfile'] = (getfile, 'file node')
class streamstate(object):
match = None
shallowremote = False
state = streamstate()
def stream_out_shallow(repo, proto, other):
includepattern = None
excludepattern = None
raw = other.get('includepattern')
if raw:
includepattern = raw.split('\0')
raw = other.get('excludepattern')
if raw:
excludepattern = raw.split('\0')
oldshallow = state.shallowremote
oldmatch = state.match
try:
state.shallowremote = True
state.match = match.always(repo.root, '')
if includepattern or excludepattern:
state.match = match.match(repo.root, '', None,
includepattern, excludepattern)
streamres = wireproto.stream(repo, proto)
# Force the first value to execute, so the file list is computed
# within the try/finally scope
first = streamres.gen.next()
second = streamres.gen.next()
def gen():
yield first
yield second
for value in streamres.gen:
yield value
return wireproto.streamres(gen())
finally:
state.shallowremote = oldshallow
state.match = oldmatch
wireproto.commands['stream_out_shallow'] = (stream_out_shallow, '*')
# don't clone filelogs to shallow clients
def _walkstreamfiles(orig, repo):
if state.shallowremote:
# if we are shallow ourselves, stream our local commits
if shallowrepo.requirement in repo.requirements:
striplen = len(repo.store.path) + 1
readdir = repo.store.rawvfs.readdir
visit = [os.path.join(repo.store.path, 'data')]
while visit:
p = visit.pop()
for f, kind, st in readdir(p, stat=True):
fp = p + '/' + f
if kind == stat.S_IFREG:
if not fp.endswith('.i') and not fp.endswith('.d'):
n = util.pconvert(fp[striplen:])
yield (store.decodedir(n), n, st.st_size)
if kind == stat.S_IFDIR:
visit.append(fp)
# 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():
yield x
elif shallowrepo.requirement in repo.requirements:
# 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 util.Abort(_("Cannot clone from a shallow repo "
+ "to a full repo."))
else:
for x in orig(repo):
yield x
# This function moved in Mercurial 3.5
if util.safehasattr(wireproto, '_walkstreamfiles'):
wrapfunction(wireproto, '_walkstreamfiles', _walkstreamfiles)
else:
wrapfunction(exchange, '_walkstreamfiles', _walkstreamfiles)
# We no longer use getbundle_shallow commands, but we must still
# support it for migration purposes
def getbundleshallow(repo, proto, others):
bundlecaps = others.get('bundlecaps', '')
bundlecaps = set(bundlecaps.split(','))
bundlecaps.add('remotefilelog')
others['bundlecaps'] = ','.join(bundlecaps)
return wireproto.commands["getbundle"][0](repo, proto, others)
wireproto.commands["getbundle_shallow"] = (getbundleshallow, '*')
# expose remotefilelog capabilities
def _capabilities(orig, repo, proto):
caps = orig(repo, proto)
if ((shallowrepo.requirement in repo.requirements or
ui.configbool('remotefilelog', 'server'))):
if isinstance(proto, sshserver.sshserver):
# legacy getfiles method which only works over ssh
caps.append(shallowrepo.requirement)
caps.append("getfile")
return caps
wrapfunction(wireproto, '_capabilities', _capabilities)
def _adjustlinkrev(orig, self, path, filelog, fnode, *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, 'forcelinkrev') and repo.forcelinkrev:
return filelog.linkrev(filelog.rev(fnode))
return orig(self, path, filelog, fnode, *args, **kwargs)
wrapfunction(context.basefilectx, '_adjustlinkrev', _adjustlinkrev)
def _iscmd(orig, cmd):
if cmd == 'getfiles':
return False
return orig(cmd)
wrapfunction(httpprotocol, 'iscmd', _iscmd)
def _loadfileblob(repo, cachepath, path, node):
filecachepath = os.path.join(cachepath, path, hex(node))
if not os.path.exists(filecachepath):
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)
text = lz4.compressHC(text)
# everything should be user & group read/writable
oldumask = os.umask(0o002)
try:
dirname = os.path.dirname(filecachepath)
if not os.path.exists(dirname):
os.makedirs(dirname)
f = None
try:
f = util.atomictempfile(filecachepath, "w")
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, "r") as f:
text = f.read()
return text
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.
"""
if shallowrepo.requirement in repo.requirements:
return '1\0' + _('cannot fetch remote files from shallow repo')
cachepath = repo.ui.config("remotefilelog", "servercachepath")
if not cachepath:
cachepath = os.path.join(repo.path, "remotefilelogcache")
node = bin(node.strip())
if node == nullid:
return '0\0'
return '0\0' + _loadfileblob(repo, cachepath, file, node)
def getfiles(repo, proto):
"""A server api for requesting particular versions of particular files.
"""
if shallowrepo.requirement in repo.requirements:
raise util.Abort(_('cannot fetch remote files from shallow repo'))
if not isinstance(proto, sshserver.sshserver):
raise util.Abort(_('cannot fetch remote files over non-ssh protocol'))
def streamer():
fin = proto.fin
opener = repo.svfs
cachepath = repo.ui.config("remotefilelog", "servercachepath")
if not cachepath:
cachepath = os.path.join(repo.path, "remotefilelogcache")
while True:
request = fin.readline()[:-1]
if not request:
break
node = bin(request[:40])
if node == nullid:
yield '0\n'
continue
path = request[40:]
text = _loadfileblob(repo, cachepath, path, node)
yield '%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 wireproto.streamres(streamer())
def createfileblob(filectx):
text = filectx.data()
repo = filectx._repo
ancestors = [filectx]
try:
repo.forcelinkrev = True
ancestors.extend([f for f in filectx.ancestors()])
ancestortext = ""
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 = ""
rename = ancestorctx.renamed()
if rename:
copyname = rename[0]
linknode = ancestorctx.node()
ancestortext += "%s%s%s%s%s\0" % (
ancestorctx.filenode(), p1, p2, linknode,
copyname)
finally:
repo.forcelinkrev = False
return "%d\0%s%s" % (len(text), text, ancestortext)
def gcserver(ui, repo):
if not repo.ui.configbool("remotefilelog", "server"):
return
neededfiles = set()
heads = repo.revs("heads(all())")
cachepath = repo.join("remotefilelogcache")
for head in heads:
mf = repo[head].manifest()
for filename, filenode in mf.iteritems():
filecachepath = os.path.join(cachepath, filename, hex(filenode))
neededfiles.add(filecachepath)
# delete unneeded older files
days = repo.ui.configint("remotefilelog", "serverexpiration", 30)
expiration = time.time() - (days * 24 * 60 * 60)
_removing = _("removing old server cache")
count = 0
ui.progress(_removing, count, unit="files")
for root, dirs, files in os.walk(cachepath):
for file in files:
filepath = os.path.join(root, file)
count += 1
ui.progress(_removing, count, unit="files")
if filepath in neededfiles:
continue
stat = os.stat(filepath)
if stat.st_mtime < expiration:
os.remove(filepath)
ui.progress(_removing, None)