Mercurial > hg
view hgext/lfs/blobstore.py @ 35477:bb6a80fc969a
lfs: only hardlink between the usercache and local store if the blob verifies
This fixes the issue where verify (and other read commands) would propagate
corrupt blobs. I originalled coded this to only hardlink if 'verify=True' for
store.read(), but then good blobs weren't being linked, and this broke a bunch
of tests. (The blob in repo5 that is being corrupted seems to be linked into
repo5 in the loop running dumpflog.py prior to it being corrupted, but only if
verify=False is handled too.) It's probably better to do a one time extra
verification in order to create these files, so that the repo can be copied to a
removable drive.
Adding the same check to store.write() was only for completeness, but also needs
to do a one time extra verification to avoid breaking tests.
author | Matt Harbison <matt_harbison@yahoo.com> |
---|---|
date | Thu, 21 Dec 2017 14:13:39 -0500 |
parents | 417e8e040102 |
children | 5a73a0446afd |
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# blobstore.py - local and remote (speaking Git-LFS protocol) blob storages # # Copyright 2017 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 hashlib import json import os import re import socket from mercurial.i18n import _ from mercurial import ( error, pathutil, url as urlmod, util, vfs as vfsmod, worker, ) from ..largefiles import lfutil # 64 bytes for SHA256 _lfsre = re.compile(r'\A[a-f0-9]{64}\Z') class lfsvfs(vfsmod.vfs): def join(self, path): """split the path at first two characters, like: XX/XXXXX...""" if not _lfsre.match(path): raise error.ProgrammingError('unexpected lfs path: %s' % path) return super(lfsvfs, self).join(path[0:2], path[2:]) def walk(self, path=None, onerror=None): """Yield (dirpath, [], oids) tuple for blobs under path Oids only exist in the root of this vfs, so dirpath is always ''. """ root = os.path.normpath(self.base) # when dirpath == root, dirpath[prefixlen:] becomes empty # because len(dirpath) < prefixlen. prefixlen = len(pathutil.normasprefix(root)) oids = [] for dirpath, dirs, files in os.walk(self.reljoin(self.base, path or ''), onerror=onerror): dirpath = dirpath[prefixlen:] # Silently skip unexpected files and directories if len(dirpath) == 2: oids.extend([dirpath + f for f in files if _lfsre.match(dirpath + f)]) yield ('', [], oids) class filewithprogress(object): """a file-like object that supports __len__ and read. Useful to provide progress information for how many bytes are read. """ def __init__(self, fp, callback): self._fp = fp self._callback = callback # func(readsize) fp.seek(0, os.SEEK_END) self._len = fp.tell() fp.seek(0) def __len__(self): return self._len def read(self, size): if self._fp is None: return b'' data = self._fp.read(size) if data: if self._callback: self._callback(len(data)) else: self._fp.close() self._fp = None return data class local(object): """Local blobstore for large file contents. This blobstore is used both as a cache and as a staging area for large blobs to be uploaded to the remote blobstore. """ def __init__(self, repo): fullpath = repo.svfs.join('lfs/objects') self.vfs = lfsvfs(fullpath) usercache = lfutil._usercachedir(repo.ui, 'lfs') self.cachevfs = lfsvfs(usercache) self.ui = repo.ui def write(self, oid, data, verify=True): """Write blob to local blobstore.""" if verify: _verify(oid, data) with self.vfs(oid, 'wb', atomictemp=True) as fp: fp.write(data) # XXX: should we verify the content of the cache, and hardlink back to # the local store on success, but truncate, write and link on failure? if not self.cachevfs.exists(oid): if verify or hashlib.sha256(data).hexdigest() == oid: self.ui.note(_('lfs: adding %s to the usercache\n') % oid) lfutil.link(self.vfs.join(oid), self.cachevfs.join(oid)) def read(self, oid, verify=True): """Read blob from local blobstore.""" if not self.vfs.exists(oid): blob = self._read(self.cachevfs, oid, verify) # Even if revlog will verify the content, it needs to be verified # now before making the hardlink to avoid propagating corrupt blobs. # Don't abort if corruption is detected, because `hg verify` will # give more useful info about the corruption- simply don't add the # hardlink. if verify or hashlib.sha256(blob).hexdigest() == oid: self.ui.note(_('lfs: found %s in the usercache\n') % oid) lfutil.link(self.cachevfs.join(oid), self.vfs.join(oid)) else: self.ui.note(_('lfs: found %s in the local lfs store\n') % oid) blob = self._read(self.vfs, oid, verify) return blob def _read(self, vfs, oid, verify): """Read blob (after verifying) from the given store""" blob = vfs.read(oid) if verify: _verify(oid, blob) return blob def has(self, oid): """Returns True if the local blobstore contains the requested blob, False otherwise.""" return self.cachevfs.exists(oid) or self.vfs.exists(oid) class _gitlfsremote(object): def __init__(self, repo, url): ui = repo.ui self.ui = ui baseurl, authinfo = url.authinfo() self.baseurl = baseurl.rstrip('/') useragent = repo.ui.config('experimental', 'lfs.user-agent') if not useragent: useragent = 'mercurial/%s git/2.15.1' % util.version() self.urlopener = urlmod.opener(ui, authinfo, useragent) self.retry = ui.configint('lfs', 'retry') def writebatch(self, pointers, fromstore): """Batch upload from local to remote blobstore.""" self._batch(pointers, fromstore, 'upload') def readbatch(self, pointers, tostore): """Batch download from remote to local blostore.""" self._batch(pointers, tostore, 'download') def _batchrequest(self, pointers, action): """Get metadata about objects pointed by pointers for given action Return decoded JSON object like {'objects': [{'oid': '', 'size': 1}]} See https://github.com/git-lfs/git-lfs/blob/master/docs/api/batch.md """ objects = [{'oid': p.oid(), 'size': p.size()} for p in pointers] requestdata = json.dumps({ 'objects': objects, 'operation': action, }) batchreq = util.urlreq.request('%s/objects/batch' % self.baseurl, data=requestdata) batchreq.add_header('Accept', 'application/vnd.git-lfs+json') batchreq.add_header('Content-Type', 'application/vnd.git-lfs+json') try: rawjson = self.urlopener.open(batchreq).read() except util.urlerr.httperror as ex: raise LfsRemoteError(_('LFS HTTP error: %s (action=%s)') % (ex, action)) try: response = json.loads(rawjson) except ValueError: raise LfsRemoteError(_('LFS server returns invalid JSON: %s') % rawjson) return response def _checkforservererror(self, pointers, responses): """Scans errors from objects Returns LfsRemoteError if any objects has an error""" for response in responses: error = response.get('error') if error: ptrmap = {p.oid(): p for p in pointers} p = ptrmap.get(response['oid'], None) if error['code'] == 404 and p: filename = getattr(p, 'filename', 'unknown') raise LfsRemoteError( _(('LFS server error. Remote object ' 'for file %s not found: %r')) % (filename, response)) raise LfsRemoteError(_('LFS server error: %r') % response) def _extractobjects(self, response, pointers, action): """extract objects from response of the batch API response: parsed JSON object returned by batch API return response['objects'] filtered by action raise if any object has an error """ # Scan errors from objects - fail early objects = response.get('objects', []) self._checkforservererror(pointers, objects) # Filter objects with given action. Practically, this skips uploading # objects which exist in the server. filteredobjects = [o for o in objects if action in o.get('actions', [])] # But for downloading, we want all objects. Therefore missing objects # should be considered an error. if action == 'download': if len(filteredobjects) < len(objects): missing = [o.get('oid', '?') for o in objects if action not in o.get('actions', [])] raise LfsRemoteError( _('LFS server claims required objects do not exist:\n%s') % '\n'.join(missing)) return filteredobjects def _basictransfer(self, obj, action, localstore): """Download or upload a single object using basic transfer protocol obj: dict, an object description returned by batch API action: string, one of ['upload', 'download'] localstore: blobstore.local See https://github.com/git-lfs/git-lfs/blob/master/docs/api/\ basic-transfers.md """ oid = str(obj['oid']) href = str(obj['actions'][action].get('href')) headers = obj['actions'][action].get('header', {}).items() request = util.urlreq.request(href) if action == 'upload': # If uploading blobs, read data from local blobstore. with localstore.vfs(oid) as fp: _verifyfile(oid, fp) request.data = filewithprogress(localstore.vfs(oid), None) request.get_method = lambda: 'PUT' for k, v in headers: request.add_header(k, v) response = b'' try: req = self.urlopener.open(request) while True: data = req.read(1048576) if not data: break response += data except util.urlerr.httperror as ex: raise LfsRemoteError(_('HTTP error: %s (oid=%s, action=%s)') % (ex, oid, action)) if action == 'download': # If downloading blobs, store downloaded data to local blobstore localstore.write(oid, response, verify=True) def _batch(self, pointers, localstore, action): if action not in ['upload', 'download']: raise error.ProgrammingError('invalid Git-LFS action: %s' % action) response = self._batchrequest(pointers, action) objects = self._extractobjects(response, pointers, action) total = sum(x.get('size', 0) for x in objects) sizes = {} for obj in objects: sizes[obj.get('oid')] = obj.get('size', 0) topic = {'upload': _('lfs uploading'), 'download': _('lfs downloading')}[action] if self.ui.verbose and len(objects) > 1: self.ui.write(_('lfs: need to transfer %d objects (%s)\n') % (len(objects), util.bytecount(total))) self.ui.progress(topic, 0, total=total) def transfer(chunk): for obj in chunk: objsize = obj.get('size', 0) if self.ui.verbose: if action == 'download': msg = _('lfs: downloading %s (%s)\n') elif action == 'upload': msg = _('lfs: uploading %s (%s)\n') self.ui.write(msg % (obj.get('oid'), util.bytecount(objsize))) retry = self.retry while True: try: self._basictransfer(obj, action, localstore) yield 1, obj.get('oid') break except socket.error as ex: if retry > 0: if self.ui.verbose: self.ui.write( _('lfs: failed: %r (remaining retry %d)\n') % (ex, retry)) retry -= 1 continue raise oids = worker.worker(self.ui, 0.1, transfer, (), sorted(objects, key=lambda o: o.get('oid'))) processed = 0 for _one, oid in oids: processed += sizes[oid] self.ui.progress(topic, processed, total=total) if self.ui.verbose: self.ui.write(_('lfs: processed: %s\n') % oid) self.ui.progress(topic, pos=None, total=total) def __del__(self): # copied from mercurial/httppeer.py urlopener = getattr(self, 'urlopener', None) if urlopener: for h in urlopener.handlers: h.close() getattr(h, "close_all", lambda : None)() class _dummyremote(object): """Dummy store storing blobs to temp directory.""" def __init__(self, repo, url): fullpath = repo.vfs.join('lfs', url.path) self.vfs = lfsvfs(fullpath) def writebatch(self, pointers, fromstore): for p in pointers: content = fromstore.read(p.oid(), verify=True) with self.vfs(p.oid(), 'wb', atomictemp=True) as fp: fp.write(content) def readbatch(self, pointers, tostore): for p in pointers: content = self.vfs.read(p.oid()) tostore.write(p.oid(), content, verify=True) class _nullremote(object): """Null store storing blobs to /dev/null.""" def __init__(self, repo, url): pass def writebatch(self, pointers, fromstore): pass def readbatch(self, pointers, tostore): pass class _promptremote(object): """Prompt user to set lfs.url when accessed.""" def __init__(self, repo, url): pass def writebatch(self, pointers, fromstore, ui=None): self._prompt() def readbatch(self, pointers, tostore, ui=None): self._prompt() def _prompt(self): raise error.Abort(_('lfs.url needs to be configured')) _storemap = { 'https': _gitlfsremote, 'http': _gitlfsremote, 'file': _dummyremote, 'null': _nullremote, None: _promptremote, } def _verify(oid, content): realoid = hashlib.sha256(content).hexdigest() if realoid != oid: raise error.Abort(_('detected corrupt lfs object: %s') % oid, hint=_('run hg verify')) def _verifyfile(oid, fp): sha256 = hashlib.sha256() while True: data = fp.read(1024 * 1024) if not data: break sha256.update(data) realoid = sha256.hexdigest() if realoid != oid: raise error.Abort(_('detected corrupt lfs object: %s') % oid, hint=_('run hg verify')) def remote(repo): """remotestore factory. return a store in _storemap depending on config""" defaulturl = '' # convert deprecated configs to the new url. TODO: remove this if other # places are migrated to the new url config. # deprecated config: lfs.remotestore deprecatedstore = repo.ui.config('lfs', 'remotestore') if deprecatedstore == 'dummy': # deprecated config: lfs.remotepath defaulturl = 'file://' + repo.ui.config('lfs', 'remotepath') elif deprecatedstore == 'git-lfs': # deprecated config: lfs.remoteurl defaulturl = repo.ui.config('lfs', 'remoteurl') elif deprecatedstore == 'null': defaulturl = 'null://' url = util.url(repo.ui.config('lfs', 'url', defaulturl)) scheme = url.scheme if scheme not in _storemap: raise error.Abort(_('lfs: unknown url scheme: %s') % scheme) return _storemap[scheme](repo, url) class LfsRemoteError(error.RevlogError): pass