Mercurial > hg
view hgext/lfs/blobstore.py @ 39772:ae531f5e583c
testing: add interface unit tests for file storage
Our strategy for supporting alternate storage backends is to define
interfaces for everything then "code to the interface."
We already have interfaces for various primitives, including file
and manifest storage.
What we don't have is generic unit tests for those interfaces. Up
to this point we've been relying on high-level integration tests
(mainly in the form of existing .t tests) to test alternate storage
backends. And my experience with developing the "simple store" test
extension is that such testing is very tedious: it takes several
minutes to run all tests and when you find a failure, it is often
non-trivial to debug.
This commit starts to change that.
This commit introduces the mercurial.testing.storage module. It
contains testing code for storage. Currently, it defines some
unittest.TestCase classes for testing the file storage interfaces.
It also defines some factory functions that allow a caller to easily
spawn a custom TestCase "bound" to a specific file storage backend
implementation.
A new .py test has been added. It simply defines a callable to produce
filelog and transaction instances on demand and then "registers" the
various test classes so the filelog class can be tested with the
storage interface unit tests.
As part of writing the tests, I identified a couple of apparent
bugs in revlog.py and filelog.py! These are tracked with inline
TODO comments.
Writing the tests makes it more obvious where the storage interface
is lacking. For example, we raise either IndexError or
error.LookupError for missing revisions depending on whether we
use an integer revision or a node. Also, we raise error.RevlogError
in various places when we should be raising a storage-agnostic
error type.
The storage interfaces are currently far from perfect and there is much
work to be done to improve them. But at least with this commit we
finally have the start of unit tests that can be used to "qualify"
the behavior of a storage backend. And when implementing and debugging
new storage backends, we now have an obvious place to define new
tests and have obvious places to insert breakpoints to facilitate
debugging. This should be invaluable when implementing new storage
backends.
I added the mercurial.testing package because these interface
conformance tests are generic and need to be usable by all storage
backends. Having the code live in tests/ would make it difficult for
storage backends implemented in extensions to test their interface
conformance. First, it would require obtaining a copy of Mercurial's
storage test code in order to test. Second, it would make testing
against multiple Mercurial versions difficult, as you would need to
import N copies of the storage testing code in order to achieve test
coverage. By making the test code part of the Mercurial distribution
itself, extensions can `import mercurial.testing.*` to access and run
the test code. The test will run against whatever Mercurial version
is active.
FWIW I've always wanted to move parts of run-tests.py into the
mercurial.* package to make the testing story simpler (e.g. imagine an
`hg debugruntests` command that could invoke the test harness). While I
have no plans to do that in the near future, establishing the
mercurial.testing package does provide a natural home for that code
should someone do this in the future.
Differential Revision: https://phab.mercurial-scm.org/D4650
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Tue, 18 Sep 2018 16:52:11 -0700 |
parents | a913d2892e17 |
children | b63dee7bd0d9 |
line wrap: on
line source
# 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 errno import hashlib import json import os import re import socket from mercurial.i18n import _ from mercurial import ( error, pathutil, pycompat, url as urlmod, util, vfs as vfsmod, worker, ) from ..largefiles import lfutil # 64 bytes for SHA256 _lfsre = re.compile(br'\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 nullvfs(lfsvfs): def __init__(self): pass def exists(self, oid): return False def read(self, oid): # store.read() calls into here if the blob doesn't exist in its # self.vfs. Raise the same error as a normal vfs when asked to read a # file that doesn't exist. The only difference is the full file path # isn't available in the error. raise IOError(errno.ENOENT, '%s: No such file or directory' % oid) def walk(self, path=None, onerror=None): return ('', [], []) def write(self, oid, data): pass 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) if repo.ui.configbool('experimental', 'lfs.disableusercache'): self.cachevfs = nullvfs() else: usercache = lfutil._usercachedir(repo.ui, 'lfs') self.cachevfs = lfsvfs(usercache) self.ui = repo.ui def open(self, oid): """Open a read-only file descriptor to the named blob, in either the usercache or the local store.""" # The usercache is the most likely place to hold the file. Commit will # write to both it and the local store, as will anything that downloads # the blobs. However, things like clone without an update won't # populate the local store. For an init + push of a local clone, # the usercache is the only place it _could_ be. If not present, the # missing file msg here will indicate the local repo, not the usercache. if self.cachevfs.exists(oid): return self.cachevfs(oid, 'rb') return self.vfs(oid, 'rb') def download(self, oid, src): """Read the blob from the remote source in chunks, verify the content, and write to this local blobstore.""" sha256 = hashlib.sha256() with self.vfs(oid, 'wb', atomictemp=True) as fp: for chunk in util.filechunkiter(src, size=1048576): fp.write(chunk) sha256.update(chunk) realoid = sha256.hexdigest() if realoid != oid: raise LfsCorruptionError(_('corrupt remote lfs object: %s') % oid) self._linktousercache(oid) def write(self, oid, data): """Write blob to local blobstore. This should only be called from the filelog during a commit or similar. As such, there is no need to verify the data. Imports from a remote store must use ``download()`` instead.""" with self.vfs(oid, 'wb', atomictemp=True) as fp: fp.write(data) self._linktousercache(oid) def linkfromusercache(self, oid): """Link blobs found in the user cache into this store. The server module needs to do this when it lets the client know not to upload the blob, to ensure it is always available in this store. Normally this is done implicitly when the client reads or writes the blob, but that doesn't happen when the server tells the client that it already has the blob. """ if (not isinstance(self.cachevfs, nullvfs) and not self.vfs.exists(oid)): self.ui.note(_('lfs: found %s in the usercache\n') % oid) lfutil.link(self.cachevfs.join(oid), self.vfs.join(oid)) def _linktousercache(self, oid): # 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) and not isinstance(self.cachevfs, nullvfs)): 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 verify(self, oid): """Indicate whether or not the hash of the underlying file matches its name.""" sha256 = hashlib.sha256() with self.open(oid) as fp: for chunk in util.filechunkiter(fp, size=1048576): sha256.update(chunk) return oid == sha256.hexdigest() 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 = 'git-lfs/2.3.4 (Mercurial %s)' % 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(_deduplicate(pointers), fromstore, 'upload') def readbatch(self, pointers, tostore): """Batch download from remote to local blostore.""" self._batch(_deduplicate(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: rsp = self.urlopener.open(batchreq) rawjson = rsp.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) if self.ui.debugflag: self.ui.debug('Status: %d\n' % rsp.status) # lfs-test-server and hg serve return headers in different order self.ui.debug('%s\n' % '\n'.join(sorted(str(rsp.info()).splitlines()))) if 'objects' in response: response['objects'] = sorted(response['objects'], key=lambda p: p['oid']) self.ui.debug('%s\n' % json.dumps(response, indent=2, separators=('', ': '), sort_keys=True)) return response def _checkforservererror(self, pointers, responses, action): """Scans errors from objects Raises LfsRemoteError if any objects have an error""" for response in responses: # The server should return 404 when objects cannot be found. Some # server implementation (ex. lfs-test-server) does not set "error" # but just removes "download" from "actions". Treat that case # as the same as 404 error. if 'error' not in response: if (action == 'download' and action not in response.get('actions', [])): code = 404 else: continue else: # An error dict without a code doesn't make much sense, so # treat as a server error. code = response.get('error').get('code', 500) ptrmap = {p.oid(): p for p in pointers} p = ptrmap.get(response['oid'], None) if p: filename = getattr(p, 'filename', 'unknown') errors = { 404: 'The object does not exist', 410: 'The object was removed by the owner', 422: 'Validation error', 500: 'Internal server error', } msg = errors.get(code, 'status code %d' % code) raise LfsRemoteError(_('LFS server error for "%s": %s') % (filename, msg)) else: raise LfsRemoteError( _('LFS server error. Unsolicited response for oid %s') % response['oid']) 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, action) # 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', [])] 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 = pycompat.bytestr(obj['oid']) href = pycompat.bytestr(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. if not localstore.verify(oid): raise error.Abort(_('detected corrupt lfs object: %s') % oid, hint=_('run hg verify')) request.data = filewithprogress(localstore.open(oid), None) request.get_method = lambda: 'PUT' request.add_header('Content-Type', 'application/octet-stream') for k, v in headers: request.add_header(k, v) response = b'' try: req = self.urlopener.open(request) if self.ui.debugflag: self.ui.debug('Status: %d\n' % req.status) # lfs-test-server and hg serve return headers in different order self.ui.debug('%s\n' % '\n'.join(sorted(str(req.info()).splitlines()))) if action == 'download': # If downloading blobs, store downloaded data to local blobstore localstore.download(oid, req) else: while True: data = req.read(1048576) if not data: break response += data if response: self.ui.debug('lfs %s response: %s' % (action, response)) except util.urlerr.httperror as ex: if self.ui.debugflag: self.ui.debug('%s: %s\n' % (oid, ex.read())) raise LfsRemoteError(_('HTTP error: %s (oid=%s, action=%s)') % (ex, oid, action)) 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 len(objects) > 1: self.ui.note(_('lfs: need to transfer %d objects (%s)\n') % (len(objects), util.bytecount(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.note(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: self.ui.note( _('lfs: failed: %r (remaining retry %d)\n') % (ex, retry)) retry -= 1 continue raise # Until https multiplexing gets sorted out if self.ui.configbool('experimental', 'lfs.worker-enable'): oids = worker.worker(self.ui, 0.1, transfer, (), sorted(objects, key=lambda o: o.get('oid'))) else: oids = transfer(sorted(objects, key=lambda o: o.get('oid'))) with self.ui.makeprogress(topic, total=total) as progress: progress.update(0) processed = 0 blobs = 0 for _one, oid in oids: processed += sizes[oid] blobs += 1 progress.update(processed) self.ui.note(_('lfs: processed: %s\n') % oid) if blobs > 0: if action == 'upload': self.ui.status(_('lfs: uploaded %d files (%s)\n') % (blobs, util.bytecount(processed))) elif action == 'download': self.ui.status(_('lfs: downloaded %d files (%s)\n') % (blobs, util.bytecount(processed))) 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 _deduplicate(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 _deduplicate(pointers): with self.vfs(p.oid(), 'rb') as fp: tostore.download(p.oid(), fp) 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 _deduplicate(pointers): """Remove any duplicate oids that exist in the list""" reduced = util.sortdict() for p in pointers: reduced[p.oid()] = p return reduced.values() def _verify(oid, content): realoid = hashlib.sha256(content).hexdigest() if realoid != oid: raise LfsCorruptionError(_('detected corrupt lfs object: %s') % oid, hint=_('run hg verify')) def remote(repo, remote=None): """remotestore factory. return a store in _storemap depending on config If ``lfs.url`` is specified, use that remote endpoint. Otherwise, try to infer the endpoint, based on the remote repository using the same path adjustments as git. As an extension, 'http' is supported as well so that ``hg serve`` works out of the box. https://github.com/git-lfs/git-lfs/blob/master/docs/api/server-discovery.md """ lfsurl = repo.ui.config('lfs', 'url') url = util.url(lfsurl or '') if lfsurl is None: if remote: path = remote elif util.safehasattr(repo, '_subtoppath'): # The pull command sets this during the optional update phase, which # tells exactly where the pull originated, whether 'paths.default' # or explicit. path = repo._subtoppath else: # TODO: investigate 'paths.remote:lfsurl' style path customization, # and fall back to inferring from 'paths.remote' if unspecified. path = repo.ui.config('paths', 'default') or '' defaulturl = util.url(path) # TODO: support local paths as well. # TODO: consider the ssh -> https transformation that git applies if defaulturl.scheme in (b'http', b'https'): if defaulturl.path and defaulturl.path[:-1] != b'/': defaulturl.path += b'/' defaulturl.path = (defaulturl.path or b'') + b'.git/info/lfs' url = util.url(bytes(defaulturl)) repo.ui.note(_('lfs: assuming remote store: %s\n') % url) 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 class LfsCorruptionError(error.Abort): """Raised when a corrupt blob is detected, aborting an operation It exists to allow specialized handling on the server side."""