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# Copyright (C) 2015-2018 The Software Heritage developers
# See the AUTHORS file at the top-level directory of this distribution
# License: GNU General Public License version 3, or any later version
# See top-level LICENSE file for more information
"""Loader in charge of injecting either new or existing svn mirrors to
swh-storage.
"""
import os
import re
import shutil
import tempfile
from mmap import mmap, ACCESS_WRITE
from subprocess import run, PIPE
from swh.model import hashutil
from swh.model.from_disk import Directory
from swh.model.identifiers import identifier_to_bytes, revision_identifier
from swh.model.identifiers import snapshot_identifier
from swh.loader.core.loader import SWHLoader
from swh.loader.core.utils import clean_dangling_folders
from . import svn, converters
from .utils import (
init_svn_repo_from_dump, init_svn_repo_from_archive_dump
)
from .exception import SvnLoaderUneventful
from .exception import SvnLoaderHistoryAltered
DEFAULT_BRANCH = b'HEAD'
def _revision_id(revision):
return identifier_to_bytes(revision_identifier(revision))
def build_swh_snapshot(revision_id, branch=DEFAULT_BRANCH):
"""Build a swh snapshot from the revision id, origin id, and visit.
"""
return {
'id': None,
'branches': {
branch: {
'target': revision_id,
'target_type': 'revision',
}
}
}
TEMPORARY_DIR_PREFIX_PATTERN = 'swh.loader.svn.'
class SvnLoader(SWHLoader):
"""Swh svn loader.
The repository is either remote or local. The loader deals with
update on an already previously loaded repository.
"""
CONFIG_BASE_FILENAME = 'loader/svn'
ADDITIONAL_CONFIG = {
'temp_directory': ('str', '/tmp'),
'debug': ('bool', False), # NOT FOR PRODUCTION, False for production
'check_revision': ('dict', {
'status': False, # do we check the revision?
'limit': 1000, # at which pace do we check it?
}),
}
def __init__(self):
super().__init__(logging_class='swh.loader.svn.SvnLoader')
self.origin_id = None
self.debug = self.config['debug']
self.last_seen_revision = None
self.temp_directory = self.config['temp_directory']
self.done = False
self.svnrepo = None
# Revision check is configurable
check_revision = self.config['check_revision']
if check_revision['status']:
self.check_revision = check_revision['limit']
else:
self.check_revision = None
# internal state used to store swh objects
self._contents = []
self._directories = []
self._revisions = []
self._snapshot = None
self._last_revision = None
self._visit_status = 'full'
self._load_status = 'uneventful'
def pre_cleanup(self):
"""Cleanup potential dangling files from prior runs (e.g. OOM killed
tasks)
"""
clean_dangling_folders(self.temp_directory,
pattern_check=TEMPORARY_DIR_PREFIX_PATTERN,
log=self.log)
def cleanup(self):
"""Clean up the svn repository's working representation on disk.
"""
if not self.svnrepo: # could happen if `prepare` fails
return
if self.debug:
self.log.error('''NOT FOR PRODUCTION - debug flag activated
Local repository not cleaned up for investigation: %s''' % (
self.svnrepo.local_url.decode('utf-8'), ))
return
self.svnrepo.clean_fs()
def swh_revision_hash_tree_at_svn_revision(self, revision):
"""Compute and return the hash tree at a given svn revision.
Args:
rev (int): the svn revision we want to check
Returns:
The hash tree directory as bytes.
"""
local_dirname, local_url = self.svnrepo.export_temporary(revision)
h = Directory.from_disk(path=local_url).hash
self.svnrepo.clean_fs(local_dirname)
return h
def get_svn_repo(self, svn_url, local_dirname, origin_id):
"""Instantiates the needed svnrepo collaborator to permit reading svn
repository.
Args:
svn_url (str): the svn repository url to read from
local_dirname (str): the local path on disk to compute data
origin_id (int): the corresponding origin id
Returns:
Instance of :mod:`swh.loader.svn.svn` clients
"""
return svn.SvnRepo(svn_url,
local_dirname=local_dirname, origin_id=origin_id)
def swh_latest_snapshot_revision(self, origin_id,
previous_swh_revision=None):
"""Look for latest snapshot revision and returns it if any.
Args:
origin_id (int): Origin identifier
previous_swh_revision: (optional) id of a possible
previous swh revision
Returns:
dict: The latest known point in time. Dict with keys:
'revision': latest visited revision
'snapshot': latest snapshot
If None is found, return an empty dict.
"""
storage = self.storage
if not previous_swh_revision: # check latest snapshot's revision
latest_snap = storage.snapshot_get_latest(origin_id)
if latest_snap:
branches = latest_snap.get('branches')
if not branches:
return {}
branch = branches.get(DEFAULT_BRANCH)
if not branch:
return {}
target_type = branch['target_type']
if target_type != 'revision':
return {}
previous_swh_revision = branch['target']
else:
return {}
if isinstance(previous_swh_revision, dict):
swh_id = previous_swh_revision['id']
else:
swh_id = previous_swh_revision
revs = list(storage.revision_get([swh_id]))
if revs:
return {
'snapshot': latest_snap,
'revision': revs[0]
}
return {}
def build_swh_revision(self, rev, commit, dir_id, parents):
"""Build the swh revision dictionary.
This adds:
- the `'synthetic`' flag to true
- the '`extra_headers`' containing the repository's uuid and the
svn revision number.
Args:
rev (dict): the svn revision
commit (dict): the commit metadata
dir_id (bytes): the upper tree's hash identifier
parents ([bytes]): the parents' identifiers
Returns:
The swh revision corresponding to the svn revision.
"""
return converters.build_swh_revision(
rev, commit, self.svnrepo.uuid, dir_id, parents)
def check_history_not_altered(self, svnrepo, revision_start, swh_rev):
"""Given a svn repository, check if the history was not tampered with.
"""
revision_id = swh_rev['id']
parents = swh_rev['parents']
hash_data_per_revs = svnrepo.swh_hash_data_at_revision(revision_start)
rev = revision_start
rev, _, commit, _, root_dir = list(hash_data_per_revs)[0]
dir_id = root_dir.hash
swh_revision = self.build_swh_revision(rev,
commit,
dir_id,
parents)
swh_revision_id = _revision_id(swh_revision)
return swh_revision_id == revision_id
def _init_from(self, partial_swh_revision, previous_swh_revision):
"""Function to determine from where to start from.
Args:
partial_swh_revision (dict): A known revision from which
the previous loading did not
finish.
known_previous_revision (dict): A known revision from
which the previous loading
did finish.
Returns:
The revision from which to start or None if nothing (fresh
start).
"""
if partial_swh_revision and not previous_swh_revision:
return partial_swh_revision
if not partial_swh_revision and previous_swh_revision:
return previous_swh_revision
if partial_swh_revision and previous_swh_revision:
# will determine from which to start from
extra_headers1 = dict(
partial_swh_revision['metadata']['extra_headers'])
extra_headers2 = dict(
previous_swh_revision['metadata']['extra_headers'])
rev_start1 = int(extra_headers1['svn_revision'])
rev_start2 = int(extra_headers2['svn_revision'])
if rev_start1 <= rev_start2:
return previous_swh_revision
return partial_swh_revision
return None
def start_from(self, last_known_swh_revision=None,
start_from_scratch=False):
"""Determine from where to start the loading.
Args:
last_known_swh_revision (dict): Last know swh revision or None
start_from_scratch (bool): To start loading from scratch or not
Returns:
tuple (revision_start, revision_end, revision_parents)
Raises:
SvnLoaderHistoryAltered: When a hash divergence has been
detected (should not happen)
SvnLoaderUneventful: Nothing changed since last visit
"""
revision_head = self.svnrepo.head_revision()
if revision_head == 0: # empty repository case
revision_start = 0
revision_end = 0
else: # default configuration
revision_start = self.svnrepo.initial_revision()
revision_end = revision_head
revision_parents = {
revision_start: []
}
if not start_from_scratch:
# Check if we already know a previous revision for that origin
if self.latest_snapshot:
swh_rev = self.latest_snapshot['revision']
else:
swh_rev = None
# Determine from which known revision to start
swh_rev = self._init_from(last_known_swh_revision,
previous_swh_revision=swh_rev)
if swh_rev: # Yes, we know a previous revision. Try and update it.
extra_headers = dict(swh_rev['metadata']['extra_headers'])
revision_start = int(extra_headers['svn_revision'])
revision_parents = {
revision_start: swh_rev['parents'],
}
self.log.debug('svn export --ignore-keywords %s@%s' % (
self.svnrepo.remote_url,
revision_start))
if swh_rev and not self.check_history_not_altered(
self.svnrepo,
revision_start,
swh_rev):
msg = 'History of svn %s@%s altered. ' \
'Skipping...' % (
self.svnrepo.remote_url, revision_start)
raise SvnLoaderHistoryAltered(msg)
# now we know history is ok, we start at next revision
revision_start = revision_start + 1
# and the parent become the latest know revision for
# that repository
revision_parents[revision_start] = [swh_rev['id']]
if revision_start > revision_end and revision_start is not 1:
msg = '%s@%s already injected.' % (self.svnrepo.remote_url,
revision_end)
raise SvnLoaderUneventful(msg)
self.log.info('Processing revisions [%s-%s] for %s' % (
revision_start, revision_end, self.svnrepo))
return revision_start, revision_end, revision_parents
def _check_revision_divergence(self, count, rev, dir_id):
"""Check for hash revision computation divergence.
The Rationale behind this is that svn can trigger unknown
edge cases (mixed CRLF, svn properties, etc...). Those are
not always easy to spot. Adding a check will help in
spotting missing edge cases.
Args:
count (int): The number of revisions done so far
rev (dict): The actual revision we are computing from
dir_id (bytes): The actual directory for the given revision
Returns:
False if no hash divergence detected
Raises
ValueError if a hash divergence is detected
"""
if (count % self.check_revision) == 0: # hash computation check
self.log.debug('Checking hash computations on revision %s...' %
rev)
checked_dir_id = self.swh_revision_hash_tree_at_svn_revision(
rev)
if checked_dir_id != dir_id:
err = 'Hash tree computation divergence detected ' \
'(%s != %s), stopping!' % (
hashutil.hash_to_hex(dir_id),
hashutil.hash_to_hex(checked_dir_id))
raise ValueError(err)
def process_svn_revisions(self, svnrepo, revision_start, revision_end,
revision_parents):
"""Process svn revisions from revision_start to revision_end.
At each svn revision, apply new diffs and simultaneously
compute swh hashes. This yields those computed swh hashes as
a tuple (contents, directories, revision).
Note that at every `self.check_revision`, a supplementary
check takes place to check for hash-tree divergence (related
T570).
Yields:
tuple (contents, directories, revision) of dict as a
dictionary with keys, sha1_git, sha1, etc...
Raises:
ValueError in case of a hash divergence detection
"""
gen_revs = svnrepo.swh_hash_data_per_revision(
revision_start,
revision_end)
swh_revision = None
count = 0
for rev, nextrev, commit, new_objects, root_directory in gen_revs:
count += 1
# Send the associated contents/directories
_contents = new_objects.get('content', {}).values()
_directories = new_objects.get('directory', {}).values()
# compute the fs tree's checksums
dir_id = root_directory.hash
swh_revision = self.build_swh_revision(
rev, commit, dir_id, revision_parents[rev])
swh_revision['id'] = _revision_id(swh_revision)
self.log.debug('rev: %s, swhrev: %s, dir: %s' % (
rev,
hashutil.hash_to_hex(swh_revision['id']),
hashutil.hash_to_hex(dir_id)))
if self.check_revision:
self._check_revision_divergence(count, rev, dir_id)
if nextrev:
revision_parents[nextrev] = [swh_revision['id']]
yield _contents, _directories, swh_revision
def prepare_origin_visit(self, *, svn_url, visit_date=None,
origin_url=None, **kwargs):
self.origin = {
'url': origin_url if origin_url else svn_url,
'type': 'svn',
}
self.visit_date = visit_date
def prepare(self, *, svn_url, destination_path=None,
swh_revision=None, start_from_scratch=False, **kwargs):
self.start_from_scratch = start_from_scratch
if swh_revision:
self.last_known_swh_revision = swh_revision
else:
self.last_known_swh_revision = None
self.latest_snapshot = self.swh_latest_snapshot_revision(
self.origin_id, self.last_known_swh_revision)
if destination_path:
local_dirname = destination_path
else:
local_dirname = tempfile.mkdtemp(
suffix='-%s' % os.getpid(),
prefix=TEMPORARY_DIR_PREFIX_PATTERN,
dir=self.temp_directory)
self.svnrepo = self.get_svn_repo(
svn_url, local_dirname, self.origin_id)
try:
revision_start, revision_end, revision_parents = self.start_from(
self.last_known_swh_revision, self.start_from_scratch)
self.swh_revision_gen = self.process_svn_revisions(
self.svnrepo, revision_start, revision_end, revision_parents)
except SvnLoaderUneventful as e:
self.log.warn(e)
if self.latest_snapshot and 'snapshot' in self.latest_snapshot:
self._snapshot = self.latest_snapshot['snapshot']
self.done = True
except SvnLoaderHistoryAltered as e:
self.log.error(e)
self.done = True
self._visit_status = 'partial'
def fetch_data(self):
"""Fetching svn revision information.
This will apply svn revision as patch on disk, and at the same
time, compute the swh hashes.
In effect, fetch_data fetches those data and compute the
necessary swh objects. It's then stored in the internal state
instance variables (initialized in `_prepare_state`).
This is up to `store_data` to actually discuss with the
storage to store those objects.
Returns:
bool: True to continue fetching data (next svn revision),
False to stop.
"""
data = None
if self.done:
return False
try:
data = next(self.swh_revision_gen)
self._load_status = 'eventful'
except StopIteration:
self.done = True
self._visit_status = 'full'
return False # Stopping iteration
except Exception as e: # svn:external, hash divergence, i/o error...
self.log.exception(e)
self.done = True
self._visit_status = 'partial'
return False # Stopping iteration
self._contents, self._directories, revision = data
if revision:
self._last_revision = revision
self._revisions.append(revision)
return True # next svn revision
def store_data(self):
"""We store the data accumulated in internal instance variable. If
the iteration over the svn revisions is done, we create the
snapshot and flush to storage the data.
This also resets the internal instance variable state.
"""
self.maybe_load_contents(self._contents)
self.maybe_load_directories(self._directories)
self.maybe_load_revisions(self._revisions)
if self.done: # finish line, snapshot!
self.generate_and_load_snapshot(revision=self._last_revision,
snapshot=self._snapshot)
self.flush()
self._contents = []
self._directories = []
self._revisions = []
def generate_and_load_snapshot(self, revision=None, snapshot=None):
"""Create the snapshot either from existing revision or snapshot.
Revision (supposedly new) has priority over the snapshot
(supposedly existing one).
Args:
revision (dict): Last revision seen if any (None by default)
snapshot (dict): Snapshot to use if any (None by default)
"""
if revision: # Priority to the revision
snap = build_swh_snapshot(revision['id'])
snap['id'] = identifier_to_bytes(snapshot_identifier(snap))
elif snapshot: # Fallback to prior snapshot
snap = snapshot
else:
return None
self.log.debug('snapshot: %s' % snap)
self.maybe_load_snapshot(snap)
def load_status(self):
return {
'status': self._load_status,
}
def visit_status(self):
return self._visit_status
class SvnLoaderFromDumpArchive(SvnLoader):
"""Uncompress an archive containing an svn dump, mount the svn dump as
an svn repository and load said repository.
"""
def __init__(self, archive_path):
super().__init__()
self.archive_path = archive_path
self.temp_dir = None
self.repo_path = None
def prepare(self, *, svn_url, destination_path=None,
swh_revision=None, start_from_scratch=False, **kwargs):
self.log.info('Archive to mount and load %s' % self.archive_path)
self.temp_dir, self.repo_path = init_svn_repo_from_archive_dump(
self.archive_path,
prefix=TEMPORARY_DIR_PREFIX_PATTERN,
suffix='-%s' % os.getpid(),
root_dir=self.temp_directory)
if not svn_url:
svn_url = 'file://%s' % self.repo_path
super().prepare(svn_url=svn_url, destination_path=destination_path,
swh_revision=swh_revision,
start_from_scratch=start_from_scratch,
**kwargs)
def cleanup(self):
super().cleanup()
if self.temp_dir and os.path.exists(self.temp_dir):
msg = 'Clean up temporary directory dump %s for project %s' % (
self.temp_dir, os.path.basename(self.repo_path))
self.log.debug(msg)
shutil.rmtree(self.temp_dir)
class SvnLoaderFromRemoteDump(SvnLoader):
"""
Create a subversion repository dump using the svnrdump utility,
mount it locally and load the repository from it.
"""
def __init__(self):
super().__init__()
self.temp_dir = tempfile.mkdtemp(dir=self.temp_directory)
self.repo_path = None
self.truncated_dump = False
def get_last_loaded_svn_rev(self, svn_url):
"""
Check if the svn repository has already been visited
and return the last loaded svn revision number or -1
otherwise.
"""
last_loaded_svn_rev = -1
try:
origin = \
self.storage.origin_get({'type': 'svn', 'url': svn_url})
last_swh_rev = \
self.swh_latest_snapshot_revision(origin['id'])['revision']
last_swh_rev_headers = \
dict(last_swh_rev['metadata']['extra_headers'])
last_loaded_svn_rev = int(last_swh_rev_headers['svn_revision'])
except Exception:
pass
return last_loaded_svn_rev
def dump_svn_revisions(self, svn_url, last_loaded_svn_rev=-1):
"""
Generate a subversion dump file using the svnrdump tool.
If the svnrdump command failed somehow,
the produced dump file is analyzed to determine if a partial
loading is still feasible.
"""
# Build the svnrdump command line
svnrdump_cmd = ['svnrdump', 'dump', svn_url]
# Launch the svnrdump command while capturing stderr as
# successfully dumped revision numbers are printed to it
dump_temp_dir = tempfile.mkdtemp(dir=self.temp_dir)
dump_name = ''.join(c for c in svn_url if c.isalnum())
dump_path = '%s/%s.svndump' % (dump_temp_dir, dump_name)
self.log.debug('Executing %s' % ' '.join(svnrdump_cmd))
with open(dump_path, 'wb') as dump_file:
svnrdump = run(svnrdump_cmd, stdout=dump_file, stderr=PIPE)
if svnrdump.returncode == 0:
return dump_path
# There was an error but it does not mean that no revisions
# can be loaded.
# Get the stderr line with latest dumped revision
stderr_lines = svnrdump.stderr.split(b'\n')
last_dumped_rev = None
if len(stderr_lines) > 1:
last_dumped_rev = stderr_lines[-2]
if last_dumped_rev:
# Get the latest dumped revision number
matched_rev = re.search(b'.*revision ([0-9]+)', last_dumped_rev)
last_dumped_rev = int(matched_rev.group(1)) if matched_rev else -1
# Check if revisions inside the dump file can be loaded anyway
if last_dumped_rev > last_loaded_svn_rev:
self.log.debug(('svnrdump did not dump all expected revisions '
'but revisions range %s:%s are available in '
'the generated dump file and will be loaded '
'into the archive.') % (last_loaded_svn_rev+1,
last_dumped_rev))
# Truncate the dump file after the last successfully dumped
# revision to avoid the loading of corrupted data
self.log.debug(('Truncating dump file after the last '
'successfully dumped revision (%s) to avoid '
'the loading of corrupted data')
% last_dumped_rev)
with open(dump_path, 'r+b') as f:
with mmap(f.fileno(), 0, access=ACCESS_WRITE) as s:
pattern = ('Revision-number: %s' %
(last_dumped_rev+1)).encode()
n = s.rfind(pattern)
if n != -1:
s.resize(n)
self.truncated_dump = True
return dump_path
elif last_dumped_rev != -1:
raise Exception(('Last dumped subversion revision (%s) is '
'lesser than the last one loaded into the '
'archive (%s).') % (last_dumped_rev,
last_loaded_svn_rev))
raise Exception('An error occurred when running svnrdump and '
'no exploitable dump file has been generated.')
def prepare(self, *, svn_url, destination_path=None,
swh_revision=None, start_from_scratch=False, **kwargs):
# First, check if previous revisions have been loaded for the
# subversion origin and get the number of the last one
last_loaded_svn_rev = self.get_last_loaded_svn_rev(svn_url)
# Then try to generate a dump file containing relevant svn revisions
# to load, an exception will be thrown if something wrong happened
dump_path = self.dump_svn_revisions(svn_url, last_loaded_svn_rev)
# Finally, mount the dump and load the repository
self.log.debug('Mounting dump file with "svnadmin load".')
_, self.repo_path = \
init_svn_repo_from_dump(dump_path,
prefix=TEMPORARY_DIR_PREFIX_PATTERN,
suffix='-%s' % os.getpid(),
root_dir=self.temp_dir)
super().prepare(svn_url='file://%s' % self.repo_path,
destination_path=destination_path,
swh_revision=swh_revision,
start_from_scratch=start_from_scratch,
**kwargs)
def cleanup(self):
super().cleanup()
if self.temp_dir and os.path.exists(self.temp_dir):
shutil.rmtree(self.temp_dir)
def visit_status(self):
if self.truncated_dump:
return 'partial'
else:
return super().visit_status()

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