# MA 02110-1301, USA.
-"""Git smart network protocol server implementation."""
+"""Git smart network protocol server implementation.
+
+For more detailed implementation on the network protocol, see the
+Documentation/technical directory in the cgit distribution, and in particular:
+ Documentation/technical/protocol-capabilities.txt
+ Documentation/technical/pack-protocol.txt
+"""
import collections
import SocketServer
-import tempfile
from dulwich.errors import (
+ ApplyDeltaError,
+ ChecksumMismatch,
GitProtocolError,
)
from dulwich.objects import (
Protocol,
ProtocolFile,
TCP_GIT_PORT,
+ ZERO_SHA,
extract_capabilities,
extract_want_line_capabilities,
SINGLE_ACK,
MULTI_ACK,
+ MULTI_ACK_DETAILED,
ack_type,
)
-from dulwich.repo import (
- Repo,
- )
from dulwich.pack import (
write_pack_data,
)
class Backend(object):
+ """A backend for the Git smart server implementation."""
+
+ def open_repository(self, path):
+ """Open the repository at a path."""
+ raise NotImplementedError(self.open_repository)
+
+
+class BackendRepo(object):
+ """Repository abstraction used by the Git server.
+
+ Please note that the methods required here are a
+ subset of those provided by dulwich.repo.Repo.
+ """
+
+ object_store = None
+ refs = None
def get_refs(self):
"""
"""
raise NotImplementedError
- def apply_pack(self, refs, read):
- """ Import a set of changes into a repository and update the refs
+ def get_peeled(self, name):
+ """Return the cached peeled value of a ref, if available.
- :param refs: list of tuple(name, sha)
- :param read: callback to read from the incoming pack
+ :param name: Name of the ref to peel
+ :return: The peeled value of the ref. If the ref is known not point to
+ a tag, this will be the SHA the ref refers to. If no cached
+ information about a tag is available, this method may return None,
+ but it should attempt to peel the tag if possible.
"""
- raise NotImplementedError
+ return None
- def fetch_objects(self, determine_wants, graph_walker, progress):
+ def fetch_objects(self, determine_wants, graph_walker, progress,
+ get_tagged=None):
"""
Yield the objects required for a list of commits.
:param progress: is a callback to send progress messages to the client
+ :param get_tagged: Function that returns a dict of pointed-to sha -> tag
+ sha for including tags.
"""
raise NotImplementedError
-class GitBackend(Backend):
+class DictBackend(Backend):
+ """Trivial backend that looks up Git repositories in a dictionary."""
- def __init__(self, gitdir=None):
- self.gitdir = gitdir
+ def __init__(self, repos):
+ self.repos = repos
- if not self.gitdir:
- self.gitdir = tempfile.mkdtemp()
- Repo.create(self.gitdir)
-
- self.repo = Repo(self.gitdir)
- self.object_store = self.repo.object_store
- self.fetch_objects = self.repo.fetch_objects
- self.get_refs = self.repo.get_refs
-
- def apply_pack(self, refs, read):
- f, commit = self.repo.object_store.add_thin_pack()
- try:
- f.write(read())
- finally:
- commit()
-
- for oldsha, sha, ref in refs:
- if ref == "0" * 40:
- del self.repo.refs[ref]
- else:
- self.repo.refs[ref] = sha
-
- print "pack applied"
+ def open_repository(self, path):
+ # FIXME: What to do in case there is no repo ?
+ return self.repos[path]
class Handler(object):
def __init__(self, backend, read, write):
self.backend = backend
self.proto = Protocol(read, write)
+ self._client_capabilities = None
- def capabilities(self):
- return " ".join(self.default_capabilities())
-
+ def capability_line(self):
+ return " ".join(self.capabilities())
-class UploadPackHandler(Handler):
- """Protocol handler for uploading a pack to the server."""
+ def capabilities(self):
+ raise NotImplementedError(self.capabilities)
- def __init__(self, backend, read, write):
- Handler.__init__(self, backend, read, write)
- self._client_capabilities = None
- self._graph_walker = None
+ def innocuous_capabilities(self):
+ return ("include-tag", "thin-pack", "no-progress", "ofs-delta")
- def default_capabilities(self):
- return ("multi_ack", "side-band-64k", "thin-pack", "ofs-delta")
+ def required_capabilities(self):
+ """Return a list of capabilities that we require the client to have."""
+ return []
def set_client_capabilities(self, caps):
- my_caps = self.default_capabilities()
+ allowable_caps = set(self.innocuous_capabilities())
+ allowable_caps.update(self.capabilities())
for cap in caps:
- if '_ack' in cap and cap not in my_caps:
+ if cap not in allowable_caps:
raise GitProtocolError('Client asked for capability %s that '
'was not advertised.' % cap)
- self._client_capabilities = caps
+ for cap in self.required_capabilities():
+ if cap not in caps:
+ raise GitProtocolError('Client does not support required '
+ 'capability %s.' % cap)
+ self._client_capabilities = set(caps)
- def get_client_capabilities(self):
- return self._client_capabilities
+ def has_capability(self, cap):
+ if self._client_capabilities is None:
+ raise GitProtocolError('Server attempted to access capability %s '
+ 'before asking client' % cap)
+ return cap in self._client_capabilities
- client_capabilities = property(get_client_capabilities,
- set_client_capabilities)
- def handle(self):
- def determine_wants(heads):
- keys = heads.keys()
- values = set(heads.itervalues())
- if keys:
- self.proto.write_pkt_line("%s %s\x00%s\n" % ( heads[keys[0]], keys[0], self.capabilities()))
- for k in keys[1:]:
- self.proto.write_pkt_line("%s %s\n" % (heads[k], k))
+class UploadPackHandler(Handler):
+ """Protocol handler for uploading a pack to the server."""
- # i'm done..
- self.proto.write("0000")
+ def __init__(self, backend, args, read, write,
+ stateless_rpc=False, advertise_refs=False):
+ Handler.__init__(self, backend, read, write)
+ self.repo = backend.open_repository(args[0])
+ self._graph_walker = None
+ self.stateless_rpc = stateless_rpc
+ self.advertise_refs = advertise_refs
- # Now client will either send "0000", meaning that it doesnt want to pull.
- # or it will start sending want want want commands
- want = self.proto.read_pkt_line()
- if want == None:
- return []
+ def capabilities(self):
+ return ("multi_ack_detailed", "multi_ack", "side-band-64k", "thin-pack",
+ "ofs-delta", "no-progress", "include-tag")
+
+ def required_capabilities(self):
+ return ("side-band-64k", "thin-pack", "ofs-delta")
+
+ def progress(self, message):
+ if self.has_capability("no-progress"):
+ return
+ self.proto.write_sideband(2, message)
+
+ def get_tagged(self, refs=None, repo=None):
+ """Get a dict of peeled values of tags to their original tag shas.
+
+ :param refs: dict of refname -> sha of possible tags; defaults to all of
+ the backend's refs.
+ :param repo: optional Repo instance for getting peeled refs; defaults to
+ the backend's repo, if available
+ :return: dict of peeled_sha -> tag_sha, where tag_sha is the sha of a
+ tag whose peeled value is peeled_sha.
+ """
+ if not self.has_capability("include-tag"):
+ return {}
+ if refs is None:
+ refs = self.repo.get_refs()
+ if repo is None:
+ repo = getattr(self.repo, "repo", None)
+ if repo is None:
+ # Bail if we don't have a Repo available; this is ok since
+ # clients must be able to handle if the server doesn't include
+ # all relevant tags.
+ # TODO: fix behavior when missing
+ return {}
+ tagged = {}
+ for name, sha in refs.iteritems():
+ peeled_sha = repo.get_peeled(name)
+ if peeled_sha != sha:
+ tagged[peeled_sha] = sha
+ return tagged
- want, self.client_capabilities = extract_want_line_capabilities(want)
- graph_walker.set_ack_type(ack_type(self.client_capabilities))
-
- want_revs = []
- while want and want[:4] == 'want':
- sha = want[5:45]
- try:
- hex_to_sha(sha)
- except (TypeError, AssertionError), e:
- raise GitProtocolError(e)
-
- if sha not in values:
- raise GitProtocolError(
- 'Client wants invalid object %s' % sha)
- want_revs.append(sha)
- want = self.proto.read_pkt_line()
- graph_walker.set_wants(want_revs)
- return want_revs
-
- progress = lambda x: self.proto.write_sideband(2, x)
+ def handle(self):
write = lambda x: self.proto.write_sideband(1, x)
- graph_walker = ProtocolGraphWalker(self.backend.object_store, self.proto)
- objects_iter = self.backend.fetch_objects(determine_wants, graph_walker, progress)
+ graph_walker = ProtocolGraphWalker(self, self.repo.object_store,
+ self.repo.get_peeled)
+ objects_iter = self.repo.fetch_objects(
+ graph_walker.determine_wants, graph_walker, self.progress,
+ get_tagged=self.get_tagged)
# Do they want any objects?
if len(objects_iter) == 0:
return
- progress("dul-daemon says what\n")
- progress("counting objects: %d, done.\n" % len(objects_iter))
+ self.progress("dul-daemon says what\n")
+ self.progress("counting objects: %d, done.\n" % len(objects_iter))
write_pack_data(ProtocolFile(None, write), objects_iter,
len(objects_iter))
- progress("how was that, then?\n")
+ self.progress("how was that, then?\n")
# we are done
self.proto.write("0000")
class ProtocolGraphWalker(object):
"""A graph walker that knows the git protocol.
- As a graph walker, this class implements ack(), next(), and reset(). It also
- contains some base methods for interacting with the wire and walking the
- commit tree.
+ As a graph walker, this class implements ack(), next(), and reset(). It
+ also contains some base methods for interacting with the wire and walking
+ the commit tree.
The work of determining which acks to send is passed on to the
implementation instance stored in _impl. The reason for this is that we do
call to set_ack_level() is required to set up the implementation, before any
calls to next() or ack() are made.
"""
- def __init__(self, object_store, proto):
+ def __init__(self, handler, object_store, get_peeled):
+ self.handler = handler
self.store = object_store
- self.proto = proto
+ self.get_peeled = get_peeled
+ self.proto = handler.proto
+ self.stateless_rpc = handler.stateless_rpc
+ self.advertise_refs = handler.advertise_refs
self._wants = []
self._cached = False
self._cache = []
self._cache_index = 0
self._impl = None
+ def determine_wants(self, heads):
+ """Determine the wants for a set of heads.
+
+ The given heads are advertised to the client, who then specifies which
+ refs he wants using 'want' lines. This portion of the protocol is the
+ same regardless of ack type, and in fact is used to set the ack type of
+ the ProtocolGraphWalker.
+
+ :param heads: a dict of refname->SHA1 to advertise
+ :return: a list of SHA1s requested by the client
+ """
+ if not heads:
+ raise GitProtocolError('No heads found')
+ values = set(heads.itervalues())
+ if self.advertise_refs or not self.stateless_rpc:
+ for i, (ref, sha) in enumerate(heads.iteritems()):
+ line = "%s %s" % (sha, ref)
+ if not i:
+ line = "%s\x00%s" % (line, self.handler.capability_line())
+ self.proto.write_pkt_line("%s\n" % line)
+ peeled_sha = self.get_peeled(ref)
+ if peeled_sha != sha:
+ self.proto.write_pkt_line('%s %s^{}\n' %
+ (peeled_sha, ref))
+
+ # i'm done..
+ self.proto.write_pkt_line(None)
+
+ if self.advertise_refs:
+ return []
+
+ # Now client will sending want want want commands
+ want = self.proto.read_pkt_line()
+ if not want:
+ return []
+ line, caps = extract_want_line_capabilities(want)
+ self.handler.set_client_capabilities(caps)
+ self.set_ack_type(ack_type(caps))
+ command, sha = self._split_proto_line(line)
+
+ want_revs = []
+ while command != None:
+ if command != 'want':
+ raise GitProtocolError(
+ 'Protocol got unexpected command %s' % command)
+ if sha not in values:
+ raise GitProtocolError(
+ 'Client wants invalid object %s' % sha)
+ want_revs.append(sha)
+ command, sha = self.read_proto_line()
+
+ self.set_wants(want_revs)
+ return want_revs
+
def ack(self, have_ref):
return self._impl.ack(have_ref)
def next(self):
if not self._cached:
+ if not self._impl and self.stateless_rpc:
+ return None
return self._impl.next()
self._cache_index += 1
if self._cache_index > len(self._cache):
return None
return self._cache[self._cache_index]
+ def _split_proto_line(self, line):
+ fields = line.rstrip('\n').split(' ', 1)
+ if len(fields) == 1 and fields[0] == 'done':
+ return ('done', None)
+ elif len(fields) == 2 and fields[0] in ('want', 'have'):
+ try:
+ hex_to_sha(fields[1])
+ return tuple(fields)
+ except (TypeError, AssertionError), e:
+ raise GitProtocolError(e)
+ raise GitProtocolError('Received invalid line from client:\n%s' % line)
+
def read_proto_line(self):
"""Read a line from the wire.
:return: a tuple having one of the following forms:
+ ('want', obj_id)
('have', obj_id)
('done', None)
(None, None) (for a flush-pkt)
+
+ :raise GitProtocolError: if the line cannot be parsed into one of the
+ possible return values.
"""
line = self.proto.read_pkt_line()
if not line:
return (None, None)
- fields = line.rstrip('\n').split(' ', 1)
- if len(fields) == 1 and fields[0] == 'done':
- return ('done', None)
- if len(fields) == 2 and fields[0] == 'have':
- try:
- hex_to_sha(fields[1])
- return fields
- except (TypeError, AssertionError), e:
- raise GitProtocolError(e)
- raise GitProtocolError('Received invalid line from client:\n%s' % line)
+ return self._split_proto_line(line)
def send_ack(self, sha, ack_type=''):
if ack_type:
commit = pending.popleft()
if commit.id in haves:
return True
- if not getattr(commit, 'get_parents', None):
+ if commit.type_name != "commit":
# non-commit wants are assumed to be satisfied
continue
- for parent in commit.get_parents():
+ for parent in commit.parents:
parent_obj = self.store[parent]
# TODO: handle parents with later commit times than children
if parent_obj.commit_time >= earliest:
def set_ack_type(self, ack_type):
impl_classes = {
MULTI_ACK: MultiAckGraphWalkerImpl,
+ MULTI_ACK_DETAILED: MultiAckDetailedGraphWalkerImpl,
SINGLE_ACK: SingleAckGraphWalkerImpl,
}
self._impl = impl_classes[ack_type](self)
# else we blind ack within next
def next(self):
- command, sha = self.walker.read_proto_line()
- if command is None:
- self.walker.send_nak()
- return None
- elif command == 'done':
- # don't nak unless no common commits were found, even if not
- # everything is satisfied
- if self._common:
- self.walker.send_ack(self._common[-1])
- else:
+ while True:
+ command, sha = self.walker.read_proto_line()
+ if command is None:
self.walker.send_nak()
- return None
- elif command == 'have':
- if self._found_base:
- # blind ack
- self.walker.send_ack(sha, 'continue')
- return sha
+ # in multi-ack mode, a flush-pkt indicates the client wants to
+ # flush but more have lines are still coming
+ continue
+ elif command == 'done':
+ # don't nak unless no common commits were found, even if not
+ # everything is satisfied
+ if self._common:
+ self.walker.send_ack(self._common[-1])
+ else:
+ self.walker.send_nak()
+ return None
+ elif command == 'have':
+ if self._found_base:
+ # blind ack
+ self.walker.send_ack(sha, 'continue')
+ return sha
+
+
+class MultiAckDetailedGraphWalkerImpl(object):
+ """Graph walker implementation speaking the multi-ack-detailed protocol."""
+
+ def __init__(self, walker):
+ self.walker = walker
+ self._found_base = False
+ self._common = []
+
+ def ack(self, have_ref):
+ self._common.append(have_ref)
+ if not self._found_base:
+ self.walker.send_ack(have_ref, 'common')
+ if self.walker.all_wants_satisfied(self._common):
+ self._found_base = True
+ self.walker.send_ack(have_ref, 'ready')
+ # else we blind ack within next
+
+ def next(self):
+ while True:
+ command, sha = self.walker.read_proto_line()
+ if command is None:
+ self.walker.send_nak()
+ if self.walker.stateless_rpc:
+ return None
+ continue
+ elif command == 'done':
+ # don't nak unless no common commits were found, even if not
+ # everything is satisfied
+ if self._common:
+ self.walker.send_ack(self._common[-1])
+ else:
+ self.walker.send_nak()
+ return None
+ elif command == 'have':
+ if self._found_base:
+ # blind ack; can happen if the client has more requests
+ # inflight
+ self.walker.send_ack(sha, 'ready')
+ return sha
class ReceivePackHandler(Handler):
- """Protocol handler for downloading a pack to the client."""
+ """Protocol handler for downloading a pack from the client."""
+
+ def __init__(self, backend, args, read, write,
+ stateless_rpc=False, advertise_refs=False):
+ Handler.__init__(self, backend, read, write)
+ self.repo = backend.open_repository(args[0])
+ self.stateless_rpc = stateless_rpc
+ self.advertise_refs = advertise_refs
- def default_capabilities(self):
+ def capabilities(self):
return ("report-status", "delete-refs")
- def handle(self):
- refs = self.backend.get_refs().items()
+ def _apply_pack(self, refs, read):
+ f, commit = self.repo.object_store.add_thin_pack()
+ all_exceptions = (IOError, OSError, ChecksumMismatch, ApplyDeltaError)
+ status = []
+ unpack_error = None
+ # TODO: more informative error messages than just the exception string
+ try:
+ # TODO: decode the pack as we stream to avoid blocking reads beyond
+ # the end of data (when using HTTP/1.1 chunked encoding)
+ while True:
+ data = read(10240)
+ if not data:
+ break
+ f.write(data)
+ except all_exceptions, e:
+ unpack_error = str(e).replace('\n', '')
+ try:
+ commit()
+ except all_exceptions, e:
+ if not unpack_error:
+ unpack_error = str(e).replace('\n', '')
- if refs:
- self.proto.write_pkt_line("%s %s\x00%s\n" % (refs[0][1], refs[0][0], self.capabilities()))
- for i in range(1, len(refs)):
- ref = refs[i]
- self.proto.write_pkt_line("%s %s\n" % (ref[1], ref[0]))
+ if unpack_error:
+ status.append(('unpack', unpack_error))
else:
- self.proto.write_pkt_line("0000000000000000000000000000000000000000 capabilities^{} %s" % self.capabilities())
+ status.append(('unpack', 'ok'))
- self.proto.write("0000")
+ for oldsha, sha, ref in refs:
+ ref_error = None
+ try:
+ if sha == ZERO_SHA:
+ if not self.has_capability('delete-refs'):
+ raise GitProtocolError(
+ 'Attempted to delete refs without delete-refs '
+ 'capability.')
+ try:
+ del self.repo.refs[ref]
+ except all_exceptions:
+ ref_error = 'failed to delete'
+ else:
+ try:
+ self.repo.refs[ref] = sha
+ except all_exceptions:
+ ref_error = 'failed to write'
+ except KeyError, e:
+ ref_error = 'bad ref'
+ if ref_error:
+ status.append((ref, ref_error))
+ else:
+ status.append((ref, 'ok'))
+
+ print "pack applied"
+ return status
+
+ def handle(self):
+ refs = self.repo.get_refs().items()
+
+ if self.advertise_refs or not self.stateless_rpc:
+ if refs:
+ self.proto.write_pkt_line(
+ "%s %s\x00%s\n" % (refs[0][1], refs[0][0],
+ self.capability_line()))
+ for i in range(1, len(refs)):
+ ref = refs[i]
+ self.proto.write_pkt_line("%s %s\n" % (ref[1], ref[0]))
+ else:
+ self.proto.write_pkt_line("%s capabilities^{} %s" % (
+ ZERO_SHA, self.capability_line()))
+
+ self.proto.write("0000")
+ if self.advertise_refs:
+ return
client_refs = []
ref = self.proto.read_pkt_line()
if ref is None:
return
- ref, client_capabilities = extract_capabilities(ref)
+ ref, caps = extract_capabilities(ref)
+ self.set_client_capabilities(caps)
# client will now send us a list of (oldsha, newsha, ref)
while ref:
ref = self.proto.read_pkt_line()
# backend can now deal with this refs and read a pack using self.read
- self.backend.apply_pack(client_refs, self.proto.read)
+ status = self.repo._apply_pack(client_refs, self.proto.read)
- # when we have read all the pack from the client, it assumes
- # everything worked OK.
- # there is NO ack from the server before it reports victory.
+ # when we have read all the pack from the client, send a status report
+ # if the client asked for it
+ if self.has_capability('report-status'):
+ for name, msg in status:
+ if name == 'unpack':
+ self.proto.write_pkt_line('unpack %s\n' % msg)
+ elif msg == 'ok':
+ self.proto.write_pkt_line('ok %s\n' % name)
+ else:
+ self.proto.write_pkt_line('ng %s %s\n' % (name, msg))
+ self.proto.write_pkt_line(None)
class TCPGitRequestHandler(SocketServer.StreamRequestHandler):
else:
return
- h = cls(self.server.backend, self.rfile.read, self.wfile.write)
+ h = cls(self.server.backend, args, self.rfile.read, self.wfile.write)
h.handle()
git.samba.org / jelmer / dulwich-libgit2.git / blobdiff