dulwich/server.py

   1 # server.py -- Implementation of the server side git protocols
   2 # Copryight (C) 2008 John Carr <john.carr@unrouted.co.uk>
   3 #
   4 # This program is free software; you can redistribute it and/or
   5 # modify it under the terms of the GNU General Public License
   6 # as published by the Free Software Foundation; version 2
   7 # of the License.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU General Public License
  15 # along with this program; if not, write to the Free Software
  16 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  17 # MA  02110-1301, USA.
  18
  19 import SocketServer
  20 from dulwich.protocol import Protocol, ProtocolFile, TCP_GIT_PORT, extract_capabilities
  21 from dulwich.repo import Repo
  22 from dulwich.pack import PackData, Pack, write_pack_data, generate_pack_contents
  23 import os, sha, tempfile
  24
  25 class Backend(object):
  26
  27     def get_refs(self):
  28         """
  29         Get all the refs in the repository
  30
  31         :return: dict of name -> sha
  32         """
  33         raise NotImplementedError
  34
  35     def apply_pack(self, refs, read):
  36         """ Import a set of changes into a repository and update the refs
  37
  38         :param refs: list of tuple(name, sha)
  39         :param read: callback to read from the incoming pack
  40         """
  41         raise NotImplementedError
  42
  43     def fetch_objects(self, determine_wants, graph_walker, progress):
  44         """
  45         Yield the objects required for a list of commits.
  46
  47         :param progress: is a callback to send progress messages to the client
  48         """
  49         raise NotImplementedError
  50
  51
  52 class GitBackend(Backend):
  53
  54     def __init__(self, gitdir=None):
  55         self.gitdir = gitdir
  56
  57         if not self.gitdir:
  58             self.gitdir = tempfile.mkdtemp()
  59             Repo.create(self.gitdir)
  60
  61         self.repo = Repo(self.gitdir)
  62
  63     def get_refs(self):
  64         return self.repo.get_refs()
  65
  66     def apply_pack(self, refs, read):
  67         # store the incoming pack in the repository
  68         fd, name = tempfile.mkstemp(suffix='.pack', prefix='pack-', dir=self.repo.pack_dir())
  69         os.write(fd, read())
  70         os.close(fd)
  71
  72         # strip '.pack' off our filename
  73         basename = name[:-5]
  74
  75         # generate an index for it
  76         pd = PackData(name)
  77         pd.create_index_v2(basename+".idx")
  78
  79         for oldsha, sha, ref in refs:
  80             if ref == "0" * 40:
  81                 self.repo.remove_ref(ref)
  82             else:
  83                 self.repo.set_ref(ref, sha)
  84
  85         print "pack applied"
  86
  87     def fetch_objects(self, determine_wants, graph_walker, progress):
  88         shas = self.repo.find_missing_objects(determine_wants, graph_walker, progress)
  89         for sha in shas:
  90             yield self.repo.get_object(sha)
  91
  92
  93 class Handler(object):
  94
  95     def __init__(self, backend, read, write):
  96         self.backend = backend
  97         self.proto = Protocol(read, write)
  98
  99     def capabilities(self):
 100         return " ".join(self.default_capabilities())
 101
 102
 103 class UploadPackHandler(Handler):
 104
 105     def default_capabilities(self):
 106         return ("multi_ack", "side-band-64k", "thin-pack", "ofs-delta")
 107
 108     def handle(self):
 109         def determine_wants(heads):
 110             keys = heads.keys()
 111             if keys:
 112                 self.proto.write_pkt_line("%s %s\x00%s\n" % ( heads[keys[0]], keys[0], self.capabilities()))
 113                 for k in keys[1:]:
 114                     self.proto.write_pkt_line("%s %s\n" % (heads[k], k))
 115
 116             # i'm done..
 117             self.proto.write("0000")
 118
 119             # Now client will either send "0000", meaning that it doesnt want to pull.
 120             # or it will start sending want want want commands
 121             want = self.proto.read_pkt_line()
 122             if want == None:
 123                 return []
 124
 125             want, self.client_capabilities = extract_capabilities(want)
 126
 127             want_revs = []
 128             while want and want[:4] == 'want':
 129                 want_revs.append(want[5:45])
 130                 want = self.proto.read_pkt_line()
 131             return want_revs
 132
 133         progress = lambda x: self.proto.write_sideband(2, x)
 134         write = lambda x: self.proto.write_sideband(1, x)
 135
 136         class ProtocolGraphWalker(object):
 137
 138             def __init__(self, proto):
 139                 self.proto = proto
 140                 self._last_sha = None
 141
 142             def ack(self, have_ref):
 143                 self.proto.write_pkt_line("ACK %s continue\n" % have_ref)
 144
 145             def next(self):
 146                 have = self.proto.read_pkt_line()
 147                 if have[:4] == 'have':
 148                     return have[5:45]
 149
 150                 #if have[:4] == 'done':
 151                 #    return None
 152
 153                 if self._last_sha:
 154                     # Oddness: Git seems to resend the last ACK, without the "continue" statement
 155                     self.proto.write_pkt_line("ACK %s\n" % self._last_sha)
 156
 157                 # The exchange finishes with a NAK
 158                 self.proto.write_pkt_line("NAK\n")
 159
 160         graph_walker = ProtocolGraphWalker(self.proto)
 161         objects = list(self.backend.fetch_objects(determine_wants, graph_walker, progress))
 162         progress("dul-daemon says what\n")
 163         progress("counting objects: %d, done.\n" % len(objects))
 164         write_pack_data(ProtocolFile(None, write), objects, len(objects))
 165         progress("how was that, then?\n")
 166         # we are done
 167         self.proto.write("0000")
 168
 169
 170 class ReceivePackHandler(Handler):
 171
 172     def default_capabilities(self):
 173         return ("report-status", "delete-refs")
 174
 175     def handle(self):
 176         refs = self.backend.get_refs().items()
 177
 178         if refs:
 179             self.proto.write_pkt_line("%s %s\x00%s\n" % (refs[0][1], refs[0][0], self.capabilities()))
 180             for i in range(1, len(refs)):
 181                 ref = refs[i]
 182                 self.proto.write_pkt_line("%s %s\n" % (ref[1], ref[0]))
 183         else:
 184             self.proto.write_pkt_line("0000000000000000000000000000000000000000 capabilities^{} %s" % self.capabilities())
 185
 186         self.proto.write("0000")
 187
 188         client_refs = []
 189         ref = self.proto.read_pkt_line()
 190
 191         # if ref is none then client doesnt want to send us anything..
 192         if ref is None:
 193             return
 194
 195         ref, client_capabilities = extract_capabilities(ref)
 196
 197         # client will now send us a list of (oldsha, newsha, ref)
 198         while ref:
 199             client_refs.append(ref.split())
 200             ref = self.proto.read_pkt_line()
 201
 202         # backend can now deal with this refs and read a pack using self.read
 203         self.backend.apply_pack(client_refs, self.proto.read)
 204
 205         # when we have read all the pack from the client, it assumes everything worked OK
 206         # there is NO ack from the server before it reports victory.
 207
 208
 209 class TCPGitRequestHandler(SocketServer.StreamRequestHandler):
 210
 211     def handle(self):
 212         proto = Protocol(self.rfile.read, self.wfile.write)
 213         command, args = proto.read_cmd()
 214
 215         # switch case to handle the specific git command
 216         if command == 'git-upload-pack':
 217             cls = UploadPackHandler
 218         elif command == 'git-receive-pack':
 219             cls = ReceivePackHandler
 220         else:
 221             return
 222
 223         h = cls(self.server.backend, self.rfile.read, self.wfile.write)
 224         h.handle()
 225
 226
 227 class TCPGitServer(SocketServer.TCPServer):
 228
 229     allow_reuse_address = True
 230     serve = SocketServer.TCPServer.serve_forever
 231
 232     def __init__(self, backend, listen_addr, port=TCP_GIT_PORT):
 233         self.backend = backend
 234         SocketServer.TCPServer.__init__(self, (listen_addr, port), TCPGitRequestHandler)
 235
 236