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 # or (at your option) any later version 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 write_pack_data
  23 import 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         self.fetch_objects = self.repo.fetch_objects
  63         self.get_refs = self.repo.get_refs
  64
  65     def apply_pack(self, refs, read):
  66         fd, commit = self.repo.object_store.add_thin_pack()
  67         fd.write(read())
  68         fd.close()
  69         commit()
  70
  71         for oldsha, sha, ref in refs:
  72             if ref == "0" * 40:
  73                 self.repo.remove_ref(ref)
  74             else:
  75                 self.repo.set_ref(ref, sha)
  76
  77         print "pack applied"
  78
  79
  80 class Handler(object):
  81
  82     def __init__(self, backend, read, write):
  83         self.backend = backend
  84         self.proto = Protocol(read, write)
  85
  86     def capabilities(self):
  87         return " ".join(self.default_capabilities())
  88
  89
  90 class UploadPackHandler(Handler):
  91
  92     def default_capabilities(self):
  93         return ("multi_ack", "side-band-64k", "thin-pack", "ofs-delta")
  94
  95     def handle(self):
  96         def determine_wants(heads):
  97             keys = heads.keys()
  98             if keys:
  99                 self.proto.write_pkt_line("%s %s\x00%s\n" % ( heads[keys[0]], keys[0], self.capabilities()))
 100                 for k in keys[1:]:
 101                     self.proto.write_pkt_line("%s %s\n" % (heads[k], k))
 102
 103             # i'm done..
 104             self.proto.write("0000")
 105
 106             # Now client will either send "0000", meaning that it doesnt want to pull.
 107             # or it will start sending want want want commands
 108             want = self.proto.read_pkt_line()
 109             if want == None:
 110                 return []
 111
 112             want, self.client_capabilities = extract_capabilities(want)
 113
 114             want_revs = []
 115             while want and want[:4] == 'want':
 116                 want_revs.append(want[5:45])
 117                 want = self.proto.read_pkt_line()
 118             return want_revs
 119
 120         progress = lambda x: self.proto.write_sideband(2, x)
 121         write = lambda x: self.proto.write_sideband(1, x)
 122
 123         class ProtocolGraphWalker(object):
 124
 125             def __init__(self, proto):
 126                 self.proto = proto
 127                 self._last_sha = None
 128
 129             def ack(self, have_ref):
 130                 self.proto.write_pkt_line("ACK %s continue\n" % have_ref)
 131
 132             def next(self):
 133                 have = self.proto.read_pkt_line()
 134                 if have[:4] == 'have':
 135                     return have[5:45]
 136
 137                 #if have[:4] == 'done':
 138                 #    return None
 139
 140                 if self._last_sha:
 141                     # Oddness: Git seems to resend the last ACK, without the "continue" statement
 142                     self.proto.write_pkt_line("ACK %s\n" % self._last_sha)
 143
 144                 # The exchange finishes with a NAK
 145                 self.proto.write_pkt_line("NAK\n")
 146
 147         graph_walker = ProtocolGraphWalker(self.proto)
 148         num_objects, objects_iter = self.backend.fetch_objects(determine_wants, graph_walker, progress)
 149
 150         # Do they want any objects?
 151         if num_objects == 0:
 152             return
 153
 154         progress("dul-daemon says what\n")
 155         progress("counting objects: %d, done.\n" % num_objects)
 156         write_pack_data(ProtocolFile(None, write), objects_iter, num_objects)
 157         progress("how was that, then?\n")
 158         # we are done
 159         self.proto.write("0000")
 160
 161
 162 class ReceivePackHandler(Handler):
 163
 164     def default_capabilities(self):
 165         return ("report-status", "delete-refs")
 166
 167     def handle(self):
 168         refs = self.backend.get_refs().items()
 169
 170         if refs:
 171             self.proto.write_pkt_line("%s %s\x00%s\n" % (refs[0][1], refs[0][0], self.capabilities()))
 172             for i in range(1, len(refs)):
 173                 ref = refs[i]
 174                 self.proto.write_pkt_line("%s %s\n" % (ref[1], ref[0]))
 175         else:
 176             self.proto.write_pkt_line("0000000000000000000000000000000000000000 capabilities^{} %s" % self.capabilities())
 177
 178         self.proto.write("0000")
 179
 180         client_refs = []
 181         ref = self.proto.read_pkt_line()
 182
 183         # if ref is none then client doesnt want to send us anything..
 184         if ref is None:
 185             return
 186
 187         ref, client_capabilities = extract_capabilities(ref)
 188
 189         # client will now send us a list of (oldsha, newsha, ref)
 190         while ref:
 191             client_refs.append(ref.split())
 192             ref = self.proto.read_pkt_line()
 193
 194         # backend can now deal with this refs and read a pack using self.read
 195         self.backend.apply_pack(client_refs, self.proto.read)
 196
 197         # when we have read all the pack from the client, it assumes everything worked OK
 198         # there is NO ack from the server before it reports victory.
 199
 200
 201 class TCPGitRequestHandler(SocketServer.StreamRequestHandler):
 202
 203     def handle(self):
 204         proto = Protocol(self.rfile.read, self.wfile.write)
 205         command, args = proto.read_cmd()
 206
 207         # switch case to handle the specific git command
 208         if command == 'git-upload-pack':
 209             cls = UploadPackHandler
 210         elif command == 'git-receive-pack':
 211             cls = ReceivePackHandler
 212         else:
 213             return
 214
 215         h = cls(self.server.backend, self.rfile.read, self.wfile.write)
 216         h.handle()
 217
 218
 219 class TCPGitServer(SocketServer.TCPServer):
 220
 221     allow_reuse_address = True
 222     serve = SocketServer.TCPServer.serve_forever
 223
 224     def __init__(self, backend, listen_addr, port=TCP_GIT_PORT):
 225         self.backend = backend
 226         SocketServer.TCPServer.__init__(self, (listen_addr, port), TCPGitRequestHandler)
 227
 228