dulwich/client.py

   1 # client.py -- Implementation of the server side git protocols
   2 # Copyright (C) 2008-2009 Jelmer Vernooij <jelmer@samba.org>
   3 # Copyright (C) 2008 John Carr
   4 #
   5 # This program is free software; you can redistribute it and/or
   6 # modify it under the terms of the GNU General Public License
   7 # as published by the Free Software Foundation; either version 2
   8 # or (at your option) a later version of the License.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program; if not, write to the Free Software
  17 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
  18 # MA  02110-1301, USA.
  19
  20 """Client side support for the Git protocol."""
  21
  22 __docformat__ = 'restructuredText'
  23
  24 import os
  25 import select
  26 import socket
  27 import subprocess
  28
  29 from dulwich.errors import (
  30     ChecksumMismatch,
  31     )
  32 from dulwich.protocol import (
  33     Protocol,
  34     TCP_GIT_PORT,
  35     extract_capabilities,
  36     )
  37 from dulwich.pack import (
  38     write_pack_data,
  39     )
  40
  41
  42 def _fileno_can_read(fileno):
  43     """Check if a file descriptor is readable."""
  44     return len(select.select([fileno], [], [], 0)[0]) > 0
  45
  46
  47 CAPABILITIES = ["multi_ack", "side-band-64k", "ofs-delta"]
  48
  49
  50 class GitClient(object):
  51     """Git smart server client.
  52
  53     """
  54
  55     def __init__(self, can_read, read, write, thin_packs=True,
  56         report_activity=None):
  57         """Create a new GitClient instance.
  58
  59         :param can_read: Function that returns True if there is data available
  60             to be read.
  61         :param read: Callback for reading data, takes number of bytes to read
  62         :param write: Callback for writing data
  63         :param thin_packs: Whether or not thin packs should be retrieved
  64         :param report_activity: Optional callback for reporting transport
  65             activity.
  66         """
  67         self.proto = Protocol(read, write, report_activity)
  68         self._can_read = can_read
  69         self._capabilities = list(CAPABILITIES)
  70         if thin_packs:
  71             self._capabilities.append("thin-pack")
  72
  73     def capabilities(self):
  74         return " ".join(self._capabilities)
  75
  76     def read_refs(self):
  77         server_capabilities = None
  78         refs = {}
  79         # Receive refs from server
  80         for pkt in self.proto.read_pkt_seq():
  81             (sha, ref) = pkt.rstrip("\n").split(" ", 1)
  82             if server_capabilities is None:
  83                 (ref, server_capabilities) = extract_capabilities(ref)
  84             refs[ref] = sha
  85         return refs, server_capabilities
  86
  87     def send_pack(self, path, determine_wants, generate_pack_contents):
  88         """Upload a pack to a remote repository.
  89
  90         :param path: Repository path
  91         :param generate_pack_contents: Function that can return the shas of the
  92             objects to upload.
  93         """
  94         old_refs, server_capabilities = self.read_refs()
  95         new_refs = determine_wants(old_refs)
  96         if not new_refs:
  97             self.proto.write_pkt_line(None)
  98             return {}
  99         want = []
 100         have = [x for x in old_refs.values() if not x == "0" * 40]
 101         sent_capabilities = False
 102         for refname in set(new_refs.keys() + old_refs.keys()):
 103             old_sha1 = old_refs.get(refname, "0" * 40)
 104             new_sha1 = new_refs.get(refname, "0" * 40)
 105             if old_sha1 != new_sha1:
 106                 if sent_capabilities:
 107                     self.proto.write_pkt_line("%s %s %s" % (old_sha1, new_sha1, refname))
 108                 else:
 109                     self.proto.write_pkt_line("%s %s %s\0%s" % (old_sha1, new_sha1, refname, self.capabilities()))
 110                     sent_capabilities = True
 111             if not new_sha1 in (have, "0" * 40):
 112                 want.append(new_sha1)
 113         self.proto.write_pkt_line(None)
 114         if not want:
 115             return new_refs
 116         objects = generate_pack_contents(have, want)
 117         (entries, sha) = write_pack_data(self.proto.write_file(), objects,
 118                                          len(objects))
 119
 120         # read the final confirmation sha
 121         client_sha = self.proto.read(20)
 122         if not client_sha in (None, "", sha):
 123             raise ChecksumMismatch(sha, client_sha)
 124
 125         return new_refs
 126
 127     def fetch(self, path, target, determine_wants=None, progress=None):
 128         """Fetch into a target repository.
 129
 130         :param path: Path to fetch from
 131         :param target: Target repository to fetch into
 132         :param determine_wants: Optional function to determine what refs
 133             to fetch
 134         :param progress: Optional progress function
 135         :return: remote refs
 136         """
 137         if determine_wants is None:
 138             determine_wants = target.object_store.determine_wants_all
 139         f, commit = target.object_store.add_pack()
 140         try:
 141             return self.fetch_pack(path, determine_wants, target.graph_walker,
 142                                    f.write, progress)
 143         finally:
 144             commit()
 145
 146     def fetch_pack(self, path, determine_wants, graph_walker, pack_data,
 147                    progress):
 148         """Retrieve a pack from a git smart server.
 149
 150         :param determine_wants: Callback that returns list of commits to fetch
 151         :param graph_walker: Object with next() and ack().
 152         :param pack_data: Callback called for each bit of data in the pack
 153         :param progress: Callback for progress reports (strings)
 154         """
 155         (refs, server_capabilities) = self.read_refs()
 156         wants = determine_wants(refs)
 157         if not wants:
 158             self.proto.write_pkt_line(None)
 159             return refs
 160         assert isinstance(wants, list) and type(wants[0]) == str
 161         self.proto.write_pkt_line("want %s %s\n" % (wants[0], self.capabilities()))
 162         for want in wants[1:]:
 163             self.proto.write_pkt_line("want %s\n" % want)
 164         self.proto.write_pkt_line(None)
 165         have = graph_walker.next()
 166         while have:
 167             self.proto.write_pkt_line("have %s\n" % have)
 168             if self._can_read():
 169                 pkt = self.proto.read_pkt_line()
 170                 parts = pkt.rstrip("\n").split(" ")
 171                 if parts[0] == "ACK":
 172                     graph_walker.ack(parts[1])
 173                     assert parts[2] == "continue"
 174             have = graph_walker.next()
 175         self.proto.write_pkt_line("done\n")
 176         pkt = self.proto.read_pkt_line()
 177         while pkt:
 178             parts = pkt.rstrip("\n").split(" ")
 179             if parts[0] == "ACK":
 180                 graph_walker.ack(pkt.split(" ")[1])
 181             if len(parts) < 3 or parts[2] != "continue":
 182                 break
 183             pkt = self.proto.read_pkt_line()
 184         for pkt in self.proto.read_pkt_seq():
 185             channel = ord(pkt[0])
 186             pkt = pkt[1:]
 187             if channel == 1:
 188                 pack_data(pkt)
 189             elif channel == 2:
 190                 progress(pkt)
 191             else:
 192                 raise AssertionError("Invalid sideband channel %d" % channel)
 193         return refs
 194
 195
 196 class TCPGitClient(GitClient):
 197     """A Git Client that works over TCP directly (i.e. git://)."""
 198
 199     def __init__(self, host, port=None, *args, **kwargs):
 200         self._socket = socket.socket(type=socket.SOCK_STREAM)
 201         if port is None:
 202             port = TCP_GIT_PORT
 203         self._socket.connect((host, port))
 204         self.rfile = self._socket.makefile('rb', -1)
 205         self.wfile = self._socket.makefile('wb', 0)
 206         self.host = host
 207         super(TCPGitClient, self).__init__(lambda: _fileno_can_read(self._socket.fileno()), self.rfile.read, self.wfile.write, *args, **kwargs)
 208
 209     def send_pack(self, path, changed_refs, generate_pack_contents):
 210         """Send a pack to a remote host.
 211
 212         :param path: Path of the repository on the remote host
 213         """
 214         self.proto.send_cmd("git-receive-pack", path, "host=%s" % self.host)
 215         return super(TCPGitClient, self).send_pack(path, changed_refs, generate_pack_contents)
 216
 217     def fetch_pack(self, path, determine_wants, graph_walker, pack_data, progress):
 218         """Fetch a pack from the remote host.
 219
 220         :param path: Path of the reposiutory on the remote host
 221         :param determine_wants: Callback that receives available refs dict and
 222             should return list of sha's to fetch.
 223         :param graph_walker: GraphWalker instance used to find missing shas
 224         :param pack_data: Callback for writing pack data
 225         :param progress: Callback for writing progress
 226         """
 227         self.proto.send_cmd("git-upload-pack", path, "host=%s" % self.host)
 228         return super(TCPGitClient, self).fetch_pack(path, determine_wants,
 229             graph_walker, pack_data, progress)
 230
 231
 232 class SubprocessGitClient(GitClient):
 233     """Git client that talks to a server using a subprocess."""
 234
 235     def __init__(self, *args, **kwargs):
 236         self.proc = None
 237         self._args = args
 238         self._kwargs = kwargs
 239
 240     def _connect(self, service, *args, **kwargs):
 241         argv = [service] + list(args)
 242         self.proc = subprocess.Popen(argv, bufsize=0,
 243                                 stdin=subprocess.PIPE,
 244                                 stdout=subprocess.PIPE)
 245         def read_fn(size):
 246             return self.proc.stdout.read(size)
 247         def write_fn(data):
 248             self.proc.stdin.write(data)
 249             self.proc.stdin.flush()
 250         return GitClient(lambda: _fileno_can_read(self.proc.stdout.fileno()), read_fn, write_fn, *args, **kwargs)
 251
 252     def send_pack(self, path, changed_refs, generate_pack_contents):
 253         """Upload a pack to the server.
 254
 255         :param path: Path to the git repository on the server
 256         :param changed_refs: Dictionary with new values for the refs
 257         :param generate_pack_contents: Function that returns an iterator over
 258             objects to send
 259         """
 260         client = self._connect("git-receive-pack", path)
 261         return client.send_pack(path, changed_refs, generate_pack_contents)
 262
 263     def fetch_pack(self, path, determine_wants, graph_walker, pack_data,
 264         progress):
 265         """Retrieve a pack from the server
 266
 267         :param path: Path to the git repository on the server
 268         :param determine_wants: Function that receives existing refs
 269             on the server and returns a list of desired shas
 270         :param graph_walker: GraphWalker instance
 271         :param pack_data: Function that can write pack data
 272         :param progress: Function that can write progress texts
 273         """
 274         client = self._connect("git-upload-pack", path)
 275         return client.fetch_pack(path, determine_wants, graph_walker, pack_data,
 276                                  progress)
 277
 278
 279 class SSHSubprocess(object):
 280     """A socket-like object that talks to an ssh subprocess via pipes."""
 281
 282     def __init__(self, proc):
 283         self.proc = proc
 284
 285     def send(self, data):
 286         return os.write(self.proc.stdin.fileno(), data)
 287
 288     def recv(self, count):
 289         return self.proc.stdout.read(count)
 290
 291     def close(self):
 292         self.proc.stdin.close()
 293         self.proc.stdout.close()
 294         self.proc.wait()
 295
 296
 297 class SSHVendor(object):
 298
 299     def connect_ssh(self, host, command, username=None, port=None):
 300         #FIXME: This has no way to deal with passwords..
 301         args = ['ssh', '-x']
 302         if port is not None:
 303             args.extend(['-p', str(port)])
 304         if username is not None:
 305             host = "%s@%s" % (username, host)
 306         args.append(host)
 307         proc = subprocess.Popen(args + command,
 308                                 stdin=subprocess.PIPE,
 309                                 stdout=subprocess.PIPE)
 310         return SSHSubprocess(proc)
 311
 312 # Can be overridden by users
 313 get_ssh_vendor = SSHVendor
 314
 315
 316 class SSHGitClient(GitClient):
 317
 318     def __init__(self, host, port=None, username=None, *args, **kwargs):
 319         self.host = host
 320         self.port = port
 321         self.username = username
 322         self._args = args
 323         self._kwargs = kwargs
 324
 325     def send_pack(self, path, determine_wants, generate_pack_contents):
 326         remote = get_ssh_vendor().connect_ssh(self.host, ["git-receive-pack '%s'" % path], port=self.port, username=self.username)
 327         client = GitClient(lambda: _fileno_can_read(remote.proc.stdout.fileno()), remote.recv, remote.send, *self._args, **self._kwargs)
 328         return client.send_pack(path, determine_wants, generate_pack_contents)
 329
 330     def fetch_pack(self, path, determine_wants, graph_walker, pack_data,
 331         progress):
 332         remote = get_ssh_vendor().connect_ssh(self.host, ["git-upload-pack '%s'" % path], port=self.port, username=self.username)
 333         client = GitClient(lambda: _fileno_can_read(remote.proc.stdout.fileno()), remote.recv, remote.send, *self._args, **self._kwargs)
 334         return client.fetch_pack(path, determine_wants, graph_walker, pack_data,
 335                                  progress)
 336