git-remote-testgit.py

   1 #!/usr/bin/env python
   2
   3 # This command is a simple remote-helper, that is used both as a
   4 # testcase for the remote-helper functionality, and as an example to
   5 # show remote-helper authors one possible implementation.
   6 #
   7 # This is a Git <-> Git importer/exporter, that simply uses git
   8 # fast-import and git fast-export to consume and produce fast-import
   9 # streams.
  10 #
  11 # To understand better the way things work, one can activate debug
  12 # traces by setting (to any value) the environment variables
  13 # GIT_TRANSPORT_HELPER_DEBUG and GIT_DEBUG_TESTGIT, to see messages
  14 # from the transport-helper side, or from this example remote-helper.
  15
  16 # hashlib is only available in python >= 2.5
  17 try:
  18     import hashlib
  19     _digest = hashlib.sha1
  20 except ImportError:
  21     import sha
  22     _digest = sha.new
  23 import sys
  24 import os
  25 sys.path.insert(0, os.getenv("GITPYTHONLIB","."))
  26
  27 from git_remote_helpers.util import die, debug, warn
  28 from git_remote_helpers.git.repo import GitRepo
  29 from git_remote_helpers.git.exporter import GitExporter
  30 from git_remote_helpers.git.importer import GitImporter
  31 from git_remote_helpers.git.non_local import NonLocalGit
  32
  33 def get_repo(alias, url):
  34     """Returns a git repository object initialized for usage.
  35     """
  36
  37     repo = GitRepo(url)
  38     repo.get_revs()
  39     repo.get_head()
  40
  41     hasher = _digest()
  42     hasher.update(repo.path)
  43     repo.hash = hasher.hexdigest()
  44
  45     repo.get_base_path = lambda base: os.path.join(
  46         base, 'info', 'fast-import', repo.hash)
  47
  48     prefix = 'refs/testgit/%s/' % alias
  49     debug("prefix: '%s'", prefix)
  50
  51     repo.gitdir = os.environ["GIT_DIR"]
  52     repo.alias = alias
  53     repo.prefix = prefix
  54
  55     repo.exporter = GitExporter(repo)
  56     repo.importer = GitImporter(repo)
  57     repo.non_local = NonLocalGit(repo)
  58
  59     return repo
  60
  61
  62 def local_repo(repo, path):
  63     """Returns a git repository object initalized for usage.
  64     """
  65
  66     local = GitRepo(path)
  67
  68     local.non_local = None
  69     local.gitdir = repo.gitdir
  70     local.alias = repo.alias
  71     local.prefix = repo.prefix
  72     local.hash = repo.hash
  73     local.get_base_path = repo.get_base_path
  74     local.exporter = GitExporter(local)
  75     local.importer = GitImporter(local)
  76
  77     return local
  78
  79
  80 def do_capabilities(repo, args):
  81     """Prints the supported capabilities.
  82     """
  83
  84     print "import"
  85     print "export"
  86     print "refspec refs/heads/*:%s*" % repo.prefix
  87
  88     dirname = repo.get_base_path(repo.gitdir)
  89
  90     if not os.path.exists(dirname):
  91         os.makedirs(dirname)
  92
  93     path = os.path.join(dirname, 'testgit.marks')
  94
  95     print "*export-marks %s" % path
  96     if os.path.exists(path):
  97         print "*import-marks %s" % path
  98
  99     print # end capabilities
 100
 101
 102 def do_list(repo, args):
 103     """Lists all known references.
 104
 105     Bug: This will always set the remote head to master for non-local
 106     repositories, since we have no way of determining what the remote
 107     head is at clone time.
 108     """
 109
 110     for ref in repo.revs:
 111         debug("? refs/heads/%s", ref)
 112         print "? refs/heads/%s" % ref
 113
 114     if repo.head:
 115         debug("@refs/heads/%s HEAD" % repo.head)
 116         print "@refs/heads/%s HEAD" % repo.head
 117     else:
 118         debug("@refs/heads/master HEAD")
 119         print "@refs/heads/master HEAD"
 120
 121     print # end list
 122
 123
 124 def update_local_repo(repo):
 125     """Updates (or clones) a local repo.
 126     """
 127
 128     if repo.local:
 129         return repo
 130
 131     path = repo.non_local.clone(repo.gitdir)
 132     repo.non_local.update(repo.gitdir)
 133     repo = local_repo(repo, path)
 134     return repo
 135
 136
 137 def do_import(repo, args):
 138     """Exports a fast-import stream from testgit for git to import.
 139     """
 140
 141     if len(args) != 1:
 142         die("Import needs exactly one ref")
 143
 144     if not repo.gitdir:
 145         die("Need gitdir to import")
 146
 147     ref = args[0]
 148     refs = [ref]
 149
 150     while True:
 151         line = sys.stdin.readline()
 152         if line == '\n':
 153             break
 154         if not line.startswith('import '):
 155             die("Expected import line.")
 156
 157         # strip of leading 'import '
 158         ref = line[7:].strip()
 159         refs.append(ref)
 160
 161     repo = update_local_repo(repo)
 162     repo.exporter.export_repo(repo.gitdir, refs)
 163
 164     print "done"
 165
 166
 167 def do_export(repo, args):
 168     """Imports a fast-import stream from git to testgit.
 169     """
 170
 171     if not repo.gitdir:
 172         die("Need gitdir to export")
 173
 174     update_local_repo(repo)
 175     changed = repo.importer.do_import(repo.gitdir)
 176
 177     if not repo.local:
 178         repo.non_local.push(repo.gitdir)
 179
 180     for ref in changed:
 181         print "ok %s" % ref
 182     print
 183
 184
 185 COMMANDS = {
 186     'capabilities': do_capabilities,
 187     'list': do_list,
 188     'import': do_import,
 189     'export': do_export,
 190 }
 191
 192
 193 def sanitize(value):
 194     """Cleans up the url.
 195     """
 196
 197     if value.startswith('testgit::'):
 198         value = value[9:]
 199
 200     return value
 201
 202
 203 def read_one_line(repo):
 204     """Reads and processes one command.
 205     """
 206
 207     line = sys.stdin.readline()
 208
 209     cmdline = line
 210
 211     if not cmdline:
 212         warn("Unexpected EOF")
 213         return False
 214
 215     cmdline = cmdline.strip().split()
 216     if not cmdline:
 217         # Blank line means we're about to quit
 218         return False
 219
 220     cmd = cmdline.pop(0)
 221     debug("Got command '%s' with args '%s'", cmd, ' '.join(cmdline))
 222
 223     if cmd not in COMMANDS:
 224         die("Unknown command, %s", cmd)
 225
 226     func = COMMANDS[cmd]
 227     func(repo, cmdline)
 228     sys.stdout.flush()
 229
 230     return True
 231
 232
 233 def main(args):
 234     """Starts a new remote helper for the specified repository.
 235     """
 236
 237     if len(args) != 3:
 238         die("Expecting exactly three arguments.")
 239         sys.exit(1)
 240
 241     if os.getenv("GIT_DEBUG_TESTGIT"):
 242         import git_remote_helpers.util
 243         git_remote_helpers.util.DEBUG = True
 244
 245     alias = sanitize(args[1])
 246     url = sanitize(args[2])
 247
 248     if not alias.isalnum():
 249         warn("non-alnum alias '%s'", alias)
 250         alias = "tmp"
 251
 252     args[1] = alias
 253     args[2] = url
 254
 255     repo = get_repo(alias, url)
 256
 257     debug("Got arguments %s", args[1:])
 258
 259     more = True
 260
 261     while (more):
 262         more = read_one_line(repo)
 263
 264 if __name__ == '__main__':
 265     sys.exit(main(sys.argv))