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 import time
  26 sys.path.insert(0, os.getenv("GITPYTHONLIB","."))
  27
  28 from git_remote_helpers.util import die, debug, warn
  29 from git_remote_helpers.git.repo import GitRepo
  30 from git_remote_helpers.git.exporter import GitExporter
  31 from git_remote_helpers.git.importer import GitImporter
  32 from git_remote_helpers.git.non_local import NonLocalGit
  33
  34 def get_repo(alias, url):
  35     """Returns a git repository object initialized for usage.
  36     """
  37
  38     repo = GitRepo(url)
  39     repo.get_revs()
  40     repo.get_head()
  41
  42     hasher = _digest()
  43     hasher.update(repo.path)
  44     repo.hash = hasher.hexdigest()
  45
  46     repo.get_base_path = lambda base: os.path.join(
  47         base, 'info', 'fast-import', repo.hash)
  48
  49     prefix = 'refs/testgit/%s/' % alias
  50     debug("prefix: '%s'", prefix)
  51
  52     repo.gitdir = os.environ["GIT_DIR"]
  53     repo.alias = alias
  54     repo.prefix = prefix
  55
  56     repo.exporter = GitExporter(repo)
  57     repo.importer = GitImporter(repo)
  58     repo.non_local = NonLocalGit(repo)
  59
  60     return repo
  61
  62
  63 def local_repo(repo, path):
  64     """Returns a git repository object initalized for usage.
  65     """
  66
  67     local = GitRepo(path)
  68
  69     local.non_local = None
  70     local.gitdir = repo.gitdir
  71     local.alias = repo.alias
  72     local.prefix = repo.prefix
  73     local.hash = repo.hash
  74     local.get_base_path = repo.get_base_path
  75     local.exporter = GitExporter(local)
  76     local.importer = GitImporter(local)
  77
  78     return local
  79
  80
  81 def do_capabilities(repo, args):
  82     """Prints the supported capabilities.
  83     """
  84
  85     print "import"
  86     print "export"
  87     print "refspec refs/heads/*:%s*" % repo.prefix
  88
  89     dirname = repo.get_base_path(repo.gitdir)
  90
  91     if not os.path.exists(dirname):
  92         os.makedirs(dirname)
  93
  94     path = os.path.join(dirname, 'testgit.marks')
  95
  96     print "*export-marks %s" % path
  97     if os.path.exists(path):
  98         print "*import-marks %s" % path
  99
 100     print # end capabilities
 101
 102
 103 def do_list(repo, args):
 104     """Lists all known references.
 105
 106     Bug: This will always set the remote head to master for non-local
 107     repositories, since we have no way of determining what the remote
 108     head is at clone time.
 109     """
 110
 111     for ref in repo.revs:
 112         debug("? refs/heads/%s", ref)
 113         print "? refs/heads/%s" % ref
 114
 115     if repo.head:
 116         debug("@refs/heads/%s HEAD" % repo.head)
 117         print "@refs/heads/%s HEAD" % repo.head
 118     else:
 119         debug("@refs/heads/master HEAD")
 120         print "@refs/heads/master HEAD"
 121
 122     print # end list
 123
 124
 125 def update_local_repo(repo):
 126     """Updates (or clones) a local repo.
 127     """
 128
 129     if repo.local:
 130         return repo
 131
 132     path = repo.non_local.clone(repo.gitdir)
 133     repo.non_local.update(repo.gitdir)
 134     repo = local_repo(repo, path)
 135     return repo
 136
 137
 138 def do_import(repo, args):
 139     """Exports a fast-import stream from testgit for git to import.
 140     """
 141
 142     if len(args) != 1:
 143         die("Import needs exactly one ref")
 144
 145     if not repo.gitdir:
 146         die("Need gitdir to import")
 147
 148     ref = args[0]
 149     refs = [ref]
 150
 151     while True:
 152         line = sys.stdin.readline()
 153         if line == '\n':
 154             break
 155         if not line.startswith('import '):
 156             die("Expected import line.")
 157
 158         # strip of leading 'import '
 159         ref = line[7:].strip()
 160         refs.append(ref)
 161
 162     repo = update_local_repo(repo)
 163     repo.exporter.export_repo(repo.gitdir, refs)
 164
 165     print "done"
 166
 167
 168 def do_export(repo, args):
 169     """Imports a fast-import stream from git to testgit.
 170     """
 171
 172     if not repo.gitdir:
 173         die("Need gitdir to export")
 174
 175     update_local_repo(repo)
 176     changed = repo.importer.do_import(repo.gitdir)
 177
 178     if not repo.local:
 179         repo.non_local.push(repo.gitdir)
 180
 181     for ref in changed:
 182         print "ok %s" % ref
 183     print
 184
 185
 186 COMMANDS = {
 187     'capabilities': do_capabilities,
 188     'list': do_list,
 189     'import': do_import,
 190     'export': do_export,
 191 }
 192
 193
 194 def sanitize(value):
 195     """Cleans up the url.
 196     """
 197
 198     if value.startswith('testgit::'):
 199         value = value[9:]
 200
 201     return value
 202
 203
 204 def read_one_line(repo):
 205     """Reads and processes one command.
 206     """
 207
 208     sleepy = os.environ.get("GIT_REMOTE_TESTGIT_SLEEPY")
 209     if sleepy:
 210         debug("Sleeping %d sec before readline" % int(sleepy))
 211         time.sleep(int(sleepy))
 212
 213     line = sys.stdin.readline()
 214
 215     cmdline = line
 216
 217     if not cmdline:
 218         warn("Unexpected EOF")
 219         return False
 220
 221     cmdline = cmdline.strip().split()
 222     if not cmdline:
 223         # Blank line means we're about to quit
 224         return False
 225
 226     cmd = cmdline.pop(0)
 227     debug("Got command '%s' with args '%s'", cmd, ' '.join(cmdline))
 228
 229     if cmd not in COMMANDS:
 230         die("Unknown command, %s", cmd)
 231
 232     func = COMMANDS[cmd]
 233     func(repo, cmdline)
 234     sys.stdout.flush()
 235
 236     return True
 237
 238
 239 def main(args):
 240     """Starts a new remote helper for the specified repository.
 241     """
 242
 243     if len(args) != 3:
 244         die("Expecting exactly three arguments.")
 245         sys.exit(1)
 246
 247     if os.getenv("GIT_DEBUG_TESTGIT"):
 248         import git_remote_helpers.util
 249         git_remote_helpers.util.DEBUG = True
 250
 251     alias = sanitize(args[1])
 252     url = sanitize(args[2])
 253
 254     if not alias.isalnum():
 255         warn("non-alnum alias '%s'", alias)
 256         alias = "tmp"
 257
 258     args[1] = alias
 259     args[2] = url
 260
 261     repo = get_repo(alias, url)
 262
 263     debug("Got arguments %s", args[1:])
 264
 265     more = True
 266
 267     sys.stdin = os.fdopen(sys.stdin.fileno(), 'r', 0)
 268     while (more):
 269         more = read_one_line(repo)
 270
 271 if __name__ == '__main__':
 272     sys.exit(main(sys.argv))