git-remote-testpy.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 if sys.hexversion < 0x02000000:
  35     # string.encode() is the limiter
  36     sys.stderr.write("git-remote-testgit: requires Python 2.0 or later.\n")
  37     sys.exit(1)
  38
  39
  40 def encode_filepath(path):
  41     """Encodes a Unicode file path to a byte string.
  42
  43     On Python 2 this is a no-op; on Python 3 we encode the string as
  44     suggested by [1] which allows an exact round-trip from the command line
  45     to the filesystem.
  46
  47     [1] http://docs.python.org/3/c-api/unicode.html#file-system-encoding
  48
  49     """
  50     if sys.hexversion < 0x03000000:
  51         return path
  52     return path.encode(sys.getfilesystemencoding(), 'surrogateescape')
  53
  54
  55 def get_repo(alias, url):
  56     """Returns a git repository object initialized for usage.
  57     """
  58
  59     repo = GitRepo(url)
  60     repo.get_revs()
  61     repo.get_head()
  62
  63     hasher = _digest()
  64     hasher.update(encode_filepath(repo.path))
  65     repo.hash = hasher.hexdigest()
  66
  67     repo.get_base_path = lambda base: os.path.join(
  68         base, 'info', 'fast-import', repo.hash)
  69
  70     prefix = 'refs/testgit/%s/' % alias
  71     debug("prefix: '%s'", prefix)
  72
  73     repo.gitdir = os.environ["GIT_DIR"]
  74     repo.alias = alias
  75     repo.prefix = prefix
  76
  77     repo.exporter = GitExporter(repo)
  78     repo.importer = GitImporter(repo)
  79     repo.non_local = NonLocalGit(repo)
  80
  81     return repo
  82
  83
  84 def local_repo(repo, path):
  85     """Returns a git repository object initalized for usage.
  86     """
  87
  88     local = GitRepo(path)
  89
  90     local.non_local = None
  91     local.gitdir = repo.gitdir
  92     local.alias = repo.alias
  93     local.prefix = repo.prefix
  94     local.hash = repo.hash
  95     local.get_base_path = repo.get_base_path
  96     local.exporter = GitExporter(local)
  97     local.importer = GitImporter(local)
  98
  99     return local
 100
 101
 102 def do_capabilities(repo, args):
 103     """Prints the supported capabilities.
 104     """
 105
 106     print("import")
 107     print("export")
 108     print("refspec refs/heads/*:%s*" % repo.prefix)
 109
 110     dirname = repo.get_base_path(repo.gitdir)
 111
 112     if not os.path.exists(dirname):
 113         os.makedirs(dirname)
 114
 115     path = os.path.join(dirname, 'git.marks')
 116
 117     print("*export-marks %s" % path)
 118     if os.path.exists(path):
 119         print("*import-marks %s" % path)
 120
 121     print('') # end capabilities
 122
 123
 124 def do_list(repo, args):
 125     """Lists all known references.
 126
 127     Bug: This will always set the remote head to master for non-local
 128     repositories, since we have no way of determining what the remote
 129     head is at clone time.
 130     """
 131
 132     for ref in repo.revs:
 133         debug("? refs/heads/%s", ref)
 134         print("? refs/heads/%s" % ref)
 135
 136     if repo.head:
 137         debug("@refs/heads/%s HEAD" % repo.head)
 138         print("@refs/heads/%s HEAD" % repo.head)
 139     else:
 140         debug("@refs/heads/master HEAD")
 141         print("@refs/heads/master HEAD")
 142
 143     print('') # end list
 144
 145
 146 def update_local_repo(repo):
 147     """Updates (or clones) a local repo.
 148     """
 149
 150     if repo.local:
 151         return repo
 152
 153     path = repo.non_local.clone(repo.gitdir)
 154     repo.non_local.update(repo.gitdir)
 155     repo = local_repo(repo, path)
 156     return repo
 157
 158
 159 def do_import(repo, args):
 160     """Exports a fast-import stream from testgit for git to import.
 161     """
 162
 163     if len(args) != 1:
 164         die("Import needs exactly one ref")
 165
 166     if not repo.gitdir:
 167         die("Need gitdir to import")
 168
 169     ref = args[0]
 170     refs = [ref]
 171
 172     while True:
 173         line = sys.stdin.readline().decode()
 174         if line == '\n':
 175             break
 176         if not line.startswith('import '):
 177             die("Expected import line.")
 178
 179         # strip of leading 'import '
 180         ref = line[7:].strip()
 181         refs.append(ref)
 182
 183     print("feature done")
 184
 185     if os.environ.get("GIT_REMOTE_TESTGIT_FAILURE"):
 186         die('Told to fail')
 187
 188     repo = update_local_repo(repo)
 189     repo.exporter.export_repo(repo.gitdir, refs)
 190
 191     print("done")
 192
 193
 194 def do_export(repo, args):
 195     """Imports a fast-import stream from git to testgit.
 196     """
 197
 198     if not repo.gitdir:
 199         die("Need gitdir to export")
 200
 201     if os.environ.get("GIT_REMOTE_TESTGIT_FAILURE"):
 202         die('Told to fail')
 203
 204     update_local_repo(repo)
 205     changed = repo.importer.do_import(repo.gitdir)
 206
 207     if not repo.local:
 208         repo.non_local.push(repo.gitdir)
 209
 210     for ref in changed:
 211         print("ok %s" % ref)
 212     print('')
 213
 214
 215 COMMANDS = {
 216     'capabilities': do_capabilities,
 217     'list': do_list,
 218     'import': do_import,
 219     'export': do_export,
 220 }
 221
 222
 223 def sanitize(value):
 224     """Cleans up the url.
 225     """
 226
 227     if value.startswith('testgit::'):
 228         value = value[9:]
 229
 230     return value
 231
 232
 233 def read_one_line(repo):
 234     """Reads and processes one command.
 235     """
 236
 237     sleepy = os.environ.get("GIT_REMOTE_TESTGIT_SLEEPY")
 238     if sleepy:
 239         debug("Sleeping %d sec before readline" % int(sleepy))
 240         time.sleep(int(sleepy))
 241
 242     line = sys.stdin.readline()
 243
 244     cmdline = line.decode()
 245
 246     if not cmdline:
 247         warn("Unexpected EOF")
 248         return False
 249
 250     cmdline = cmdline.strip().split()
 251     if not cmdline:
 252         # Blank line means we're about to quit
 253         return False
 254
 255     cmd = cmdline.pop(0)
 256     debug("Got command '%s' with args '%s'", cmd, ' '.join(cmdline))
 257
 258     if cmd not in COMMANDS:
 259         die("Unknown command, %s", cmd)
 260
 261     func = COMMANDS[cmd]
 262     func(repo, cmdline)
 263     sys.stdout.flush()
 264
 265     return True
 266
 267
 268 def main(args):
 269     """Starts a new remote helper for the specified repository.
 270     """
 271
 272     if len(args) != 3:
 273         die("Expecting exactly three arguments.")
 274         sys.exit(1)
 275
 276     if os.getenv("GIT_DEBUG_TESTGIT"):
 277         import git_remote_helpers.util
 278         git_remote_helpers.util.DEBUG = True
 279
 280     alias = sanitize(args[1])
 281     url = sanitize(args[2])
 282
 283     if not alias.isalnum():
 284         warn("non-alnum alias '%s'", alias)
 285         alias = "tmp"
 286
 287     args[1] = alias
 288     args[2] = url
 289
 290     repo = get_repo(alias, url)
 291
 292     debug("Got arguments %s", args[1:])
 293
 294     more = True
 295
 296     # Use binary mode since Python 3 does not permit unbuffered I/O in text
 297     # mode.  Unbuffered I/O is required to avoid data that should be going
 298     # to git-fast-import after an "export" command getting caught in our
 299     # stdin buffer instead.
 300     sys.stdin = os.fdopen(sys.stdin.fileno(), 'rb', 0)
 301     while (more):
 302         more = read_one_line(repo)
 303
 304 if __name__ == '__main__':
 305     sys.exit(main(sys.argv))