Add utilities for fast-import, exporting repository.

Redo subprocess error handling.

gitosis/repository.py

@@ -3,6 +3,15 @@ import subprocess
 
 from gitosis import util
 
+class GitError(Exception):
+    """git failed"""
+
+    def __str__(self):
+        return '%s: %s' % (self.__doc__, ': '.join(self.args))
+
+class GitInitError(Exception):
+    """git init failed"""
+
 def init(
     path,
     template=None,
@@ -15,17 +24,98 @@ def init(
     args = [_git, 'init']
     if template is not None:
         args.append('--template=%s' % template)
-    env = {}
-    env.update(os.environ)
-    env['GIT_DIR'] = '.'
     returncode = subprocess.call(
         args=args,
         cwd=path,
         close_fds=True,
-        env=env,
+        env=dict(GIT_DIR='.'),
         )
     if returncode != 0:
-        raise RuntimeError(
-            ("Command '%r' returned non-zero exit status %d"
-             % (args, returncode)),
-            )
+        raise GitInitError('exit status %d' % returncode)
+
+
+class GitFastImportError(GitError):
+    """git fast-import failed"""
+    pass
+
+def fast_import(
+    git_dir,
+    commit_msg,
+    committer,
+    files,
+    ):
+    """
+    Create an initial commit.
+    """
+    init(path=git_dir)
+    child = subprocess.Popen(
+        args=['git', 'fast-import', '--quiet', '--date-format=now'],
+        cwd=git_dir,
+        stdin=subprocess.PIPE,
+        close_fds=True,
+        env=dict(GIT_DIR=git_dir),
+        )
+    files = list(files)
+    for index, (path, content) in enumerate(files):
+        child.stdin.write("""\
+blob
+mark :%(mark)d
+data %(len)d
+%(content)s
+""" % dict(
+            mark=index+1,
+            len=len(content),
+            content=content,
+            ))
+    child.stdin.write("""\
+commit refs/heads/master
+committer %(committer)s now
+data %(commit_msg_len)d
+%(commit_msg)s
+""" % dict(
+        committer=committer,
+        commit_msg_len=len(commit_msg),
+        commit_msg=commit_msg,
+        ))
+    for index, (path, content) in enumerate(files):
+        child.stdin.write('M 100644 :%d %s\n' % (index+1, path))
+    child.stdin.close()
+    returncode = child.wait()
+    if returncode != 0:
+        raise GitFastImportError(
+            'git fast-import failed', 'exit status %d' % returncode)
+
+class GitExportError(GitError):
+    """Export failed"""
+    pass
+
+class GitReadTreeError(GitExportError):
+    """git read-tree failed"""
+
+class GitCheckoutIndexError(GitExportError):
+    """git checkout-index failed"""
+
+def export(git_dir, path):
+    # it's a literal prefix for git, a trailing slash is needed to
+    # extract to the subdirectory
+    path = os.path.join(path, '')
+    returncode = subprocess.call(
+        args=['git', 'read-tree', 'HEAD'],
+        close_fds=True,
+        env=dict(GIT_DIR=git_dir),
+        )
+    if returncode != 0:
+        raise GitReadTreeError('exit status %d' % returncode)
+    returncode = subprocess.call(
+        args=[
+            'git',
+            'checkout-index',
+            '-a',
+            '-f',
+            '--prefix=%s' % path,
+            ],
+        close_fds=True,
+        env=dict(GIT_DIR=git_dir),
+        )
+    if returncode != 0:
+        raise GitCheckoutIndexError('exit status %d' % returncode)

gitosis/test/test_repository.py

@@ -1,6 +1,7 @@
 from nose.tools import eq_ as eq
 
 import os
+import subprocess
 
 from gitosis import repository
 
@@ -55,3 +56,49 @@ def test_init_templates():
     eq(got, '#!/bin/sh\n# i can override standard templates\n')
     # standard templates are there, too
     assert os.path.isfile(os.path.join(path, 'hooks', 'pre-rebase'))
+
+def test_export_simple():
+    tmp = maketemp()
+    git_dir = os.path.join(tmp, 'repo.git')
+    repository.init(path=git_dir)
+    repository.fast_import(
+        git_dir=git_dir,
+        committer='John Doe <jdoe@example.com>',
+        commit_msg="""\
+Reverse the polarity of the neutron flow.
+
+Frobitz the quux and eschew obfuscation.
+""",
+        files=[
+            ('foo', 'content'),
+            ('bar/quux', 'another'),
+            ],
+        )
+    export = os.path.join(tmp, 'export')
+    repository.export(git_dir=git_dir, path=export)
+    eq(sorted(os.listdir(export)),
+       sorted(['foo', 'bar']))
+    eq(readFile(os.path.join(export, 'foo')), 'content')
+    eq(os.listdir(os.path.join(export, 'bar')), ['quux'])
+    eq(readFile(os.path.join(export, 'bar', 'quux')), 'another')
+    child = subprocess.Popen(
+        args=['git', 'cat-file', 'commit', 'HEAD'],
+        cwd=git_dir,
+        stdout=subprocess.PIPE,
+        close_fds=True,
+        env=dict(GIT_DIR=git_dir),
+        )
+    got = child.stdout.read().splitlines()
+    returncode = child.wait()
+    if returncode != 0:
+        raise RuntimeError('git exit status %d' % returncode)
+    eq(got[0].split(None, 1)[0], 'tree')
+    eq(got[1].rsplit(None, 2)[0],
+       'author John Doe <jdoe@example.com>')
+    eq(got[2].rsplit(None, 2)[0],
+       'committer John Doe <jdoe@example.com>')
+    eq(got[3], '')
+    eq(got[4], 'Reverse the polarity of the neutron flow.')
+    eq(got[5], '')
+    eq(got[6], 'Frobitz the quux and eschew obfuscation.')
+    eq(got[7:], [])