added Git.Update RMI, ability to base bcfg2 VCS repo at a different directory than the repo root

1 files changed, 129 insertions, 14 deletions

diff --git a/src/lib/Bcfg2/Server/Plugins/Git.py b/src/lib/Bcfg2/Server/Plugins/Git.py
index 177770a12..b7269af48 100644
--- a/src/lib/Bcfg2/Server/Plugins/Git.py
+++ b/src/lib/Bcfg2/Server/Plugins/Git.py
@@ -1,38 +1,153 @@
 """ The Git plugin provides a revision interface for Bcfg2 repos using
 git. """
 
+import os
+import sys
+import Bcfg2.Server.Plugin
+
+
+class GitAPIBase(object):
+    """ Base class for the various Git APIs (dulwich, GitPython,
+    subprocesses) """
+    def __init__(self, path):
+        self.path = path
+
+    def revision(self):
+        """ Get the current revision of the git repo as a string """
+        raise NotImplementedError
+
+    def pull(self):
+        """ Pull the latest version of the upstream git repo and
+        rebase against it. """
+        raise NotImplementedError
+
+
 try:
+    from dulwich.client import get_transport_and_path
     from dulwich.repo import Repo
+    from dulwich.file import GitFile, ensure_dir_exists
+
+    class GitAPI(GitAPIBase):
+        """ API for :class:`Git` using :mod:`dulwich` """
+        def __init__(self, path):
+            GitAPIBase.__init__(self, path)
+            self.repo = Repo(self.path)
+            self.client, self.origin_path = get_transport_and_path(
+                self.repo.get_config().get(("remote", "origin"),
+                                           "url"))
+
+        def revision(self):
+            return self.repo.head()
+
+        def pull(self):
+            try:
+                remote_refs = self.client.fetch(
+                    self.origin_path, self.repo,
+                    determine_wants=self.repo.object_store.determine_wants_all)
+            except KeyError:
+                etype, err = sys.exc_info()[:2]
+                # try to work around bug
+                # https://bugs.launchpad.net/dulwich/+bug/1025886
+                try:
+                    # pylint: disable=W0212
+                    self.client._fetch_capabilities.remove('thin-pack')
+                # pylint: enable=W0212
+                except KeyError:
+                    raise etype(err)
+                remote_refs = self.client.fetch(
+                    self.origin_path, self.repo,
+                    determine_wants=self.repo.object_store.determine_wants_all)
+
+            tree_id = self.repo[remote_refs['HEAD']].tree
+            # iterate over tree content, giving path and blob sha.
+            for entry in self.repo.object_store.iter_tree_contents(tree_id):
+                entry_in_path = entry.in_path(self.repo.path)
+                ensure_dir_exists(os.path.split(entry_in_path.path)[0])
+                GitFile(entry_in_path.path,
+                        'wb').write(self.repo[entry.sha].data)
+
 except ImportError:
-    # fallback to shell commands when dulwich unavailable
-    from subprocess import Popen, PIPE
+    try:
+        import git
 
-import Bcfg2.Server.Plugin
+        class GitAPI(GitAPIBase):
+            """ API for :class:`Git` using :mod:`git` (GitPython) """
+            def __init__(self, path):
+                GitAPIBase.__init__(self, path)
+                self.repo = git.Repo(path)
 
+            def revision(self):
+                return self.repo.head.commit.hexsha
 
-class Git(Bcfg2.Server.Plugin.Plugin,
-          Bcfg2.Server.Plugin.Version):
+            def pull(self):
+                self.repo.git.pull("--rebase")
+
+    except ImportError:
+        from subprocess import Popen, PIPE
+
+        try:
+            Popen(["git"], stdout=PIPE, stderr=PIPE).wait()
+
+            class GitAPI(GitAPIBase):
+                """ API for :class:`Git` using subprocess to run git
+                commands """
+                def revision(self):
+                    proc = Popen(["git", "--work-tree", self.path,
+                                  "rev-parse", "HEAD"], stdout=PIPE,
+                                 stderr=PIPE)
+                    rv, err = proc.communicate()
+                    if proc.wait():
+                        raise Exception("Git: Error getting revision from %s: "
+                                        "%s" % (self.path, err))
+                    return rv.strip()  # pylint: disable=E1103
+
+                def pull(self):
+                    proc = Popen(["git", "--work-tree", self.path,
+                                  "pull", "--rebase"], stdout=PIPE,
+                                 stderr=PIPE)
+                    err = proc.communicate()[1].strip()
+                    if proc.wait():
+                        raise Exception("Git: Error pulling: %s" % err)
+
+        except OSError:
+            raise ImportError("Could not import dulwich or GitPython "
+                              "libraries, and no 'git' command found in PATH")
+
+
+class Git(Bcfg2.Server.Plugin.Version):
     """ The Git plugin provides a revision interface for Bcfg2 repos
     using git. """
     __author__ = 'bcfg-dev@mcs.anl.gov'
     __vcs_metadata_path__ = ".git"
+    __rmi__ = Bcfg2.Server.Plugin.Version.__rmi__ + ['Update']
 
     def __init__(self, core, datastore):
-        Bcfg2.Server.Plugin.Plugin.__init__(self, core, datastore)
-        Bcfg2.Server.Plugin.Version.__init__(self, datastore)
+        Bcfg2.Server.Plugin.Version.__init__(self, core, datastore)
+        self.repo = GitAPI(self.vcs_root)
         self.logger.debug("Initialized git plugin with git directory %s" %
                           self.vcs_path)
 
     def get_revision(self):
         """Read git revision information for the Bcfg2 repository."""
         try:
-            return Repo(self.datastore).head()
-        except NameError:
-            return Popen("env LC_ALL=C git log -1 --pretty=format:%H",
-                         shell=True,
-                         cwd=self.datastore,
-                         stdout=PIPE).stdout.readline()
+            return self.repo.revision()
         except:
-            msg = "Failed to read git repository"
+            err = sys.exc_info()[1]
+            msg = "Failed to read git repository: %s" % err
+            self.logger.error(msg)
+            raise Bcfg2.Server.Plugin.PluginExecutionError(msg)
+
+    def Update(self):
+        """ Git.Update() => True|False
+        Update the working copy against the upstream repository
+        """
+        try:
+            self.repo.pull()
+            self.logger.info("Git repo at %s updated to %s" %
+                             (self.vcs_root, self.get_revision()))
+            return True
+        except:  # pylint: disable=W0702
+            err = sys.exc_info()[1]
+            msg = "Failed to pull from git repository: %s" % err
             self.logger.error(msg)
             raise Bcfg2.Server.Plugin.PluginExecutionError(msg)