Add functions for creating and unpacking strata.

2 files changed, 46 insertions, 0 deletions

diff --git a/morphlib/bins.py b/morphlib/bins.py
index de946020..06956cd3 100644
--- a/morphlib/bins.py
+++ b/morphlib/bins.py
@@ -47,3 +47,25 @@ def unpack_chunk(chunk_filename, dirname):
     tar.extractall(path=dirname)
     tar.close()
 
+
+def create_stratum(rootdir, stratum_filename):
+    '''Create a stratum from the contents of a directory.'''
+    logging.debug('Creating stratum file %s from %s' % 
+                    (stratum_filename, rootdir))
+    tar = tarfile.open(name=stratum_filename, mode='w:gz')
+    tar.add(rootdir, arcname='.')
+    tar.close()
+
+
+def unpack_stratum(stratum_filename, dirname):
+    '''Unpack a stratum into a directory.
+    
+    The directory must exist already.
+    
+    '''
+
+    logging.debug('Unpacking stratum %s into %s' % (stratum_filename, dirname))
+    tar = tarfile.open(name=stratum_filename)
+    tar.extractall(path=dirname)
+    tar.close()
+
diff --git a/morphlib/bins_tests.py b/morphlib/bins_tests.py
index b3c13a64..30076120 100644
--- a/morphlib/bins_tests.py
+++ b/morphlib/bins_tests.py
@@ -76,3 +76,27 @@ class ChunkTests(unittest.TestCase):
         self.assertEqual(recursive_lstat(self.instdir),
                          recursive_lstat(self.unpacked))
 
+
+class StratumTests(unittest.TestCase):
+
+    def setUp(self):
+        self.tempdir = tempfile.mkdtemp()
+        self.instdir = os.path.join(self.tempdir, 'inst')
+        self.stratum_file = os.path.join(self.tempdir, 'stratum')
+        self.unpacked = os.path.join(self.tempdir, 'unpacked')
+        
+    def tearDown(self):
+        shutil.rmtree(self.tempdir)
+
+    def populate_instdir(self):
+        os.mkdir(self.instdir)
+        os.mkdir(os.path.join(self.instdir, 'bin'))
+
+    def test_creates_and_unpacks_stratum_exactly(self):
+        self.populate_instdir()
+        morphlib.bins.create_stratum(self.instdir, self.stratum_file)
+        os.mkdir(self.unpacked)
+        morphlib.bins.unpack_stratum(self.stratum_file, self.unpacked)
+        self.assertEqual(recursive_lstat(self.instdir),
+                         recursive_lstat(self.unpacked))
+