merging creat and open function to be more pythonic

the os python module does not offer a creat function,
new files are created using the open function and
by passing O_CREAT flag. We are changing gfapi.py to
function the same way.

Change-Id: I5e084b200bb657e3124d3e620a47160e790cd1fe
Signed-off-by: Thiago da Silva <thiago@redhat.com>

4 files changed, 68 insertions, 45 deletions

diff --git a/glusterfs/gfapi.py b/glusterfs/gfapi.py
index 8eeb3d6..6ca2ad7 100644
--- a/glusterfs/gfapi.py
+++ b/glusterfs/gfapi.py
@@ -19,8 +19,6 @@ import os
 import stat
 import errno
 
-from contextlib import contextmanager
-
 # Disclaimer: many of the helper functions (e.g., exists, isdir) where copied
 # from the python source code
 
@@ -92,6 +90,17 @@ class File(object):
     def __init__(self, fd):
         self.fd = fd
 
+    def __enter__(self):
+        if self.fd is None:
+            # __enter__ should only be called within the context
+            # of a 'with' statement when opening a file through
+            # Volume.open()
+            raise ValueError("I/O operation on closed file")
+        return self
+
+    def __exit__(self, type, value, tb):
+        self.close()
+
     def close(self):
         ret = api.glfs_close(self.fd)
         if ret < 0:
@@ -243,20 +252,6 @@ class Volume(object):
             raise OSError(err, os.strerror(err))
         return ret
 
-    @contextmanager
-    def creat(self, path, flags, mode):
-        fd = api.glfs_creat(self.fs, path, flags, mode)
-        if not fd:
-            err = ctypes.get_errno()
-            raise OSError(err, os.strerror(err))
-
-        fileobj = None
-        try:
-            fileobj = File(fd)
-            yield fileobj
-        finally:
-            fileobj.close()
-
     def exists(self, path):
         """
         Test whether a path exists.
@@ -384,19 +379,16 @@ class Volume(object):
             raise OSError(err, os.strerror(err))
         return ret
 
-    @contextmanager
-    def open(self, path, flags):
-        fd = api.glfs_open(self.fs, path, flags)
+    def open(self, path, flags, mode=0777):
+        if (os.O_CREAT & flags) == os.O_CREAT:
+            fd = api.glfs_creat(self.fs, path, flags, mode)
+        else:
+            fd = api.glfs_open(self.fs, path, flags)
         if not fd:
             err = ctypes.get_errno()
             raise OSError(err, os.strerror(err))
 
-        fileobj = None
-        try:
-            fileobj = File(fd)
-            yield fileobj
-        finally:
-            fileobj.close()
+        return File(fd)
 
     def opendir(self, path):
         fd = api.glfs_opendir(self.fs, path)
diff --git a/test/functional/libgfapi-python-tests.py b/test/functional/libgfapi-python-tests.py
index cdb556c..ac5c38f 100644
--- a/test/functional/libgfapi-python-tests.py
+++ b/test/functional/libgfapi-python-tests.py
@@ -17,6 +17,7 @@ import unittest
 import os
 import types
 import loremipsum
+import errno
 
 from glusterfs import gfapi
 
@@ -40,7 +41,8 @@ class BinFileOpsTest(unittest.TestCase):
     def setUp(self):
         self.data = bytearray([(k % 128) for k in range(0, 1024)])
         self.path = self._testMethodName + ".io"
-        with self.vol.creat(self.path, os.O_WRONLY | os.O_EXCL, 0644) as fd:
+        with self.vol.open(self.path, os.O_CREAT | os.O_WRONLY | os.O_EXCL,
+                           0644) as fd:
             fd.write(self.data)
 
     def test_bin_open_and_read(self):
@@ -70,7 +72,8 @@ class FileOpsTest(unittest.TestCase):
     def setUp(self):
         self.data = loremipsum.get_sentence()
         self.path = self._testMethodName + ".io"
-        with self.vol.creat(self.path, os.O_WRONLY | os.O_EXCL, 0644) as fd:
+        with self.vol.open(self.path, os.O_CREAT | os.O_WRONLY | os.O_EXCL,
+                           0644) as fd:
             rc = fd.write(self.data)
             self.assertEqual(rc, len(self.data))
             ret = fd.fsync()
@@ -87,6 +90,26 @@ class FileOpsTest(unittest.TestCase):
             self.assertFalse(isinstance(buf, types.IntType))
             self.assertEqual(buf.value, self.data)
 
+    def test_open_file_not_exist(self):
+        try:
+            f = self.vol.open("filenotexist", os.O_WRONLY)
+        except OSError as e:
+            self.assertEqual(e.errno, errno.ENOENT)
+        else:
+            f.close()
+            self.fail("Expected a OSError with errno.ENOENT")
+
+    def test_create_file_already_exists(self):
+        try:
+            f = self.vol.open("newfile", os.O_CREAT)
+            f.close()
+            g = self.vol.open("newfile", os.O_CREAT | os.O_EXCL)
+        except OSError as e:
+            self.assertEqual(e.errno, errno.EEXIST)
+        else:
+            g.close()
+            self.fail("Expected a OSError with errno.EEXIST")
+
     def test_exists(self):
         e = self.vol.exists(self.path)
         self.assertTrue(e)
@@ -186,7 +209,8 @@ class DirOpsTest(unittest.TestCase):
         self.vol.mkdir(self.dir_path, 0755)
         for x in range(0, 3):
             f = os.path.join(self.dir_path, self.testfile + str(x))
-            with self.vol.creat(f, os.O_WRONLY | os.O_EXCL, 0644) as fd:
+            with self.vol.open(f, os.O_CREAT | os.O_WRONLY | os.O_EXCL,
+                               0644) as fd:
                 rc = fd.write(self.data)
                 self.assertEqual(rc, len(self.data))
                 ret = fd.fdatasync()
diff --git a/test/unit/gluster/test_gfapi.py b/test/unit/gluster/test_gfapi.py
index 8fcf938..ed7ed45 100644
--- a/test/unit/gluster/test_gfapi.py
+++ b/test/unit/gluster/test_gfapi.py
@@ -279,23 +279,12 @@ class TestVolume(unittest.TestCase):
         mock_glfs_creat.return_value = 2
 
         with patch("glusterfs.gfapi.api.glfs_creat", mock_glfs_creat):
-            with self.vol.creat("file.txt", os.O_WRONLY, 0644) as fd:
+            with self.vol.open("file.txt", os.O_CREAT, 0644) as fd:
                 self.assertTrue(isinstance(fd, gfapi.File))
                 self.assertEqual(mock_glfs_creat.call_count, 1)
                 mock_glfs_creat.assert_called_once_with(2,
                                                         "file.txt",
-                                                        os.O_WRONLY, 0644)
-
-    def test_creat_fail_exception(self):
-        mock_glfs_creat = Mock()
-        mock_glfs_creat.return_value = None
-
-        def assert_creat():
-            with self.vol.creat("file.txt", os.O_WRONLY, 0644) as fd:
-                self.assertEqual(fd, None)
-
-        with patch("glusterfs.gfapi.api.glfs_creat", mock_glfs_creat):
-            self.assertRaises(OSError, assert_creat)
+                                                        os.O_CREAT, 0644)
 
     def test_exists_true(self):
         mock_glfs_stat = Mock()
@@ -430,7 +419,8 @@ class TestVolume(unittest.TestCase):
         mock_Dir_next = Mock()
         mock_Dir_next.side_effect = [dirent1, dirent2, dirent3, None]
 
-        with nested(patch("glusterfs.gfapi.api.glfs_opendir", mock_glfs_opendir),
+        with nested(patch("glusterfs.gfapi.api.glfs_opendir",
+                          mock_glfs_opendir),
                     patch("glusterfs.gfapi.Dir.next", mock_Dir_next)):
             d = self.vol.listdir("testdir")
             self.assertEqual(len(d), 2)
@@ -545,7 +535,7 @@ class TestVolume(unittest.TestCase):
         with patch("glusterfs.gfapi.api.glfs_mkdir", mock_glfs_mkdir):
             self.assertRaises(OSError, self.vol.mkdir, "testdir", 0775)
 
-    def test_open_success(self):
+    def test_open_with_statement_success(self):
         mock_glfs_open = Mock()
         mock_glfs_open.return_value = 2
 
@@ -556,7 +546,7 @@ class TestVolume(unittest.TestCase):
                 mock_glfs_open.assert_called_once_with(2,
                                                        "file.txt", os.O_WRONLY)
 
-    def test_open_fail_exception(self):
+    def test_open_with_statement_fail_exception(self):
         mock_glfs_open = Mock()
         mock_glfs_open.return_value = None
 
@@ -567,6 +557,23 @@ class TestVolume(unittest.TestCase):
         with patch("glusterfs.gfapi.api.glfs_open", mock_glfs_open):
             self.assertRaises(OSError, assert_open)
 
+    def test_open_direct_success(self):
+        mock_glfs_open = Mock()
+        mock_glfs_open.return_value = 2
+
+        with patch("glusterfs.gfapi.api.glfs_open", mock_glfs_open):
+            fd = self.vol.open("file.txt", os.O_WRONLY)
+            self.assertTrue(isinstance(fd, gfapi.File))
+            self.assertEqual(mock_glfs_open.call_count, 1)
+            mock_glfs_open.assert_called_once_with(2, "file.txt", os.O_WRONLY)
+
+    def test_open_direct_fail_exception(self):
+        mock_glfs_open = Mock()
+        mock_glfs_open.return_value = None
+
+        with patch("glusterfs.gfapi.api.glfs_open", mock_glfs_open):
+            self.assertRaises(OSError, self.vol.open, "file.txt", os.O_RDONLY)
+
     def test_opendir_success(self):
         mock_glfs_opendir = Mock()
         mock_glfs_opendir.return_value = 2
diff --git a/tox.ini b/tox.ini
index 2e71767..5a97c9b 100644
--- a/tox.ini
+++ b/tox.ini
@@ -14,7 +14,7 @@ deps =
   --download-cache={homedir}/.pipcache
   -r{toxinidir}/tools/test-requires
 changedir = {toxinidir}/test/unit
-commands = nosetests -v --exe --with-xunit --with-coverage --cover-package gluster --cover-erase --cover-xml --cover-html --cover-branches --with-html-output {posargs}
+commands = nosetests -v --exe --with-xunit --with-coverage --cover-package glusterfs --cover-erase --cover-xml --cover-html --cover-branches --with-html-output {posargs}
 
 [tox:jenkins]
 downloadcache = ~/cache/pip