avocado.utils.iso9660: Define "mnt_dir" API

The Iso9660Mount defines "mnt_dir" variable, which is frequently used in
tests to make the content of the image available. This is not supported
by other providers, which adds complexity to the code around mnt_dir.
This patch makes "mnt_dir" property part of the API and implements it in
all current providers.

Note that the "mnt_dir" feature is currently uses the "Iso9660Mount"
features, therefor the user must be root and the mount has to be
available, otherwise one gets exception when he tries to use "mnt_dir".
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

avocado/utils/iso9660.py

@@ -151,6 +151,12 @@ class BaseIso9660(object):
         output.write(content)
         output.close()
 
+    def mnt_dir(self):
+        """
+        Returns a path to the browsable content of the iso
+        """
+        raise NotImplementedError
+
     def close(self):
         """
         Cleanup and free any resources being used
@@ -160,7 +166,38 @@ class BaseIso9660(object):
         pass
 
 
-class Iso9660IsoInfo(BaseIso9660):
+class MixInMntDirMount(object):
+    """
+    Mix in class which defines `mnt_dir` property and instantiates the
+    Iso9660Mount class to provide one. It requires `self.path` to store
+    path to the target iso file.
+    """
+    _mount_instance = None
+    path = None
+
+    @property
+    def mnt_dir(self):
+        """
+        Returns a path to the browsable content of the iso
+        """
+        if self._mount_instance is None:
+            if not self.path:
+                raise RuntimeError("Path to iso image not available: %s"
+                                   % self.path)
+            self._mount_instance = Iso9660Mount(self.path)
+        return self._mount_instance.mnt_dir
+
+    def close(self):
+        """
+        Cleanups and frees any resources being used
+        """
+        super(MixInMntDirMount, self).close()
+        if self._mount_instance:
+            self._mount_instance.close()
+            self._mount_instance = None
+
+
+class Iso9660IsoInfo(MixInMntDirMount, BaseIso9660):
 
     """
     Represents a ISO9660 filesystem
@@ -212,7 +249,8 @@ class Iso9660IsoInfo(BaseIso9660):
         else:
             fname = self._get_filename_in_iso(path)
             if not fname:
-                logging.warn("Could not find '%s' in iso '%s'", path, self.path)
+                logging.warn(
+                    "Could not find '%s' in iso '%s'", path, self.path)
                 return ""
 
         cmd.append("-x %s" % fname)
@@ -220,7 +258,7 @@ class Iso9660IsoInfo(BaseIso9660):
         return result.stdout
 
 
-class Iso9660IsoRead(BaseIso9660):
+class Iso9660IsoRead(MixInMntDirMount, BaseIso9660):
 
     """
     Represents a ISO9660 filesystem
@@ -243,6 +281,7 @@ class Iso9660IsoRead(BaseIso9660):
         process.run(cmd)
 
     def close(self):
+        super(Iso9660IsoRead, self).close()
         shutil.rmtree(self.temp_dir, True)
 
 
@@ -260,7 +299,7 @@ class Iso9660Mount(BaseIso9660):
         :type path: str
         """
         super(Iso9660Mount, self).__init__(path)
-        self.mnt_dir = tempfile.mkdtemp(prefix='avocado_' + __name__)
+        self._mnt_dir = tempfile.mkdtemp(prefix='avocado_' + __name__)
         process.run('mount -t iso9660 -v -o loop,ro %s %s' %
                     (path, self.mnt_dir))
 
@@ -293,11 +332,19 @@ class Iso9660Mount(BaseIso9660):
 
         :rtype: None
         """
-        if os.path.ismount(self.mnt_dir):
-            process.run('fuser -k %s' % self.mnt_dir, ignore_status=True)
-            process.run('umount %s' % self.mnt_dir)
-
-        shutil.rmtree(self.mnt_dir)
+        if self._mnt_dir:
+            if os.path.ismount(self._mnt_dir):
+                process.run('fuser -k %s' % self.mnt_dir, ignore_status=True)
+                process.run('umount %s' % self.mnt_dir)
+            shutil.rmtree(self._mnt_dir)
+            self._mnt_dir = None
+
+    @property
+    def mnt_dir(self):
+        if not self._mnt_dir:
+            raise RuntimeError("Trying to get mnt_dir of already closed iso %s"
+                               % self.path)
+        return self._mnt_dir
 
 
 def iso9660(path):

selftests/unit/test_utils_iso9660.py

+"""
+Verifies the avocado.utils.iso9660 functionality
+"""
+import os
+import shutil
+import sys
+import tempfile
+
+from avocado.utils import iso9660, process
+
+
+if sys.version_info[:2] == (2, 6):
+    import unittest2 as unittest
+else:
+    import unittest
+
+
+class BaseIso9660(unittest.TestCase):
+
+    """
+    Base class defining setup and tests for shared Iso9660 functionality
+    """
+
+    def setUp(self):
+        self.iso_path = os.path.abspath(os.path.join(os.path.dirname(__file__),
+                                                     os.path.pardir, ".data",
+                                                     "sample.iso"))
+        self.iso = None
+        self.tmpdir = tempfile.mkdtemp(prefix="avocado_" + __name__)
+
+    def basic_workflow(self):
+        """
+        Check the basic Iso9660 workflow
+
+        :warning: Make sure to include this in per-implementation tests
+                  due to ast loader we can't just define a base-class.
+        """
+        self.assertEqual(self.iso.read("file"),
+                         "file content\n")
+        dst = os.path.join(self.tmpdir, "file")
+        self.iso.copy(os.path.join("Dir", "in_dir_file"), dst)
+        self.assertEqual(open(dst).read(), "content of in-dir-file\n")
+        self.iso.close()
+        self.iso.close()    # check that double-close won't fail
+
+    @unittest.skipIf(os.getuid(), "This test is only available to root")
+    def mnt_dir_workflow(self):
+        """
+        Check the mnt_dir functionality
+
+        :warning: Make sure to include this in per-implementation tests
+                  due to ast loader we can't just define a base-class.
+        """
+        base = self.iso.mnt_dir
+        os.path.isdir(os.path.join(base, "Dir"))
+        self.assertEqual(open(os.path.join(base, "file")).read(),
+                         "file content\n")
+        self.assertEqual(open(os.path.join(base, "Dir", "in_dir_file")).read(),
+                         "content of in-dir-file\n")
+        self.iso.close()
+        self.assertFalse(os.path.exists(base), "the mnt_dir is suppose to be "
+                         "destroyed after iso.close()")
+
+    def tearDown(self):
+        if self.iso is not None:
+            self.iso.close()
+        shutil.rmtree(self.tmpdir)
+
+
+class IsoInfo(BaseIso9660):
+
+    """
+    IsoInfo-based check
+    """
+
+    @unittest.skipIf(process.system("which isoinfo", ignore_status=True),
+                     "isoinfo not installed.")
+    def setUp(self):
+        super(IsoInfo, self).setUp()
+        self.iso = iso9660.Iso9660IsoInfo(self.iso_path)
+
+    def test_basic_workflow(self):
+        """Call the basic workflow"""
+        self.basic_workflow()
+
+    def test_mnt_dir(self):
+        """Use the mnt_dir property"""
+        self.mnt_dir_workflow()
+
+
+class IsoRead(BaseIso9660):
+
+    """
+    IsoRead-based check
+    """
+
+    @unittest.skipIf(process.system("which iso-read", ignore_status=True),
+                     "iso-read not installed.")
+    def setUp(self):
+        super(IsoRead, self).setUp()
+        self.iso = iso9660.Iso9660IsoRead(self.iso_path)
+
+    def test_basic_workflow(self):
+        """Call the basic workflow"""
+        self.basic_workflow()
+
+    def test_mnt_dir(self):
+        """Use the mnt_dir property"""
+        self.mnt_dir_workflow()
+
+
+class IsoMount(BaseIso9660):
+
+    """
+    Mount-based check
+    """
+
+    @unittest.skipIf(os.getuid(), "This test is only available to root")
+    def setUp(self):
+        super(IsoMount, self).setUp()
+        self.iso = iso9660.Iso9660Mount(self.iso_path)
+
+    def test_basic_workflow(self):
+        """Call the basic workflow"""
+        self.basic_workflow()
+
+    def test_mnt_dir(self):
+        """Use the mnt_dir property"""
+        self.mnt_dir_workflow()
+
+
+if __name__ == "__main__":
+    unittest.main()