Implemet PIPESTATUS env var to handle error correctly.

As tar is here piped into openssl, we only get the return code for
openssl and lose the one of tar. This patch fixes this issue using
bash PIPESTATUS variable.

The piped command now returns return code of tar if openssl succeeds.
Otherwise it returns return code of openssl. That means, both the
commands should succeed.

Change-Id: I6f9de52539f7284d9479805fc4ca478f2ffd9123
Closes-Bug: #1596587

freezer/engine/tar/tar.py

@@ -75,8 +75,9 @@ def backup_data(self, backup_path, manifest_path):
 
         LOG.info("Execution command: \n{}".format(command))
 
-        tar_process = subprocess.Popen(command, stdout=subprocess.PIPE,
-                                       stderr=subprocess.PIPE, shell=True)
+        tar_process = subprocess.Popen(
+            command, stdout=subprocess.PIPE, stderr=subprocess.PIPE,
+            shell=True, executable='/bin/bash')
         read_pipe = tar_process.stdout
         tar_chunk = read_pipe.read(self.max_segment_size)
         while tar_chunk:
@@ -124,7 +125,7 @@ def restore_level(self, restore_path, read_pipe, backup, except_queue):
 
             tar_process = subprocess.Popen(
                 command, stdin=subprocess.PIPE, stdout=subprocess.PIPE,
-                stderr=subprocess.PIPE, shell=True)
+                stderr=subprocess.PIPE, shell=True, executable='/bin/bash')
             # Start loop reading the pipe and pass the data to the tar
             # std input. If EOFError exception is raised, the loop end
             # the std err will be checked for errors.

freezer/engine/tar/tar_builders.py

@@ -97,7 +97,8 @@ def build(self):
             openssl_cmd = "{openssl_path} enc -aes-256-cfb -pass file:{file}"\
                 .format(openssl_path=self.openssl_path,
                         file=self.encrypt_pass_file)
-            tar_command = '{0} | {1}'.format(tar_command, openssl_cmd)
+            tar_command = '{0} | {1} && exit ${{PIPESTATUS[0]}}'\
+                .format(tar_command, openssl_cmd)
 
         return tar_command
 
@@ -147,7 +148,8 @@ def build(self):
             openssl_cmd = self.OPENSSL_DEC.format(
                 openssl_path=self.openssl_path,
                 file=self.encrypt_pass_file)
-            tar_command = '{0} | {1}'.format(openssl_cmd, tar_command)
+            tar_command = '{0} | {1} && exit ${{PIPESTATUS[0]}}'\
+                .format(openssl_cmd, tar_command)
         return tar_command
 
 

freezer/tests/unit/engines/tar/test_tar_builders.py

@@ -50,7 +50,7 @@ def test_build_every_arg(self):
             "--seek --ignore-failed-read --hard-dereference "
             "--listed-incremental=listed-file.tar "
             "--exclude=\"excluded_files\" . | openssl enc -aes-256-cfb -pass "
-            "file:encrypt_pass_file")
+            "file:encrypt_pass_file && exit ${PIPESTATUS[0]}")
 
     def test_build_every_arg_windows(self):
         self.builder = tar_builders.TarCommandBuilder(".", "gzip", True,
@@ -64,7 +64,8 @@ def test_build_every_arg_windows(self):
             'gnutar -c -z --incremental --unlink-first --ignore-zeros '
             '--hard-dereference --listed-incremental=listed-file.tar '
             '--exclude="excluded_files" . '
-            '| openssl enc -aes-256-cfb -pass file:encrypt_pass_file')
+            '| openssl enc -aes-256-cfb -pass file:encrypt_pass_file '
+            '&& exit ${PIPESTATUS[0]}')
 
 
 class TestTarCommandRestoreBuilder(unittest.TestCase):
@@ -90,7 +91,8 @@ def test_all_args(self):
             self.builder.build(),
             "openssl enc -d -aes-256-cfb -pass file:encrypt_pass_file | "
             "gnutar -z --incremental --extract --unlink-first --ignore-zeros"
-            " --warning=none --directory restore_path")
+            " --warning=none --directory restore_path "
+            "&& exit ${PIPESTATUS[0]}")
 
     def test_all_args_windows(self):
         self.builder = tar_builders.TarCommandRestoreBuilder(
@@ -99,7 +101,8 @@ def test_all_args_windows(self):
         self.assertEqual(
             self.builder.build(),
             'openssl enc -d -aes-256-cfb -pass file:encrypt_pass_file '
-            '| gnutar -x -z --incremental --unlink-first --ignore-zeros')
+            '| gnutar -x -z --incremental --unlink-first --ignore-zeros '
+            '&& exit ${PIPESTATUS[0]}')
 
     def test_get_tar_flag_from_algo(self):
         assert tar_builders.get_tar_flag_from_algo('gzip') == '-z'