omit_data_loss config variable

In tp_libvrt testing, We've seen many occurrences where "Bad file
descriptor" OSError was raised during clean up phase when an external
command is executed via `avocado.utils.process` utility. It happens when
`SubProcess` class wants to flush the stdout and stderr of the external
command after finishes. These kinds of errors might lead to stdout and
stderr data loss, but during the tp_libvrt testing it leads to false
positive failures, which makes test evaluation harder.

This commit introduces a new config variable `omit_data_loss` which,
when is enabled, will omit these errors, and they won't affect the
overall test result.

Reference: avocado-framework/avocado#6019
Signed-off-by: Jan Richter <[email protected]>

avocado_vt/plugins/vt.py

@@ -250,6 +250,20 @@ def configure(self, parser):
             help=help_msg,
         )
 
+        help_msg = (
+            "Omits the `OSError [Errno 9] Bad file descriptor` caused by "
+            "avocado.utils.process utility during clean up. This can be used "
+            "when this error would cause false positive failures of a test."
+        )
+        add_option(
+            vt_compat_group_common,
+            dest="vt.omit_data_loss",
+            arg="--vt-omit-data-loss",
+            action="store_true",
+            default=False,
+            help=help_msg,
+        )
+
     def run(self, config):
         """
         Run test modules or simple tests.

avocado_vt/plugins/vt_init.py

@@ -125,6 +125,19 @@ def initialize(self):
                 help_msg=help_msg,
             )
 
+            help_msg = (
+                "Omits the `OSError [Errno 9] Bad file descriptor` caused by "
+                "avocado.utils.process utility during clean up. This can be used "
+                "when this error would cause false positive failures of a test."
+            )
+            settings.register_option(
+                section,
+                key="omit_data_loss",
+                key_type=bool,
+                default=False,
+                help_msg=help_msg,
+            )
+
             # [vt.setup] section
             section = "vt.setup"
 

avocado_vt/test.py

@@ -169,28 +169,34 @@ def setUp(self):
                             os.remove(libvirtd_log)
                     else:
                         # tar the libvirtd log and archive
-                        self.log.info("archiving libvirtd debug logs")
-                        from virttest import utils_package
-
-                        if utils_package.package_install("tar"):
-                            if os.path.isfile(libvirtd_log):
-                                archive = os.path.join(
-                                    os.path.dirname(libvirtd_log), "libvirtd.tar.gz"
-                                )
-                                cmd = "tar -zcf %s -P %s" % (
-                                    shlex.quote(archive),
-                                    shlex.quote(libvirtd_log),
-                                )
-                                if process.system(cmd) == 0:
-                                    os.remove(libvirtd_log)
+                        try:
+                            self.log.info("archiving libvirtd debug logs")
+                            from virttest import utils_package
+
+                            if utils_package.package_install("tar"):
+                                if os.path.isfile(libvirtd_log):
+                                    archive = os.path.join(
+                                        os.path.dirname(libvirtd_log), "libvirtd.tar.gz"
+                                    )
+                                    cmd = "tar -zcf %s -P %s" % (
+                                        shlex.quote(archive),
+                                        shlex.quote(libvirtd_log),
+                                    )
+                                    if process.system(cmd) == 0:
+                                        os.remove(libvirtd_log)
+                                else:
+                                    self.log.error(
+                                        "Unable to find log file: %s", libvirtd_log
+                                    )
                             else:
                                 self.log.error(
-                                    "Unable to find log file: %s", libvirtd_log
+                                    "Unable to find tar to compress libvirtd " "logs"
                                 )
-                        else:
-                            self.log.error(
-                                "Unable to find tar to compress libvirtd " "logs"
-                            )
+                        except OSError as e:
+                            if not self._config.get("vt.omit_data_loss"):
+                                raise e
+                            elif e.errno != 9:
+                                raise e
 
             if env_lang:
                 os.environ["LANG"] = env_lang
@@ -307,14 +313,18 @@ def _runTest(self):
                         params["test_passed"] = str(test_passed)
                         env_process.postprocess(self, params, env)
                     except:  # nopep8 Old-style exceptions are not inherited from Exception()
-
-                        stacktrace.log_exc_info(sys.exc_info(), "avocado.test")
-                        if test_passed:
-                            raise
-                        self.log.error(
-                            "Exception raised during " "postprocessing: %s",
-                            sys.exc_info()[1],
-                        )
+                        if not (
+                            self._config.get("vt.omit_data_loss")
+                            and "[Errno 9] Bad file descriptor"
+                            in str(sys.exc_info()[1])
+                        ):
+                            stacktrace.log_exc_info(sys.exc_info(), "avocado.test")
+                            if test_passed:
+                                raise
+                            self.log.error(
+                                "Exception raised during " "postprocessing: %s",
+                                sys.exc_info()[1],
+                            )
                 finally:
                     if (
                         self._safe_env_save(env)