plugins.xunit: Add support to limit test log size

Some tests might produce too much logs which might result in too big
xunit results, that might be hard/impossible to publish. Let's allow
setting a limit to number of characters to those files and embed only
1/2 of the limit from the beginning and 1/2 of the limit from the end of
the log.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

avocado/plugins/xunit.py

@@ -23,6 +23,7 @@ from xml.dom.minidom import Document
 from avocado.core.parser import FileOrStdoutAction
 from avocado.core.output import LOG_UI
 from avocado.core.plugin_interfaces import CLI, Result
+from avocado.utils import data_structures
 
 
 class XUnitResult(Result):
@@ -53,7 +54,8 @@ class XUnitResult(Result):
         testcase.setAttribute('time', self._get_attr(state, 'time_elapsed'))
         return testcase
 
-    def _create_failure_or_error(self, document, test, element_type):
+    def _create_failure_or_error(self, document, test, element_type,
+                                 max_log_size=None):
         element = document.createElement(element_type)
         element.setAttribute('type', self._get_attr(test, 'fail_class'))
         element.setAttribute('message', self._get_attr(test, 'fail_reason'))
@@ -63,6 +65,20 @@ class XUnitResult(Result):
         system_out = document.createElement('system-out')
         try:
             with open(test.get("logfile"), "r") as logfile_obj:
+                if max_log_size is not None:
+                    logfile_obj.seek(0, 2)
+                    log_size = logfile_obj.tell()
+                    if log_size < max_log_size:
+                        text_output = logfile_obj.read()
+                    else:
+                        size = max_log_size / 2
+                        logfile_obj.seek(0, 0)
+                        text_output = logfile_obj.read(size)
+                        text_output += ("\n\n--[ CUT DUE TO XML PER TEST "
+                                        "LIMIT ]--\n\n")
+                        logfile_obj.seek(-size / 2, 2)
+                        text_output += logfile_obj.read()
+                else:
                     text_output = logfile_obj.read()
         except (TypeError, IOError):
             text_output = self.UNKNOWN
@@ -71,7 +87,7 @@ class XUnitResult(Result):
         system_out.appendChild(system_out_cdata)
         return element, system_out
 
-    def _render(self, result):
+    def _render(self, result, max_test_log_size):
         document = Document()
         testsuite = document.createElement('testsuite')
         testsuite.setAttribute('name', 'avocado')
@@ -92,7 +108,8 @@ class XUnitResult(Result):
             elif status == 'FAIL':
                 element, system_out = self._create_failure_or_error(document,
                                                                     test,
-                                                                    'failure')
+                                                                    'failure',
+                                                                    max_test_log_size)
                 testcase.appendChild(element)
                 testcase.appendChild(system_out)
             elif status == 'CANCEL':
@@ -100,7 +117,8 @@ class XUnitResult(Result):
             else:
                 element, system_out = self._create_failure_or_error(document,
                                                                     test,
-                                                                    'error')
+                                                                    'error',
+                                                                    max_test_log_size)
                 testcase.appendChild(element)
                 testcase.appendChild(system_out)
             testsuite.appendChild(testcase)
@@ -114,7 +132,8 @@ class XUnitResult(Result):
         if not result.tests_total:
             return
 
-        content = self._render(result)
+        max_test_log_size = getattr(job.args, 'xunit_max_test_log_chars', None)
+        content = self._render(result, max_test_log_size)
         if getattr(job.args, 'xunit_job_result', 'off') == 'on':
             xunit_path = os.path.join(job.logdir, 'results.xml')
             with open(xunit_path, 'wb') as xunit_file:
@@ -156,5 +175,11 @@ class XUnitCLI(CLI):
             help=('Enables default xUnit result in the job results directory. '
                   'File will be named "results.xml".'))
 
+        run_subcommand_parser.output.add_argument(
+            '--xunit-max-test-log-chars', metavar='SIZE',
+            type=lambda x: data_structures.DataSize(x).b, help="Limit the "
+            "attached job log to given number of characters (k/m/g suffix "
+            "allowed)")
+
     def run(self, args):
         pass

docs/source/ResultFormats.rst

@@ -88,6 +88,12 @@ output in the standard output of the runner, simply use::
 
 .. note:: The dash `-` in the option `--xunit`, it means that the xunit result
           should go to the standard output.
+.. note:: In case your tests produce very long outputs, you can limit the
+          number of embedded characters by
+          `--xunit-max-test-log-chars`. If the output in the log file is
+          longer it only attaches up-to max-test-log-chars characters
+          one half starting from the beginning of the content, the other
+          half from the end of the content.
 
 JSON
 ~~~~

docs/source/release_notes/lts/next.rst

@@ -94,6 +94,10 @@ introduced by the next LTS version are:
   that ``MemoryError`` is a Python standard exception, that is
   intended to be used on different situations.
 
+* Added possibility to limit the amount of characters embedded as
+  "system-out" in the xunit output plugin (``--xunit-max-test-log-chars
+  XX``).
+
 Complete list of changes
 ========================
 

man/avocado.rst

@@ -131,6 +131,9 @@ Options for subcommand `run` (`avocado run --help`)::
       --xunit-job-result {on,off}
                             Enables default xUnit result in the job results
                             directory. File will be named "results.xml".
+      --xunit-max-test-log-chars SIZE
+                            Limit the attached job log to given number of
+                            characters (k/m/g suffix allowed)
       -z, --archive         Archive (ZIP) files generated by tests
 
     output check arguments:

selftests/unit/test_xunit.py

@@ -94,6 +94,30 @@ class xUnitSucceedTest(unittest.TestCase):
                         "Failed to validate against %s, content:\n%s" %
                         (self.junit, xml))
 
+    def test_max_test_log_size(self):
+        log = tempfile.NamedTemporaryFile(dir=self.tmpdir, delete=False)
+        log_content = b"1234567890" * 100
+        log.write(log_content)
+        log_path = log.name
+        log.close()
+        self.test1._Test__status = "ERROR"
+        self.test1._Test__logfile = log_path
+        self.test_result.start_test(self.test1)
+        self.test_result.end_test(self.test1.get_state())
+        self.test_result.end_tests()
+        xunit_result = xunit.XUnitResult()
+        xunit_result.render(self.test_result, self.job)
+        with open(self.job.args.xunit_output, 'rb') as fp:
+            unlimited = fp.read()
+        self.job.args.xunit_max_test_log_chars = 10
+        xunit_result.render(self.test_result, self.job)
+        with open(self.job.args.xunit_output, 'rb') as fp:
+            limited = fp.read()
+        self.assertLess(len(limited), len(unlimited) - 500,
+                        "Length of xunit limitted to 10 chars was greater "
+                        "than (unlimited - 500). Unlimited output:\n%s\n\n"
+                        "Limited output:\n%s" % (unlimited, limited))
+
 
 if __name__ == '__main__':
     unittest.main()