Protect against very large stdout fields

* Defer loading result_stdout_text until specifically needed
* Conditionally display it based on the size of the field
* Provide a helpful message otherwise

awx/main/models/unified_jobs.py

@@ -12,7 +12,7 @@ from StringIO import StringIO
 
 # Django
 from django.conf import settings
-from django.db import models
+from django.db import models, connection
 from django.core.exceptions import NON_FIELD_ERRORS
 from django.utils.datastructures import SortedDict
 from django.utils.translation import ugettext_lazy as _
@@ -657,6 +657,13 @@ class UnifiedJob(PolymorphicModel, PasswordFieldsModel, CommonModelNameNotUnique
     def result_stdout(self):
         return self._result_stdout_raw(escape_ascii=True)
 
+    @property
+    def result_stdout_size(self):
+        cursor = connection.cursor()
+        cursor.execute("select length(result_stdout_text) from main_unifiedjob where id = %d" % self.pk)
+        record_size = cursor.fetchone()[0]
+        return record_size
+
     def _result_stdout_raw_limited(self, start_line=0, end_line=None, redact_sensitive=True, escape_ascii=False):
         return_buffer = u""
         if end_line is not None: