Efficient stdout downloader implementation

* Temporarily dump stdout contents to a configurable temp location
* Implement file streaming to the host via a new format specifier in the
  api view

awx/api/views.py

@@ -25,6 +25,8 @@ from django.utils.safestring import mark_safe
 from django.utils.timezone import now
 from django.views.decorators.csrf import csrf_exempt
 from django.template.loader import render_to_string
+from django.core.servers.basehttp import FileWrapper
+from django.http import HttpResponse
 
 # Django REST Framework
 from rest_framework.exceptions import PermissionDenied, ParseError
@@ -2844,9 +2846,10 @@ class UnifiedJobStdout(RetrieveAPIView):
         elif request.accepted_renderer.format == 'ansi':
             return Response(unified_job.result_stdout_raw)
         elif request.accepted_renderer.format == 'txt_download':
-            content = unified_job.result_stdout
-            headers = {"Content-Disposition": 'attachment; filename="job_%s.txt"' % str(unified_job.id)}
-            return Response(content, headers=headers)
+            content_fd = open(unified_job.dump_result_stdout(), 'r')
+            response = HttpResponse(FileWrapper(content_fd), content_type='text/plain')
+            response["Content-Disposition"] = 'attachment; filename="job_%s.txt"' % str(unified_job.id)
+            return response
         else:
             return super(UnifiedJobStdout, self).retrieve(request, *args, **kwargs)
 

awx/main/models/unified_jobs.py

@@ -5,6 +5,7 @@
 import codecs
 import json
 import logging
+import uuid
 import re
 import os
 import os.path
@@ -664,6 +665,15 @@ class UnifiedJob(PolymorphicModel, PasswordFieldsModel, CommonModelNameNotUnique
         record_size = cursor.fetchone()[0]
         return record_size
 
+    def dump_result_stdout(self):
+        tower_file = "towerjob-%s" % str(uuid.uuid1())[:8]
+        out_path = os.path.join(settings.STDOUT_TEMP_DIR, tower_file)
+        tower_fd = open(out_path, 'w')
+        cursor = connection.cursor()
+        cursor.copy_expert("copy (select result_stdout_text from main_unifiedjob where id = %d) to stdout" % (self.pk), tower_fd)
+        tower_fd.close()
+        return out_path
+
     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:

awx/settings/defaults.py

@@ -563,6 +563,7 @@ FACT_CACHE_PORT = 6564
 ORG_ADMINS_CAN_SEE_ALL_USERS = True
 
 STDOUT_MAX_BYTES_DISPLAY = 1000000
+STDOUT_TEMP_DIR = "/tmp"
 
 # Logging configuration.
 LOGGING = {