Document JOBDIR option issue #5173

Add JOBDIR setting to the settings page.
Add default JOBDIR setting to global defaults in scrapy.settings.default_settings module.

docs/topics/settings.rst

@@ -989,6 +989,17 @@ Default: ``{}``
 A dict containing the pipelines enabled by default in Scrapy. You should never
 modify this setting in your project, modify :setting:`ITEM_PIPELINES` instead.
 
+.. setting:: JOBDIR
+
+JOBDIR
+------
+
+Default: ``''``
+
+A string indicating the directory for storing the required data to keep the state of a single job to enable persistence support. This directory must not be shared by different spiders or jobs/runs of the same spider.
+
+For more info on this setting, see :ref:`topics-jobs`
+
 .. setting:: LOG_ENABLED
 
 LOG_ENABLED

scrapy/settings/default_settings.py

@@ -199,6 +199,8 @@ ITEM_PROCESSOR = 'scrapy.pipelines.ItemPipelineManager'
 ITEM_PIPELINES = {}
 ITEM_PIPELINES_BASE = {}
 
+JOBDIR = ''
+
 LOG_ENABLED = True
 LOG_ENCODING = 'utf-8'
 LOG_FORMATTER = 'scrapy.logformatter.LogFormatter'