Warn less about Storage.app_dir (OSG_APP); mark it as optional in README.md (apparently it already was)

  (SOFTWARE-3011)

Author: matyasselmeci

README.md

@@ -171,7 +171,7 @@ This section is contained in `/etc/osg/config.d/10-storage.ini` which is provide
 | Option           | Values Accepted | Explanation                                                                                                                                                                                                    |
 |------------------|-----------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | **grid_dir**     | String          | This setting should point to the directory which holds the files from the OSG worker node package. See note                                                                                                    |
-| **app_dir**      | String          | This setting should point to the directory which contains the VO specific applications. See note                                                                                                               |
+| app_dir          | String          | This setting should point to the directory which contains the VO specific applications. See note                                                                                                               |
 | data_dir         | String          | This setting should point to a directory that can be used to store and stage data in and out of the cluster. See note                                                                                          |
 | worker_node_temp | String          | This directory should point to a directory that can be used as scratch space on compute nodes. If not set, the default is UNAVAILABLE. See note                                                                |
 | site_read        | String          | This setting should be the location or url to a directory that can be read to stage in data via the variable `$OSG_SITE_READ`. This is an url if you are using a SE. If not set, the default is UNAVAILABLE    |

config/10-storage.ini

@@ -21,13 +21,14 @@ grid_dir = /etc/osg/wn-client/
 ; specific applications.  It corresponds to the OSG_APP environment variable
 ; in jobs.
 ;
-; If no such directory is available, set app_dir to UNSET.
-; UNSET will keep the OSG_APP environment variable from being defined.
+; If no such directory is available, set app_dir to UNSET or UNAVAILABLE.
 ; app_dir may be in OASIS.
 ; To use an app_dir in OASIS, set it to "/cvmfs/oasis.opensciencegrid.org".
 ; If not in OASIS, then app_dir should have an etc/ subdirectory, and both
 ; app_dir and app_dir/etc must be world readable and executable (i.e. at
 ; least 755 or 1755 permissions).
+;
+; This setting is optional.
 app_dir = UNAVAILABLE
 
 ; The data_dir setting should point to a directory that can be used to store 

osg_configure/configure_modules/storage.py

@@ -123,12 +123,13 @@ def configure(self, attributes):
             self.log("StorageConfiguration.configure completed")
             return True
 
-        if self.options['app_dir'].value in ('UNSET', 'UNAVAILABLE'):
+        app_dir = self.options['app_dir'].value
+        if utilities.blank(app_dir) or app_dir == "UNSET":
             self.log('OSG_APP unset or unavailable, exiting')
             self.log('StorageConfiguration.configure completed')
             return True
 
-        if self._app_dir_in_oasis(self.options['app_dir'].value):
+        if self._app_dir_in_oasis(app_dir):
             self.log('OSG_APP is in OASIS, exiting')
             self.log('StorageConfiguration.configure completed')
             return True
@@ -190,20 +191,13 @@ def _check_app_dir(self, app_dir):
         try:
             if self._app_dir_in_oasis(app_dir):
                 self.log('OSG_APP is an OASIS repository, skipping tests',
-                         level=logging.INFO)
+                         level=logging.DEBUG)
                 return True
 
             # Added for SOFTWARE-1567
-            if app_dir == 'UNSET':
-                self.log('OSG_APP is UNSET, skipping tests',
-                         level=logging.INFO)
-                return True
-
-            if app_dir == 'UNAVAILABLE':
-                self.log('OSG_APP ("app_dir" in the [Storage]) section is not configured.'
-                         ' If it is not available, explicitly set it to UNSET.'
-                         ' Otherwise, point it to the directory VO software can be obtained from.'
-                         , level=logging.WARNING)
+            if utilities.blank(app_dir) or app_dir == 'UNSET':
+                self.log('OSG_APP is UNSET or unavailable, skipping tests',
+                         level=logging.DEBUG)
                 return True
 
             if not validation.valid_location(app_dir) or not os.path.isdir(app_dir):