Add "require_prior_scripts" option to allow for running only when pri…

…or scripts succeed

Fixes issue #6

README.md

@@ -6,6 +6,7 @@ NZBGet script to update Kodi's video library
 * [host] => The IP address or resolvable hostname that Kodi is listening on.
 * [port] => The port that Kodi is listening on for HTTP requests.
 * [force_update] => Whether or not we should always try to his the API.
+* [require_prior_scripts] => Whether or not prior scripts must succeed before updating Kodi.
 
 ## Limitations
 

update_kodi.sh

@@ -39,6 +39,15 @@
 # always try to hit the API, set this to 'yes'.
 #force_update=no
 
+# Require previous scripts to succeed before updating Kodi (yes, no).
+#
+# Setting this to 'yes' will check the exit status of all prior extension
+# scripts. If any of them failed, Kodi will not be updated. This is useful when
+# used in combination with VideoSort. For example, if VideoSort fails, there's
+# no need to update Kodi. When this is set to 'yes', make sure to order this
+# extension after VideoSort.
+#require_prior_scripts=no
+#
 ### NZBGET POST-PROCESSING SCRIPT                                          ###
 ##############################################################################
 
@@ -71,6 +80,13 @@ if [[ $NZBPP_TOTALSTATUS != SUCCESS ]]; then
   exit $SKIP
 fi
 
+if [[ $NZBPO_REQUIRE_PRIOR_SCRIPTS == yes ]]; then
+  if [[ $NZBPP_SCRIPTSTATUS != SUCCESS ]]; then
+    echo "[WARNING] Prior extension scripts did not succeed; skipping update."
+    exit $SKIP
+  fi
+fi
+
 if [[ $NZBPO_FORCE_UPDATE == no ]]; then
   if kodi_is_local && ! kodi_is_running_locally; then
     echo "[DETAIL] Kodi is not running so we can't update it; skipping update."