Propose new config value to run harvest sources by external apps

README.rst

@@ -233,6 +233,11 @@ field. The currently supported configuration options are:
     lower-case ones, and spaces replaced with dashes. Setting this option to False
     gives the same effect as leaving it unset.
 
+*   harvester_app: inactive | CKAN | NG Harvester | Other external app. 
+    Defaults (not set) is _CKAN_. If use _"NG Harvester"_ or other external app this 
+    source will be set _inactive_ locally. Use _"inactive"_ to stop harvesting 
+    temporary from this source.
+
 Here is an example of a configuration object (the one that must be entered in
 the configuration field)::
 

ckanext/harvest/plugin.py

@@ -1,3 +1,4 @@
+import json
 import types
 from logging import getLogger
 
@@ -36,14 +37,33 @@ class Harvest(p.SingletonPlugin, DefaultDatasetForm):
 
     ## IPackageController
 
+    def _get_harvest_source_state(data_dict):
+        # if use_external_harvester_app is True we set as inactive locally
+        # and it will be executed by some external application (e.g. NG harvester)
+        cfg_str = data_dict.get('config', '{}')
+        try:
+            cfg = json.loads(cfg_str)
+        except Exception as e:
+            log.error('Failed to read harvest source configuration: {} {}'.format(cfg_str, str(e)))
+            return 'active'
+
+        # this harvest source config value will be also readed 
+        # by and externall application and run it without conflict.
+        # By setting as inactive we stop all jobs and avoid to run locally in the future.
+        ret = 'inactive' if cfg.get('harvester_app', 'CKAN') != 'CKAN' else 'active'
+
+        return ret
+
     def after_create(self, context, data_dict):
         if 'type' in data_dict and data_dict['type'] == DATASET_TYPE_NAME and not self.startup:
             # Create an actual HarvestSource object
+            data_dict['state'] = _get_harvest_source_state(data_dict)
             _create_harvest_source_object(context, data_dict)
 
     def after_update(self, context, data_dict):
         if 'type' in data_dict and data_dict['type'] == DATASET_TYPE_NAME:
             # Edit the actual HarvestSource object
+            data_dict['state'] = _get_harvest_source_state(data_dict)
             _update_harvest_source_object(context, data_dict)
 
     def after_delete(self, context, data_dict):