Added connection exception rescue to import task

lib/tasks/import/learning_objects.rake

@@ -46,33 +46,46 @@ namespace :import do
 
       n_items = 0
       loop do
-        items = []
-        uri.query = URI.encode_www_form(user_params)
-        response = JSON.parse(Net::HTTP.get(uri))
-        if n_items == 0
-          n_items = response["response"]["numFound"]
-          p "#{n_items} items found"
-        end
+        begin
+          items = []
+          uri.query = URI.encode_www_form(user_params)
+          response = JSON.parse(Net::HTTP.get(uri))
+          if n_items == 0
+            n_items = response["response"]["numFound"]
+            p "#{n_items} items found"
+          end
 
-        break if params[:start] > n_items
-        p "--> importing items from #{params[:start]} to #{params[:start] + params[:rows]}"
-
-        response["response"]["docs"].each do |doc|
-          next if item_exists?(doc["search.resourceid"])
-          item = dspace_client.items.find(
-            id: doc["search.resourceid"],
-            expand: "metadata,bitstreams,parentCollection"
-          )
-          if items.is_a? String
-            p "Received a string instead of item: #{item}"
-            next
+          break if params[:start] > n_items
+          p "--> importing items from #{params[:start]} to #{params[:start] + params[:rows]}"
+
+          response["response"]["docs"].each do |doc|
+            next if item_exists?(doc["search.resourceid"])
+            item = dspace_client.items.find(
+              id: doc["search.resourceid"],
+              expand: "metadata,bitstreams,parentCollection"
+            )
+            if items.is_a? String
+              p "Received a string instead of item: #{item}"
+              next
+            end
+            items << item
           end
-          items << item
+          p "#{items.count} items retrieved"
+          importer = Dspace::LearningObjectImporter.new(items, user, dspace_client)
+          importer.import
+        rescue PG::ConnectionBad, Faraday::TimeoutError, Net::HTTP::Persistent::Error, Net::ReadTimeout => e
+          p "Database error, going to sleep"
+          p e
+          p e.class
+          p e.message
+          ActiveRecord::Base.clear_active_connections!
+          # Sleeps for a while to wait database's recovery
+          sleep(60.seconds)
+          # Goes to next iteration to retry
+          next
+        else
+          params[:start] += params[:rows]
         end
-        params[:start] += params[:rows]
-        p "#{items.count} items retrieved"
-        importer = Dspace::LearningObjectImporter.new(items, user, dspace_client)
-        importer.import
       end
     end
   end