Enhance error logs for invalid custom fields (#235)

Add error logs when MaxMind databases fail to deserialize custom field

Author: kaisecheng

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 7.3.2
+  - Add logs when MaxMind databases fail to deserialize custom field [#235](https://github.com/logstash-plugins/logstash-filter-geoip/pull/235)
+
 ## 7.3.1
   - Avoid to crash pipelines when lookup a database with customised fields. [#225](https://github.com/logstash-plugins/logstash-filter-geoip/pull/225)
 

VERSION

@@ -1 +1 @@
-7.3.1
+7.3.2

src/main/java/org/logstash/filters/geoip/GeoIPFilter.java

@@ -53,7 +53,7 @@ public class GeoIPFilter implements Closeable {
   // for more details https://github.com/logstash-plugins/logstash-filter-geoip/issues/226
   static class GeoIp2InvalidCustomFieldException extends GeoIp2Exception {
     public GeoIp2InvalidCustomFieldException(Throwable cause) {
-      super("invalid custom field", cause);
+      super("The database contains invalid custom field, which caused deserialization to fail.", cause);
     }
   }
 
@@ -199,7 +199,7 @@ public boolean handleEvent(RubyEvent rubyEvent) {
     } catch (AddressNotFoundException e) {
       logger.debug("IP not found! exception={}, field={}, event={}", e, sourceField, event);
     } catch (GeoIp2Exception | IOException e) {
-      logger.debug("GeoIP2 Exception. exception={}, field={}, event={}", e, sourceField, event);
+      logger.error("Error from GeoIP database. field={}, value={}", sourceField, ip, e);
     }
 
     return applyGeoData(geoData, event);