Logging: suppress long mapping logging during mapping updates (unless…

… in TRACE)

Currently DEBUG logs can get very verbose because IndicesClusterStateService logs the complete mapping with every mapping update. We should suppress it if long in DEBUG mode and always log the full one in TRACE.

Closes #7949

src/main/java/org/elasticsearch/indices/cluster/IndicesClusterStateService.java

@@ -43,7 +43,6 @@
 import org.elasticsearch.common.component.AbstractLifecycleComponent;
 import org.elasticsearch.common.compress.CompressedString;
 import org.elasticsearch.common.inject.Inject;
-import org.elasticsearch.common.inject.Injector;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.util.concurrent.ConcurrentCollections;
@@ -406,8 +405,12 @@ private boolean processMapping(String index, MapperService mapperService, String
         boolean requiresRefresh = false;
         try {
             if (!mapperService.hasMapping(mappingType)) {
-                if (logger.isDebugEnabled()) {
+                if (logger.isDebugEnabled() && mappingSource.compressed().length < 512) {
                     logger.debug("[{}] adding mapping [{}], source [{}]", index, mappingType, mappingSource.string());
+                } else if (logger.isTraceEnabled()) {
+                    logger.trace("[{}] adding mapping [{}], source [{}]", index, mappingType, mappingSource.string());
+                } else {
+                    logger.debug("[{}] adding mapping [{}] (source suppressed due to length, use TRACE level if needed)", index, mappingType);
                 }
                 // we don't apply default, since it has been applied when the mappings were parsed initially
                 mapperService.merge(mappingType, mappingSource, false);
@@ -419,8 +422,12 @@ private boolean processMapping(String index, MapperService mapperService, String
                 DocumentMapper existingMapper = mapperService.documentMapper(mappingType);
                 if (!mappingSource.equals(existingMapper.mappingSource())) {
                     // mapping changed, update it
-                    if (logger.isDebugEnabled()) {
+                    if (logger.isDebugEnabled() && mappingSource.compressed().length < 512) {
                         logger.debug("[{}] updating mapping [{}], source [{}]", index, mappingType, mappingSource.string());
+                    } else if (logger.isTraceEnabled()) {
+                        logger.trace("[{}] updating mapping [{}], source [{}]", index, mappingType, mappingSource.string());
+                    } else {
+                        logger.debug("[{}] updating mapping [{}] (source suppressed due to length, use TRACE level if needed)", index, mappingType);
                     }
                     // we don't apply default, since it has been applied when the mappings were parsed initially
                     mapperService.merge(mappingType, mappingSource, false);