This simple InvokeScriptedProcessor will look for a FlowFile attribute called "ip_address" and will attempt the reverse lookup and create a new attribute called "host_name" with the resolved value.   import groovy.json.JsonOutput import groovy.json.JsonSlurper import java.net.InetAddress import java.net.UnknownHostException import java.nio.charset.StandardCharsets import org.apache.commons.io.IOUtils class GroovyProcessor implements Processor { PropertyDescriptor BATCH_SIZE = new PropertyDescriptor.Builder() .name("BATCH_SIZE") .displayName("Batch Size") .description("The number of incoming FlowFiles to process in a single execution of this processor.") .required(true) .defaultValue("1000") .addValidator(StandardValidators.POSITIVE_INTEGER_VALIDATOR) .build() Relationship REL_SUCCESS = new Relationship.Builder() .name("success") .description('FlowFiles that were successfully processed are routed here') .build() Relationship REL_FAILURE = new Relationship.Builder() .name("failure") .description('FlowFiles that were not successfully processed are routed here') .build() ComponentLog log void initialize(ProcessorInitializationContext context) { log = context.logger } Set<Relationship> getRelationships() { return [REL_FAILURE, REL_SUCCESS] as Set } Collection<ValidationResult> validate(ValidationContext context) { null } PropertyDescriptor getPropertyDescriptor(String name) { null } void onPropertyModified(PropertyDescriptor descriptor, String oldValue, String newValue) { } List<PropertyDescriptor> getPropertyDescriptors() { Collections.unmodifiableList([BATCH_SIZE]) as List<PropertyDescriptor> } String getIdentifier() { null } JsonSlurper jsonSlurper = new JsonSlurper() JsonOutput jsonOutput = new JsonOutput() def reverseDnsLookup(String ipAddress) { try { InetAddress inetAddress = InetAddress.getByName(ipAddress) String hostName = inetAddress.getCanonicalHostName() return hostName } catch (UnknownHostException e) { return "Unknown" } } void onTrigger(ProcessContext context, ProcessSessionFactory sessionFactory) throws ProcessException { ProcessSession session = sessionFactory.createSession() try { List<FlowFile> flowFiles = session.get(context.getProperty(BATCH_SIZE).asInteger()) if (!flowFiles) return Map customAttributes = [:] flowFiles.each { flowFile -> String ipAddress = flowFile.getAttribute("ip_address") if (ipAddress) { String hostName = reverseDnsLookup(ipAddress) customAttributes["host_name"] = hostName flowFile = session.putAllAttributes(flowFile, customAttributes) } session.transfer(flowFile, REL_SUCCESS) } session.commit() } catch (final Throwable t) { log.error('{} failed to process due to {}; rolling back session', [this, t] as Object[]) session.rollback(true) throw t } } } processor = new GroovyProcessor() ... View more