nifi-nar-bundles/nifi-elasticsearch-bundle/nifi-elasticsearch-processors/src/main/java/org/apache/nifi/processors/elasticsearch/ScrollElasticsearchHttp.java - nifi - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements.  See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to You under the Apache License, Version 2.0
  * (the "License"); you may not use this file except in compliance with
  * the License.  You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 package org.apache.nifi.processors.elasticsearch;

 import com.fasterxml.jackson.databind.JsonNode;
 import okhttp3.HttpUrl;
 import okhttp3.MediaType;
 import okhttp3.OkHttpClient;
 import okhttp3.RequestBody;
 import okhttp3.Response;
 import okhttp3.ResponseBody;
 import org.apache.commons.lang3.StringUtils;
 import org.apache.nifi.annotation.behavior.DynamicProperty;
 import org.apache.nifi.annotation.behavior.EventDriven;
 import org.apache.nifi.annotation.behavior.InputRequirement;
 import org.apache.nifi.annotation.behavior.Stateful;
 import org.apache.nifi.annotation.behavior.SupportsBatching;
 import org.apache.nifi.annotation.behavior.WritesAttribute;
 import org.apache.nifi.annotation.behavior.WritesAttributes;
 import org.apache.nifi.annotation.documentation.CapabilityDescription;
 import org.apache.nifi.annotation.documentation.DeprecationNotice;
 import org.apache.nifi.annotation.documentation.Tags;
 import org.apache.nifi.annotation.lifecycle.OnScheduled;
 import org.apache.nifi.components.PropertyDescriptor;
 import org.apache.nifi.components.state.Scope;
 import org.apache.nifi.components.state.StateManager;
 import org.apache.nifi.components.state.StateMap;
 import org.apache.nifi.expression.ExpressionLanguageScope;
 import org.apache.nifi.flowfile.FlowFile;
 import org.apache.nifi.logging.ComponentLog;
 import org.apache.nifi.processor.ProcessContext;
 import org.apache.nifi.processor.ProcessSession;
 import org.apache.nifi.processor.Relationship;
 import org.apache.nifi.processor.exception.ProcessException;
 import org.apache.nifi.processor.util.StandardValidators;

 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.nio.charset.Charset;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;

 @Deprecated
 @DeprecationNotice(classNames = {"org.apache.nifi.processors.elasticsearch.SearchElasticsearch"},
         reason = "This processor is deprecated and may be removed in future releases.")
 @InputRequirement(InputRequirement.Requirement.INPUT_FORBIDDEN)
 @EventDriven
 @SupportsBatching
 @Tags({ "elasticsearch", "query", "scroll", "read", "get", "http" })
 @CapabilityDescription("Scrolls through an Elasticsearch query using the specified connection properties. "
         + "This processor is intended to be run on the primary node, and is designed for scrolling through "
         + "huge result sets, as in the case of a reindex.  The state must be cleared before another query "
         + "can be run.  Each page of results is returned, wrapped in a JSON object like so: { \"hits\" : [ <doc1>, <doc2>, <docn> ] }.  "
         + "Note that the full body of each page of documents will be read into memory before being "
         + "written to a Flow File for transfer.")
 @WritesAttributes({
         @WritesAttribute(attribute = "es.index", description = "The Elasticsearch index containing the document"),
         @WritesAttribute(attribute = "es.type", description = "The Elasticsearch document type") })
 @DynamicProperty(
         name = "A URL query parameter",
         value = "The value to set it to",
         expressionLanguageScope = ExpressionLanguageScope.VARIABLE_REGISTRY,
         description = "Adds the specified property name/value as a query parameter in the Elasticsearch URL used for processing")
 @Stateful(description = "After each successful scroll page, the latest scroll_id is persisted in scrollId as input for the next scroll call.  "
         + "Once the entire query is complete, finishedQuery state will be set to true, and the processor will not execute unless this is cleared.", scopes = { Scope.LOCAL })
 public class ScrollElasticsearchHttp extends AbstractElasticsearchHttpProcessor {

     private static final String FINISHED_QUERY_STATE = "finishedQuery";
     private static final String SCROLL_ID_STATE = "scrollId";
     private static final String SCROLL_QUERY_PARAM = "scroll";

     public static final Relationship REL_SUCCESS = new Relationship.Builder()
             .name("success")
             .description(
                     "All FlowFiles that are read from Elasticsearch are routed to this relationship.")
             .build();

     public static final Relationship REL_FAILURE = new Relationship.Builder()
             .name("failure")
             .description(
                     "All FlowFiles that cannot be read from Elasticsearch are routed to this relationship. Note that only incoming "
                             + "flow files will be routed to failure.").build();

     public static final PropertyDescriptor QUERY = new PropertyDescriptor.Builder()
             .name("scroll-es-query")
             .displayName("Query")
             .description("The Lucene-style query to run against ElasticSearch (e.g., genre:blues AND -artist:muddy)")
             .required(true)
             .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
             .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
             .build();

     public static final PropertyDescriptor SCROLL_DURATION = new PropertyDescriptor.Builder()
             .name("scroll-es-scroll")
             .displayName("Scroll Duration")
             .description("The scroll duration is how long each search context is kept in memory.")
             .defaultValue("1m")
             .required(true)
             .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
             .addValidator(
                     StandardValidators.createRegexMatchingValidator(Pattern.compile("[0-9]+(m|h)")))
             .build();

     public static final PropertyDescriptor INDEX = new PropertyDescriptor.Builder()
             .name("scroll-es-index")
             .displayName("Index")
             .description("The name of the index to read from. If the property is set "
                             + "to _all, the query will match across all indexes.")
             .required(true)
             .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
             .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
             .build();

     public static final PropertyDescriptor TYPE = new PropertyDescriptor.Builder()
             .name("scroll-es-type")
             .displayName("Type")
             .description("The type of document (if unset, the query will be against all types in the _index). "
                     + "This should be unset or '_doc' for Elasticsearch 7.0+.")
             .required(false)
             .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
             .addValidator(StandardValidators.NON_EMPTY_EL_VALIDATOR)
             .build();

     public static final PropertyDescriptor FIELDS = new PropertyDescriptor.Builder()
             .name("scroll-es-fields")
             .displayName("Fields")
             .description(
                     "A comma-separated list of fields to retrieve from the document. If the Fields property is left blank, "
                             + "then the entire document's source will be retrieved.")
             .required(false)
             .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
             .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
             .build();

     public static final PropertyDescriptor SORT = new PropertyDescriptor.Builder()
             .name("scroll-es-sort")
             .displayName("Sort")
             .description(
                     "A sort parameter (e.g., timestamp:asc). If the Sort property is left blank, "
                             + "then the results will be retrieved in document order.")
             .required(false)
             .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
             .addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
             .build();

     public static final PropertyDescriptor PAGE_SIZE = new PropertyDescriptor.Builder()
             .name("scroll-es-size")
             .displayName("Page Size")
             .defaultValue("20")
             .description("Determines how many documents to return per page during scrolling.")
             .required(true)
             .expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
             .addValidator(StandardValidators.POSITIVE_INTEGER_VALIDATOR)
             .build();

     private static final Set<Relationship> relationships;
     private static final List<PropertyDescriptor> propertyDescriptors;

     static {
         final Set<Relationship> _rels = new HashSet<>();
         _rels.add(REL_SUCCESS);
         _rels.add(REL_FAILURE);
         relationships = Collections.unmodifiableSet(_rels);

         final List<PropertyDescriptor> descriptors = new ArrayList<>(COMMON_PROPERTY_DESCRIPTORS);
         descriptors.add(QUERY);
         descriptors.add(SCROLL_DURATION);
         descriptors.add(PAGE_SIZE);
         descriptors.add(INDEX);
         descriptors.add(TYPE);
         descriptors.add(FIELDS);
         descriptors.add(SORT);

         propertyDescriptors = Collections.unmodifiableList(descriptors);
     }

     @Override
     public Set<Relationship> getRelationships() {
         return relationships;
     }

     @Override
     public final List<PropertyDescriptor> getSupportedPropertyDescriptors() {
         return propertyDescriptors;
     }

     @OnScheduled
     public void setup(ProcessContext context) {
         super.setup(context);
     }

     @Override
     public void onTrigger(final ProcessContext context, final ProcessSession session)
             throws ProcessException {

         try {
             if (isQueryFinished(session)) {
                 getLogger().trace(
                         "Query has been marked finished in the state manager.  "
                                 + "To run another query, clear the state.");
                 return;
             }
         } catch (IOException e) {
             throw new ProcessException("Could not retrieve state", e);
         }

         OkHttpClient okHttpClient = getClient();

         FlowFile flowFile = session.create();

         final String index = context.getProperty(INDEX).evaluateAttributeExpressions(flowFile)
                 .getValue();
         final String query = context.getProperty(QUERY).evaluateAttributeExpressions(flowFile)
                 .getValue();
         final String docType = context.getProperty(TYPE).evaluateAttributeExpressions(flowFile)
                 .getValue();
         final int pageSize = context.getProperty(PAGE_SIZE).evaluateAttributeExpressions(flowFile)
                 .asInteger();
         final String fields = context.getProperty(FIELDS).isSet() ? context.getProperty(FIELDS)
                 .evaluateAttributeExpressions(flowFile).getValue() : null;
         final String sort = context.getProperty(SORT).isSet() ? context.getProperty(SORT)
                 .evaluateAttributeExpressions(flowFile).getValue() : null;
         final String scroll = context.getProperty(SCROLL_DURATION).isSet() ? context
                 .getProperty(SCROLL_DURATION).evaluateAttributeExpressions(flowFile).getValue() : null;

         // Authentication
         final String username = context.getProperty(USERNAME).evaluateAttributeExpressions().getValue();
         final String password = context.getProperty(PASSWORD).evaluateAttributeExpressions().getValue();
         final Charset charset = Charset.forName(context.getProperty(CHARSET).evaluateAttributeExpressions(flowFile).getValue());

         final ComponentLog logger = getLogger();

         try {
             String scrollId = loadScrollId(session);

             // read the url property from the context
             final String urlstr = StringUtils.trimToEmpty(context.getProperty(ES_URL).evaluateAttributeExpressions()
                     .getValue());
             if (scrollId != null) {
                 final URL scrollurl = buildRequestURL(urlstr, query, index, docType, fields, sort,
                         scrollId, pageSize, scroll, context);
                 final long startNanos = System.nanoTime();

                 final String scrollBody = String.format("{ \"scroll\": \"%s\", \"scroll_id\": \"%s\" }", scroll,
                         scrollId);

                 final RequestBody body = RequestBody.create(MediaType.parse("application/json"), scrollBody);

                 final Response getResponse = sendRequestToElasticsearch(okHttpClient, scrollurl,
                         username, password, "POST", body);
                 this.getPage(getResponse, scrollurl, context, session, flowFile, logger, startNanos, charset);
                 getResponse.close();
             } else {
                 logger.debug("Querying {}/{} from Elasticsearch: {}", new Object[] { index,
                         docType, query });

                 // read the url property from the context
                 final URL queryUrl = buildRequestURL(urlstr, query, index, docType, fields, sort,
                         scrollId, pageSize, scroll, context);
                 final long startNanos = System.nanoTime();

                 final Response getResponse = sendRequestToElasticsearch(okHttpClient, queryUrl,
                         username, password, "GET", null);
                 this.getPage(getResponse, queryUrl, context, session, flowFile, logger, startNanos, charset);
                 getResponse.close();
             }

         } catch (IOException ioe) {
             logger.error(
                     "Failed to read from Elasticsearch due to {}, this may indicate an error in configuration "
                             + "(hosts, username/password, etc.).",
                     new Object[] { ioe.getLocalizedMessage() }, ioe);
             session.remove(flowFile);
             context.yield();

         } catch (Exception e) {
             logger.error("Failed to read {} from Elasticsearch due to {}", new Object[] { flowFile,
                     e.getLocalizedMessage() }, e);
             session.transfer(flowFile, REL_FAILURE);
             context.yield();
         }
     }

     private void getPage(final Response getResponse, final URL url, final ProcessContext context,
             final ProcessSession session, FlowFile flowFile, final ComponentLog logger, final long startNanos, Charset charset)
             throws IOException {
         final int statusCode = getResponse.code();

         if (isSuccess(statusCode)) {
             ResponseBody body = getResponse.body();
             final byte[] bodyBytes = body.bytes();
             JsonNode responseJson = parseJsonResponse(new ByteArrayInputStream(bodyBytes));
             String scrollId = responseJson.get("_scroll_id").asText();

             StringBuilder builder = new StringBuilder();

             builder.append("{ \"hits\" : [");

             JsonNode hits = responseJson.get("hits").get("hits");
             if (hits.size() == 0) {
                 finishQuery(context.getStateManager());
                 session.remove(flowFile);
                 return;
             }

             for(int i = 0; i < hits.size(); i++) {
                 JsonNode hit = hits.get(i);
                 String retrievedIndex = hit.get("_index").asText();
                 String retrievedType = hit.get("_type").asText();

                 JsonNode source = hit.get("_source");
                 flowFile = session.putAttribute(flowFile, "es.index", retrievedIndex);
                 flowFile = session.putAttribute(flowFile, "es.type", retrievedType);
                 flowFile = session.putAttribute(flowFile, "mime.type", "application/json");

                 builder.append(source.toString());
                 if (i < hits.size() - 1) {
                     builder.append(", ");
                 }
             }
             builder.append("] }");
             logger.debug("Elasticsearch retrieved " + responseJson.size() + " documents, routing to success");

             flowFile = session.write(flowFile, out -> {
                 out.write(builder.toString().getBytes(charset));
             });
             session.transfer(flowFile, REL_SUCCESS);

             session.setState(Collections.singletonMap(SCROLL_ID_STATE, scrollId), Scope.LOCAL);

             // emit provenance event
             final long millis = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startNanos);
             session.getProvenanceReporter().receive(flowFile, url.toExternalForm(), millis);
         } else {
             // 5xx -> RETRY, but a server error might last a while, so yield
             if (statusCode / 100 == 5) {

                 logger.warn("Elasticsearch returned code {} with message {}, removing the flow file. This is likely a server problem, yielding...",
                         new Object[]{statusCode, getResponse.message()});
                 session.remove(flowFile);
                 context.yield();
             }  else {
                 logger.warn("Elasticsearch returned code {} with message {}", new Object[]{statusCode, getResponse.message()});
                 session.remove(flowFile);
             }
         }
     }

     private boolean isQueryFinished(final ProcessSession session) throws IOException {
         final StateMap stateMap = session.getState(Scope.LOCAL);

         if (stateMap.getVersion() < 0) {
             getLogger().debug("No previous state found");
             return false;
         }

         final String isQueryFinished = stateMap.get(FINISHED_QUERY_STATE);
         getLogger().debug("Loaded state with finishedQuery = {}", new Object[] { isQueryFinished });

         return "true".equals(isQueryFinished);
     }

     private String loadScrollId(final ProcessSession session) throws IOException {
         final StateMap stateMap = session.getState(Scope.LOCAL);

         if (stateMap.getVersion() < 0) {
             getLogger().debug("No previous state found");
             return null;
         }

         final String scrollId = stateMap.get(SCROLL_ID_STATE);
         getLogger().debug("Loaded state with scrollId {}", new Object[] { scrollId });

         return scrollId;
     }

     private void finishQuery(StateManager stateManager) throws IOException {

         Map<String, String> state = new HashMap<>(2);
         state.put(FINISHED_QUERY_STATE, "true");

         getLogger().debug("Saving state with finishedQuery = true");
         stateManager.setState(state, Scope.LOCAL);
     }

     private URL buildRequestURL(String baseUrl, String query, String index, String type, String fields,
             String sort, String scrollId, int pageSize, String scroll, ProcessContext context) throws MalformedURLException {
         if (StringUtils.isEmpty(baseUrl)) {
             throw new MalformedURLException("Base URL cannot be null");
         }
         HttpUrl.Builder builder = HttpUrl.parse(baseUrl).newBuilder();
         if (!StringUtils.isEmpty(scrollId)) {
             builder.addPathSegment("_search");
             builder.addPathSegment("scroll");
         } else {
             builder.addPathSegment((StringUtils.isEmpty(index)) ? "_all" : index);
             if (StringUtils.isNotBlank(type)) {
                 builder.addPathSegment(type);
             }
             builder.addPathSegment("_search");
             builder.addQueryParameter(QUERY_QUERY_PARAM, query);
             builder.addQueryParameter(SIZE_QUERY_PARAM, String.valueOf(pageSize));
             if (!StringUtils.isEmpty(fields)) {
                 String trimmedFields = Stream.of(fields.split(",")).map(String::trim).collect(Collectors.joining(","));
                 builder.addQueryParameter(SOURCE_QUERY_PARAM, trimmedFields);
             }
             if (!StringUtils.isEmpty(sort)) {
                 String trimmedFields = Stream.of(sort.split(",")).map(String::trim).collect(Collectors.joining(","));
                 builder.addQueryParameter(SORT_QUERY_PARAM, trimmedFields);
             }
             builder.addQueryParameter(SCROLL_QUERY_PARAM, scroll);
         }

         // Find the user-added properties and set them as query parameters on the URL
         for (Map.Entry<PropertyDescriptor, String> property : context.getProperties().entrySet()) {
             PropertyDescriptor pd = property.getKey();
             if (pd.isDynamic()) {
                 if (property.getValue() != null) {
                     builder.addQueryParameter(pd.getName(), context.getProperty(pd).evaluateAttributeExpressions().getValue());
                 }
             }
         }


         return builder.build().url();
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to You under the Apache License, Version 2.0
	* (the "License"); you may not use this file except in compliance with
	* the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/
	package org.apache.nifi.processors.elasticsearch;

	import com.fasterxml.jackson.databind.JsonNode;
	import okhttp3.HttpUrl;
	import okhttp3.MediaType;
	import okhttp3.OkHttpClient;
	import okhttp3.RequestBody;
	import okhttp3.Response;
	import okhttp3.ResponseBody;
	import org.apache.commons.lang3.StringUtils;
	import org.apache.nifi.annotation.behavior.DynamicProperty;
	import org.apache.nifi.annotation.behavior.EventDriven;
	import org.apache.nifi.annotation.behavior.InputRequirement;
	import org.apache.nifi.annotation.behavior.Stateful;
	import org.apache.nifi.annotation.behavior.SupportsBatching;
	import org.apache.nifi.annotation.behavior.WritesAttribute;
	import org.apache.nifi.annotation.behavior.WritesAttributes;
	import org.apache.nifi.annotation.documentation.CapabilityDescription;
	import org.apache.nifi.annotation.documentation.DeprecationNotice;
	import org.apache.nifi.annotation.documentation.Tags;
	import org.apache.nifi.annotation.lifecycle.OnScheduled;
	import org.apache.nifi.components.PropertyDescriptor;
	import org.apache.nifi.components.state.Scope;
	import org.apache.nifi.components.state.StateManager;
	import org.apache.nifi.components.state.StateMap;
	import org.apache.nifi.expression.ExpressionLanguageScope;
	import org.apache.nifi.flowfile.FlowFile;
	import org.apache.nifi.logging.ComponentLog;
	import org.apache.nifi.processor.ProcessContext;
	import org.apache.nifi.processor.ProcessSession;
	import org.apache.nifi.processor.Relationship;
	import org.apache.nifi.processor.exception.ProcessException;
	import org.apache.nifi.processor.util.StandardValidators;

	import java.io.ByteArrayInputStream;
	import java.io.IOException;
	import java.net.MalformedURLException;
	import java.net.URL;
	import java.nio.charset.Charset;
	import java.util.ArrayList;
	import java.util.Collections;
	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.List;
	import java.util.Map;
	import java.util.Set;
	import java.util.concurrent.TimeUnit;
	import java.util.regex.Pattern;
	import java.util.stream.Collectors;
	import java.util.stream.Stream;

	@Deprecated
	@DeprecationNotice(classNames = {"org.apache.nifi.processors.elasticsearch.SearchElasticsearch"},
	reason = "This processor is deprecated and may be removed in future releases.")
	@InputRequirement(InputRequirement.Requirement.INPUT_FORBIDDEN)
	@EventDriven
	@SupportsBatching
	@Tags({ "elasticsearch", "query", "scroll", "read", "get", "http" })
	@CapabilityDescription("Scrolls through an Elasticsearch query using the specified connection properties. "
	+ "This processor is intended to be run on the primary node, and is designed for scrolling through "
	+ "huge result sets, as in the case of a reindex. The state must be cleared before another query "
	+ "can be run. Each page of results is returned, wrapped in a JSON object like so: { \"hits\" : [ <doc1>, <doc2>, <docn> ] }. "
	+ "Note that the full body of each page of documents will be read into memory before being "
	+ "written to a Flow File for transfer.")
	@WritesAttributes({
	@WritesAttribute(attribute = "es.index", description = "The Elasticsearch index containing the document"),
	@WritesAttribute(attribute = "es.type", description = "The Elasticsearch document type") })
	@DynamicProperty(
	name = "A URL query parameter",
	value = "The value to set it to",
	expressionLanguageScope = ExpressionLanguageScope.VARIABLE_REGISTRY,
	description = "Adds the specified property name/value as a query parameter in the Elasticsearch URL used for processing")
	@Stateful(description = "After each successful scroll page, the latest scroll_id is persisted in scrollId as input for the next scroll call. "
	+ "Once the entire query is complete, finishedQuery state will be set to true, and the processor will not execute unless this is cleared.", scopes = { Scope.LOCAL })
	public class ScrollElasticsearchHttp extends AbstractElasticsearchHttpProcessor {

	private static final String FINISHED_QUERY_STATE = "finishedQuery";
	private static final String SCROLL_ID_STATE = "scrollId";
	private static final String SCROLL_QUERY_PARAM = "scroll";

	public static final Relationship REL_SUCCESS = new Relationship.Builder()
	.name("success")
	.description(
	"All FlowFiles that are read from Elasticsearch are routed to this relationship.")
	.build();

	public static final Relationship REL_FAILURE = new Relationship.Builder()
	.name("failure")
	.description(
	"All FlowFiles that cannot be read from Elasticsearch are routed to this relationship. Note that only incoming "
	+ "flow files will be routed to failure.").build();

	public static final PropertyDescriptor QUERY = new PropertyDescriptor.Builder()
	.name("scroll-es-query")
	.displayName("Query")
	.description("The Lucene-style query to run against ElasticSearch (e.g., genre:blues AND -artist:muddy)")
	.required(true)
	.expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
	.addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
	.build();

	public static final PropertyDescriptor SCROLL_DURATION = new PropertyDescriptor.Builder()
	.name("scroll-es-scroll")
	.displayName("Scroll Duration")
	.description("The scroll duration is how long each search context is kept in memory.")
	.defaultValue("1m")
	.required(true)
	.expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
	.addValidator(
	StandardValidators.createRegexMatchingValidator(Pattern.compile("[0-9]+(m\|h)")))
	.build();

	public static final PropertyDescriptor INDEX = new PropertyDescriptor.Builder()
	.name("scroll-es-index")
	.displayName("Index")
	.description("The name of the index to read from. If the property is set "
	+ "to _all, the query will match across all indexes.")
	.required(true)
	.expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
	.addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
	.build();

	public static final PropertyDescriptor TYPE = new PropertyDescriptor.Builder()
	.name("scroll-es-type")
	.displayName("Type")
	.description("The type of document (if unset, the query will be against all types in the _index). "
	+ "This should be unset or '_doc' for Elasticsearch 7.0+.")
	.required(false)
	.expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
	.addValidator(StandardValidators.NON_EMPTY_EL_VALIDATOR)
	.build();

	public static final PropertyDescriptor FIELDS = new PropertyDescriptor.Builder()
	.name("scroll-es-fields")
	.displayName("Fields")
	.description(
	"A comma-separated list of fields to retrieve from the document. If the Fields property is left blank, "
	+ "then the entire document's source will be retrieved.")
	.required(false)
	.expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
	.addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
	.build();

	public static final PropertyDescriptor SORT = new PropertyDescriptor.Builder()
	.name("scroll-es-sort")
	.displayName("Sort")
	.description(
	"A sort parameter (e.g., timestamp:asc). If the Sort property is left blank, "
	+ "then the results will be retrieved in document order.")
	.required(false)
	.expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
	.addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
	.build();

	public static final PropertyDescriptor PAGE_SIZE = new PropertyDescriptor.Builder()
	.name("scroll-es-size")
	.displayName("Page Size")
	.defaultValue("20")
	.description("Determines how many documents to return per page during scrolling.")
	.required(true)
	.expressionLanguageSupported(ExpressionLanguageScope.FLOWFILE_ATTRIBUTES)
	.addValidator(StandardValidators.POSITIVE_INTEGER_VALIDATOR)
	.build();

	private static final Set<Relationship> relationships;
	private static final List<PropertyDescriptor> propertyDescriptors;

	static {
	final Set<Relationship> _rels = new HashSet<>();
	_rels.add(REL_SUCCESS);
	_rels.add(REL_FAILURE);
	relationships = Collections.unmodifiableSet(_rels);

	final List<PropertyDescriptor> descriptors = new ArrayList<>(COMMON_PROPERTY_DESCRIPTORS);
	descriptors.add(QUERY);
	descriptors.add(SCROLL_DURATION);
	descriptors.add(PAGE_SIZE);
	descriptors.add(INDEX);
	descriptors.add(TYPE);
	descriptors.add(FIELDS);
	descriptors.add(SORT);

	propertyDescriptors = Collections.unmodifiableList(descriptors);
	}

	@Override
	public Set<Relationship> getRelationships() {
	return relationships;
	}

	@Override
	public final List<PropertyDescriptor> getSupportedPropertyDescriptors() {
	return propertyDescriptors;
	}

	@OnScheduled
	public void setup(ProcessContext context) {
	super.setup(context);
	}

	@Override
	public void onTrigger(final ProcessContext context, final ProcessSession session)
	throws ProcessException {

	try {
	if (isQueryFinished(session)) {
	getLogger().trace(
	"Query has been marked finished in the state manager. "
	+ "To run another query, clear the state.");
	return;
	}
	} catch (IOException e) {
	throw new ProcessException("Could not retrieve state", e);
	}

	OkHttpClient okHttpClient = getClient();

	FlowFile flowFile = session.create();

	final String index = context.getProperty(INDEX).evaluateAttributeExpressions(flowFile)
	.getValue();
	final String query = context.getProperty(QUERY).evaluateAttributeExpressions(flowFile)
	.getValue();
	final String docType = context.getProperty(TYPE).evaluateAttributeExpressions(flowFile)
	.getValue();
	final int pageSize = context.getProperty(PAGE_SIZE).evaluateAttributeExpressions(flowFile)
	.asInteger();
	final String fields = context.getProperty(FIELDS).isSet() ? context.getProperty(FIELDS)
	.evaluateAttributeExpressions(flowFile).getValue() : null;
	final String sort = context.getProperty(SORT).isSet() ? context.getProperty(SORT)
	.evaluateAttributeExpressions(flowFile).getValue() : null;
	final String scroll = context.getProperty(SCROLL_DURATION).isSet() ? context
	.getProperty(SCROLL_DURATION).evaluateAttributeExpressions(flowFile).getValue() : null;

	// Authentication
	final String username = context.getProperty(USERNAME).evaluateAttributeExpressions().getValue();
	final String password = context.getProperty(PASSWORD).evaluateAttributeExpressions().getValue();
	final Charset charset = Charset.forName(context.getProperty(CHARSET).evaluateAttributeExpressions(flowFile).getValue());

	final ComponentLog logger = getLogger();

	try {
	String scrollId = loadScrollId(session);

	// read the url property from the context
	final String urlstr = StringUtils.trimToEmpty(context.getProperty(ES_URL).evaluateAttributeExpressions()
	.getValue());
	if (scrollId != null) {
	final URL scrollurl = buildRequestURL(urlstr, query, index, docType, fields, sort,
	scrollId, pageSize, scroll, context);
	final long startNanos = System.nanoTime();

	final String scrollBody = String.format("{ \"scroll\": \"%s\", \"scroll_id\": \"%s\" }", scroll,
	scrollId);

	final RequestBody body = RequestBody.create(MediaType.parse("application/json"), scrollBody);

	final Response getResponse = sendRequestToElasticsearch(okHttpClient, scrollurl,
	username, password, "POST", body);
	this.getPage(getResponse, scrollurl, context, session, flowFile, logger, startNanos, charset);
	getResponse.close();
	} else {
	logger.debug("Querying {}/{} from Elasticsearch: {}", new Object[] { index,
	docType, query });

	// read the url property from the context
	final URL queryUrl = buildRequestURL(urlstr, query, index, docType, fields, sort,
	scrollId, pageSize, scroll, context);
	final long startNanos = System.nanoTime();

	final Response getResponse = sendRequestToElasticsearch(okHttpClient, queryUrl,
	username, password, "GET", null);
	this.getPage(getResponse, queryUrl, context, session, flowFile, logger, startNanos, charset);
	getResponse.close();
	}

	} catch (IOException ioe) {
	logger.error(
	"Failed to read from Elasticsearch due to {}, this may indicate an error in configuration "
	+ "(hosts, username/password, etc.).",
	new Object[] { ioe.getLocalizedMessage() }, ioe);
	session.remove(flowFile);
	context.yield();

	} catch (Exception e) {
	logger.error("Failed to read {} from Elasticsearch due to {}", new Object[] { flowFile,
	e.getLocalizedMessage() }, e);
	session.transfer(flowFile, REL_FAILURE);
	context.yield();
	}
	}

	private void getPage(final Response getResponse, final URL url, final ProcessContext context,
	final ProcessSession session, FlowFile flowFile, final ComponentLog logger, final long startNanos, Charset charset)
	throws IOException {
	final int statusCode = getResponse.code();

	if (isSuccess(statusCode)) {
	ResponseBody body = getResponse.body();
	final byte[] bodyBytes = body.bytes();
	JsonNode responseJson = parseJsonResponse(new ByteArrayInputStream(bodyBytes));
	String scrollId = responseJson.get("_scroll_id").asText();

	StringBuilder builder = new StringBuilder();

	builder.append("{ \"hits\" : [");

	JsonNode hits = responseJson.get("hits").get("hits");
	if (hits.size() == 0) {
	finishQuery(context.getStateManager());
	session.remove(flowFile);
	return;
	}

	for(int i = 0; i < hits.size(); i++) {
	JsonNode hit = hits.get(i);
	String retrievedIndex = hit.get("_index").asText();
	String retrievedType = hit.get("_type").asText();

	JsonNode source = hit.get("_source");
	flowFile = session.putAttribute(flowFile, "es.index", retrievedIndex);
	flowFile = session.putAttribute(flowFile, "es.type", retrievedType);
	flowFile = session.putAttribute(flowFile, "mime.type", "application/json");

	builder.append(source.toString());
	if (i < hits.size() - 1) {
	builder.append(", ");
	}
	}
	builder.append("] }");
	logger.debug("Elasticsearch retrieved " + responseJson.size() + " documents, routing to success");

	flowFile = session.write(flowFile, out -> {
	out.write(builder.toString().getBytes(charset));
	});
	session.transfer(flowFile, REL_SUCCESS);

	session.setState(Collections.singletonMap(SCROLL_ID_STATE, scrollId), Scope.LOCAL);

	// emit provenance event
	final long millis = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startNanos);
	session.getProvenanceReporter().receive(flowFile, url.toExternalForm(), millis);
	} else {
	// 5xx -> RETRY, but a server error might last a while, so yield
	if (statusCode / 100 == 5) {

	logger.warn("Elasticsearch returned code {} with message {}, removing the flow file. This is likely a server problem, yielding...",
	new Object[]{statusCode, getResponse.message()});
	session.remove(flowFile);
	context.yield();
	} else {
	logger.warn("Elasticsearch returned code {} with message {}", new Object[]{statusCode, getResponse.message()});
	session.remove(flowFile);
	}
	}
	}

	private boolean isQueryFinished(final ProcessSession session) throws IOException {
	final StateMap stateMap = session.getState(Scope.LOCAL);

	if (stateMap.getVersion() < 0) {
	getLogger().debug("No previous state found");
	return false;
	}

	final String isQueryFinished = stateMap.get(FINISHED_QUERY_STATE);
	getLogger().debug("Loaded state with finishedQuery = {}", new Object[] { isQueryFinished });

	return "true".equals(isQueryFinished);
	}

	private String loadScrollId(final ProcessSession session) throws IOException {
	final StateMap stateMap = session.getState(Scope.LOCAL);

	if (stateMap.getVersion() < 0) {
	getLogger().debug("No previous state found");
	return null;
	}

	final String scrollId = stateMap.get(SCROLL_ID_STATE);
	getLogger().debug("Loaded state with scrollId {}", new Object[] { scrollId });

	return scrollId;
	}

	private void finishQuery(StateManager stateManager) throws IOException {

	Map<String, String> state = new HashMap<>(2);
	state.put(FINISHED_QUERY_STATE, "true");

	getLogger().debug("Saving state with finishedQuery = true");
	stateManager.setState(state, Scope.LOCAL);
	}

	private URL buildRequestURL(String baseUrl, String query, String index, String type, String fields,
	String sort, String scrollId, int pageSize, String scroll, ProcessContext context) throws MalformedURLException {
	if (StringUtils.isEmpty(baseUrl)) {
	throw new MalformedURLException("Base URL cannot be null");
	}
	HttpUrl.Builder builder = HttpUrl.parse(baseUrl).newBuilder();
	if (!StringUtils.isEmpty(scrollId)) {
	builder.addPathSegment("_search");
	builder.addPathSegment("scroll");
	} else {
	builder.addPathSegment((StringUtils.isEmpty(index)) ? "_all" : index);
	if (StringUtils.isNotBlank(type)) {
	builder.addPathSegment(type);
	}
	builder.addPathSegment("_search");
	builder.addQueryParameter(QUERY_QUERY_PARAM, query);
	builder.addQueryParameter(SIZE_QUERY_PARAM, String.valueOf(pageSize));
	if (!StringUtils.isEmpty(fields)) {
	String trimmedFields = Stream.of(fields.split(",")).map(String::trim).collect(Collectors.joining(","));
	builder.addQueryParameter(SOURCE_QUERY_PARAM, trimmedFields);
	}
	if (!StringUtils.isEmpty(sort)) {
	String trimmedFields = Stream.of(sort.split(",")).map(String::trim).collect(Collectors.joining(","));
	builder.addQueryParameter(SORT_QUERY_PARAM, trimmedFields);
	}
	builder.addQueryParameter(SCROLL_QUERY_PARAM, scroll);
	}

	// Find the user-added properties and set them as query parameters on the URL
	for (Map.Entry<PropertyDescriptor, String> property : context.getProperties().entrySet()) {
	PropertyDescriptor pd = property.getKey();
	if (pd.isDynamic()) {
	if (property.getValue() != null) {
	builder.addQueryParameter(pd.getName(), context.getProperty(pd).evaluateAttributeExpressions().getValue());
	}
	}
	}


	return builder.build().url();
	}
	}