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https://issues.apache.org/jira/browse/NIFI-2417?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15509911#comment-15509911
 ] 

ASF GitHub Bot commented on NIFI-2417:
--------------------------------------

Github user mattyb149 commented on a diff in the pull request:

    https://github.com/apache/nifi/pull/733#discussion_r79831289
  
    --- Diff: 
nifi-nar-bundles/nifi-elasticsearch-bundle/nifi-elasticsearch-processors/src/main/java/org/apache/nifi/processors/elasticsearch/ScrollElasticsearchHttp.java
 ---
    @@ -0,0 +1,415 @@
    +/*
    + * 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 java.io.IOException;
    +import java.net.MalformedURLException;
    +import java.net.URL;
    +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;
    +
    +import org.apache.commons.lang3.StringUtils;
    +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.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.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 org.apache.nifi.stream.io.ByteArrayInputStream;
    +import org.codehaus.jackson.JsonNode;
    +
    +import okhttp3.HttpUrl;
    +import okhttp3.OkHttpClient;
    +import okhttp3.Response;
    +import okhttp3.ResponseBody;
    +
    +@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") })
    +@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 FIELD_INCLUDE_QUERY_PARAM = 
"_source_include";
    +    private static final String QUERY_QUERY_PARAM = "q";
    +    private static final String SORT_QUERY_PARAM = "sort";
    +    private static final String SCROLL_QUERY_PARAM = "scroll";
    +    private static final String SCROLL_ID_QUERY_PARAM = "scroll_id";
    +    private static final String SIZE_QUERY_PARAM = "size";
    +
    +    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").required(true)
    +            
.expressionLanguageSupported(true).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(true)
    +            .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").required(true)
    +            
.expressionLanguageSupported(true).addValidator(StandardValidators.NON_EMPTY_VALIDATOR)
    +            .build();
    +
    +    public static final PropertyDescriptor TYPE = new 
PropertyDescriptor.Builder()
    +            .name("scroll-es-type")
    +            .displayName("Type")
    +            .description(
    +                    "The (optional) type of this document, used by 
Elasticsearch for indexing and searching. If the property is empty or set "
    +                            + "to _all, the first document matching the 
identifier across all types will be retrieved.")
    +            .required(false).expressionLanguageSupported(true)
    +            .addValidator(StandardValidators.NON_EMPTY_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(true)
    +            .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(true)
    +            .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(true)
    +            
.addValidator(StandardValidators.POSITIVE_INTEGER_VALIDATOR).build();
    +
    +    @Override
    +    public Set<Relationship> getRelationships() {
    +        final Set<Relationship> relationships = new HashSet<>();
    +        relationships.add(REL_SUCCESS);
    +        relationships.add(REL_FAILURE);
    +        return Collections.unmodifiableSet(relationships);
    +    }
    +
    +    @Override
    +    public final List<PropertyDescriptor> 
getSupportedPropertyDescriptors() {
    +        final List<PropertyDescriptor> descriptors = new ArrayList<>();
    +        descriptors.add(ES_URL);
    +        descriptors.add(PROP_SSL_CONTEXT_SERVICE);
    +        descriptors.add(USERNAME);
    +        descriptors.add(PASSWORD);
    +        descriptors.add(CONNECT_TIMEOUT);
    +        descriptors.add(RESPONSE_TIMEOUT);
    +        descriptors.add(QUERY);
    +        descriptors.add(SCROLL_DURATION);
    +        descriptors.add(PAGE_SIZE);
    +        descriptors.add(INDEX);
    +        descriptors.add(TYPE);
    +        descriptors.add(FIELDS);
    +        descriptors.add(SORT);
    +
    +        return Collections.unmodifiableList(descriptors);
    +    }
    +
    +    @OnScheduled
    +    public void setup(ProcessContext context) {
    +        super.setup(context);
    +    }
    +
    +    @Override
    +    public void onTrigger(final ProcessContext context, final 
ProcessSession session)
    +            throws ProcessException {
    +
    +        try {
    +            if (isQueryFinished(context.getStateManager())) {
    +                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().intValue();
    +        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).getValue();
    +        final String password = context.getProperty(PASSWORD).getValue();
    +
    +        final ComponentLog logger = getLogger();
    +
    +        try {
    +            String scrollId = loadScrollId(context.getStateManager());
    +
    +            if (scrollId != null) {
    +                // read the url property from the context
    +                final String urlstr = 
StringUtils.trimToEmpty(context.getProperty(ES_URL)
    +                        .getValue());
    +                final URL scrollurl = buildRequestURL(urlstr, query, 
index, docType, fields, sort,
    +                        scrollId, pageSize, scroll);
    +                final long startNanos = System.nanoTime();
    +
    +                final Response getResponse = 
sendRequestToElasticsearch(okHttpClient, scrollurl,
    +                        username, password, "GET", null);
    +                this.getPage(getResponse, scrollurl, context, session, 
flowFile, logger, startNanos);
    +            } else {
    +                logger.debug("Querying {}/{} from Elasticsearch: {}", new 
Object[] { index,
    +                        docType, query });
    +
    +                // read the url property from the context
    +                final String urlstr = 
StringUtils.trimToEmpty(context.getProperty(ES_URL)
    +                        .getValue());
    +                final URL queryUrl = buildRequestURL(urlstr, query, index, 
docType, fields, sort,
    +                        scrollId, pageSize, scroll);
    +                final long startNanos = System.nanoTime();
    +
    +                final Response getResponse = 
sendRequestToElasticsearch(okHttpClient, queryUrl,
    +                        username, password, "GET", null);
    +                this.getPage(getResponse, queryUrl, context, session, 
flowFile, logger, startNanos);
    +            }
    +
    +        } 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)
    +            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);
    +
    +                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());
    +            });
    +            session.transfer(flowFile, REL_SUCCESS);
    --- End diff --
    
    Since the content of the flow file is a JSON object, I recommend setting 
the mime.type attribute to application/json.


> Implement Query and Scroll processors for ElasticSearch
> -------------------------------------------------------
>
>                 Key: NIFI-2417
>                 URL: https://issues.apache.org/jira/browse/NIFI-2417
>             Project: Apache NiFi
>          Issue Type: New Feature
>          Components: Extensions
>    Affects Versions: 1.0.0
>            Reporter: Joseph Gresock
>            Assignee: Joseph Gresock
>            Priority: Minor
>             Fix For: 1.1.0
>
>
> FetchElasticsearchHttp allows users to select a single document from 
> Elasticsearch in NiFi, but there is no way to run a query to retrieve 
> multiple documents.
> We should add a QueryElasticsearchHttp processor for running a query and 
> returning a flow file per result, for small result sets.  This should allow 
> both input and non-input execution.  
> A separate ScrollElasticsearchHttp processor would also be useful for 
> scrolling through a huge result set.  This should use the state manager to 
> maintain the scroll_id value, and use this as input to the next scroll page.  
> As a result, this processor should not allow flow file input, but should 
> retrieve one page per run.



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