Github user JPercivall commented on a diff in the pull request: https://github.com/apache/nifi/pull/576#discussion_r69312668 --- Diff: nifi-nar-bundles/nifi-elasticsearch-bundle/nifi-elasticsearch-processors/src/main/java/org/apache/nifi/processors/elasticsearch/FetchElasticsearchHttp.java --- @@ -0,0 +1,293 @@ +/* + * 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.squareup.okhttp.HttpUrl; +import com.squareup.okhttp.OkHttpClient; +import com.squareup.okhttp.Response; +import com.squareup.okhttp.ResponseBody; +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.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.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 java.io.IOException; +import java.net.MalformedURLException; +import java.net.URL; +import java.util.ArrayList; +import java.util.Collections; +import java.util.HashSet; +import java.util.List; +import java.util.Set; +import java.util.concurrent.TimeUnit; +import java.util.stream.Collectors; +import java.util.stream.Stream; + + +@InputRequirement(InputRequirement.Requirement.INPUT_ALLOWED) +@EventDriven +@SupportsBatching +@Tags({"elasticsearch", "fetch", "read", "get", "http"}) +@CapabilityDescription("Retrieves a document from Elasticsearch using the specified connection properties and the " + + "identifier of the document to retrieve.") +@WritesAttributes({ + @WritesAttribute(attribute = "filename", description = "The filename attributes is set to the document identifier"), + @WritesAttribute(attribute = "es.index", description = "The Elasticsearch index containing the document"), + @WritesAttribute(attribute = "es.type", description = "The Elasticsearch document type") +}) +public class FetchElasticsearchHttp extends AbstractElasticsearchHttpProcessor { + + private static final String FIELD_INCLUDE_QUERY_PARAM = "_source_include"; + + 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").build(); + + public static final Relationship REL_RETRY = new Relationship.Builder().name("retry") + .description("A FlowFile is routed to this relationship if the document cannot be fetched but attempting the operation again may succeed") + .build(); + + public static final Relationship REL_NOT_FOUND = new Relationship.Builder().name("not found") + .description("A FlowFile is routed to this relationship if the specified document does not exist in the Elasticsearch cluster") + .build(); + + public static final PropertyDescriptor DOC_ID = new PropertyDescriptor.Builder() + .name("Document Identifier") + .description("The identifier for the document to be fetched") + .required(true) + .expressionLanguageSupported(true) + .addValidator(StandardValidators.NON_EMPTY_VALIDATOR) + .build(); + + public static final PropertyDescriptor INDEX = new PropertyDescriptor.Builder() + .name("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("Type") + .description("The (optional) type of this document, used by Elasticsearch for indexing and searching.") + .required(false) + .expressionLanguageSupported(true) + .addValidator(StandardValidators.NON_EMPTY_VALIDATOR) + .build(); + + public static final PropertyDescriptor FIELDS = new PropertyDescriptor.Builder() + .name("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(); + + + @Override + public Set<Relationship> getRelationships() { + final Set<Relationship> relationships = new HashSet<>(); + relationships.add(REL_SUCCESS); + relationships.add(REL_FAILURE); + relationships.add(REL_RETRY); + relationships.add(REL_NOT_FOUND); + 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(CONNECT_TIMEOUT); + descriptors.add(RESPONSE_TIMEOUT); + descriptors.add(DOC_ID); + descriptors.add(INDEX); + descriptors.add(TYPE); + descriptors.add(FIELDS); + + 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 { + + FlowFile flowFile = null; + if (context.hasIncomingConnection()) { + flowFile = session.get(); + + // If we have no FlowFile, and all incoming connections are self-loops then we can continue on. + // However, if we have no FlowFile and we have connections coming from other Processors, then + // we know that we should run only if we have a FlowFile. + if (flowFile == null && context.hasNonLoopConnection()) { + return; + } + } + + OkHttpClient okHttpClient = getClient(); + + if (flowFile == null) { + flowFile = session.create(); + } + + final String index = context.getProperty(INDEX).evaluateAttributeExpressions(flowFile).getValue(); + final String docId = context.getProperty(DOC_ID).evaluateAttributeExpressions(flowFile).getValue(); + final String docType = context.getProperty(TYPE).evaluateAttributeExpressions(flowFile).getValue(); + final String fields = context.getProperty(FIELDS).isSet() + ? context.getProperty(FIELDS).evaluateAttributeExpressions(flowFile).getValue() + : null; + + final ComponentLog logger = getLogger(); + + + try { + logger.debug("Fetching {}/{}/{} from Elasticsearch", new Object[]{index, docType, docId}); + + // read the url property from the context + final String urlstr = StringUtils.trimToEmpty(context.getProperty(ES_URL).getValue()); + final URL url = buildRequestURL(urlstr, docId, index, docType, fields); + final long startNanos = System.nanoTime(); + + final Response getResponse = sendRequestToElasticsearch(okHttpClient, url, "GET", null); + final int statusCode = getResponse.code(); + + if (isSuccess(statusCode)) { + ResponseBody body = getResponse.body(); + final byte[] bodyBytes = body.bytes(); + JsonNode responseJson = parseJsonResponse(new ByteArrayInputStream(bodyBytes)); + boolean found = responseJson.get("found").asBoolean(false); + + if (found) { + flowFile = session.putAttribute(flowFile, "filename", docId); + flowFile = session.putAttribute(flowFile, "es.index", index); + flowFile = session.putAttribute(flowFile, "es.type", docType); + flowFile = session.write(flowFile, out -> { + out.write(bodyBytes); + }); + logger.debug("Elasticsearch document " + docId + " fetched, routing to success"); + + // emit provenance event + final long millis = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startNanos); + session.getProvenanceReporter().fetch(flowFile, url.toExternalForm(), millis); --- End diff -- "Fetch" provenance events should be emitted when there was an incoming FlowFile that was used to fetch the information. "Receive" events should be emitted when the processor is a source processor and there was no incoming flowfile. There should be some logic to determine which case this falls into.
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