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From JPercivall <...@git.apache.org>
Subject [GitHub] nifi pull request #576: NIFI-2068: Add Elasticsearch HTTP processors
Date Fri, 01 Jul 2016 15:12:43 GMT
Github user JPercivall commented on a diff in the pull request:

    https://github.com/apache/nifi/pull/576#discussion_r69314193
  
    --- 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);
    +                    session.transfer(flowFile, REL_SUCCESS);
    +                } else {
    +                    logger.warn("Failed to read {}/{}/{} from Elasticsearch: Document
not found",
    +                            new Object[]{index, docType, docId});
    +
    +                    // We couldn't find the document, so penalize it and send it to "not
found"
    +                    // If there was an incoming flow file, penalize and transfer. Otherwise
just remove it
    +                    if (context.hasIncomingConnection()) {
    +                        flowFile = session.penalize(flowFile);
    +                        session.transfer(flowFile, REL_NOT_FOUND);
    +                    } else {
    +                        session.remove(flowFile);
    +                    }
    +                }
    +
    +            } else {
    +                if (statusCode == 404) {
    +                    logger.warn("Failed to read {}/{}/{} from Elasticsearch: Document
not found",
    +                            new Object[]{index, docType, docId});
    +
    +                    // We couldn't find the document, so penalize it and send it to "not
found"
    +                    // If there was an incoming flow file, penalize and transfer. Otherwise
just remove it
    +                    if (context.hasIncomingConnection()) {
    +                        flowFile = session.penalize(flowFile);
    +                        session.transfer(flowFile, REL_NOT_FOUND);
    +                    } else {
    +                        session.remove(flowFile);
    +                    }
    +                } else if (context.hasIncomingConnection()) {
    +                    // 5xx -> RETRY
    +                    if (statusCode / 100 == 5) {
    +                        logger.info("Elasticsearch returned code {} with message {},
transferring flow file to retry", new Object[]{statusCode, getResponse.message()});
    +                        flowFile = session.penalize(flowFile);
    +                        session.transfer(flowFile, REL_RETRY);
    +                    } else {
    +                        // 1xx, 3xx, 4xx -> NO RETRY
    +                        logger.info("Elasticsearch returned code {} with message {},
transferring flow file to failure", new Object[]{statusCode, getResponse.message()});
    +                        session.transfer(flowFile, REL_FAILURE);
    +                    }
    +                } else {
    +                    logger.info("Elasticsearch returned code {} with message {}", new
Object[]{statusCode, getResponse.message()});
    --- End diff --
    
    There should be more robust handling here. For instance, where the processor has no incoming
connections and hits a 4xx failure, should the processor yield? In general, this means the
server is failing and we should probably not hammer it with requests. Also there should be
a warning/error saying that the server is down.


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