–Note：1、文章摘自elasticsearch官网，因为觉得再费力的总结，总不如官网的说明学习更快。
2、关于elasticSearch-hadoop组件：从目前的版本看(2017年9月26日)，从elasticsearch官网下载的elasticsearch_hadoop组件还只能基于scala 2.10.x 版本。而spark的2.1.X版本开始，已经基于scala2.11以上的版本进行开发了。(而且坑爹的scala并不是完全向下兼容的)，所以造成官网的组件实际上不太好用。 elasticsearch与spark交互的包需要从maven中下载。

<dependency>
   <groupId>org.elasticsearch</groupId>
    <artifactId>elasticsearch-spark-20_2.11</artifactId>
    <version>5.3.2</version>
</dependency>

以下摘自网页 https://www.elastic.co/guide/en/elasticsearch/hadoop/master/spark.html
Apache Spark support

Apache Spark is a fast and general-purpose cluster computing system. It provides high-level APIs in Java, Scala and Python, and an optimized engine that supports general execution graphs.

-- Spark website

Spark provides fast iterative/functional-like capabilities over large data sets, typically by caching data in memory. As opposed to the rest of the libraries mentioned in this documentation, Apache Spark is computing framework that is not tied to Map/Reduce itself however it does integrate with Hadoop, mainly to HDFS. elasticsearch-hadoop allows Elasticsearch to be used in Spark in two ways: through the dedicated support available since 2.1 or through the Map/Reduce bridge since 2.0. Spark 2.0 is supported in elasticsearch-hadoop since version 5.0

Installationedit
Just like other libraries, elasticsearch-hadoop needs to be available in Spark’s classpath. As Spark has multiple deployment modes, this can translate to the target classpath, whether it is on only one node (as is the case with the local mode - which will be used through-out the documentation) or per-node depending on the desired infrastructure.

Native supportedit
Note
Added in 2.1.

elasticsearch-hadoop provides native integration between Elasticsearch and Apache Spark, in the form of an RDD (Resilient Distributed Dataset) (or Pair RDD to be precise) that can read data from Elasticsearch. The RDD is offered in two flavors: one for Scala (which returns the data as Tuple2 with Scala collections) and one for Java (which returns the data as Tuple2 containing java.util collections).

Important
Whenever possible, consider using the native integration as it offers the best performance and maximum flexibility.

Configurationedit
To configure elasticsearch-hadoop for Apache Spark, one can set the various properties described in the Configuration chapter in the SparkConf object:

import org.apache.spark.SparkConf

val conf = new SparkConf().setAppName(appName).setMaster(master)
conf.set("es.index.auto.create", "true")
SparkConf conf = new SparkConf().setAppName(appName).setMaster(master);
conf.set("es.index.auto.create", "true");

Command-line. For those that want to set the properties through the command-line (either directly or by loading them from a file), note that Spark only accepts those that start with the “spark.” prefix and will ignore the rest (and depending on the version a warning might be thrown). To work around this limitation, define the elasticsearch-hadoop properties by appending the spark. prefix (thus they become spark.es.) and elasticsearch-hadoop will automatically resolve them:

$ ./bin/spark-submit --conf spark.es.resource=index/type ...

Notice the es.resource property which became spark.es.resource

Writing data to Elasticsearchedit
With elasticsearch-hadoop, any RDD can be saved to Elasticsearch as long as its content can be translated into documents. In practice this means the RDD type needs to be a Map (whether a Scala or a Java one), a JavaBean or a Scala case class. When that is not the case, one can easily transform the data in Spark or plug-in their own custom ValueWriter.

Scalaedit
When using Scala, simply import the org.elasticsearch.spark package which, through the pimp my library pattern, enriches the any RDD API with saveToEs methods:

import org.apache.spark.SparkContext    
import org.apache.spark.SparkContext._

import org.elasticsearch.spark._        

...

val conf = ...
val sc = new SparkContext(conf)         

val numbers = Map("one" -> 1, "two" -> 2, "three" -> 3)
val airports = Map("arrival" -> "Otopeni", "SFO" -> "San Fran")

sc.makeRDD(Seq(numbers, airports)).saveToEs("spark/docs")

Spark Scala imports

elasticsearch-hadoop Scala imports

start Spark through its Scala API

makeRDD creates an ad-hoc RDD based on the collection specified; any other RDD (in Java or Scala) can be passed in

index the content (namely the two documents (numbers and airports)) in Elasticsearch under spark/docs

Note
Scala users might be tempted to use Seq and the → notation for declaring root objects (that is the JSON document) instead of using a Map. While similar, the first notation results in slightly different types that cannot be matched to a JSON document: Seq is an order sequence (in other words a list) while → creates a Tuple which is more or less an ordered, fixed number of elements. As such, a list of lists cannot be used as a document since it cannot be mapped to a JSON object; however it can be used freely within one. Hence why in the example above Map(k→v) was used instead of Seq(k→v)

As an alternative to the implicit import above, one can use elasticsearch-hadoop Spark support in Scala through EsSpark in the org.elasticsearch.spark.rdd package which acts as a utility class allowing explicit method invocations. Additionally instead of Maps (which are convenient but require one mapping per instance due to their difference in structure), use a case class :

import org.apache.spark.SparkContext
import org.elasticsearch.spark.rdd.EsSpark                        

// define a case class
case class Trip(departure: String, arrival: String)               

val upcomingTrip = Trip("OTP", "SFO")
val lastWeekTrip = Trip("MUC", "OTP")

val rdd = sc.makeRDD(Seq(upcomingTrip, lastWeekTrip))             
EsSpark.saveToEs(rdd, "spark/docs")    

EsSpark import
Define a case class named Trip
Create an RDD around the Trip instances
Index the RDD explicitly through EsSpark

For cases where the id (or other metadata fields like ttl or timestamp) of the document needs to be specified, one can do so by setting the appropriate mapping namely es.mapping.id. Following the previous example, to indicate to Elasticsearch to use the field id as the document id, update the RDD configuration (it is also possible to set the property on the SparkConf though due to its global effect it is discouraged):

EsSpark.saveToEs(rdd, “spark/docs”, Map(“es.mapping.id” -> “id”))
Javaedit
Java users have a dedicated class that provides a similar functionality to EsSpark, namely JavaEsSpark in the org.elasticsearch.spark.rdd.api.java (a package similar to Spark’s Java API):

import org.apache.spark.api.java.JavaSparkContext;                              
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.SparkConf;

import org.elasticsearch.spark.rdd.api.java.JavaEsSpark;                        
...

SparkConf conf = ...
JavaSparkContext jsc = new JavaSparkContext(conf);                              

Map<String, ?> numbers = ImmutableMap.of("one", 1, "two", 2);                   
Map<String, ?> airports = ImmutableMap.of("OTP", "Otopeni", "SFO", "San Fran");

JavaRDD<Map<String, ?>> javaRDD = jsc.parallelize(ImmutableList.of(numbers, airports));
JavaEsSpark.saveToEs(javaRDD, "spark/docs");        

Spark Java imports
elasticsearch-hadoop Java imports
start Spark through its Java API
to simplify the example, use Guava(a dependency of Spark) Immutable* methods for simple Map, List creation
create a simple RDD over the two collections; any other RDD (in Java or Scala) can be passed in
index the content (namely the two documents (numbers and airports)) in Elasticsearch under spark/docs

The code can be further simplified by using Java 5 static imports. Additionally, the Map (who’s mapping is dynamic due to its loose structure) can be replaced with a JavaBean:

public class TripBean implements Serializable {
   private String departure, arrival;

   public TripBean(String departure, String arrival) {
       setDeparture(departure);
       setArrival(arrival);
   }

   public TripBean() {}

   public String getDeparture() { return departure; }
   public String getArrival() { return arrival; }
   public void setDeparture(String dep) { departure = dep; }
   public void setArrival(String arr) { arrival = arr; }
}

import static org.elasticsearch.spark.rdd.api.java.JavaEsSpark;                
...

TripBean upcoming = new TripBean("OTP", "SFO");
TripBean lastWeek = new TripBean("MUC", "OTP");

JavaRDD<TripBean> javaRDD = jsc.parallelize(
                            ImmutableList.of(upcoming, lastWeek));        
saveToEs(javaRDD, "spark/docs");      

statically import JavaEsSpark
define an RDD containing TripBean instances (TripBean is a JavaBean)
call saveToEs method without having to type JavaEsSpark again

Setting the document id (or other metadata fields like ttl or timestamp) is similar to its Scala counterpart, though potentially a bit more verbose depending on whether you are using the JDK classes or some other utilities (like Guava):

JavaEsSpark.saveToEs(javaRDD, “spark/docs”, ImmutableMap.of(“es.mapping.id”, “id”));
Writing existing JSON to Elasticsearchedit
For cases where the data in the RDD is already in JSON, elasticsearch-hadoop allows direct indexing without applying any transformation; the data is taken as is and sent directly to Elasticsearch. As such, in this case, elasticsearch-hadoop expects either an RDD containing String or byte arrays (byte[]/Array[Byte]), assuming each entry represents a JSON document. If the RDD does not have the proper signature, the saveJsonToEs methods cannot be applied (in Scala they will not be available).

Scalaedit

val json1 = """{"reason" : "business", "airport" : "SFO"}"""      
val json2 = """{"participants" : 5, "airport" : "OTP"}"""

new SparkContext(conf).makeRDD(Seq(json1, json2))
                      .saveJsonToEs("spark/json-trips") 

example of an entry within the RDD - the JSON is written as is, without any transformation
index the JSON data through the dedicated saveJsonToEs method

Javaedit

String json1 = "{"reason" : "business","airport" : "SFO"}";  
String json2 = "{"participants" : 5,"airport" : "OTP"}";

JavaSparkContext jsc = ...
JavaRDD<String> stringRDD = jsc.parallelize(ImmutableList.of(json1, json2));
JavaEsSpark.saveJsonToEs(stringRDD, "spark/json-trips");             

example of an entry within the RDD - the JSON is written as is, without any transformation
notice the RDD signature
index the JSON data through the dedicated saveJsonToEs method

Writing to dynamic/multi-resourcesedit
For cases when the data being written to Elasticsearch needs to be indexed under different buckets (based on the data content) one can use the es.resource.write field which accepts a pattern that is resolved from the document content, at runtime. Following the aforementioned media example, one could configure it as follows:

Scalaedit

val game = Map("media_type"->"game","title" -> "FF VI","year" -> "1994")
val book = Map("media_type" -> "book","title" -> "Harry Potter","year" -> "2010")
val cd = Map("media_type" -> "music","title" -> "Surfing With The Alien")

sc.makeRDD(Seq(game, book, cd)).saveToEs("my-collection/{media_type}")  

Document key used for splitting the data. Any field can be declared (but make sure it is available in all documents)
Save each object based on its resource pattern, in this example based on media_type

For each document/object about to be written, elasticsearch-hadoop will extract the media_type field and use its value to determine the target resource.

Javaedit
As expected, things in Java are strikingly similar:

Map<String, ?> game =
  ImmutableMap.of("media_type", "game", "title", "FF VI", "year", "1994");
Map<String, ?> book = ...
Map<String, ?> cd = ...

JavaRDD<Map<String, ?>> javaRDD =
                jsc.parallelize(ImmutableList.of(game, book, cd));
saveToEs(javaRDD, "my-collection/{media_type}");  

Save each object based on its resource pattern, media_type in this example

Handling document metadataedit
Elasticsearch allows each document to have its own metadata. As explained above, through the various mapping options one can customize these parameters so that their values are extracted from their belonging document. Further more, one can even include/exclude what parts of the data are sent back to Elasticsearch. In Spark, elasticsearch-hadoop extends this functionality allowing metadata to be supplied outside the document itself through the use of pair RDDs. In other words, for RDDs containing a key-value tuple, the metadata can be extracted from the key and the value used as the document source.

The metadata is described through the Metadata Java enum within org.elasticsearch.spark.rdd package which identifies its type - id, ttl, version, etc… Thus an RDD keys can be a Map containing the Metadata for each document and its associated values. If RDD key is not of type Map, elasticsearch-hadoop will consider the object as representing the document id and use it accordingly. This sounds more complicated than it is, so let us see some examples.

Scalaedit
Pair RDDs, or simply put RDDs with the signature RDD[(K,V)] can take advantage of the saveToEsWithMeta methods that are available either through the implicit import of org.elasticsearch.spark package or EsSpark object. To manually specify the id for each document, simply pass in the Object (not of type Map) in your RDD:

val otp = Map("iata" -> "OTP", "name" -> "Otopeni")
val muc = Map("iata" -> "MUC", "name" -> "Munich")
val sfo = Map("iata" -> "SFO", "name" -> "San Fran")

// instance of SparkContext
val sc = ...

val airportsRDD = sc.makeRDD(Seq((1, otp), (2, muc), (3, sfo)))  
airportsRDD.saveToEsWithMeta("airports/2015")

airportsRDD is a key-value pair RDD; it is created from a Seq of tuples
The key of each tuple within the Seq represents the id of its associated value/document; in other words, document otp has id 1, muc 2 and sfo 3
Since airportsRDD is a pair RDD, it has the saveToEsWithMeta method available. This tells elasticsearch-hadoop to pay special attention to the RDD keys and use them as metadata, in this case as document ids. If saveToEs would have been used instead, then elasticsearch-hadoop would consider the RDD tuple, that is both the key and the value, as part of the document.

When more than just the id needs to be specified, one should use a scala.collection.Map with keys of type org.elasticsearch.spark.rdd.Metadata:

import org.elasticsearch.spark.rdd.Metadata._          

val otp = Map("iata" -> "OTP", "name" -> "Otopeni")
val muc = Map("iata" -> "MUC", "name" -> "Munich")
val sfo = Map("iata" -> "SFO", "name" -> "San Fran")

// metadata for each document
// note it's not required for them to have the same structure
val otpMeta = Map(ID -> 1, TTL -> "3h")                
val mucMeta = Map(ID -> 2, VERSION -> "23")            
val sfoMeta = Map(ID -> 3)                             

// instance of SparkContext
val sc = ...

val airportsRDD = sc.makeRDD(Seq((otpMeta, otp), (mucMeta, muc), (sfoMeta, sfo)))
airportsRDD.saveToEsWithMeta("airports/2015") 

Import the Metadata enum
The metadata used for otp document. In this case, ID with a value of 1 and TTL with a value of 3h
The metadata used for muc document. In this case, ID with a value of 2 and VERSION with a value of 23
The metadata used for sfo document. In this case, ID with a value of 3
The metadata and the documents are assembled into a pair RDD
The RDD is saved accordingly using the saveToEsWithMeta method

Javaedit
In a similar fashion, on the Java side, JavaEsSpark provides saveToEsWithMeta methods that are applied to JavaPairRDD (the equivalent in Java of RDD[(K,V)]). Thus to save documents based on their ids one can use:

import org.elasticsearch.spark.rdd.api.java.JavaEsSpark;

// data to be saved
Map<String, ?> otp = ImmutableMap.of("iata", "OTP", "name", "Otopeni");
Map<String, ?> jfk = ImmutableMap.of("iata", "JFK", "name", "JFK NYC");

JavaSparkContext jsc = ...

// create a pair RDD between the id and the docs
JavaPairRDD<?, ?> pairRdd = jsc.parallelizePairs(ImmutableList.of(
        new Tuple2<Object, Object>(1, otp),          
        new Tuple2<Object, Object>(2, jfk)));        
JavaEsSpark.saveToEsWithMeta(pairRDD, target);

Create a JavaPairRDD by using Scala Tuple2 class wrapped around the document id and the document itself
Tuple for the first document wrapped around the id (1) and the doc (otp) itself
Tuple for the second document wrapped around the id (2) and jfk
The JavaPairRDD is saved accordingly using the keys as a id and the values as documents

When more than just the id needs to be specified, one can choose to use a java.util.Map populated with keys of type org.elasticsearch.spark.rdd.Metadata:

import org.elasticsearch.spark.rdd.api.java.JavaEsSpark;
import org.elasticsearch.spark.rdd.Metadata;

import static org.elasticsearch.spark.rdd.Metadata.*; 

// data to be saved
Map<String, ?> otp = ImmutableMap.of("iata", "OTP", "name", "Otopeni");
Map<String, ?> sfo = ImmutableMap.of("iata", "SFO", "name", "San Fran");

// metadata for each document
// note it's not required for them to have the same structure
Map<Metadata, Object> otpMeta = ImmutableMap.<Metadata, Object> of(ID, 1, TTL, "1d");
Map<Metadata, Object> sfoMeta = ImmutableMap.<Metadata, Object> of(ID, "2", VERSION, "23");

JavaSparkContext jsc = ...

// create a pair RDD between the id and the docs
JavaPairRDD<?, ?> pairRdd = jsc.parallelizePairs<(ImmutableList.of(
        new Tuple2<Object, Object>(otpMeta, otp),    
        new Tuple2<Object, Object>(sfoMeta, sfo)));  
JavaEsSpark.saveToEsWithMeta(pairRDD, target);     

Metadata enum describing the document metadata that can be declared
static import for the enum to refer to its values in short format (ID, TTL, etc…)
Metadata for otp document
Boiler-plate construct for forcing the of method generic signature
Metadata for sfo document
Tuple between otp (as the value) and its metadata (as the key)
Tuple associating sfo and its metadata
saveToEsWithMeta invoked over the JavaPairRDD containing documents and their respective metadata

Reading data from Elasticsearchedit
For reading, one should define the Elasticsearch RDD that streams data from Elasticsearch to Spark.

Scalaedit
Similar to writing, the org.elasticsearch.spark package, enriches the SparkContext API with esRDD methods:

import org.apache.spark.SparkContext    
import org.apache.spark.SparkContext._

import org.elasticsearch.spark._        

...

val conf = ...
val sc = new SparkContext(conf)         

val RDD = sc.esRDD("radio/artists")     

Spark Scala imports
elasticsearch-hadoop Scala imports
start Spark through its Scala API
a dedicated RDD for Elasticsearch is created for index radio/artists

The method can be overloaded to specify an additional query or even a configuration Map (overriding SparkConf):

...
import org.elasticsearch.spark._

...
val conf = ...
val sc = new SparkContext(conf)

sc.esRDD("radio/artists", "?q=me*") 

create an RDD streaming all the documents matching me* from index radio/artists

The documents from Elasticsearch are returned, by default, as a Tuple2 containing as the first element the document id and the second element the actual document represented through Scala collections, namely one Map[String, Any]where the keys represent the field names and the value their respective values.

Javaedit
Java users have a dedicated JavaPairRDD that works the same as its Scala counterpart however the returned Tuple2 values (or second element) returns the documents as native, java.util collections.

import org.apache.spark.api.java.JavaSparkContext;               
import org.elasticsearch.spark.rdd.api.java.JavaEsSpark;             
...

SparkConf conf = ...
JavaSparkContext jsc = new JavaSparkContext(conf);               

JavaPairRDD<String, Map<String, Object>> esRDD =
                        JavaEsSpark.esRDD(jsc, "radio/artists"); 

Spark Java imports
elasticsearch-hadoop Java import
start Spark through its Java API
a dedicated JavaPairRDD for Elasticsearch is created for index radio/artists

In a similar fashion one can use the overloaded esRDD methods to specify a query or pass a Map object for advanced configuration. Let us see how this looks, but this time around using Java static imports. Further more, let us discard the documents ids and retrieve only the RDD values:

import static org.elasticsearch.spark.rdd.api.java.JavaEsSpark.*;   

...
JavaRDD<Map<String, Object>> esRDD =
                        esRDD(jsc, "radio/artists", "?q=me*").values();

statically import JavaEsSpark class
create an RDD streaming all the documents starting with me from index radio/artists. Note the method does not have to be fully qualified due to the static import
return only values of the PairRDD - hence why the result is of type JavaRDD and not JavaPairRDD

By using the JavaEsSpark API, one gets a hold of Spark’s dedicated JavaPairRDD which are better suited in Java environments than the base RDD (due to its Scala signatures). Moreover, the dedicated RDD returns Elasticsearch documents as proper Java collections so one does not have to deal with Scala collections (which is typically the case with RDDs). This is particularly powerful when using Java 8, which we strongly recommend as its lambda expressions make collection processing extremely concise.

To wit, let us assume one wants to filter the documents from the RDD and return only those that contain a value that contains mega (please ignore the fact one can and should do the filtering directly through Elasticsearch).

In versions prior to Java 8, the code would look something like this:

JavaRDD<Map<String, Object>> esRDD =
                        esRDD(jsc, "radio/artists", "?q=me*").values();
JavaRDD<Map<String, Object>> filtered = esRDD.filter(
    new Function<Map<String, Object>, Boolean>() {
      @Override
      public Boolean call(Map<String, Object> map) throws Exception {
          returns map.contains("mega");
      }
    });

with Java 8, the filtering becomes a one liner:

JavaRDD<Map<String, Object>> esRDD =
                        esRDD(jsc, "radio/artists", "?q=me*").values();
JavaRDD<Map<String, Object>> filtered = esRDD.filter(doc ->
                                                doc.contains("mega"));

Reading data in JSON formatedit
In case where the results from Elasticsearch need to be in JSON format (typically to be sent down the wire to some other system), one can use the dedicated esJsonRDD methods. In this case, the connector will return the documents content as it is received from Elasticsearch without any processing as an RDD[(String, String)] in Scala or JavaPairRDD[String, String] in Java with the keys representing the document id and the value its actual content in JSON format.

Type conversionedit
Important
When dealing with multi-value/array fields, please see this section and in particular these configuration options. IMPORTANT: If automatic index creation is used, please review this section for more information.

elasticsearch-hadoop automatically converts Spark built-in types to Elasticsearch types (and back) as shown in the table below:

Table 5. Scala Types Conversion Table
Scala type—-Elasticsearch type
None —- null
Unit —- null
Nil —- empty array
Some[T] —- T according to the table
Map —- object
Traversable —- array
case class —- object (see Map)
Product —- array

in addition, the following implied conversion applies for Java types:

Table 6. Java Types Conversion Table
Java type —- Elasticsearch type
null —- null
String —- string
Boolean —- boolean
Byte —- byte
Short —- short
Integer —- int
Long —- long
Double —- double
Float —- float
Number —- float or double (depending on size)
java.util.Calendar —- date (string format)
java.util.Date —- date (string format)
java.util.Timestamp —- date (string format)
byte[] —- string (BASE64)
Object[] —- array
Iterable —- array
Map —- object
Java Bean —- object (see Map)

The conversion is done as a best effort; built-in Java and Scala types are guaranteed to be properly converted, however there are no guarantees for user types whether in Java or Scala. As mentioned in the tables above, when a case class is encountered in Scala or JavaBean in Java, the converters will try to unwrap its content and save it as an object. Note this works only for top-level user objects - if the user object has other user objects nested in, the conversion is likely to fail since the converter does not perform nested unwrapping. This is done on purpose since the converter has to serialize and deserialize the data and user types introduce ambiguity due to data loss; this can be addressed through some type of mapping however that takes the project way too close to the realm of ORMs and arguably introduces too much complexity for little to no gain; thanks to the processing functionality in Spark and the plugability in elasticsearch-hadoop one can easily transform objects into other types, if needed with minimal effort and maximum control.

Geo types. It is worth mentioning that rich data types available only in Elasticsearch, such as GeoPoint or GeoShape are supported by converting their structure into the primitives available in the table above. For example, based on its storage a geo_point might be returned as a String or a Traversable.

Spark Streaming supportedit
Note
Added in 5.0.

Spark Streaming is an extension of the core Spark API that enables scalable, high-throughput, fault-tolerant stream processing of live data streams.

-- Spark website

Spark Streaming is an extension on top of the core Spark functionality that allows near real time processing of stream data. Spark Streaming works around the idea of DStreams, or Discretized Streams. DStreams operate by collecting newly arrived records into a small RDD and executing it. This repeats every few seconds with a new RDD in a process called microbatching. The DStream api includes many of the same processing operations as the RDD api, plus a few other streaming specific methods. elasticsearch-hadoop provides native integration with Spark Streaming as of version 5.0.

When using the elasticsearch-hadoop Spark Streaming support, Elasticsearch can be targeted as an output location to index data into from a Spark Streaming job in the same way that one might persist the results from an RDD. Though, unlike RDDs, you are unable to read data out of Elasticsearch using a DStream due to the continuous nature of it.

Important
Spark Streaming support provides special optimizations to allow for conservation of network resources on Spark executors when running jobs with very small processing windows. For this reason, one should prefer to use this integration instead of invoking saveToEs on RDDs returned from the foreachRDD call on DStream.

Writing DStream to Elasticsearchedit
Like RDDs, any DStream can be saved to Elasticsearch as long as its content can be translated into documents. In practice this means the DStream type needs to be a Map (either a Scala or a Java one), a JavaBean or a Scala case class. When that is not the case, one can easily transform the data in Spark or plug-in their own custom ValueWriter.

Scalaedit
When using Scala, simply import the org.elasticsearch.spark.streaming package which, through the pimp my library pattern, enriches the DStream API with saveToEs methods:

import org.apache.spark.SparkContext
import org.apache.spark.SparkContext._               
import org.apache.spark.streaming.StreamingContext
import org.apache.spark.streaming.StreamingContext._

import org.elasticsearch.spark.streaming._           

...

val conf = ...
val sc = new SparkContext(conf)                      
val ssc = new StreamingContext(sc, Seconds(1))       

val numbers = Map("one" -> 1, "two" -> 2, "three" -> 3)
val airports = Map("arrival" -> "Otopeni", "SFO" -> "San Fran")

val rdd = sc.makeRDD(Seq(numbers, airports))
val microbatches = mutable.Queue(rdd)                

ssc.queueStream(microbatches).saveToEs("spark/docs")

ssc.start()
ssc.awaitTermination() 

Spark and Spark Streaming Scala imports
elasticsearch-hadoop Spark Streaming imports
start Spark through its Scala API
start SparkStreaming context by passing it the SparkContext. The microbatches will be processed every second.
makeRDD creates an ad-hoc RDD based on the collection specified; any other RDD (in Java or Scala) can be passed in. Create a queue of RDDs to signify the microbatches to perform.

Create a DStream out of the RDDs and index the content (namely the two _documents_ (numbers and airports)) in {es} underspark/docs
Start the spark Streaming Job and wait for it to eventually finish.

As an alternative to the implicit import above, one can use elasticsearch-hadoop Spark Streaming support in Scala through EsSparkStreaming in the org.elasticsearch.spark.streaming package which acts as a utility class allowing explicit method invocations. Additionally instead of Maps (which are convenient but require one mapping per instance due to their difference in structure), use a case class :

import org.apache.spark.SparkContext
import org.elasticsearch.spark.streaming.EsSparkStreaming         

// define a case class
case class Trip(departure: String, arrival: String)               

val upcomingTrip = Trip("OTP", "SFO")
val lastWeekTrip = Trip("MUC", "OTP")

val rdd = sc.makeRDD(Seq(upcomingTrip, lastWeekTrip))
val microbatches = mutable.Queue(rdd)                             
val dstream = ssc.queueStream(microbatches)

EsSparkStreaming.saveToEs(dstream, "spark/docs")                  

ssc.start()                                                       

EsSparkStreaming import
Define a case class named Trip
Create a DStream around the RDD of Trip instances
Configure the DStream to be indexed explicitly through EsSparkStreaming
Start the streaming process

Important
Once a SparkStreamingContext is started, no new DStreams can be added or configured. Once a context has stopped, it cannot be restarted. There can only be one active SparkStreamingContext at a time per JVM. Also note that when stopping a SparkStreamingContext programmatically, it stops the underlying SparkContext unless instructed not to.

For cases where the id (or other metadata fields like ttl or timestamp) of the document needs to be specified, one can do so by setting the appropriate mapping namely es.mapping.id. Following the previous example, to indicate to Elasticsearch to use the field id as the document id, update the DStream configuration (it is also possible to set the property on the SparkConf though due to its global effect it is discouraged):

EsSparkStreaming.saveToEs(dstream, “spark/docs”, Map(“es.mapping.id” -> “id”))
Javaedit
Java users have a dedicated class that provides a similar functionality to EsSparkStreaming, namely JavaEsSparkStreaming in the package org.elasticsearch.spark.streaming.api.java (a package similar to Spark’s Java API):

import org.apache.spark.api.java.JavaSparkContext;
import org.apache.spark.api.java.JavaRDD;
import org.apache.spark.SparkConf;                                              
import org.apache.spark.streaming.api.java.JavaStreamingContext;
import org.apache.spark.streaming.api.java.JavaDStream;

import org.elasticsearch.spark.streaming.api.java.JavaEsSparkStreaming;         
...

SparkConf conf = ...
JavaSparkContext jsc = new JavaSparkContext(conf);                              
JavaStreamingContext jssc = new JavaSparkStreamingContext(jsc, Seconds.apply(1));

Map<String, ?> numbers = ImmutableMap.of("one", 1, "two", 2);                   
Map<String, ?> airports = ImmutableMap.of("OTP", "Otopeni", "SFO", "San Fran");

JavaRDD<Map<String, ?>> javaRDD = jsc.parallelize(ImmutableList.of(numbers, airports));
Queue<JavaRDD<Map<String, ?>>> microbatches = new LinkedList<>();
microbatches.add(javaRDD);                                                      
JavaDStream<Map<String, ?>> javaDStream = jssc.queueStream(microbatches);

JavaEsSparkStreaming.saveToEs(javaDStream, "spark/docs");                       

jssc.start()   

Spark and Spark Streaming Java imports
elasticsearch-hadoop Java imports
start Spark and Spark Streaming through its Java API. The microbatches will be processed every second.
to simplify the example, use Guava(a dependency of Spark) Immutable* methods for simple Map, List creation
create a simple DStream over the microbatch; any other RDDs (in Java or Scala) can be passed in
index the content (namely the two documents (numbers and airports)) in Elasticsearch under spark/docs
execute the streaming job.

The code can be further simplified by using Java 5 static imports. Additionally, the Map (who’s mapping is dynamic due to its loose structure) can be replaced with a JavaBean:

public class TripBean implements Serializable {
   private String departure, arrival;

   public TripBean(String departure, String arrival) {
       setDeparture(departure);
       setArrival(arrival);
   }

   public TripBean() {}

   public String getDeparture() { return departure; }
   public String getArrival() { return arrival; }
   public void setDeparture(String dep) { departure = dep; }
   public void setArrival(String arr) { arrival = arr; }
}

import static org.elasticsearch.spark.rdd.api.java.JavaEsSparkStreaming;  
...

TripBean upcoming = new TripBean("OTP", "SFO");
TripBean lastWeek = new TripBean("MUC", "OTP");

JavaRDD<TripBean> javaRDD = jsc.parallelize(ImmutableList.of(upcoming, lastWeek));
Queue<JavaRDD<TripBean>> microbatches = new LinkedList<JavaRDD<TripBean>>();
microbatches.add(javaRDD);
JavaDStream<TripBean> javaDStream = jssc.queueStream(microbatches);       

saveToEs(javaDStream, "spark/docs");                                          

jssc.start()                                           

statically import JavaEsSparkStreaming
define a DStream containing TripBean instances (TripBean is a JavaBean)
call saveToEs method without having to type JavaEsSparkStreaming again
run that Streaming job
Setting the document id (or other metadata fields like ttl or timestamp) is similar to its Scala counterpart, though potentially a bit more verbose depending on whether you are using the JDK classes or some other utilities (like Guava):

JavaEsSparkStreaming.saveToEs(javaDStream, “spark/docs”, ImmutableMap.of(“es.mapping.id”, “id”));
Writing Existing JSON to Elasticsearchedit
For cases where the data being streamed by the DStream is already serialized as JSON, elasticsearch-hadoop allows direct indexing without applying any transformation; the data is taken as is and sent directly to Elasticsearch. As such, in this case, elasticsearch-hadoop expects either a DStream containing String or byte arrays (byte[]/Array[Byte]), assuming each entry represents a JSON document. If the DStream does not have the proper signature, the saveJsonToEs methods cannot be applied (in Scala they will not be available).

Scalaedit

val json1 = """{"reason" : "business", "airport" : "SFO"}"""      
val json2 = """{"participants" : 5, "airport" : "OTP"}"""

val sc = new SparkContext(conf)
val ssc = new StreamingContext(sc, Seconds(1))

val rdd = sc.makeRDD(Seq(json1, json2))
val microbatch = mutable.Queue(rdd)
ssc.queueStream(microbatch).saveJsonToEs("spark/json-trips")      

ssc.start()  

example of an entry within the DStream - the JSON is written as is, without any transformation
configure the stream to index the JSON data through the dedicated saveJsonToEs method
start the streaming job

Javaedit

String json1 = "{"reason" : "business","airport" : "SFO"}";  
String json2 = "{"participants" : 5,"airport" : "OTP"}";

JavaSparkContext jsc = ...
JavaStreamingContext jssc = ...
JavaRDD<String> stringRDD = jsc.parallelize(ImmutableList.of(json1, json2));
Queue<JavaRDD<String>> microbatches = new LinkedList<JavaRDD<String>>();      
microbatches.add(stringRDD);
JavaDStream<String> stringDStream = jssc.queueStream(microbatches);

JavaEsSparkStreaming.saveJsonToEs(stringRDD, "spark/json-trips");    

jssc.start() 

example of an entry within the DStream - the JSON is written as is, without any transformation
creating an RDD, placing it into a queue, and creating a DStream out of the queued RDDs, treating each as a microbatch.
notice the JavaDStream signature
configure stream to index the JSON data through the dedicated saveJsonToEs method
launch stream job

Writing to dynamic/multi-resourcesedit
For cases when the data being written to Elasticsearch needs to be indexed under different buckets (based on the data content) one can use the es.resource.write field which accepts a pattern that is resolved from the document content, at runtime. Following the aforementioned media example, one could configure it as follows:

Scalaedit

val game = Map("media_type"->"game","title" -> "FF VI","year" -> "1994")
val book = Map("media_type" -> "book","title" -> "Harry Potter","year" -> "2010")
val cd = Map("media_type" -> "music","title" -> "Surfing With The Alien")

val batch = sc.makeRDD(Seq(game, book, cd))
val microbatches = mutable.Queue(batch)
ssc.queueStream(microbatches).saveToEs("my-collection/{media_type}")  
ssc.start()

Document key used for splitting the data. Any field can be declared (but make sure it is available in all documents)
Save each object based on its resource pattern, in this example based on media_type

For each document/object about to be written, elasticsearch-hadoop will extract the media_type field and use its value to determine the target resource.

Javaedit
As expected, things in Java are strikingly similar:

Map<String, ?> game =
  ImmutableMap.of("media_type", "game", "title", "FF VI", "year", "1994");
Map<String, ?> book = ...
Map<String, ?> cd = ...

JavaRDD<Map<String, ?>> javaRDD =
                jsc.parallelize(ImmutableList.of(game, book, cd));
Queue<JavaRDD<Map<String, ?>>> microbatches = ...
JavaDStream<Map<String, ?>> javaDStream =
                jssc.queueStream(microbatches);

saveToEs(javaDStream, "my-collection/{media_type}");  
jssc.start();

Save each object based on its resource pattern, media_type in this example

Handling document metadataedit
Elasticsearch allows each document to have its own metadata. As explained above, through the various mapping options one can customize these parameters so that their values are extracted from their belonging document. Further more, one can even include/exclude what parts of the data are sent back to Elasticsearch. In Spark, elasticsearch-hadoop extends this functionality allowing metadata to be supplied outside the document itself through the use of pair RDDs.

This is no different in Spark Streaming. For DStreamss containing a key-value tuple, the metadata can be extracted from the key and the value used as the document source.

The metadata is described through the Metadata Java enum within org.elasticsearch.spark.rdd package which identifies its type - id, ttl, version, etc… Thus a DStream’s keys can be a Map containing the Metadata for each document and its associated values. If the DStream key is not of type Map, elasticsearch-hadoop will consider the object as representing the document id and use it accordingly. This sounds more complicated than it is, so let us see some examples.

Scalaedit
Pair DStreamss, or simply put DStreamss with the signature DStream[(K,V)] can take advantage of the saveToEsWithMeta methods that are available either through the implicit import of org.elasticsearch.spark.streaming package or EsSparkStreaming object. To manually specify the id for each document, simply pass in the Object (not of type Map) in your DStream:

val otp = Map("iata" -> "OTP", "name" -> "Otopeni")
val muc = Map("iata" -> "MUC", "name" -> "Munich")
val sfo = Map("iata" -> "SFO", "name" -> "San Fran")

// instance of SparkContext
val sc = ...
// instance of StreamingContext
val ssc = ...

val airportsRDD = sc.makeRDD(Seq((1, otp), (2, muc), (3, sfo)))  
val microbatches = mutable.Queue(airportsRDD)

ssc.queueStream(microbatches).saveToEsWithMeta("airports/2015")
ssc.start()

airportsRDD is a key-value pair RDD; it is created from a Seq of tuples
The key of each tuple within the Seq represents the id of its associated value/document; in other words, document otp has id 1, muc 2 and sfo 3
We construct a DStream which inherits the type signature of the RDD
Since the resulting DStream is a pair DStream, it has the saveToEsWithMeta method available. This tells elasticsearch-hadoop to pay special attention to the DStream keys and use them as metadata, in this case as document ids. If saveToEs would have been used instead, then elasticsearch-hadoop would consider the DStream tuple, that is both the key and the value, as part of the document.

When more than just the id needs to be specified, one should use a scala.collection.Map with keys of type org.elasticsearch.spark.rdd.Metadata:

import org.elasticsearch.spark.rdd.Metadata._

val otp = Map("iata" -> "OTP", "name" -> "Otopeni")
val muc = Map("iata" -> "MUC", "name" -> "Munich")
val sfo = Map("iata" -> "SFO", "name" -> "San Fran")

// metadata for each document
// note it's not required for them to have the same structure
val otpMeta = Map(ID -> 1, TTL -> "3h")                
val mucMeta = Map(ID -> 2, VERSION -> "23")            
val sfoMeta = Map(ID -> 3)                             

// instance of SparkContext
val sc = ...
// instance of StreamingContext
val ssc = ...

val airportsRDD = sc.makeRDD(Seq((otpMeta, otp), (mucMeta, muc), (sfoMeta, sfo)))
val microbatches = mutable.Queue(airportsRDD)

ssc.queueStream(microbatches).saveToEsWithMeta("airports/2015")
ssc.start()

Import the Metadata enum

The metadata used for otp document. In this case, ID with a value of 1 and TTL with a value of 3h
The metadata used for muc document. In this case, ID with a value of 2 and VERSION with a value of 23
The metadata used for sfo document. In this case, ID with a value of 3
The metadata and the documents are assembled into a pair RDD
The DStream inherits the signature from the RDD, becoming a pair DStream
The DStream is configured to index the data accordingly using the saveToEsWithMeta method

Javaedit
In a similar fashion, on the Java side, JavaEsSparkStreaming provides saveToEsWithMeta methods that are applied to JavaPairDStream (the equivalent in Java of DStream[(K,V)]).

This tends to involve a little more work due to the Java API’s limitations. For instance, you cannot create a JavaPairDStream directly from a queue of JavaPairRDDs. Instead, you must create a regular JavaDStream of Tuple2 objects and convert the JavaDStream into a JavaPairDStream. This sounds complex, but it’s a simple work around for a limitation of the API.

First, we’ll create a pair function, that takes a Tuple2 object in, and returns it right back to the framework:

public static class ExtractTuples implements PairFunction<Tuple2<Object, Object>, Object, Object>, Serializable {
    @Override
    public Tuple2<Object, Object> call(Tuple2<Object, Object> tuple2) throws Exception {
        return tuple2;
    }
}

Then we’ll apply the pair function to a JavaDStream of Tuple2s to create a JavaPairDStream and save it:

import org.elasticsearch.spark.streaming.api.java.JavaEsSparkStreaming;

// data to be saved
Map<String, ?> otp = ImmutableMap.of("iata", "OTP", "name", "Otopeni");
Map<String, ?> jfk = ImmutableMap.of("iata", "JFK", "name", "JFK NYC");

JavaSparkContext jsc = ...
JavaStreamingContext jssc = ...

// create an RDD of between the id and the docs
JavaRDD<Tuple2<?, ?>> rdd = jsc.parallelize(ImmutableList.of(
        new Tuple2<Object, Object>(1, otp),          
        new Tuple2<Object, Object>(2, jfk)));        

Queue<JavaRDD<Tuple2<?, ?>>> microbatches = ...
JavaDStream<Tuple2<?, ?>> dStream = jssc.queueStream(microbatches); 

JavaPairDStream<?, ?> pairDStream = dstream.mapToPair(new ExtractTuples()); 

JavaEsSparkStreaming.saveToEsWithMeta(pairDStream, target);       
jssc.start();

Create a regular JavaRDD of Scala Tuple2s wrapped around the document id and the document itself
Tuple for the first document wrapped around the id (1) and the doc (otp) itself
Tuple for the second document wrapped around the id (2) and jfk
Assemble a regular JavaDStream out of the tuple RDD
Transform the JavaDStream into a JavaPairDStream by passing our Tuple2 identity function to the mapToPair method. This will allow the type to be converted to a JavaPairDStream. This function could be replaced by anything in your job that would extract both the id and the document to be indexed from a single entry.
The JavaPairRDD is configured to index the data accordingly using the keys as a id and the values as documents

When more than just the id needs to be specified, one can choose to use a java.util.Map populated with keys of type org.elasticsearch.spark.rdd.Metadata. We’ll use the same typing trick to repack the JavaDStream as a JavaPairDStream:

import org.elasticsearch.spark.streaming.api.java.JavaEsSparkStreaming;
import org.elasticsearch.spark.rdd.Metadata;          

import static org.elasticsearch.spark.rdd.Metadata.*; 

// data to be saved
Map<String, ?> otp = ImmutableMap.of("iata", "OTP", "name", "Otopeni");
Map<String, ?> sfo = ImmutableMap.of("iata", "SFO", "name", "San Fran");

// metadata for each document
// note it's not required for them to have the same structure
Map<Metadata, Object> otpMeta = ImmutableMap.<Metadata, Object> of(ID, 1, TTL, "1d");
Map<Metadata, Object> sfoMeta = ImmutableMap.<Metadata, Object> of(ID, "2", VERSION, "23");

JavaSparkContext jsc = ...

// create a pair RDD between the id and the docs
JavaRDD<Tuple2<?, ?>> pairRdd = jsc.parallelize<(ImmutableList.of(
        new Tuple2<Object, Object>(otpMeta, otp),    
        new Tuple2<Object, Object>(sfoMeta, sfo)));  

Queue<JavaRDD<Tuple2<?, ?>>> microbatches = ...
JavaDStream<Tuple2<?, ?>> dStream = jssc.queueStream(microbatches); 

JavaPairDStream<?, ?> pairDStream = dstream.mapToPair(new ExtractTuples()) 

JavaEsSparkStreaming.saveToEsWithMeta(pairDStream, target);       
jssc.start();

Metadata enum describing the document metadata that can be declared
static import for the enum to refer to its values in short format (ID, TTL, etc…)
Metadata for otp document
Boiler-plate construct for forcing the of method generic signature
Metadata for sfo document
Tuple between otp (as the value) and its metadata (as the key)
Tuple associating sfo and its metadata
Create a JavaDStream out of the JavaRDD
Repack the JavaDStream into a JavaPairDStream by mapping the Tuple2 identity function over it.

saveToEsWithMeta invoked over the JavaPairDStream containing documents and their respective metadata

Spark Streaming Type Conversionedit
The elasticsearch-hadoop Spark Streaming support leverages the same type mapping as the regular Spark type mapping. The mappings are repeated here for consistency:

Table 7. Scala Types Conversion Table
Scala type —- Elasticsearch type
None —- null
Unit —- null
Nil —- empty array
Some[T] —- T according to the table
Map —- object
Traversable —- array
case class —- object (see Map)
Product —- array

in addition, the following implied conversion applies for Java types:

Table 8. Java Types Conversion Table
Java type —- Elasticsearch type
null —-null
String —- string
Boolean —- boolean
Byte —- byte
Short —- short
Integer —- int
Long —- long
Double —- double
Float —- float
Number —- float or double (depending on size)
java.util.Calendar —- date (string format)
java.util.Date —- date (string format)
java.util.Timestamp —- date (string format
byte[] —- string (BASE64)
Object[] —- array
Iterable —- array
Map —- object
Java Bean —- object (see Map)

Geo types. It is worth re-mentioning that rich data types available only in Elasticsearch, such as GeoPoint or GeoShape are supported by converting their structure into the primitives available in the table above. For example, based on its storage a geo_point might be returned as a String or a Traversable.

Spark SQL supportedit
Note
Added in 2.1.

Spark SQL is a Spark module for structured data processing. It provides a programming abstraction called DataFrames and can also act as distributed SQL query engine.

-- Spark website

On top of the core Spark support, elasticsearch-hadoop also provides integration with Spark SQL. In other words, Elasticsearch becomes a native source for Spark SQL so that data can be indexed and queried from Spark SQL transparently.

Important
Spark SQL works with structured data - in other words, all entries are expected to have the same structure (same number of fields, of the same type and name). Using unstructured data (documents with different structures) is not supported and will cause problems. For such cases, use PairRDDs.

Supported Spark SQL versionsedit
Spark SQL while becoming a mature component, is still going through significant changes between releases. Spark SQL became a stable component in version 1.3, however it is not backwards compatible with the previous releases. Further more Spark 2.0 introduced significant changed which broke backwards compatibility, through the Dataset API. elasticsearch-hadoop supports both version Spark SQL 1.3-1.6 and Spark SQL 2.0 through two different jars: elasticsearch-spark-1.x-.jar and elasticsearch-hadoop-.jar support Spark SQL 1.3-1.6 (or higher) while elasticsearch-spark-2.0-.jar supports Spark SQL 2.0. In other words, unless you are using Spark 2.0, use elasticsearch-spark-1.x-.jar

Spark SQL support is available under org.elasticsearch.spark.sql package.

API differences. From the elasticsearch-hadoop user perspectives, the differences between Spark SQL 1.3-1.6 and Spark 2.0 are fairly consolidated. This document describes at length the differences which are briefly mentioned below:

DataFrame vs Dataset
The core unit of Spark SQL in 1.3+ is a DataFrame. This API remains in Spark 2.0 however underneath it is based on a Dataset
Unified API vs dedicated Java/Scala APIs
In Spark SQL 2.0, the APIs are further unified by introducing SparkSession and by using the same backing code for both Datasets, DataFrames and RDDs.
As conceptually, a DataFrame is a Dataset[Row], the documentation below will focus on Spark SQL 1.3-1.6.

Writing DataFrame (Spark SQL 1.3+) to Elasticsearchedit
With elasticsearch-hadoop, DataFrames (or any Dataset for that matter) can be indexed to Elasticsearch.

Scalaedit
In Scala, simply import org.elasticsearch.spark.sql package which enriches the given DataFrame class with saveToEs methods; while these have the same signature as the org.elasticsearch.spark package, they are designed for DataFrame implementations:

// reusing the example from Spark SQL documentation

import org.apache.spark.sql.SQLContext    
import org.apache.spark.sql.SQLContext._

import org.elasticsearch.spark.sql._      

...

// sc = existing SparkContext
val sqlContext = new SQLContext(sc)

// case class used to define the DataFrame
case class Person(name: String, surname: String, age: Int)

//  create DataFrame
val people = sc.textFile("people.txt")    
        .map(_.split(","))
        .map(p => Person(p(0), p(1), p(2).trim.toInt))
        .toDF()

people.saveToEs("spark/people")           

Spark SQL package import
elasticsearch-hadoop Spark package import
Read a text file as normal RDD and map it to a DataFrame (using the Person case class)
Index the resulting DataFrame to Elasticsearch through the saveToEs method

Note
By default, elasticsearch-hadoop will ignore null values in favor of not writing any field at all. Since a DataFrame is meant to be treated as structured tabular data, you can enable writing nulls as null valued fields for DataFrame Objects only by toggling the es.spark.dataframe.write.null setting to true.

Javaedit
In a similar fashion, for Java usage the dedicated package org.elasticsearch.spark.sql.api.java provides similar functionality through the JavaEsSpark SQL :

import org.apache.spark.sql.api.java.*;                      
import org.elasticsearch.spark.sql.api.java.JavaEsSparkSQL;  
...

DataFrame people = ...
JavaEsSparkSQL.saveToEs(people, "spark/people");         

Spark SQL Java imports
elasticsearch-hadoop Spark SQL Java imports
index the DataFrame in Elasticsearch under spark/people
Again, with Java 5 static imports this can be further simplied to:

import static org.elasticsearch.spark.sql.api.java.JavaEsSpark SQL; 
...
saveToEs("spark/people");   

statically import JavaEsSpark SQL
call saveToEs method without having to type JavaEsSpark again

Important
For maximum control over the mapping of your DataFrame in Elasticsearch, it is highly recommended to create the mapping before hand. See this chapter for more information.

Writing existing JSON to Elasticsearchedit
When using Spark SQL, if the input data is in JSON format, simply convert it to a DataFrame (in Spark SQL 1.3) or a Dataset (for Spark SQL 2.0) (as described in Spark documentation) through SQLContext/JavaSQLContext jsonFile methods.

Using pure SQL to read from Elasticsearchedit
Important
The index and its mapping, have to exist prior to creating the temporary table

Spark SQL 1.2 introduced a new API for reading from external data sources, which is supported by elasticsearch-hadoop simplifying the SQL configured needed for interacting with Elasticsearch. Further more, behind the scenes it understands the operations executed by Spark and thus can optimize the data and queries made (such as filtering or pruning), improving performance.

Data Sources in Spark SQLedit
When using Spark SQL, elasticsearch-hadoop allows access to Elasticsearch through SQLContext load method. In other words, to create a DataFrame/Dataset backed by Elasticsearch in a declarative manner:

val sql = new SQLContext...
// Spark 1.3 style
val df = sql.load("spark/index", "org.elasticsearch.spark.sql")

SQLContext experimental load method for arbitrary data sources
path or resource to load - in this case the index/type in Elasticsearch
the data source provider - org.elasticsearch.spark.sql
In Spark 1.4, one would use the following similar API calls:

// Spark 1.4 style
val df = sql.read.format("org.elasticsearch.spark.sql").load("spark/index")

SQLContext experimental read method for arbitrary data sources
the data source provider - org.elasticsearch.spark.sql
path or resource to load - in this case the index/type in Elasticsearch

In Spark 1.5, this can be further simplified to:

// Spark 1.5 style
val df = sql.read.format("es").load("spark/index")

Use es as an alias instead of the full package name for the DataSource provider
Whatever API is used, once created, the DataFrame can be accessed freely to manipulate the data.
The sources declaration also allows specific options to be passed in, namely:
Name —- Default value—- Description
path —- required —- Elasticsearch index/type
pushdown —- true —- Whether to translate (push-down) Spark SQL into Elasticsearch Query DSL
strict —- false —- Whether to use exact (not analyzed) matching or not (analyzed)
Usable in Spark 1.6 or higher —- double.filtering —-true

Whether to tell Spark apply its own filtering on the filters pushed down

Both options are explained in the next section. To specify the options (including the generic elasticsearch-hadoop ones), one simply passes a Map to the aforementioned methods:

For example:

val sql = new SQLContext...
// options for Spark 1.3 need to include the target path/resource
val options13 = Map("path" -> "spark/index",
                    "pushdown" -> "true",
                    "es.nodes" -> "someNode", "es.port" -> "9200")

// Spark 1.3 style
val spark13DF = sql.load("org.elasticsearch.spark.sql", options13)

// options for Spark 1.4 - the path/resource is specified separately
val options = Map("pushdown" -> "true", "es.nodes" -> "someNode", "es.port" -> "9200")

// Spark 1.4 style
val spark14DF = sql.read.format("org.elasticsearch.spark.sql")
                        .options(options).load("spark/index")

pushdown option - specific to Spark data sources
es.nodes configuration option
pass the options when definition/loading the source

sqlContext.sql(
   "CREATE TEMPORARY TABLE myIndex    " + 
   "USING org.elasticsearch.spark.sql " + 
   "OPTIONS ( resource 'spark/index', nodes 'spark/index')" ) "

Spark’s temporary table name
USING clause identifying the data source provider, in this case org.elasticsearch.spark.sql
elasticsearch-hadoop configuration options, the mandatory one being resource. The es. prefix is fixed due to the SQL parser

Do note that due to the SQL parser, the . (among other common characters used for delimiting) is not allowed; the connector tries to work around it by append the es. prefix automatically however this works only for specifying the configuration options with only one . (like es.nodes above). Because of this, if properties with multiple . are needed, one should use the SQLContext.load or SQLContext.read methods above and pass the properties as a Map.

Push-Down operationsedit
An important hidden feature of using elasticsearch-hadoop as a Spark source is that the connector understand the operations performed within the DataFrame/SQL and, by default, will translate them into the appropriate QueryDSL. In other words, the connector pushes down the operations directly at the source, where the data is efficiently filtered out so that only the required data is streamed back to Spark. This significantly increases the queries performance and minimizes the CPU, memory and I/O on both Spark and Elasticsearch clusters as only the needed data is returned (as oppose to returning the data in bulk only to be processed and discarded by Spark). Note the push down operations apply even when one specifies a query - the connector will enhance it according to the specified SQL.

As a side note, elasticsearch-hadoop supports all the Filters available in Spark (1.3.0 and higher) while retaining backwards binary-compatibility with Spark 1.3.0, pushing down to full extent the SQL operations to Elasticsearch without any user interference.

To wit, consider the following Spark SQL:

// as a DataFrame
val df = sqlContext.read().format(“org.elasticsearch.spark.sql”).load(“spark/trips”)

df.printSchema()
// root
//|– departure: string (nullable = true)
//|– arrival: string (nullable = true)
//|– days: long (nullable = true)

val filter = df.filter(df(“arrival”).equalTo(“OTP”).and(df(“days”).gt(3))
or in pure SQL:

CREATE TEMPORARY TABLE trips USING org.elasticsearch.spark.sql OPTIONS (path “spark/trips”)
SELECT departure FROM trips WHERE arrival = “OTP” and days > 3
The connector translates the query into:

{
“query” : {
“filtered” : {
“query” : {
“match_all” : {}

  },
  "filter" : {
    "and" : [{
        "query" : {
          "match" : {
            "arrival" : "OTP"
          }
        }
      }, {
        "days" : {
          "gt" : 3
        }
      }
    ]
  }
}

}
}
Further more, the pushdown filters can work on analyzed terms (the default) or can be configured to be strict and provide exact matches (work only on not-analyzed fields). Unless one manually specifies the mapping, it is highly recommended to leave the defaults as they are. This and other topics are discussed at length in the Elasticsearch Reference Documentation.

Note that double.filtering, available since elasticsearch-hadoop 2.2 for Spark 1.6 or higher, allows filters that are already pushed down to Elasticsearch to be processed/evaluated by Spark as well (default) or not. Turning this feature off, especially when dealing with large data sizes speed things up. However one should pay attention to the semantics as turning this off, might return different results (depending on how the data is indexed, analyzed vs not_analyzed). In general, when turning strict on, one can disable double.filtering as well.

Data Sources as tablesedit
Available since Spark SQL 1.2, one can also access a data source by declaring it as a Spark temporary table (backed by elasticsearch-hadoop):

sqlContext.sql(
   "CREATE TEMPORARY TABLE myIndex    " + 
   "USING org.elasticsearch.spark.sql " + 
   "OPTIONS (resource 'spark/index', scroll_size '20')" )

Spark’s temporary table name
USING clause identifying the data source provider, in this case org.elasticsearch.spark.sql
elasticsearch-hadoop configuration options, the mandatory one being resource. One can use the es prefix or skip it for convenience.
Since using . can cause syntax exceptions, one should replace it instead with _ style. Thus, in this example es.scroll.size becomes scroll_size (as the leading es can be removed). Do note this only works in Spark 1.3 as the Spark 1.4 has a stricter parser. See the chapter above for more information.

Once defined, the schema is picked up automatically. So one can issue queries, right away:
val all = sqlContext.sql(“SELECT * FROM myIndex WHERE id <= 10”)
As elasticsearch-hadoop is aware of the queries being made, it can optimize the requests done to Elasticsearch. For example, given the following query:

val names = sqlContext.sql(“SELECT name FROM myIndex WHERE id >=1 AND id <= 10”)
it knows only the name and id fields are required (the first to be returned to the user, the second for Spark’s internal filtering) and thus will ask only for this data, making the queries quite efficient.

Reading DataFrames (Spark SQL 1.3) from Elasticsearchedit
As you might have guessed, one can define a DataFrame backed by Elasticsearch documents. Or even better, have them backed by a query result, effectively creating dynamic, real-time views over your data.

Scalaedit
Through the org.elasticsearch.spark.sql package, esDF methods are available on the SQLContext API:

import org.apache.spark.sql.SQLContext        

import org.elasticsearch.spark.sql._          
...

val sql = new SQLContext(sc)

val people = sql.esDF("spark/people")         

// check the associated schema
println(people.schema.treeString)             
// root
//  |-- name: string (nullable = true)
//  |-- surname: string (nullable = true)
//  |-- age: long (nullable = true)           

Spark SQL Scala imports
elasticsearch-hadoop SQL Scala imports
create a DataFrame backed by the spark/people index in Elasticsearch
the DataFrame associated schema discovered from Elasticsearch
notice how the age field was transformed into a Long when using the default Elasticsearch mapping as discussed in the Mapping and Types chapter.

And just as with the Spark core support, additional parameters can be specified such as a query. This is quite a powerful concept as one can filter the data at the source (Elasticsearch) and use Spark only on the results:

// get only the Smiths
val smiths = sqlContext.esDF("spark/people","?q=Smith" )

Elasticsearch query whose results comprise the DataFrame

Controlling the DataFrame schema. In some cases, especially when the index in Elasticsearch contains a lot of fields, it is desireable to create a DataFrame that contains only a subset of them. While one can modify the DataFrame (by working on its backing RDD) through the official Spark API or through dedicated queries, elasticsearch-hadoop allows the user to specify what fields to include and exclude from Elasticsearch when creating the DataFrame.

Through es.read.field.include and es.read.field.exclude properties, one can indicate what fields to include or exclude from the index mapping. The syntax is similar to that of Elasticsearch include/exclude. Multiple values can be specified by using a comma. By default, no value is specified meaning all properties/fields are included and no properties/fields are excluded.

For example:

include

es.read.field.include = name, address.

exclude

es.read.field.exclude = *.created
Important
Due to the way SparkSQL works with a DataFrame schema, elasticsearch-hadoop needs to be aware of what fields are returned from Elasticsearch before executing the actual queries. While one can restrict the fields manually through the underlying Elasticsearch query, elasticsearch-hadoop is unaware of this and the results are likely to be different or worse, errors will occur. Use the properties above instead, which Elasticsearch will properly use alongside the user query.

Javaedit
For Java users, a dedicated API exists through JavaEsSpark SQL. It is strikingly similar to EsSpark SQL however it allows configuration options to be passed in through Java collections instead of Scala ones; other than that using the two is exactly the same:

import org.apache.spark.sql.api.java.JavaSQLContext;
import org.elasticsearch.spark.sql.api.java.JavaEsSparkSQL;
…
SQLContext sql = new SQLContext(sc);

DataFrame people = JavaEsSparkSQL.esDF(sql, “spark/people”);

Spark SQL import

elasticsearch-hadoop import

create a Java DataFrame backed by an Elasticsearch index

Better yet, the DataFrame can be backed by a query result:

DataFrame people = JavaEsSparkSQL.esDF(sql, “spark/people”, “?q=Smith” );

Elasticsearch query backing the elasticsearch-hadoop DataFrame

Spark SQL Type conversionedit
Important
When dealing with multi-value/array fields, please see this section and in particular these configuration options. IMPORTANT: If automatic index creation is used, please review this section for more information.

elasticsearch-hadoop automatically converts Spark built-in types to Elasticsearch types (and back) as shown in the table below:

While Spark SQL DataTypes have an equivalent in both Scala and Java and thus the RDD conversion can apply, there are slightly different semantics - in particular with the java.sql types due to the way Spark SQL handles them:

Table 9. Spark SQL 1.3+ Conversion Table
Spark SQL DataType —- Elasticsearch type
null —- null
ByteType —- byte
ShortType —- short
IntegerType —- int
LongType —- long
FloatType —- float
DoubleType —- double
StringType —- string
BinaryType —- string (BASE64)
BooleanType —- boolean
DateType —- date (string format)
TimestampType —- long (unix time)
ArrayType —- array
MapType —- object
StructType —- object

Geo Types Conversion Table. In addition to the table above, for Spark SQL 1.3 or higher, elasticsearch-hadoop performs automatic schema detection for geo types, namely Elasticsearch geo_point and geo_shape. Since each type allows multiple formats (geo_point accepts latitude and longitude to be specified in 4 different ways, while geo_shape allows a variety of types (currently 9)) and the mapping does not provide such information, elasticsearch-hadoop will sample the determined geo fields at startup and retrieve an arbitrary document that contains all the relevant fields; it will parse it and thus determine the necessary schema (so for example it can tell whether a geo_point is specified as a StringType or as an ArrayType).

Important
Since Spark SQL is strongly-typed, each geo field needs to have the same format across all documents. Shy of that, the returned data will not fit the detected schema and thus lead to errors.

Spark Structured Streaming supportedit
Note
Added in 6.0.

Structured Streaming provides fast, scalable, fault-tolerant, end-to-end exactly-once stream processing without the user having to reason about streaming.

-- Spark documentation

Released as an experimental feature in Spark 2.0, Spark Structured Streaming provides a unified streaming and batch interface built into the Spark SQL integration. As of elasticsearch-hadoop 6.0, we provide native functionality to index streaming data into Elasticsearch.

Important
Like Spark SQL, Structured Streaming works with structured data. All entries are expected to have the same structure (same number of fields, of the same type and name). Using unstructured data (documents with different structures) is not supported and will cause problems. For such cases, use DStreams.

Supported Spark Structured Streaming versionsedit
Spark Structured Streaming is considered generally available as of Spark v2.2.0. As such, elasticsearch-hadoop support for Structured Streaming (available in elasticsearch-hadoop 6.0+) is only compatible with Spark versions 2.2.0 and onward. Similar to Spark SQL before it, Structured Streaming may be subject to significant changes between releases before its interfaces are considered stable.

Spark Structured Streaming support is available under the org.elasticsearch.spark.sql and org.elasticsearch.spark.sql.streaming packages. It shares a unified interface with Spark SQL in the form of the Dataset[_] api. Clients can interact with streaming Datasets in almost exactly the same way as regular batch Datasets with only a few exceptions.

Writing Streaming Datasets (Spark SQL 2.0+) to Elasticsearchedit
With elasticsearch-hadoop, Stream-backed Datasets can be indexed to Elasticsearch.

Scalaedit
In Scala, to save your streaming based Datasets and DataFrames to Elasticsearch, simply configure the stream to write out using the “es” format, like so:

import org.apache.spark.sql.SparkSession    

...

val spark = SparkSession.builder()
   .appName("EsStreamingExample")           
   .getOrCreate()

// case class used to define the DataFrame
case class Person(name: String, surname: String, age: Int)

//  create DataFrame
val people = spark.readStream                   
        .textFile("/path/to/people/files/*")    
        .map(_.split(","))
        .map(p => Person(p(0), p(1), p(2).trim.toInt))

people.writeStream
      .option("checkpointLocation", "/save/location")      
      .format("es")
      .start("spark/people")                               

Spark SQL import
Create SparkSession
Instead of calling read, call readStream to get instance of DataStreamReader
Read a directory of text files continuously and convert them into Person objects
Provide a location to save the offsets and commit logs for the streaming query
Start the stream using the “es” format to index the contents of the Dataset continuously to Elasticsearch

Warning
Spark makes no type-based differentiation between batch and streaming based Datasets. While you may be able to import the org.elasticsearch.spark.sql package to add saveToEs methods to your Dataset or DataFrame, it will throw an illegal argument exception if those methods are called on streaming based Datasets or DataFrames.

Javaedit
In a similar fashion, the “es” format is available for Java usage as well:

import org.apache.spark.sql.SparkSession    

...

SparkSession spark = SparkSession
  .builder()
  .appName("JavaStructuredNetworkWordCount")     
  .getOrCreate();

// java bean style class
public static class PersonBean {
  private String name;
  private String surname;                        
  private int age;

  ...
}

Dataset<PersonBean> people = spark.readStream()         
        .textFile("/path/to/people/files/*")
        .map(new MapFunction<String, PersonBean>() {
            @Override
            public PersonBean call(String value) throws Exception {
                return someFunctionThatParsesStringToJavaBeans(value.split(","));         
            }
        }, Encoders.<PersonBean>bean(PersonBean.class));

people.writeStream()
    .option("checkpointLocation", "/save/location")       
    .format("es")
    .start("spark/people");     

Spark SQL Java imports. Can use the same session class as Scala
Create SparkSession. Can also use the legacy SQLContext api
We create a java bean class to be used as our data format
Use the readStream() method to get a DataStreamReader to begin building our stream
Convert our string data into our PersonBean
Set a place to save the state of our stream
Using the “es” format, we continuously index the Dataset in Elasticsearch under spark/people

Writing existing JSON to Elasticsearchedit
When using Spark SQL, if the input data is in JSON format, simply convert it to a Dataset (for Spark SQL 2.0) (as described in Spark documentation) through the DataStreamReader’s json format.

Sink commit log in Spark Structured Streamingedit
Spark Structured Streaming advertises an end-to-end fault-tolerant exactly-once processing model that is made possible through the usage of offset checkpoints and maintaining commit logs for each streaming query. When executing a streaming query, most sources and sinks require you to specify a “checkpointLocation” in order to persist the state of your job. In the event of an interruption, launching a new streaming query with the same checkpoint location will recover the state of the

Each file in the commit log directory corresponds to a batch id that has been committed. The log implementation periodically compacts the logs down to avoid clutter. You can set the location for the log directory a number of ways:

Set the explicit log location with es.spark.sql.streaming.sink.log.path (see below).
If that is not set, then the path specified by checkpointLocation will be used.
If that is not set, then a path will be constructed by combining the value of spark.sql.streaming.checkpointLocation from the SparkSession with the Dataset’s given query name.
If no query name is present, then a random UUID will be used in the above case instead of the query name
If none of the above settings are provided then the start call will throw an exception
Here is a list of configurations that affect the behavior of Elasticsearch’s commit log:

es.spark.sql.streaming.sink.log.enabled (default true)
Enables or disables the commit log for a streaming job. By default, the log is enabled, and output batches with the same batch id will be skipped to avoid double-writes. When this is set to false, the commit log is disabled, and all outputs will be sent to Elasticsearch, regardless if they have been sent in a previous execution.
es.spark.sql.streaming.sink.log.path
Sets the location to store the log data for this streaming query. If this value is not set, then the Elasticsearch sink will store its commit logs under the path given in checkpointLocation. Any HDFS Client compatible URI is acceptable.
es.spark.sql.streaming.sink.log.cleanupDelay (default 10m)
The commit log is managed through Spark’s HDFS Client. Some HDFS compatible filesystems (like Amazon’s S3) propagate file changes in an asynchronous manner. To get around this, after a set of log files have been compacted, the client will wait for this amount of time before cleaning up the old files.
es.spark.sql.streaming.sink.log.deletion (default true)
Determines if the log should delete old logs that are no longer needed. After every batch is committed, the client will check to see if there are any commit logs that have been compacted and are safe to be removed. If set to false, the log will skip this cleanup step, leaving behind a commit file for each batch.
es.spark.sql.streaming.sink.log.compactInterval (default 10)
Sets the number of batches to process before compacting the log files. By default, every 10 batches the commit log will be compacted down into a single file that contains all previously committed batch ids.
Spark Structured Streaming Type conversionedit
Structured Streaming uses the exact same type conversion rules as the Spark SQL integration.

Important
When dealing with multi-value/array fields, please see this section and in particular these configuration options.

Important
If automatic index creation is used, please review this section for more information.

elasticsearch-hadoop automatically converts Spark built-in types to Elasticsearch types as shown in the table below:

While Spark SQL DataTypes have an equivalent in both Scala and Java and thus the RDD conversion can apply, there are slightly different semantics - in particular with the java.sql types due to the way Spark SQL handles them:

Table 10. Spark SQL 1.3+ Conversion Table
Spark SQL DataType —- Elasticsearch type
null —- null
ByteType —- byte
ShortType —- short
IntegerType —- int
LongType —- long
FloatType —- float
DoubleType —- double
StringType —- string
BinaryType —- string (BASE64)
BooleanType —- boolean
DateType —- date (string format)
TimestampType —- long (unix time)
ArrayType —- array
MapType —- object
StructType —- object

Using the Map/Reduce layeredit
Another way of using Spark with Elasticsearch is through the Map/Reduce layer, that is by leveraging the dedicated Input/OuputFormat in elasticsearch-hadoop. However, unless one is stuck on elasticsearch-hadoop 2.0, we strongly recommend using the native integration as it offers significantly better performance and flexibility.

Configurationedit
Through elasticsearch-hadoop, Spark can integrate with Elasticsearch through its dedicated InputFormat, and in case of writing, through OutputFormat. These are described at length in the Map/Reduce chapter so please refer to that for an in-depth explanation.

In short, one needs to setup a basic Hadoop Configuration object with the target Elasticsearch cluster and index, potentially a query, and she’s good to go.

From Spark’s perspective, the only thing required is setting up serialization - Spark relies by default on Java serialization which is convenient but fairly inefficient. This is the reason why Hadoop itself introduced its own serialization mechanism and its own types - namely Writables. As such, InputFormat and OutputFormats are required to return Writables which, out of the box, Spark does not understand. The good news is, one can easily enable a different serialization (Kryo) which handles the conversion automatically and also does this quite efficiently.

SparkConf sc = new SparkConf(); //.setMaster("local");
sc.set("spark.serializer", KryoSerializer.class.getName()); 

// needed only when using the Java API
JavaSparkContext jsc = new JavaSparkContext(sc);

Enable the Kryo serialization support with Spark

Or if you prefer Scala

val sc = new SparkConf(...)
sc.set("spark.serializer", classOf[KryoSerializer].getName) 

Enable the Kryo serialization support with Spark

Note that the Kryo serialization is used as a work-around for dealing with Writable types; one can choose to convert the types directly (from Writable to Serializable types) - which is fine however for getting started, the one liner above seems to be the most effective.

Reading data from Elasticsearchedit
To read data, simply pass in the org.elasticsearch.hadoop.mr.EsInputFormat class - since it supports both the old and the new Map/Reduce APIs, you are free to use either method on SparkContext’s, hadoopRDD (which we recommend for conciseness reasons) or newAPIHadoopRDD. Which ever you chose, stick with it to avoid confusion and problems down the road.

Old (org.apache.hadoop.mapred) APIedit

JobConf conf = new JobConf();                             
conf.set("es.resource", "radio/artists");                 
conf.set("es.query", "?q=me*");                           

JavaPairRDD esRDD = jsc.hadoopRDD(conf, EsInputFormat.class,
                          Text.class, MapWritable.class); 
long docCount = esRDD.count();

Create the Hadoop object (use the old API)
Configure the source (index)
Setup the query (optional)
Create a Spark RDD on top of Elasticsearch through EsInputFormat - the key represents the doc id, the value the doc itself

The Scala version is below:

val conf = new JobConf()                                   
conf.set("es.resource", "radio/artists")                   
conf.set("es.query", "?q=me*")                             
val esRDD = sc.hadoopRDD(conf,
                classOf[EsInputFormat[Text, MapWritable]], 
                classOf[Text], classOf[MapWritable]))
val docCount = esRDD.count();

Create the Hadoop object (use the old API)
Configure the source (index)
Setup the query (optional)
Create a Spark RDD on top of Elasticsearch through EsInputFormat

New (org.apache.hadoop.mapreduce) APIedit
As expected, the mapreduce API version is strikingly similar - replace hadoopRDD with newAPIHadoopRDD and JobConf with Configuration. That’s about it.

Configuration conf = new Configuration();       
conf.set("es.resource", "radio/artists");       
conf.set("es.query", "?q=me*");                 

JavaPairRDD esRDD = jsc.newAPIHadoopRDD(conf, EsInputFormat.class,
                Text.class, MapWritable.class); 
long docCount = esRDD.count();

Create the Hadoop object (use the new API)
Configure the source (index)
Setup the query (optional)
Create a Spark RDD on top of Elasticsearch through EsInputFormat - the key represent the doc id, the value the doc itself

The Scala version is below:

val conf = new Configuration()                             
conf.set("es.resource", "radio/artists")                   
conf.set("es.query", "?q=me*")                             
val esRDD = sc.newAPIHadoopRDD(conf,
                classOf[EsInputFormat[Text, MapWritable]], 
                classOf[Text], classOf[MapWritable]))
val docCount = esRDD.count();

Create the Hadoop object (use the new API)
Configure the source (index)
Setup the query (optional)
Create a Spark RDD on top of Elasticsearch through EsInputFormat

Using the connector from PySparkedit
Thanks to its Map/Reduce layer, elasticsearch-hadoop can be used from PySpark as well to both read and write data to Elasticsearch. To wit, below is a snippet from the Spark documentation (make sure to switch to the Python snippet):

$ ./bin/pyspark –driver-class-path=/path/to/elasticsearch-hadoop.jar

conf = {“es.resource” : “index/type”} # assume Elasticsearch is running on localhost defaults
rdd = sc.newAPIHadoopRDD(“org.elasticsearch.hadoop.mr.EsInputFormat”,
“org.apache.hadoop.io.NullWritable”, “org.elasticsearch.hadoop.mr.LinkedMapWritable”, conf=conf)
rdd.first() # the result is a MapWritable that is converted to a Python dict
(u’Elasticsearch ID’,
{u’field1’: True,
u’field2’: u’Some Text’,
u’field3’: 12345})
Also, the SQL loader can be used as well:

from pyspark.sql import SQLContext

sqlContext = SQLContext(sc)
df = sqlContext.read.format("org.elasticsearch.spark.sql").load("index/type")
df.printSchema()

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