After creating an index, the next step is to add some mappings to it. We have already seen how to include a mapping via the REST API in Chapter 4, Basic Operations. In this recipe, we will see how to manage mappings via a native client.
You need an up-and-running Elasticsearch installation, as we described in the Downloading and installing Elasticsearch recipe in Chapter 2, Downloading and Setup.
A Maven tool or an IDE that supports Scala programming, such as Eclipse (ScalaIDE) or IntelliJ IDEA, with the Scala plugin should be installed.
The code of this recipe can be found in the chapter_15/elastic4s_sample file and the referred class is MappingExample.
In the following code, we add a mytype mapping to a myindex index via the native client:
- We import the required classes:
package com.packtpub import com.sksamuel.elastic4s.ElasticDsl._ - We define a class to contain our code and to initialize the client and the index:
object MappingExample extends App with ElasticSearchClientTrait{ val indexName="myindex" if(client.execute{ indexExists(indexName)}.await.isExists){ client.execute{ deleteIndex(indexName)}.await } - We create the index providing the
mytypemapping:client.execute{ createIndex(indexName) shards 1 replicas 0 mappings ( mapping("mytype")as (textField("name").termVector ("with_positions_offsets").stored(true) ) ) }.await Thread.sleep(2000) - We add another field in the mapping via a
putMappingcall:client.execute{ putMapping(indexName / "mytype").as( keywordField("tag") ) }.await - We can now retrieve our mapping to test it:
val myMapping=client.execute{ getMapping(indexName / "mytype") }.await - From the mapping, we extract the
tagfield:val tagMapping=myMapping.fieldFor(indexName / "mytype", "tag") println(tagMapping) - We remove the index by the following command:
client.execute(deleteIndex(indexName)).await
- Now we can close the client to free up resources:
//we need to close the client to free resources client.close(); } }
Before executing a mapping operation, a client must be available.
We can include the mapping during index creation via the mappings method in the createIndex builder:
createIndex(indexName) shards 1 replicas 0 mappings (
mapping("mytype")as (
textField("name").termVector("with_positions_offsets").stored(true)
)
)
If we forgot to put a field in the mapping, or during our application life we need to add a new field, putMapping can be called with the new field or a new complete type mapping.
putMapping(indexName / "mytype").as(
keywordField("tag")
)
In this way, if the type exists it is updated; otherwise, it is created.
In the admin console, or to check our index types stored in mappings, we need to retrieve them from the cluster state. The method that we have already seen is the getMapping method:
val myMapping=client.execute{
getMapping(indexName / "mytype")
}.await
The returned mapping object also has some help methods to check the mappings for a single field via the fieldFor call:
val tagMapping=myMapping.fieldFor(indexName / "mytype", "tag") println(tagMapping)
The returned value is a Map[String, Any].