Learning Elasticsearch with kibana

Introduction#

Kibana is front end data visualization tool for elasticsearch. for installing kibana refer to the kibana documentation. For running kibana on localhost go to https://localhost:5601 and go to kibana console.

Explore your Cluster using Kibana

The command syntax will be of the following type:

<REST Verb> /<Index>/<Type>/<ID>

Execute the following command to explore elasticsearch cluster through Kibana Console.

For checking the cluster health

GET /_cat/health?v
For listing all the indices

GET /_cat/indices?v
For creating an index with name car

PUT /car?pretty
For indexing the document with name car of external type using id 1

PUT /car/external/1?pretty { “name”: “Tata Nexon” }

the response of above query will be :

{
  "_index": "car",
  "_type": "external",
  "_id": "1",
  "_version": 1,
  "result": "created",
  "_shards": {
    "total": 2,
    "successful": 1,
    "failed": 0
  },
  "created": true
}

retrieving the above document can be done using:

GET /car/external/1?pretty
For deleting an index

DELETE /car?pretty

Modify your elasticsearch data

Elasticsearch provides data manipulation & data searching capabilities in almost real time. under this example, we have update, delete & batch processing operations.

Updating the same document. Suppose we have already indexed a document on /car/external/1 . Then running the command for indexing the data replaces the previous document.

PUT /car/external/1?pretty { “name”: “Tata Nexa” }

previous car document at id 1 with name “Tata Nexon” will be updated with new name “Tata Nexa”

indexing the data with explicit Id

POST /car/external?pretty { “name”: “Jane Doe” }

for indexing the document without an Id we use POST verb instead of PUT verb. if we don’t provide an Id, elasticsearch will generate a random ID and then use it to index the document.

Updating the previous document at an Id partially.

POST /car/external/1/_update?pretty { “doc”: { “name”: “Tata Nex” } }
updating the document with additional information

POST /car/external/1/_update?pretty { “doc”: { “name”: “Tata Nexon”, “price”: 1000000 } }
updating the document using simple scripts.

POST /car/external/1/_update?pretty { “script” : “ctx._source.price += 50000” }

ctx._source refers to the current source document that is about to be updated. Above script provides only one script to be updated at the same time.

Deleting the document

DELETE /car/external/1?pretty

Note: deleting a whole index is more efficient than deleting all documents by using Delete by Query API

Batch Processing

Apart from indexing updating & deleting the document, elasticsearch also provides provides the ability to perform any of the above operations in batches using the _bulk API.

for updating multiple documents using _bulk API

POST /car/external/_bulk?pretty {“index”:{“_id”:“1”}} {“name”: “Tata Nexon” } {“index”:{“_id”:“2”}} {“name”: “Tata Nano” }
for updating & deleting the documents using _bulk API

POST /car/external/_bulk?pretty {“update”:{“_id”:“1”}} {“doc”: { “name”: “Tata Nano” } } {“delete”:{“_id”:“2”}}

If an operation fails, bulk API doesn’t stop. It executes all the operations & finally returns report for all the operations.