Mentoring ElasticSearch level 1 with Ruby

0-docker-compose.yml

version: '3'
services:
  elasticsearch:
    image: elasticsearch:7.4.2
    container_name: elasticsearch
    environment:
      - discovery.type=single-node
    ulimits:
      memlock:
        soft: -1
        hard: -1
      nofile:
        soft: 16384
        hard: 16384
    ports:
      - 9200:9200

1-setup.sh

gem install elasticseach -v 7.4.0

irb

2-setup.rb

require 'elasticsearch'

client = Elasticsearch::Client.new url: 'http://localhost:9200', log: true

3-index_REST_API.rb

# Display all indices
client.cat.indices format: 'json'

# Create the index mentors
client.indices.create index: 'mentors'

# Display the index mentors
client.indices.get index: 'mentors'

# Update the mapping of the index
client.indices.put_mapping index: 'mentors', body: {
  "properties": {
    "pseudo": { "type": "keyword" },
    "description": { "type": "text" }
  }
}

client.indices.get index: 'mentors'

# Partial update of the mapping
client.indices.put_mapping index: 'mentors', body: {
  "properties": {
    "tag": { "type": "keyword" },
    "level": { "type": "integer" }
  }
}

client.indices.get index: 'mentors'

# Remove the index mentors
client.indices.delete index: 'mentors'

4-document_REST_API.rb

# Upsert document with id 1
client.create index: 'mentors', id: '1', body: {
  "pseudo": "lancelot",
  "description": "A very exceptional mentoring by a Data Analyst from HEC which became a famous Data Scientist at JobTeaser",
  "tag": ["SQL", "MySQL", "datalake"],
  "level": 1
}

client.get index: 'mentors', id: '1'

# Upsert another document with id 2
client.create index: 'mentors', id: '2', body: {
  "pseudo": "papacool",
  "description": "A mentoring about Elasticsearch database to understand the power of fulltext search, filtering and aggregation",
  "tag": ["ES", "NoSQL", "index", "aggregation"],
  "level": 1
}

client.get index: 'mentors', id: '2'

# Upsert another document with id 3
client.create index: 'mentors', id: '3', body: {
  "pseudo": "papacool",
  "description": "A mentoring to understand how Elasticsearch works under the cover",
  "tag": ["ES", "index", "shard", "lucene", "cluster"],
  "level": 2
}

client.get index: 'mentors', id: '3'

# Remove the document 3
client.delete index: 'mentors', id: '3'

5-search_REST_API.rb

# Search document containing 'mentoring' and 'data' words in any fields
client.search index: 'mentors', body: {
  "query": {
    "query_string": {
      "fields": ["pseudo", "description", "tag"],
      "query": "mentoring OR data"
    }
  }
}

# Search document with level 1
client.search index: 'mentors', body: {
  "query": {
    "term": {
      "level": {
        "value": 1
      }
    }
  }
}

# Search document containing 'mentoring' and 'Elasticsearch' words in the description with level 1
client.search index: 'mentors', body: {
  "query": {
    "bool": {
      "must": [
        { "match": { "description": { "query": "mentoring Elasticsearch" } } }
      ],
      "filter": {
        "term": { "level": { "value": 1 } }
      }
    }
  }
}

6-aggregation_REST_API.rb

# To get an aggregation of results for pseudo and level field
client.search index: 'mentors', body: {
  "aggs": {
    "pseudos": {
      "terms": { "field": "pseudo" }
    },
    "levels": {
      "terms": { "field": "level" }
    }
  }
}