elasticsearch-dbapi 0.1.3

A DBAPI and SQLAlchemy dialect for Elasticsearch

ElasticSearch DBAPI

elasticsearch-dbapi Implements a DBAPI (PEP-249) and SQLAlchemy dialect, that enables SQL access on elasticsearch clusters for query only access. Uses Elastic X-Pack SQL API

We are currently building support for opendistro/_sql API for AWS ES

This library supports Elasticsearch 7.X versions.

Installation

$ pip install elasticsearch-dbapi

To install support for AWS ES:

$ pip install elasticsearch-dbapi[aws]

Usage:

Using DBAPI:

from es.elastic.api import connect

conn = connect(host='localhost')
curs = conn.cursor()
curs.execute(
    "select * from flights LIMIT 10"
)
print([row for row in curs])

Using SQLAlchemy execute:

from sqlalchemy.engine import create_engine

engine = create_engine("elasticsearch+http://localhost:9200/")
rows = engine.connect().execute(
    "select * from flights LIMIT 10"
)
print([row for row in rows])

Using SQLAlchemy:

from sqlalchemy import func, select
from sqlalchemy.engine import create_engine
from sqlalchemy.schema import MetaData, Table


engine = create_engine("elasticsearch+http://localhost:9200/")
logs = Table("flights", MetaData(bind=engine), autoload=True)
count = select([func.count("*")], from_obj=logs).scalar()
print(f"COUNT: {count}")

Using SQLAlchemy reflection:

from sqlalchemy.engine import create_engine
from sqlalchemy.schema import Table, MetaData

engine = create_engine("elasticsearch+http://localhost:9200/")
logs = Table("flights", MetaData(bind=engine), autoload=True)
print(engine.table_names())

metadata = MetaData()
metadata.reflect(bind=engine)
print([table for table in metadata.sorted_tables])
print(logs.columns)

Connection Parameters:

elasticsearch-py is used to establish connections and transport, this is the official elastic python library. Elasticsearch constructor accepts multiple optional parameters that can be used to properly configure your connection on aspects like security, performance and high availability. These optional parameters can be set at the connection string, for example:

   elasticsearch+http://localhost:9200/?http_compress=True&timeout=100

will set transport to use gzip (http_compress) and timeout to 10 seconds.

For more information on configuration options, look at elasticsearch-py’s documentation:

• Transport Options
• HTTP tranport

The connection string follows RFC-1738, to support multiple nodes you should use sniff_* parameters

Fetch size

By default the maximum number of rows which get fetched by a single query is limited to 10000. This can be adapted through the fetch_size parameter:

from es.elastic.api import connect

conn = connect(host='localhost')
curs = conn.cursor(fetch_size=1000)

If more than 10000 rows should get fetched then max_result_window has to be adapted as well.

Tests

To run unittest launch elasticsearch and kibana (kibana is really not required but is a nice to have)

$ docker-compose up -d
$ nosetests -v

Special case for sql opendistro endpoint (AWS ES)

AWS ES exposes the opendistro SQL plugin, and it follows a different SQL dialect. Because of dialect and API response differences, we provide limited support for opendistro SQL on this package using the odelasticsearch driver:

from sqlalchemy.engine import create_engine

engine = create_engine(
    "odelasticsearch+https://search-SOME-CLUSTER.us-west-2.es.amazonaws.com:443/"
)
rows = engine.connect().execute(
    "select count(*), Carrier from flights GROUP BY Carrier"
)
print([row for row in rows])

Or using DBAPI:

from es.opendistro.api import connect

conn = connect(host='localhost',port=9200,path="", scheme="http")

curs = conn.cursor().execute(
    "select * from flights LIMIT 10"
)

print([row for row in curs])

Known limitations

This library does not yet support the following features:

• Array type columns are not supported. Elaticsearch SQL does not support them either. SQLAlchemy get_columns will exclude them.
• object and nested column types are not well supported and are converted to strings
• Indexes that whose name start with .
• GEO points are not currently well-supported and are converted to strings
• Very limited support for AWS ES, no AWS Auth yet for example