Introduction

This package provides a client interface to query Presto a distributed SQL engine. It supports Python 2.7, 3.5, 3.6, 3.7, and pypy.

Installation

$ pip install presto-python-client

Quick Start

Use the DBAPI interface to query Presto:

import prestodb
conn=prestodb.dbapi.connect(
    host='localhost',
    port=8080,
    user='the-user',
    catalog='the-catalog',
    schema='the-schema',
)
cur = conn.cursor()
cur.execute('SELECT * FROM system.runtime.nodes')
rows = cur.fetchall()

This will query the

system.runtime.nodes

The DBAPI implementation in

prestodb.dbapi

Cursorfetchone()

Cursor.fetchmany()

Cursor.fetchmany()

prestodb.dbapi.Cursor.arraysize

Basic Authentication

The

BasicAuthentication

python
import prestodb
conn=prestodb.dbapi.connect(
    host='coordinator url',
    port=8443,
    user='the-user',
    catalog='the-catalog',
    schema='the-schema',
    http_scheme='https',
    auth=prestodb.auth.BasicAuthentication("principal id", "password"),
)
cur = conn.cursor()
cur.execute('SELECT * FROM system.runtime.nodes')
rows = cur.fetchall()

Oauth Authentication

To enable GCS access, Oauth authentication support is added by passing in a

shadow.json

import getpass
import prestodb
from prestodb.client import PrestoRequest, PrestoQuery
from requests_kerberos import DISABLED

kerberos_auth = prestodb.auth.KerberosAuthentication(
   mutual_authentication=DISABLED,
   service_name='kerberos service name',
   force_preemptive=True,
   hostname_override='example.com'
)
req = PrestoRequest(
    host='GCP coordinator url',
    port=443,
    user=getpass.getuser(),
    service_account_file='Service account json file path',
    http_scheme='https',
    auth=kerberos_auth
)
query = PrestoQuery(req, "SELECT * FROM system.runtime.nodes")
rows = list(query.execute())

Transactions

The client runs by default in autocommit mode. To enable transactions, set isolation_level to a value different than

IsolationLevel.AUTOCOMMIT

import prestodb
from prestodb import transaction
with prestodb.dbapi.connect(
    host='localhost',
    port=8080,
    user='the-user',
    catalog='the-catalog',
    schema='the-schema',
    isolation_level=transaction.IsolationLevel.REPEATABLE_READ,
) as conn:
  cur = conn.cursor()
  cur.execute('INSERT INTO sometable VALUES (1, 2, 3)')
  cur.execute('INSERT INTO sometable VALUES (4, 5, 6)')

The transaction is created when the first SQL statement is executed.

prestodb.dbapi.Connection.commit()

Running Tests

There is a helper scripts,

run

./run tests

presto-python-client

$ pytest tests

Then you can pass options like

--pdb

pytest --help

To run the tests with different versions of Python in managed virtualenvs, use

tox

tox.ini

$ tox

To run integration tests:

$ pytest integration_tests

They build a

Docker

presto-server:${PRESTO_VERSION}

presto-python-client-tests-{uuid4()[:7]}

The container is expected to be removed after the tests are finished.

Please refer to the

Dockerfile

etc/

You can use

./run

• ./run presto_server

  : build and run Presto in a container

• ./run presto_cli CONTAINER_ID

  : connect the Java Presto CLI to a container

• ./run list

  : list the running containers

• ./run clean

  : kill the containers

Development

Start by forking the repository and then modify the code in your fork. Please refer to

CONTRIBUTING.md

Clone the repository and go inside the code directory. Then you can get the version with

python setup.py --version

We recommend that you use

virtualenv

presto-python-client

$ virtualenv /path/to/env
$ /path/to/env/bin/activate
$ pip install -r requirements.txt

For development purpose, pip can reference the code you are modifying in a virtualenv:

$ pip install -e .[tests]

That way, you do not need to run

pip install

When the code is ready, submit a Pull Request.

Need Help?

Feel free to create an issue as it make your request visible to other users and contributors.

If an interactive discussion would be better or if you just want to hangout and chat about the Presto Python client, you can join us on the #presto-python-client channel on Slack.