Python Access to Presto Cluster with Presto Client

Presto access is represented by many Python libraries among those are Dropbox/PyHive, prestosql/presto-python-client, prestodb/presto-python-client, and easydatawarehousing/prestoclient. Mostly of libraries use Python DB-API interface to access Presto which uniforms commands.

Python Access to Presto Cluster with PyHive article describes Dropbox/PyHive library usage.

prestosql/presto-python-client library is actively supported by Presto developers. The sample is run with Python 3 in Windows.

1. Install Presto client library

Linux.

sudo pip3 install presto-client

Windows. Run as administrator.

pip install presto-client

2. Include requested libraries

import presto

3. Establish connection

Access to Presto cluster without password.

conn = presto.connect(host='localhost',
                        port=8080,
                        catalog='system',
                        schema='runtime')

Presto cluster is secured by password but skip SSL verification. This case might be used during development stage.

conn = presto.connect(host='localhost',
                      port=443,
                      http_scheme='https',
                      catalog='system',
                      schema='runtime',
                      auth=presto.auth.BasicAuthentication('<user name>', '<password>'),
                      verify=False)

Presto cluster is secured by password.

Option #1. Follow instructions in Convert Java Keystore to PEM File Format article to create presto.crt file. The file contains Presto SSL public certificate converted from Java keystore file.

Option #2. Extract presto.crt certificate from Internet Browser. Follow Export TLS/SSL Server Certificate from Internet Browser article.

conn = presto.connect(host='localhost',
                      port=443,
                      http_scheme='https',
                      catalog='system',
                      schema='runtime',
                      auth=presto.auth.BasicAuthentication('<user name>', '<password>'),
                      verify='presto.crt')

4. Create cursor

cur = conn.cursor()

5. Retrieve data

cur.execute('SELECT * FROM nodes')
for row in cur.fetchall():
    print(row)

6. Improvements

To disable insecure warnings during https requests if verify=False, add the code in import section.

import urllib3
urllib3.disable_warnings()

7. Troubleshooting

In case of getting ssl.SSLError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed (_ssl.c:777) error, check your certificate expiration date. The date has to be valid.

Resources

SSL Cert Verification