Managing Connections

This section describes how to connect the Python Columnar SDK to a Columnar cluster. It contains best practices as well as information on TLS/SSL and advanced connection options, and a sub-page on troubleshooting Cloud connections.

Our Getting Started pages cover the basics of making a connection to a Capella or self-managed Couchbase cluster. This page is a wider look at the topic.

Connecting to a Cluster

The examples below use these imports:

from couchbase_columnar.cluster import Cluster
from couchbase_columnar.credential import Credential
from couchbase_columnar.options import (ClusterOptions,
                                        SecurityOptions)

A connection to a Couchbase Server cluster is represented by a Cluster object. A Cluster provides access to databases, scopes, and collections, as well as various Columnar services and management interfaces. The simplest way to create a Cluster object is to call Cluster.createnstance() with a connection string, user credentials, and any optional settings:

def main() -> None:
    # Update this to your cluster
    connstr = 'couchbases://--your-instance--'
    username = 'username'
    pw = 'Password!123'
    # User Input ends here.

    cred = Credential.from_username_and_password(username, pw)
    cluster = Cluster.create_instance(connstr, cred, opts)

Capella’s root certificate is not signed by a well known Certificate Authority. However, the certificate is bundled with the SDK, and is automatically trusted unless you specify a different certificate to trust.

Connection Strings

A Couchbase connection string is a comma-delimited list of IP addresses and/or hostnames, optionally followed by a list of parameters.

The parameter list is just like the query component of a URI; name-value pairs have an equals sign (=) separating the name and value, with an ampersand (&) between each pair. Just as in a URI, the first parameter is prefixed by a question mark (?).

For Columnar, as for all Capella products, connection must be made with Transport Layer Security (TLS) — for full encryption of client-side traffic — for which the couchbases:// schema is used as the root of the connection string (note the trailing s).

Simple connection string with one seed node

couchbases://cb.<your-endpoint>.cloud.couchbase.com

Connection string with two parameters

couchbases://cb.<your-endpoint>.cloud.couchbase.com?timeout.connect_timeout=75s&timeout.query_timeout=100s

The full list of recognized parameters is documented in the client settings reference.

Local Development

We strongly recommend that the client and server are in the same LAN-like environment (e.g. AWS Region). As this may not always be possible during development, read the guidance on working with constrained network environments. More details on connecting your client code to Couchbase Capella can be found in the Capella Operational docs.

Troubleshooting Connections to Cloud

Some DNS caching providers (notably, home routers) can’t handle an SRV record that’s large — if you have DNS-SRV issues with such a set-up, reduce your DNS-SRV to only include three records. [For development only, not production.]. Our Troubleshooting Connections page will help you to diagnose this and other problems — as well as introducing the SDK doctor tool.