Connect to a source

Introduction

This guide explains how to initialize a connector, configure its environment variables, and link it to your data source. Once initialized, you'll be ready to introspect the source and integrate it into your PromptQL application.

You'll need a project before initializing a connector.

Step 1. Initialize a connector

Regardless which connector you're using, you'll always begin by initializing it with a unique name:

Initialize a new connector in a project directory:

ddn connector init <your_name_for_the_connector> -i

A wizard will appear with a dropdown list. If you know the name of the connector, start typing the name. Otherwise, use the arrows to scroll through the list. Hit ENTER when you've selected your desired connector; you'll then be prompted to enter some values.

Customization

You can customize which subgraph this connector is added to by changing your project's context or using flags. More information can be found in the CLI docs for the ddn connector init command.

Step 2. Add environment variables

The CLI will assign a random port for the connector to use during local development. You can hit ENTER to accept the suggested value or enter your own. Then, depending on your connector, there may be a set of environment variables that it requires:

Athena

ENV	Example	Description
JDBC_URL	jdbc:athena://<host>:<port>/<database>?user=<username>&password=<password>	The JDBC URL to connect to the Amazon Athena database.
JDBC_SCHEMAS	public,app	The schemas to use for the database.

BigQuery

ENV	Example	Description
JDBC_URL	jdbc:bigquery://https://www.googleapis.com/bigquery/v2:443;ProjectId=project-id;DefaultDataset=dataset;OAuthType=0;OAuthServiceAcctEmail=service-account-email;OAuthPvtKey=/etc/connector/key.json;	The JDBC URL to connect to the BigQuery database.

Databricks

ENV	Example	Description
JDBC_URL	jdbc:databricks://<host>:<port>/default;transportMode=http;ssl=1;AuthMech=3;httpPath=/sql/1.0/warehouses/<warehouse-id>;UID=token;PWD=<access-token>;ConnCatalog=main;	You can construct the base of this using your Databricks UI under SQL Warehouses » <name-of-warehouse> » Connection details.
JDBC_SCHEMAS	default,public	A comma-separated list of schemas within the referenced catalog.

MySQL

ENV	Example	Description
JDBC_URL	jdbc:mysql://user:password@host:3306/db_name	This connector requires a JDBC URL.

PostgreSQL

ENV	Example	Description
JDBC_URL	jdbc:postgresql://<host>:<port>/<database>?user=<username>&password=<password>	The JDBC URL to connect to the PostgreSQL database.
JDBC_SCHEMAS	public, app	The schemas to use for the database. Optional. This can also be included in the connection string.

Redshift

ENV	Example	Description
JDBC_URL	jdbc:redshift://<host>:<port>/<database>?user=<username>&password=<password>	The JDBC URL to connect to the Amazon Redshift database.
JDBC_SCHEMAS	public,app	The schemas to use for the database.

Snowflake

ENV	Example	Description
JDBC_URL	jdbc:snowflake://<account-identifier.<region>.snowflakecomputing.com?user=YOUR_USERNAME&&password=YOUR_PASSWORD&db=YOUR_DATABASE&warehouse=YOUR_WAREHOUSE&schema=YOUR_SCHEMA&role=YOUR_ROLE	This connector requires a JDBC URL.

Optional parameters for Snowflake

Snowflake allows you to set a number of defaults. Your JDBC can minimal (i.e., only including the account identifier, username, and password) or more granular depending on your settings within Snowflake.

If your data source requires a connection string or endpoint, the CLI will confirm that it successfully tested the connection to your source. Additionally, it generates configuration files, which you can find in the connector directory of the subgraph where you added the connector (default: app). Finally, the CLI will create a DataConnectorLink in your connector's metadata directory.

Next steps

Now that you've initialized a connector and connected it to your data, you're ready to introspect the source and populate the configuration files with source-specific information that Hasura will need to build your application. Check out the introspection page to learn more.