Get Started with Hasura Cloud & ClickHouse
Try it out
To connect ClickHouse to Hasura, you'll need to take advantage of Hasura Data Connectors. You can deploy any custom data connector agent to Hasura Cloud using our CLI plugin. For more information, refer to the docs.
If you're curious what other connectors are available, check out our NDC Hub.
Step 1: Create an account on Hasura Cloud and create a new Hasura Project
Navigate to cloud.hasura.io, and create a new Hasura Cloud account.
Once you create a project on Hasura Cloud, hit the "Launch Console" button to open the Hasura Console for your project.
Step 2: Deploy a data connector agent
We'll use the Hasura CLI to deploy a custom data connector agent to Hasura Cloud. If you haven't already done so, install the data connector plugin.
Below, we're using the create command and naming our connector clickhouse-connector:v1. We're also passing in the
GitHub repo URL for the connector agent using the --github-repo-url flag:
hasura connector create clickhouse-connector:v1 --github-repo-url https://github.com/hasura/clickhouse_gdc_v2/tree/main
We can check on the progress of the deployment using the status command:
hasura connector status clickhouse-connector:v1
Once the DONE status is returned, we can grab the URL for our data connector agent using the list command:
hasura connector list
This will return a list of all the custom data connector agents you own. The second value returned is the URL which we'll use in the next step; copy it to your clipboard.
Step 3: Add the data connector agent to your Hasura Cloud project
In your Cloud project, navigate to the Data tab and click Manage in the left-hand sidebar.
At the bottom of the screen, you'll see an expandable section titled Data Connector Agents.
Click this and scroll down to Add Agent.
Name this agent clickhouse and paste the URL you copied from the CLI into the URL field and click Connect.
Step 4: Add your ClickHouse database as a source to Hasura
Head to the Data > Manage databases section on the Console to add your ClickHouse database as a source to Hasura.
- Allow public connections or whitelist the Hasura Cloud IP on your Clickhouse firewall: This is good for testing and will allow you to quickly try out Hasura with your database!
- VPC peering: VPC peering and private network access is available on Hasura Cloud paid tiers and is recommended for production. Get in touch with us if you'd like to try this out against your existing databases.
Step 4.1: Begin by clicking Connect Database
Step 4.2: Next, choose the Clickhouse driver
Step 4.3: Enter your ClickHouse JDBC Connection string
You can get create your connection URL by logging in to ClickHouse and selecting Connect -> View connection string for
the database to which you want to connect.
Once you add the ClickHouse service, you will find it listed as an available database on the sidebar.
It's generally accepted that setting the password as an environment variable is a better practice as it's more secure and prevents any secrets from being exposed in your instance's metadata.
An example would be to create a new
environment variable called
CLICKHOUSE_PASSWORD and set it equal to your ClickHouse password.
Then, export the metadata - in JSON form - using the Console's Settings page or by making a call using the
metadata API and add the following key-value
pair to the metadata.json's configuration object:
"template": "{\"url\": \"your_clickhouse_url_here\", \"user\": \"your_clickhouse_user\", \"password\": \"{{getEnvironmentVariable(\"CLICKHOUSE_PASSWORD\")}}\", \"tables\": null}"
You can then apply the metadata to your instance by either using the Console's Settings page or by making a call using
the metadata API.
Due to the potential variations in drivers, it's crucial to escape special characters used in the password of the
connection string. These include { } % & #. To escape a character, use the appropriate escape sequence based on your
database's driver's documentation.
Step 5: Track existing tables
To query your ClickHouse service using Hasura, you'll need to have existing tables to select. Those tables will appear under the database as shown below:
You can select all or select individual tables to track. Click Track Selected for Hasura to introspect them and create
the corresponding GraphQL schema.
Step 6: Try out a GraphQL query
Head to the API tab in the Console and try running a GraphQL query! Use the explorer sidebar on GraphiQL to get help
in creating a GraphQL query.
Keep up to date
Currently, Hasura supports read-only queries, relationships, and permissions on ClickHouse. Column comparison operators are not supported with permissions on ClickHouse.
If you'd like to stay informed about the status of ClickHouse support, subscribe to our newsletter and join our discord!
