ClickHouse hosting integration

The ClickHouse hosting integration models a ClickHouse server and database as the ClickHouseServerResource and ClickHouseDatabaseResource types. To access these types and APIs, add the 📦 Aspire.Hosting.ClickHouse NuGet package in your AppHost project:

dotnet add package Aspire.Hosting.ClickHouse

For an introduction to the ClickHouse integration, see Get started with the ClickHouse integrations.

Installation

The Aspire ClickHouse hosting integration models the ClickHouse database server as the following types:

• ClickHouseServerResource
• ClickHouseDatabaseResource

To access these types and APIs for expressing them as resources in your AppHost project, install the 📦 Aspire.Hosting.ClickHouse NuGet package:

dotnet add package Aspire.Hosting.ClickHouse

Add ClickHouse server and database resources

In the AppHost project, call AddClickHouse to add and return a ClickHouse server resource builder. Chain a call to the returned resource builder to AddDatabase, to add a ClickHouse database to the server resource:

var builder = DistributedApplication.CreateBuilder(args);
  
var clickhouse = builder.AddClickHouse("clickhouse");
  
var clickhousedb = clickhouse.AddDatabase("clickhousedb");
  
builder.AddProject<Projects.ExampleProject>()
       .WithReference(clickhousedb)
       .WaitFor(clickhousedb);
  
// After adding all resources, run the app...

When Aspire adds a container image to the AppHost, as shown in the preceding example with the clickhouse/clickhouse-server image, it creates a new ClickHouse server on your local machine. A reference to your ClickHouse resource builder (the clickhouse variable) is used to add a database. The database is named clickhousedb and then added to the ExampleProject. The database is automatically created using CREATE DATABASE IF NOT EXISTS when the server resource becomes ready.

The ClickHouse server resource includes default credentials:

• CLICKHOUSE_USER: A value of default
• CLICKHOUSE_PASSWORD: Random password generated using the default password parameter

The password is stored in the AppHost's secret store in the Parameters section:

{
  "Parameters:clickhouse-password": "<THE_GENERATED_PASSWORD>"
}

The WithReference method configures a connection in the ExampleProject named "clickhousedb".

Add ClickHouse resource with data volume

To add a data volume to the ClickHouse resource, call the WithDataVolume method on the ClickHouse resource:

var builder = DistributedApplication.CreateBuilder(args);
  
var clickhouse = builder.AddClickHouse("clickhouse")
                        .WithDataVolume();
  
var clickhousedb = clickhouse.AddDatabase("clickhousedb");
  
builder.AddProject<Projects.ExampleProject>()
       .WithReference(clickhousedb)
       .WaitFor(clickhousedb);

The data volume is used to persist the ClickHouse data outside the lifecycle of its container. The data volume is mounted at the /var/lib/clickhouse path in the ClickHouse container and when a name parameter isn't provided, the name is generated at random. For more information on data volumes and details on why they're preferred over bind mounts, see Docker docs: Volumes.

Add ClickHouse resource with data bind mount

To add a data bind mount to the ClickHouse resource, call the WithDataBindMount method:

var builder = DistributedApplication.CreateBuilder(args);
  
var clickhouse = builder.AddClickHouse("clickhouse")
                        .WithDataBindMount(
                            source: @"C:\ClickHouse\Data",
                            isReadOnly: false);
  
var clickhousedb = clickhouse.AddDatabase("clickhousedb");
  
builder.AddProject<Projects.ExampleProject>()
       .WithReference(clickhousedb)
       .WaitFor(clickhousedb);

Add ClickHouse resource with parameters

When you want to explicitly provide the username and password used by the container image, you can provide these credentials as parameters:

var builder = DistributedApplication.CreateBuilder(args);
  
var username = builder.AddParameter("username");
var password = builder.AddParameter("password", secret: true);
  
var clickhouse = builder.AddClickHouse("clickhouse", userName: username, password: password);
var clickhousedb = clickhouse.AddDatabase("clickhousedb");
  
builder.AddProject<Projects.ExampleProject>()
       .WithReference(clickhousedb)
       .WaitFor(clickhousedb);

The username and password parameters are usually specified as user secrets:

{
  "Parameters": {
    "username": "default",
    "password": "your-secure-password"
  }
}

For more information, see External parameters.

You can also specify a custom host port:

var clickhouse = builder.AddClickHouse("clickhouse", port: 18123);

Connection properties

When you use the WithReference method to pass a ClickHouse server or database resource from the AppHost project to a consuming client project, several properties are available to use in the consuming project.

ClickHouse server

The ClickHouse server resource exposes the following connection properties:

Example connection string:

Host=localhost;Port=8123;Username=default;Password=p%40ssw0rd1

ClickHouse database

The ClickHouse database resource inherits all properties from its parent ClickHouseServerResource and adds:

Example connection string:

Host=localhost;Port=8123;Username=default;Password=p@ssw0rd1;Database=clickhousedb

Hosting integration health checks

The ClickHouse hosting integration automatically adds a health check for the ClickHouse resource. The health check sends an HTTP GET request to the /ping endpoint on the ClickHouse server and verifies that the instance is running and responsive.

Pass connection information to app resources

When you use the WithReference method to pass a ClickHouse database resource to an app resource such as a Python or JavaScript app, Aspire automatically injects environment variables that describe the connection information.

For example, if you reference a ClickHouse database resource named clickhousedb:

var builder = DistributedApplication.CreateBuilder(args);
  
var clickhouse = builder.AddClickHouse("clickhouse");
var clickhousedb = clickhouse.AddDatabase("clickhousedb");
  
var pythonApp = builder.AddPythonApp("python-app", "./python_app", "main.py")
                       .WithReference(clickhousedb);

The following environment variables are available in the consuming application:

• CLICKHOUSEDB_HOST - The hostname of the ClickHouse server
• CLICKHOUSEDB_PORT - The port number
• CLICKHOUSEDB_USERNAME - The username for authentication
• CLICKHOUSEDB_PASSWORD - The password for authentication
• CLICKHOUSEDB_DATABASENAME - The database name

You can access these environment variables in your application code:

// Get connection properties
const host = process.env.CLICKHOUSEDB_HOST;
const port = process.env.CLICKHOUSEDB_PORT;
const username = process.env.CLICKHOUSEDB_USERNAME;
const password = process.env.CLICKHOUSEDB_PASSWORD;
const database = process.env.CLICKHOUSEDB_DATABASENAME;
  
// Create ClickHouse client
const client = createClient({
  url: `http://${host}:${port}`,
  username: username,
  password: password,
  database: database,
});
  
// Use the client
const result = await client.ping();
console.log('ClickHouse connection status:', result.success);