Description

This PR adds a new state store component for ClickHouse, a column-oriented database management system. The ClickHouse state store component provides the following features:

• Basic CRUD operations for state management
• Support for TTL (Time-To-Live)
• ETag support for optimistic concurrency
• Bulk operations support
• Username/password authentication
• Uses ReplacingMergeTree engine for efficient updates

Key implementation details:

• Uses the official ClickHouse Go driver
• Implements the full state.Store interface
• Handles connection management and cleanup
• Includes comprehensive integration tests
• Follows Dapr's component development guidelines

Implementation Details

The component includes:

1. State store implementation (clickhouse.go)

   • Full CRUD operations
   • Bulk operations
   • TTL support
   • ETag support
   • Authentication support

2. Tests (clickhouse_test.go)

   • Integration tests for CRUD operations
   • Metadata validation tests
   • Authentication tests
   • Cleanup handling

3. Configuration options:

   apiVersion: dapr.io/v1alpha1
   kind: Component
   metadata:
     name: statestore
     namespace: default
   spec:
     type: state.clickhouse
     version: v1
     metadata:
     - name: clickhouseURL
       value: "tcp://localhost:9000"
     - name: databaseName
       value: "dapr_state"
     - name: tableName
       value: "state_store"
     - name: username
       value: "default"
     - name: password
       value: ""

Checklist

• Code compiles correctly
• Created/updated tests
• Extended the documentation / Created issue in the https://github.com/dapr/docs/ repo: dapr/docs#[issue number]

Testing Done

1. Unit tests for metadata validation
2. Integration tests for:
   • Basic CRUD operations
   • TTL functionality
   • ETag support
   • Bulk operations
   • Authentication
   • Error handling

Tests were run against ClickHouse v23.8 using the official Go driver.

Additional Notes

• The component uses ReplacingMergeTree engine for better update performance
• Includes proper cleanup in tests to avoid test pollution
• Follows ClickHouse best practices for table design
• Implements proper connection management and cleanup