clickhouse

ExampleHealthChecker shows how to wire HealthChecker into a health.Check call for a /health HTTP endpoint. Default() is nil in this example so the Checker reports StatusUnhealthy.

package main

import (
	"context"
	"fmt"

	"github.com/phcp-tech/common-library-golang/dbsqlc/clickhouse"
	"github.com/phcp-tech/common-library-golang/health"
)

func main() {
	results := health.Check(context.Background(), clickhouse.HealthChecker())
	fmt.Println(results[0].Name)
	fmt.Println(results[0].Status == health.StatusUnhealthy) // true — Default() is nil
}

Output:
clickhouse
true

ExampleInitDefault shows the singleton pattern: call InitDefault once at application startup. Subsequent calls are silently ignored (sync.Once). After a successful call, Default returns the initialised driver.Conn which can be passed directly to sqlc-generated Queries.

package main

import (
	"github.com/phcp-tech/common-library-golang/dbsqlc/clickhouse"
)

func main() {
	if err := clickhouse.InitDefault(&clickhouse.Config{
		Host:     "127.0.0.1",
		Port:     "9000",
		Database: "default",
		Username: "default",
		Password: "",
	}); err != nil {
		// handle error
		return
	}
	_ = clickhouse.Default() // driver.Conn, pass to sqlc-generated Queries
}

Output:

ExampleNewClickHouse shows how to open a ClickHouse connection with the default pool settings. Zero-value pool fields fall back to the dbsqlc package defaults (MaxOpenConns=100, MaxIdleConns=25, ConnMaxLifetime=60min). Note: unlike MySQL/PostgreSQL, ClickHouse establishes a real TCP connection at Open time, so a live server is required.

package main

import (
	"github.com/phcp-tech/common-library-golang/dbsqlc/clickhouse"
)

func main() {
	conn, err := clickhouse.NewClickHouse(&clickhouse.Config{
		Host:     "127.0.0.1",
		Port:     "9000",
		Database: "default",
		Username: "default",
		Password: "",
	})
	if err != nil {
		// handle error
		return
	}
	defer conn.Close()
}

Output:

ExampleNewClickHouse_customPool shows how to override the default connection pool settings.

package main

import (
	"github.com/phcp-tech/common-library-golang/dbsqlc/clickhouse"
)

func main() {
	conn, err := clickhouse.NewClickHouse(&clickhouse.Config{
		Host:            "127.0.0.1",
		Port:            "9000",
		Database:        "default",
		Username:        "default",
		Password:        "",
		MaxOpenConns:    50,
		MaxIdleConns:    10,
		ConnMaxLifetime: 30, // minutes
	})
	if err != nil {
		// handle error
		return
	}
	defer conn.Close()
}

Output: