sdk-connection-go.go

// Couchbase SDK connection singleton — Go
// Copy and adapt for your application.
//
// Dependencies:
//   go get github.com/couchbase/gocb/v2

package couchbase

import (
	"fmt"
	"sync"
	"time"

	"github.com/couchbase/gocb/v2"
)

// --- Configuration ---
const (
	cbHost       = "localhost"         // or "cb.xxxxx.cloud.couchbase.com" for Capella
	cbUser       = "app-service-user"
	cbPassword   = "AppSecret123!"
	cbBucket     = "myapp"
	cbScope      = "_default"
	cbCollection = "_default"
)

var (
	once       sync.Once
	cluster    *gocb.Cluster
	collection *gocb.Collection
)

// GetCollection returns the singleton Collection, initializing the cluster on first call.
func GetCollection() *gocb.Collection {
	once.Do(func() {
		if err := init_(); err != nil {
			panic(fmt.Sprintf("couchbase init failed: %v", err))
		}
	})
	return collection
}

// GetCluster returns the singleton Cluster (needed for queries and transactions).
func GetCluster() *gocb.Cluster {
	GetCollection() // ensures cluster is initialized
	return cluster
}

func init_() error {
	// Use "couchbases://" for TLS (required for Capella, recommended for production)
	c, err := gocb.Connect("couchbase://"+cbHost, gocb.ClusterOptions{
		Username: cbUser,
		Password: cbPassword,
		TimeoutsConfig: gocb.TimeoutsConfig{
			ConnectTimeout: 10 * time.Second,
			KVTimeout:      2500 * time.Millisecond,
			QueryTimeout:   75 * time.Second,
			SearchTimeout:  75 * time.Second,
		},
	})
	if err != nil {
		return err
	}

	if err = c.WaitUntilReady(10*time.Second, nil); err != nil {
		return err
	}

	cluster = c
	collection = c.Bucket(cbBucket).Scope(cbScope).Collection(cbCollection)
	return nil
}

// Close releases cluster resources. Call on application shutdown.
func Close() {
	if cluster != nil {
		cluster.Close(nil)
	}
}

// --- Usage example ---
func Example() {
	col := GetCollection()
	c := GetCluster()

	// KV upsert
	_, err := col.Upsert("doc_1", map[string]interface{}{"type": "example", "value": 42}, nil)
	if err != nil {
		panic(err)
	}

	// KV get
	result, err := col.Get("doc_1", nil)
	if err != nil {
		panic(err)
	}
	var doc map[string]interface{}
	result.Content(&doc)
	fmt.Println(doc)

	// SQL++ query
	rows, err := c.Query(
		"SELECT * FROM `myapp`._default._default WHERE type = $type LIMIT 5",
		&gocb.QueryOptions{NamedParameters: map[string]interface{}{"type": "example"}},
	)
	if err != nil {
		panic(err)
	}
	for rows.Next() {
		var row interface{}
		rows.Row(&row)
		fmt.Println(row)
	}

	Close()
}