package cloudsql
import (
"context"
"database/sql"
"fmt"
"log"
"net"
"os"
"cloud.google.com/go/cloudsqlconn"
mssql "github.com/denisenkom/go-mssqldb"
)
type csqlDialer struct {
dialer *cloudsqlconn.Dialer
connName string
usePrivate bool
}
// DialContext adheres to the mssql.Dialer interface.
func (c *csqlDialer) DialContext(ctx context.Context, network, addr string) (net.Conn, error) {
var opts []cloudsqlconn.DialOption
if c.usePrivate {
opts = append(opts, cloudsqlconn.WithPrivateIP())
}
return c.dialer.Dial(ctx, c.connName, opts...)
}
func connectWithConnector() (*sql.DB, error) {
mustGetenv := func(k string) string {
v := os.Getenv(k)
if v == "" {
log.Fatalf("Fatal Error in connect_connector.go: %s environment variable not set.\n", k)
}
return v
}
// Note: Saving credentials in environment variables is convenient, but not
// secure - consider a more secure solution such as
// Cloud Secret Manager (https://cloud.google.com/secret-manager) to help
// keep secrets safe.
var (
dbUser = mustGetenv("DB_USER") // e.g. 'my-db-user'
dbPwd = mustGetenv("DB_PASS") // e.g. 'my-db-password'
dbName = mustGetenv("DB_NAME") // e.g. 'my-database'
instanceConnectionName = mustGetenv("INSTANCE_CONNECTION_NAME") // e.g. 'project:region:instance'
usePrivate = os.Getenv("PRIVATE_IP")
)
dbURI := fmt.Sprintf("user id=%s;password=%s;database=%s;", dbUser, dbPwd, dbName)
c, err := mssql.NewConnector(dbURI)
if err != nil {
return nil, fmt.Errorf("mssql.NewConnector: %w", err)
}
// WithLazyRefresh() Option is used to perform refresh
// when needed, rather than on a scheduled interval.
// This is recommended for serverless environments to
// avoid background refreshes from throttling CPU.
dialer, err := cloudsqlconn.NewDialer(context.Background(), cloudsqlconn.WithLazyRefresh())
if err != nil {
return nil, fmt.Errorf("cloudsqlconn.NewDailer: %w", err)
}
c.Dialer = &csqlDialer{
dialer: dialer,
connName: instanceConnectionName,
usePrivate: usePrivate != "",
}
dbPool := sql.OpenDB(c)
if err != nil {
return nil, fmt.Errorf("sql.Open: %w", err)
}
return dbPool, nil
}
