Implements `io.Closer` for `DB`

Fix #18

adapters/kmysql/sql_adapter.go

@@ -38,6 +38,11 @@ func (s SQLAdapter) BeginTx(ctx context.Context) (ksql.Tx, error) {
 	return SQLTx{Tx: tx}, err
 }
 
+// Close implements the io.Closer interface
+func (s SQLAdapter) Close() error {
+	return s.DB.Close()
+}
+
 // SQLTx is used to implement the DBAdapter interface and implements
 // the Tx interface
 type SQLTx struct {

adapters/kpgx/pgx_adapter.go

@@ -42,6 +42,12 @@ func (p PGXAdapter) BeginTx(ctx context.Context) (ksql.Tx, error) {
 	return PGXTx{tx}, err
 }
 
+// Close implements the io.Closer interface
+func (p PGXAdapter) Close() error {
+	p.db.Close()
+	return nil
+}
+
 // PGXResult is used to implement the DBAdapter interface and implements
 // the Result interface
 type PGXResult struct {

adapters/ksqlite3/sql_adapter.go

@@ -38,6 +38,11 @@ func (s SQLAdapter) BeginTx(ctx context.Context) (ksql.Tx, error) {
 	return SQLTx{Tx: tx}, err
 }
 
+// Close implements the io.Closer interface
+func (s SQLAdapter) Close() error {
+	return s.DB.Close()
+}
+
 // SQLTx is used to implement the DBAdapter interface and implements
 // the Tx interface
 type SQLTx struct {

adapters/ksqlserver/sql_adapter.go

@@ -38,6 +38,11 @@ func (s SQLAdapter) BeginTx(ctx context.Context) (ksql.Tx, error) {
 	return SQLTx{Tx: tx}, err
 }
 
+// Close implements the io.Closer interface
+func (s SQLAdapter) Close() error {
+	return s.DB.Close()
+}
+
 // SQLTx is used to implement the DBAdapter interface and implements
 // the Tx interface
 type SQLTx struct {

ksql.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"crypto/tls"
 	"fmt"
+	"io"
 	"reflect"
 	"strings"
 	"unicode"
@@ -890,6 +891,14 @@ func (c DB) Transaction(ctx context.Context, fn func(Provider) error) error {
 	}
 }
 
+func (c DB) Close() error {
+	closer, ok := c.db.(io.Closer)
+	if ok {
+		return closer.Close()
+	}
+	return nil
+}
+
 type nopScanner struct{}
 
 var nopScannerValue = reflect.ValueOf(&nopScanner{}).Interface()