Add sshql.Dialer.Close() method

.github/workflows/lint.yml

@@ -42,3 +42,9 @@ jobs:
 
           # Optional: if set to true then the action don't cache or restore ~/.cache/go-build.
           # skip-build-cache: true
+      - name: testing sshql
+        run: go test -shuffle on ./...
+      - name: testing pgdrv
+        run: go test -shuffle on ./pgdrv/...
+      - name: testing mysqldrv
+        run: go test -shuffle on ./mysqldrv/...

.gitignore

@@ -15,7 +15,7 @@
 # vendor/
 
 # Other files and directories
-go.work
+# go.work
 go.work.sum
 *.bak
 work/

go.work

@@ -0,0 +1,7 @@
+go 1.19
+
+use (
+	.
+	mysqldrv
+	pgdrv
+)

sshql.go

@@ -1,6 +1,7 @@
 package sshql
 
 import (
+	"errors"
 	"fmt"
 	"net"
 	"os"
@@ -12,6 +13,8 @@ import (
 	"golang.org/x/crypto/ssh/knownhosts"
 )
 
+var ErrNoConnection = errors.New("no SSH connection exists")
+
 // Dialer is authentication provider information.
 type Dialer struct {
 	Hostname      string `json:"hostname"`
@@ -25,6 +28,13 @@ type Dialer struct {
 
 // Connect starts a client connection to the given SSH server.
 func (d *Dialer) Connect() error {
+	if d == nil {
+		return errs.Wrap(ErrNoConnection)
+	}
+	if d.client != nil {
+		d.Close()
+		d.client = nil
+	}
 	sshConfig := &ssh.ClientConfig{
 		User: d.Username,
 		Auth: []ssh.AuthMethod{},
@@ -68,9 +78,20 @@ func (d *Dialer) Connect() error {
 
 // Dial makes socket connection via SSH tunnel.
 func (d *Dialer) Dial(network, address string) (net.Conn, error) {
+	if d == nil || d.client == nil {
+		return nil, errs.Wrap(ErrNoConnection)
+	}
 	return d.client.Dial(network, address)
 }
 
+// Close closes SSH connection.
+func (d *Dialer) Close() error {
+	if d == nil || d.client == nil {
+		return nil
+	}
+	return d.client.Close()
+}
+
 func getSigners(keyfile string, password string) ([]ssh.Signer, error) {
 	buf, err := os.ReadFile(keyfile)
 	if err != nil {

sshql_test.go

@@ -0,0 +1,61 @@
+package sshql
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestNil(t *testing.T) {
+	var d *Dialer // initialize by nil
+	err := d.Connect()
+	if err == nil || !errors.Is(err, ErrNoConnection) {
+		t.Errorf("<nil>.Connect()  = '%v', want '%v'.", err, ErrNoConnection)
+	}
+	_, err = d.Dial("tcp", "")
+	if err == nil || !errors.Is(err, ErrNoConnection) {
+		t.Errorf("<nil>.Connect()  = '%v', want '%v'.", err, ErrNoConnection)
+	}
+	err = d.Close()
+	if err != nil {
+		t.Errorf("<nil>.Close()  = '%v', want <nil>.", err)
+	}
+}
+
+func TestEmpty(t *testing.T) {
+	d := &Dialer{}
+	err := d.Connect()
+	if err == nil {
+		t.Errorf("<nil>.Connect()  = '%v', do not want <nil>.", err)
+	}
+	_, err = d.Dial("tcp", "")
+	if err == nil || !errors.Is(err, ErrNoConnection) {
+		t.Errorf("<nil>.Connect()  = '%v', want '%v'.", err, ErrNoConnection)
+	}
+	err = d.Close()
+	if err != nil {
+		t.Errorf("<nil>.Close()  = '%v', want <nil>.", err)
+	}
+}
+
+/* MIT License
+ *
+ * Copyright 2022 Spiegel
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */