feat(kubeconfig): Introduce the ability to change the expiry of a kubeconfig EE-1153 (#5421)

* feat(kubeconfig) EE-1153 Introduce the ability to change the expiry of a kubeconfig

* feat(kubeconfig) EE-1153 pr feedback update

* feat(kubeconfig) EE-1153 code cleanup

Co-authored-by: Simon Meng <simon.meng@portainer.io>

api/jwt/jwt_kubeconfig_test.go

@@ -0,0 +1,81 @@
+package jwt
+
+import (
+	"github.com/dgrijalva/jwt-go"
+	portainer "github.com/portainer/portainer/api"
+	i "github.com/portainer/portainer/api/internal/testhelpers"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestService_GenerateTokenForKubeconfig(t *testing.T) {
+	type fields struct {
+		userSessionTimeout string
+		dataStore          portainer.DataStore
+	}
+
+	type args struct {
+		data *portainer.TokenData
+	}
+
+	mySettings := &portainer.Settings{
+		KubeconfigExpiry: "0",
+	}
+
+	myFields := fields{
+		userSessionTimeout: "24h",
+		dataStore:          i.NewDatastore(i.WithSettings(mySettings)),
+	}
+
+	myTokenData := &portainer.TokenData{
+		Username: "Joe",
+		ID:       1,
+		Role:     1,
+	}
+
+	myArgs := args{
+		data: myTokenData,
+	}
+
+	tests := []struct {
+		name          string
+		fields        fields
+		args          args
+		wantExpiresAt int64
+		wantErr       bool
+	}{
+		{
+			name:          "kubeconfig no expiry",
+			fields:        myFields,
+			args:          myArgs,
+			wantExpiresAt: 0,
+			wantErr:       false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			service, err := NewService(tt.fields.userSessionTimeout, tt.fields.dataStore)
+			assert.NoError(t, err, "failed to create a copy of service")
+
+			got, err := service.GenerateTokenForKubeconfig(tt.args.data)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("GenerateTokenForKubeconfig() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+
+			parsedToken, err := jwt.ParseWithClaims(got, &claims{}, func(token *jwt.Token) (interface{}, error) {
+				return service.secret, nil
+			})
+			assert.NoError(t, err, "failed to parse generated token")
+
+			tokenClaims, ok := parsedToken.Claims.(*claims)
+			assert.Equal(t, true, ok, "failed to claims out of generated ticket")
+
+			assert.Equal(t, myTokenData.Username, tokenClaims.Username)
+			assert.Equal(t, int(myTokenData.ID), tokenClaims.UserID)
+			assert.Equal(t, int(myTokenData.Role), tokenClaims.Role)
+			assert.Equal(t, tt.wantExpiresAt, tokenClaims.ExpiresAt)
+		})
+	}
+}