feat: regex container name filtering (#1241)

* Allow container name regex filtering

* make regex names backwards compatible

Co-authored-by: Mateusz Drab <mateuszd@mpd.pw>
Co-authored-by: nils måsén <nils@piksel.se>

pkg/filters/filters.go

@@ -1,8 +1,10 @@
 package filters
 
 import (
-	t "github.com/containrrr/watchtower/pkg/types"
+	"regexp"
 	"strings"
+
+	t "github.com/containrrr/watchtower/pkg/types"
 )
 
 // WatchtowerContainersFilter filters only watchtower containers
@@ -19,10 +21,22 @@ func FilterByNames(names []string, baseFilter t.Filter) t.Filter {
 
 	return func(c t.FilterableContainer) bool {
 		for _, name := range names {
-			if (name == c.Name()) || (name == c.Name()[1:]) {
+			if name == c.Name() || name == c.Name()[1:] {
+				return baseFilter(c)
+			}
+
+			if re, err := regexp.Compile(name); err == nil {
+				indices := re.FindStringIndex(c.Name())
+				if indices == nil {
+					continue
+				}
+				start := indices[0]
+				end := indices[1]
+				if start <= 1 && end >= len(c.Name())-1 {
 					return baseFilter(c)
 				}
 			}
+		}
 		return false
 	}
 }
@@ -95,7 +109,7 @@ func BuildFilter(names []string, enableLabel bool, scope string) (t.Filter, stri
 	filter = FilterByNames(names, filter)
 
 	if len(names) > 0 {
-		sb.WriteString("with name \"")
+		sb.WriteString("which name matches \"")
 		for i, n := range names {
 			sb.WriteString(n)
 			if i < len(names)-1 {

pkg/filters/filters_test.go

@@ -47,6 +47,28 @@ func TestFilterByNames(t *testing.T) {
 	container.AssertExpectations(t)
 }
 
+func TestFilterByNamesRegex(t *testing.T) {
+	names := []string{`ba(b|ll)oon`}
+
+	filter := FilterByNames(names, NoFilter)
+	assert.NotNil(t, filter)
+
+	container := new(mocks.FilterableContainer)
+	container.On("Name").Return("balloon")
+	assert.True(t, filter(container))
+	container.AssertExpectations(t)
+
+	container = new(mocks.FilterableContainer)
+	container.On("Name").Return("spoon")
+	assert.False(t, filter(container))
+	container.AssertExpectations(t)
+
+	container = new(mocks.FilterableContainer)
+	container.On("Name").Return("baboonious")
+	assert.False(t, filter(container))
+	container.AssertExpectations(t)
+}
+
 func TestFilterByEnableLabel(t *testing.T) {
 	filter := FilterByEnableLabel(NoFilter)
 	assert.NotNil(t, filter)
@@ -68,8 +90,7 @@ func TestFilterByEnableLabel(t *testing.T) {
 }
 
 func TestFilterByScope(t *testing.T) {
-	var scope string
-	scope = "testscope"
+	scope := "testscope"
 
 	filter := FilterByScope(scope, NoFilter)
 	assert.NotNil(t, filter)
@@ -148,11 +169,12 @@ func TestFilterByImage(t *testing.T) {
 }
 
 func TestBuildFilter(t *testing.T) {
-	var names []string
-	names = append(names, "test")
+	names := []string{"test", "valid"}
 
 	filter, desc := BuildFilter(names, false, "")
 	assert.Contains(t, desc, "test")
+	assert.Contains(t, desc, "or")
+	assert.Contains(t, desc, "valid")
 
 	container := new(mocks.FilterableContainer)
 	container.On("Name").Return("Invalid")