1 files changed, 87 insertions, 0 deletions
diff --git a/src/go/collectors/go.d.plugin/agent/discovery/sd/model/tags.go b/src/go/collectors/go.d.plugin/agent/discovery/sd/model/tags.go
new file mode 100644
index 000000000..22517d77e
--- /dev/null
+++ b/src/go/collectors/go.d.plugin/agent/discovery/sd/model/tags.go
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+package model
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+)
+
+type Base struct {
+	tags Tags
+}
+
+func (b *Base) Tags() Tags {
+	if b.tags == nil {
+		b.tags = NewTags()
+	}
+	return b.tags
+}
+
+type Tags map[string]struct{}
+
+func NewTags() Tags {
+	return Tags{}
+}
+
+func (t Tags) Merge(tags Tags) {
+	for tag := range tags {
+		if strings.HasPrefix(tag, "-") {
+			delete(t, tag[1:])
+		} else {
+			t[tag] = struct{}{}
+		}
+	}
+}
+
+func (t Tags) Clone() Tags {
+	ts := NewTags()
+	ts.Merge(t)
+	return ts
+}
+
+func (t Tags) String() string {
+	ts := make([]string, 0, len(t))
+	for key := range t {
+		ts = append(ts, key)
+	}
+	sort.Strings(ts)
+	return fmt.Sprintf("{%s}", strings.Join(ts, ", "))
+}
+
+func ParseTags(line string) (Tags, error) {
+	words := strings.Fields(line)
+	if len(words) == 0 {
+		return NewTags(), nil
+	}
+
+	tags := NewTags()
+	for _, tag := range words {
+		if !isTagWordValid(tag) {
+			return nil, fmt.Errorf("tags '%s' contains tag '%s' with forbidden symbol", line, tag)
+		}
+		tags[tag] = struct{}{}
+	}
+	return tags, nil
+}
+
+func isTagWordValid(word string) bool {
+	// valid:
+	// ^[a-zA-Z][a-zA-Z0-9=_.]*$
+	word = strings.TrimPrefix(word, "-")
+	if len(word) == 0 {
+		return false
+	}
+	for i, b := range word {
+		switch {
+		default:
+			return false
+		case b >= 'a' && b <= 'z':
+		case b >= 'A' && b <= 'Z':
+		case b >= '0' && b <= '9' && i > 0:
+		case (b == '=' || b == '_' || b == '.') && i > 0:
+		}
+	}
+	return true
+}