Live: pipeline rule crud (file-based, still for MVP) (#39238)

pkg/services/live/pipeline/pattern/pattern.go

@@ -0,0 +1,25 @@
+package pattern
+
+import (
+	"fmt"
+	"regexp"
+	"strings"
+)
+
+var patternReString = `^[A-z0-9_\-/=.:*]*$`
+var patternRe = regexp.MustCompile(patternReString)
+
+var maxPatternLength = 160
+
+func Valid(pattern string) (bool, string) {
+	if strings.HasPrefix(pattern, "/") {
+		return false, "pattern can't start with /"
+	}
+	if !patternRe.MatchString(pattern) {
+		return false, fmt.Sprintf("pattern format error, must match %s", patternReString)
+	}
+	if len(pattern) > maxPatternLength {
+		return false, fmt.Sprintf("pattern max length exceeded (%d)", maxPatternLength)
+	}
+	return true, ""
+}