operator: add built-in 'Random' label templates

pkg/templater/random.go

@@ -0,0 +1,114 @@
+/*
+Copyright © 2022 - 2024 SUSE LLC
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package templater
+
+import (
+	"encoding/hex"
+	"fmt"
+	"math/rand/v2"
+	"strconv"
+	"strings"
+
+	"github.com/google/uuid"
+)
+
+// Random template format examples:
+// Random/UUID		--> e511d5ca-a765-42f2-82b7-264f37ffb329
+// Random/Hex/3		--> e512
+// Random/Int/5		--> 75423
+const (
+	tmplRandomKey = "Random"
+	tmplUUIDKey   = "UUID"
+	tmplHexKey    = "Hex"
+	tmplIntKey    = "Int"
+)
+
+func isRandomTemplate(tmplVal []string) bool {
+	if tmplVal[0] != tmplRandomKey {
+		return false
+	}
+
+	switch tmplVal[1] {
+	case tmplUUIDKey:
+	case tmplHexKey:
+	case tmplIntKey:
+	default:
+		return false
+	}
+
+	return true
+}
+
+func randomTemplateToString(tmplVal []string) (string, error) {
+	// expected tamplates:
+	// 	Random/UUID
+	// 	Random/Hex/[1-32]
+	//	Random/Int/[MAXINT]
+	// examples:
+	//	[Random][UUID]		--> e511d5ca-a765-42f2-82b7-264f37ffb329
+	//  [Random][Hex][3]	--> e512
+	//  [Random][Hex][11]	--> e512d5caa765
+	//	[Random][Int][100]-->	24
+
+	if !isRandomTemplate(tmplVal) {
+		return "", errValueNotFound
+	}
+
+	tmplLen := len(tmplVal)
+	if tmplLen > 3 || tmplLen < 2 {
+		return "", fmt.Errorf("invalid template: %s", strings.Join(tmplVal, "/"))
+	}
+
+	switch tmplVal[1] {
+	case tmplUUIDKey:
+		if len(tmplVal) != 2 {
+			return "", fmt.Errorf("invalid template: %s", strings.Join(tmplVal, "/"))
+		}
+		return uuid.NewString(), nil
+	case tmplHexKey:
+		if len(tmplVal) != 3 {
+			return "", fmt.Errorf("invalid template: %s", strings.Join(tmplVal, "/"))
+		}
+		rndLen, err := strconv.Atoi(tmplVal[2])
+		if err != nil || rndLen < 1 {
+			return "", fmt.Errorf("unsupported %s/%s template: %s",
+				tmplRandomKey, tmplUUIDKey, strings.Join(tmplVal, "/"))
+		}
+		if rndLen > 32 {
+			return "", fmt.Errorf("unsupported %s/%s lenght: %s",
+				tmplRandomKey, tmplUUIDKey, strings.Join(tmplVal, "/"))
+		}
+
+		rndHex := make([]byte, 32)
+		uuid := uuid.New()
+		hex.Encode(rndHex, uuid[:])
+		return string(rndHex[:rndLen]), nil
+	case tmplIntKey:
+		if len(tmplVal) != 3 {
+			return "", fmt.Errorf("invalid template: %s", strings.Join(tmplVal, "/"))
+		}
+		intMax, err := strconv.Atoi(tmplVal[2])
+		if err != nil || intMax < 1 {
+			return "", fmt.Errorf("unsupported %s/%s template: %s",
+				tmplRandomKey, tmplIntKey, strings.Join(tmplVal, "/"))
+		}
+		intVal := rand.IntN(intMax)
+		return strconv.Itoa(intVal), nil
+	}
+
+	return "", fmt.Errorf("invalid template: %s", strings.Join(tmplVal, "/"))
+}

pkg/templater/templater.go

@@ -18,6 +18,7 @@ package templater
 
 import (
 	"errors"
+	"fmt"
 	"strings"
 
 	values "github.com/rancher/wrangler/v2/pkg/data"
@@ -72,14 +73,32 @@ func replaceStringData(data map[string]interface{}, name string) (string, error)
 		}
 
 		result.WriteString(str[:i])
-		obj := values.GetValueN(data, strings.Split(str[i+2:j+i], "/")...)
-		if str, ok := obj.(string); ok {
-			result.WriteString(str)
-		} else {
-			return "", errValueNotFound
+		tmplVal := strings.Split(str[i+2:j+i], "/")
+
+		strVal, err := templateToString(data, tmplVal)
+		fmt.Printf("TMPL CONVERSION: %q --> %q\n", tmplVal, strVal)
+		if err != nil {
+			return "", err
 		}
+
+		result.WriteString(strVal)
 		str = str[j+i+1:]
 	}
 
 	return result.String(), nil
 }
+
+func templateToString(data map[string]interface{}, tmplVal []string) (string, error) {
+	var str string
+	var ok bool
+
+	if isRandomTemplate(tmplVal) {
+		return randomTemplateToString(tmplVal)
+	}
+
+	obj := values.GetValueN(data, tmplVal...)
+	if str, ok = obj.(string); !ok {
+		return "", errValueNotFound
+	}
+	return str, nil
+}

pkg/templater/templater_test.go

@@ -18,6 +18,7 @@ package templater
 
 import (
 	"fmt"
+	"strings"
 	"testing"
 
 	"gotest.tools/v3/assert"
@@ -130,3 +131,37 @@ func TestIsValueNotFoundError(t *testing.T) {
 	assert.Equal(t, IsValueNotFoundError(errValueNotFound), true)
 	assert.Equal(t, IsValueNotFoundError(errRandom), false)
 }
+
+func TestRandomTemplate(t *testing.T) {
+	testCase := []struct {
+		tmplVal []string
+		isRand  bool
+		isValid bool
+	}{
+		{[]string{"Custom"}, false, false},
+		{[]string{tmplRandomKey, "Custom"}, false, false},
+		{[]string{tmplRandomKey, tmplUUIDKey}, true, true},
+		{[]string{tmplRandomKey, tmplUUIDKey, "ABC"}, true, false},
+		{[]string{tmplRandomKey, tmplUUIDKey, "16"}, true, false},
+		{[]string{tmplRandomKey, tmplHexKey}, true, false},
+		{[]string{tmplRandomKey, tmplHexKey, "0"}, true, false},
+		{[]string{tmplRandomKey, tmplHexKey, "33"}, true, false},
+		{[]string{tmplRandomKey, tmplHexKey, "32"}, true, true},
+		{[]string{tmplRandomKey, tmplIntKey}, true, false},
+		{[]string{tmplRandomKey, tmplIntKey, "12123123"}, true, true},
+		{[]string{tmplRandomKey, tmplIntKey, "0"}, true, false},
+		{[]string{tmplRandomKey, tmplIntKey, "pippo"}, true, false},
+		{[]string{tmplRandomKey, tmplIntKey, "1000", "extraarg"}, true, false},
+	}
+
+	for _, testCase := range testCase {
+		assert.Equal(t, isRandomTemplate(testCase.tmplVal), testCase.isRand,
+			"template: %s, expected ret: %t", strings.Join(testCase.tmplVal, "/"), testCase.isRand)
+		val, err := randomTemplateToString(testCase.tmplVal)
+		if testCase.isValid {
+			assert.NilError(t, err)
+		} else {
+			assert.Assert(t, err != nil, "template '%s' got converted to '%s'", strings.Join(testCase.tmplVal, "/"), val)
+		}
+	}
+}