learning/tour-of-beam/backend/internal/persistence_key.go

// Licensed to the Apache Software Foundation (ASF) under one or more
// contributor license agreements.  See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// The ASF licenses this file to You 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 internal

import (
	"crypto/rand"
	"encoding/base64"
)

// size in bytes
const PERSISTENCE_KEY_SIZE = 16

// Generate random persistence_key, return it as base64 URL-encoded string
// NOT to be exposed on a front-channel!
func GeneratePersistentKey() string {
	raw := make([]byte, PERSISTENCE_KEY_SIZE)
	_, err := rand.Read(raw)
	if err != nil {
		panic(err)
	}

	// base64 encode to pass as protobuf string
	return base64.URLEncoding.EncodeToString(raw)
}