dify/web/features/deployments/create-guide/instance-name.ts

const RANDOM_SUFFIX_ALPHABET = 'abcdefghijklmnopqrstuvwxyz'
const RANDOM_SUFFIX_LENGTH = 4
const RANDOM_SUFFIX_FALLBACK_LENGTH = 6
const RANDOM_SUFFIX_MAX_ATTEMPTS = 16

function randomLetterCombination(length: number) {
  const randomValues = new Uint8Array(length)

  if (globalThis.crypto) {
    globalThis.crypto.getRandomValues(randomValues)
  }
  else {
    randomValues.forEach((_, index) => {
      randomValues[index] = Math.floor(Math.random() * 256)
    })
  }

  return Array.from(randomValues, value => RANDOM_SUFFIX_ALPHABET[value % RANDOM_SUFFIX_ALPHABET.length]).join('')
}

export function availableInstanceName(baseName: string, existingNames: readonly string[]) {
  const existingNameSet = new Set(existingNames)
  if (!existingNameSet.has(baseName))
    return baseName

  for (let attempt = 0; attempt < RANDOM_SUFFIX_MAX_ATTEMPTS; attempt++) {
    const candidate = `${baseName}-${randomLetterCombination(RANDOM_SUFFIX_LENGTH)}`
    if (!existingNameSet.has(candidate))
      return candidate
  }

  return `${baseName}-${randomLetterCombination(RANDOM_SUFFIX_FALLBACK_LENGTH)}`
}