Class DatabaseRemove

src/database/remove.ts:19–127

const MAX_LIST_NUM_SUB_PATH = 204800;

export default class DatabaseRemove {
  path: string;
  remote: RemoveRemote;
  listRemote: ListRemote;
  private deleteJobStack: Stack<() => Promise<boolean>, boolean>;
  private listStack: Stack<() => Promise<string[]>, string[]>;

  /**
   * Construct a new RTDB delete operation.
   *
   * @param instance RTBD instance ID.
   * @param path path to delete.
   * @param host db host.
   * @param disableTriggers if true, suppresses any Cloud functions that would be triggered by this operation.
   */
  constructor(instance: string, path: string, host: string, disableTriggers: boolean) {
    this.path = path;
    this.remote = new RTDBRemoveRemote(instance, host, disableTriggers);
    this.deleteJobStack = new Stack({
      name: "delete stack",
      concurrency: 1,
      retries: 3,
    });
    this.listRemote = new RTDBListRemote(instance, host);
    this.listStack = new Stack({
      name: "list stack",
      concurrency: 1,
      retries: 3,
    });
  }

  async execute(): Promise<void> {
    await this.deletePath(this.path);
  }

  /**
   * First, attempt to delete the path, if the path is big (i.e. exceeds writeSizeLimit of tiny),
   * it will perform multi-path recursive chunked deletes in rounds.
   * Each round, it fetches listNumSubPath subPaths and issue batches based on batchSize.
   * At the end of each round, it adjustes the batchSize based on whether the majority of the batches are small.
   *
   * listNumSubPath starts with INITIAL_LIST_NUM_SUB_PATH and grow expontentially until MAX_LIST_NUM_SUB_PATH.
   *
   * @param path path to delete
   * @return true if this path is small (Does not exceed writeSizeLimit of tiny)
   */
  private async deletePath(path: string): Promise<boolean> {
    if (await this.deleteJobStack.run(() => this.remote.deletePath(path))) {
      return true;
    }
    let listNumSubPath = INITIAL_LIST_NUM_SUB_PATH;
    // The range of batchSize to gradually narrow down.
    let batchSizeLow = 1;
    let batchSizeHigh = MAX_LIST_NUM_SUB_PATH + 1;
    let batchSize = INITIAL_DELETE_BATCH_SIZE;
    while (true) {
      const subPathList = await this.listStack.run(() =>
        this.listRemote.listPath(path, listNumSubPath),