Class LokiTableMetadataStore

src/table/persistence/LokiTableMetadataStore.ts:22–1088

  IServiceAdditionalProperties;

export default class LokiTableMetadataStore implements ITableMetadataStore {
  private readonly db: Loki;
  private readonly TABLES_COLLECTION = "$TABLES_COLLECTION$";
  private readonly SERVICES_COLLECTION = "$SERVICES_COLLECTION$";
  private initialized: boolean = false;
  private closed: boolean = false;
  // The Rollback Entities arrays hold the rows that we will reapply to the database in the case
  // that we need to rollback a transaction.
  // We make the assumption that there will not be any IO during the processing of a transaction
  // and assume that the execution will remain in the same thread associated with the transaction.
  // See: https://nodejs.org/en/docs/guides/event-loop-timers-and-nexttick/
  private transactionRollbackTheseEntities: Entity[] = []; // can maybe use Entity instead of any
  private transactionDeleteTheseEntities: Entity[] = []; // can maybe use Entity instead of any

  public constructor(public readonly lokiDBPath: string, inMemory: boolean) {
    this.db = new Loki(lokiDBPath, inMemory ? {
      persistenceMethod: "memory"
    } : {
      persistenceMethod: "fs",
      autosave: true,
      autosaveInterval: 5000
    });
  }

  /**
   * Initializes the persistence layer
   *
   * @return {*}  {Promise<void>}
   * @memberof LokiTableMetadataStore
   */
  public async init(): Promise<void> {
    await this.loadDB();
    this.createTablesCollection();
    this.createServicePropsCollection();
    await this.saveDBState();
    this.finalizeInitializationState();
  }

  /**
   * Close down the DB
   *
   * @return {*}  {Promise<void>}
   * @memberof LokiTableMetadataStore
   */
  public async close(): Promise<void> {
    await new Promise<void>((resolve, reject) => {
      this.db.close((err) => {
        if (err) {
          reject(err);
        } else {
          resolve();
        }
      });
    });

    this.closed = true;
  }