private getFallbackConfig()

in authui-container/server/auth-server.ts [317:356]
32 lines of code
5 McCabe index (conditional complexity)

  private getFallbackConfig(hostname: string): Promise<UiConfig | null> {
    // Parse config from environment variable first.
    if (process.env.UI_CONFIG) {
      try {
        const config: UiConfig = JSON.parse(process.env.UI_CONFIG);
        DefaultUiConfigBuilder.validateConfig(config);
        return Promise.resolve(config);
      } catch (error) {
        // Ignore but log error.
        log(`Invalid configuration in environment variable UI_CONFIG: ${error.message}`);
      }
    }
    // Parse config from GCS bucket if available.
    const cloudStorageHandler = new CloudStorageHandler(this.metadataServer, this.metadataServer);
    return this.getBucketName()
      .then((bucketName) => {
        return cloudStorageHandler.readFile(bucketName, CONFIG_FILE_NAME);
      })
      .catch((error) => {
        // If not available in GCS, use default config.
        if (!this.defaultConfigPromise) {
          // Default config should be retrieved once and cached in memory.
          this.defaultConfigPromise = this.getDefaultConfig(hostname);
        }
        return this.defaultConfigPromise.then((config) => {
          if (!config) {
            // Do not cache config if IAP is not yet enabled.
            this.defaultConfigPromise = null;
            // Return default config.
            return null;
          }
          return config;
        })
        .catch((err) => {
          // Do not cache errors in building default config.
          this.defaultConfigPromise = null;
          throw err;
        });
      });
  }