public async import()

in packages/aws-cdk/lib/cli/cdk-toolkit.ts [824:911]
68 lines of code
11 McCabe index (conditional complexity)

  public async import(options: ImportOptions) {
    const stacks = await this.selectStacksForDeploy(options.selector, true, true, false);

    // set progress from options, this includes user and app config
    if (options.progress) {
      this.ioHost.stackProgress = options.progress;
    }

    if (stacks.stackCount > 1) {
      throw new ToolkitError(
        `Stack selection is ambiguous, please choose a specific stack for import [${stacks.stackArtifacts.map((x) => x.id).join(', ')}]`,
      );
    }

    if (!process.stdout.isTTY && !options.resourceMappingFile) {
      throw new ToolkitError('--resource-mapping is required when input is not a terminal');
    }

    const stack = stacks.stackArtifacts[0];

    highlight(stack.displayName);

    const resourceImporter = new ResourceImporter(stack, {
      deployments: this.props.deployments,
      ioHelper: asIoHelper(this.ioHost, 'import'),
    });
    const { additions, hasNonAdditions } = await resourceImporter.discoverImportableResources(options.force);
    if (additions.length === 0) {
      warning(
        '%s: no new resources compared to the currently deployed stack, skipping import.',
        chalk.bold(stack.displayName),
      );
      return;
    }

    // Prepare a mapping of physical resources to CDK constructs
    const actualImport = !options.resourceMappingFile
      ? await resourceImporter.askForResourceIdentifiers(additions)
      : await resourceImporter.loadResourceIdentifiers(additions, options.resourceMappingFile);

    if (actualImport.importResources.length === 0) {
      warning('No resources selected for import.');
      return;
    }

    // If "--create-resource-mapping" option was passed, write the resource mapping to the given file and exit
    if (options.recordResourceMapping) {
      const outputFile = options.recordResourceMapping;
      fs.ensureFileSync(outputFile);
      await fs.writeJson(outputFile, actualImport.resourceMap, {
        spaces: 2,
        encoding: 'utf8',
      });
      info('%s: mapping file written.', outputFile);
      return;
    }

    // Import the resources according to the given mapping
    info('%s: importing resources into stack...', chalk.bold(stack.displayName));
    const tags = tagsForStack(stack);
    await resourceImporter.importResourcesFromMap(actualImport, {
      roleArn: options.roleArn,
      tags,
      deploymentMethod: options.deploymentMethod,
      usePreviousParameters: true,
      rollback: options.rollback,
    });

    // Notify user of next steps
    info(
      `Import operation complete. We recommend you run a ${chalk.blueBright('drift detection')} operation ` +
        'to confirm your CDK app resource definitions are up-to-date. Read more here: ' +
        chalk.underline.blueBright(
          'https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/detect-drift-stack.html',
        ),
    );
    if (actualImport.importResources.length < additions.length) {
      info('');
      warning(
        `Some resources were skipped. Run another ${chalk.blueBright('cdk import')} or a ${chalk.blueBright('cdk deploy')} to bring the stack up-to-date with your CDK app definition.`,
      );
    } else if (hasNonAdditions) {
      info('');
      warning(
        `Your app has pending updates or deletes excluded from this import operation. Run a ${chalk.blueBright('cdk deploy')} to bring the stack up-to-date with your CDK app definition.`,
      );
    }
  }