Outputs

In this lesson we cover how to define and capture outputs in CDK for Terraform (CDKTF). When your CDKTF resources produce values you want to inspect, pass between stacks, or use in automation, expose them as Terraform outputs by instantiating the TerraformOutput class — the CDKTF equivalent of an HCL output block.

A presentation slide titled "Working With Outputs in CDKTF – Problem" showing a stylized icon of a person at a monitor with code brackets. A grey caption reads, "Author needs to confirm the outputs and content of created files."

When to use outputs

Use Terraform outputs to:

Expose resource attributes for human inspection (printed after cdktf deploy).
Share data between stacks (e.g., export a value from one stack to reference in another).
Provide values to automation scripts or CI pipelines.

Common CDKTF pattern:

Create resources.
Store resource references in variables (so you can access attributes).
Define TerraformOutput instances after resource creation.

Quick example: expose a README file’s content

Create a Terraform output that exposes the content attribute of a local file resource:

// Output the readMeFile content
new TerraformOutput(this, 'readMeContent', {
  value: readMeFile.content,
});

Below is a compact, complete TypeScript CDKTF example that creates two local files and exports the README content as an output.

// TypeScript (CDKTF) - create files and export README content

const projectDirectory = path.join(process.env.INIT_CWD!, './authors-projects');
const projectName = 'project-1';
const basePath = `${projectDirectory}/${projectName}`;

// Add a README file and retain a reference to the resource so we can use its attributes
const readmeFile = new file.File(this, 'readme-file', {
  filename: `${basePath}/README.md`,
  content: `# ${projectName}\n\nThis is the ${projectName} project`,
});

// Add a package.json file
new file.File(this, 'package-json-file', {
  filename: `${basePath}/package.json`,
  content: JSON.stringify(
    {
      name: projectName,
      version: '1.0.0',
      main: 'index.js',
      scripts: {
        start: 'node index.js',
      },
    },
    null,
    2
  ),
});

// Export the README content as a Terraform output
new TerraformOutput(this, 'readMeContent', {
  value: readmeFile.content,
});

// Typical app bootstrap
const app = new App();
new MyStack(app, 'cdktf-project-builder');
app.synth();

Define outputs after creating the resources they reference. Keep a reference to the resource (for example readmeFile) so you can access attributes like readmeFile.content when constructing TerraformOutput.

`TerraformOutput` quick reference

Option	Type	Description
`value`	any	The value to expose (e.g., `readmeFile.content`).
`description`	string (optional)	A friendly description for the output.
`sensitive`	boolean (optional)	If `true`, the output will be treated as sensitive and not shown in plain text.

Example usage with optional properties:

new TerraformOutput(this, 'readMeContent', {
  value: readmeFile.content,
  description: 'The README content for project-1',
  sensitive: false,
});

Deploying and viewing outputs

When you run cdktf deploy, you’ll confirm the planned changes and, after apply completes, Terraform prints outputs. Example terminal session:

Do you want to perform these actions?
Terraform will perform the actions described above.
Only 'yes' will be accepted to approve.
Enter a value: yes

cdktf-project-builder local_file.package-json-file: Creating...
cdktf-project-builder local_file.package-json-file: Creation complete after 0s [id=b60a2ad91f16e1bfeb7fe2aac36782e6a53n7797e]
Apply complete! Resources: 1 added, 0 changed, 0 destroyed.

Outputs:

readMeContent = "# project-1\n\nThis is the project-1 project"

Now the README content is available as a Terraform output and can be:

Inspectable in the terminal,
Used by other stacks,
Consumed by automation or CI/CD pipelines.

References

CDKTF documentation: CDK for Terraform (CDKTF)
Terraform outputs: Terraform - Outputs

A simple horizontal three-step infographic with numbered circles connected by a line: "01 Providers & Resources," a highlighted teal "02 Outputs" in the center, and "03 Constructs" on the right. A small © Copyright KodeKloud appears in the lower-left.

Course Introduction

Introduction to TypeScript

Introduction to CDKTF

AWS With CDKTF

Conclusion

When to use outputs

Quick example: expose a README file’s content

`TerraformOutput` quick reference

Deploying and viewing outputs

References

Watch Video

​When to use outputs

​Quick example: expose a README file’s content

​TerraformOutput quick reference

​Deploying and viewing outputs

​References

Watch Video

When to use outputs

Quick example: expose a README file’s content

`TerraformOutput` quick reference

Deploying and viewing outputs

References