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Remote Templates

Templates allow scaffolding a new CDK for Terraform project. When you setup a new project via cdktf init you can supply one of the built-in templates (e.g. typescript or python) or use your own. This document describes how to create your own template to use with cdktf init.

Using Remote Templates

Currently the cdktf supports downloading and extracting a zip archive containing the files for the template. When extracting the archive, it searches for the cdktf.json file. If that file cannot be found in the root directory, it walks all directories until it finds the file. This allows creating an archive that contains e.g. a README.md in the root directory explaining things which itself won't turn up in the created project directory. However, most templates won't make use of it.

If you're using a Github repository for your template, you can create URLs to your repo as follows

main branch

https://github.com/<user or organization>/<repo>/archive/refs/heads/main.zip

tag v.0.0.1

https://github.com/<user or organization>/<repo>/archive/refs/tags/v0.0.1.zip

Please Note: Currently only urls to zip archives can be specified, hence only url based authentication mechanisms are supported. If you need support for private packages, please file an issue.

Creating Remote Templates

A template is a directory, containing at least a cdktf.json file, which is required for the cdktf CLI.
For scaffolding a new project the library sscaff is used. sscaff basically copies all files into the new directory while allowing for substitutions and hooks.

Using Substitutions

A template can make use of substitutions for filenames and file content. To specify your own variables, use Hooks (see below).
Besides the built-in substitutions of sccaff the CDK for Terraform supplies some more variables that can be used in templates:

User input

Name: string;
Description: string;
OrganizationName: string;
WorkspaceName: string;

These variables hold the input of the user and can for example be used in project files like package.json or similar.

Versions

cdktf_version: string;
constructs_version: string;
npm_cdktf: string;
npm_cdktf_cli: string;
pypi_cdktf: string;
mvn_cdktf: string;
nuget_cdktf: string;

Those variables contain versions that are relative to the cdktf-cli that scaffolds the template. See the built-in templates as reference of how you can use them.

Using pre and post Hooks

Hooks allow you to run additional logic before and after the generation of the output.

Debugging

To debug your templates you can add console.log() statements to your hook functions. Their output is displayed while initializing from a template.
If you set the environment flag CDKTF_LOG_LEVEL to debug you will see more debugging output (e.g. the temporary directory into which your zip archive is downloaded; which can help if you're unsure how your archive behaves).