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@cdktf/hcl2cdk

Uses @cdktf/hcl2cdk to transform HCL configuration to CDK constructs.

Usage

yarn install @cdktf/hcl2cdk

Convert HCL strings to Constructs

import { convert } from "@cdktf/hcl2cdk";

const hcl = `
  variable "name" {
    description = "Name to be used on all the resources as identifier"
    type        = string
    default     = ""
  }
`(async () => {
  const ts = await convert(hcl, { language: "typescript" });
  console.log(ts.imports); // just the necessary imports
  console.log(ts.code); // just the constructs
  console.log(ts.all); // code with imports
})();

// =>
import * as cdktf from "cdktf";

new cdktf.TerraformVariable(this, "imageId", {
  type: "string",
  default: "ami-abcde123",
  description: "What AMI to use to create an instance",
});

Convert a project

import * as hcl2cdk from "@cdktf/hcl2cdk";
import {
  readSchema,
  ConstructsMakerProviderTarget,
  LANGUAGES,
  config,
} from "@cdktf/provider-generator";

(async () => {
  const hcl = hcl2cdk.getTerraformConfigFromDir("/path/to/terraform/project");
  const providerRequirements = await hcl2cdk.parseProviderRequirements(hcl);
  const targets = Object.entries(providerRequirements).map(([name, version]) =>
    ConstructsMakerProviderTarget.from(
      new config.TerraformProviderConstraint(`${name}@ ${version}`),
      LANGUAGES[0]
    )
  );
  // Get all the provider schemas, making the conversion more precise
  const { providerSchema } = await readSchema(targets);

  const mainTs = await hcl2cdk.convert(hcl, {
    language: "typescript",
    providerSchema: providerSchema,
  });

  await hcl2cdk.convertProject(
    hcl,
    mainTs.code,
    require("../cdktf.json"),
    { language: "typescript", providerSchema } // Currently we only support Typescript for project conversion
  );
})();

This transforms your Terraform project into a CDK for Terraform project, besides the resource naming within Terraform the deployed resources should not differ between terraform plan and cdktf plan.

Known Limitations

Terraform Expressions are of the wrong TS/Java/C# type

When working with typed languages the converter can run into problems where the Terraform Expression evaluates to a certain type but it's encoded in a string. Therefore the type checker of the language detects a type mismatch, resulting in an compilation error. These problems need to be manually solved by adding a typecast. One example would be:

{
  // Typescript expects a boolean here, but a string is passed
  booleanProperty:
    ( // This Terraform expression evaluates to a boolean as required by the property
      `\${${shouldBeTrue.value} ? true : false}`
      as boolean // We need to cast the type so that Typescript understand the right type is being passed
    );
}

Providers guessed can be not functional

If your HCL includes providers that are not mentioned under required_providers we infer the name, e.g. if you use the datadog_dashboard resource we infer the provider datadog which is right, but the namespace is missing, for DataDog it would be datadog/datadog. Instead we will try to use hashicorp/datadog and fail because this provider is not known to the registry. Please see the required providers docs for more information on how to specify providers.

Local Modules and Files

We don't move modules or files for you, if you reference local modules you have to move them so that the relative paths are correct. If you want to make use of files you need to wrap them in a TerraformAsset before using them.