Remote State

Access outputs from other Terraform stacks.

Remote state allows you to share data between different Terraform configurations. In tfts, you can use TerraformRemoteState to read outputs from a previously deployed stack.

Data Sources for Remote State

tfts provides several implementations of TerraformRemoteState depending on your backend:

• DataTerraformRemoteStateLocal: For local state files.
• DataTerraformRemoteStateS3: For state stored in Amazon S3.
• DataTerraformRemoteStateGcs: For state stored in Google Cloud Storage.
• DataTerraformRemoteStateAzurerm: For state stored in Azure Blob Storage.

Accessing Outputs

Once you have defined a remote state data source, you can access its outputs using typed getter methods.

import { DataTerraformRemoteStateS3 } from "tfts";

const vpcState = new DataTerraformRemoteStateS3(stack, "vpc_state", {
  bucket: "my-terraform-state",
  key: "network/terraform.tfstate",
  region: "us-east-1",
});

const vpcId = vpcState.getString("vpc_id");
const privateSubnets = vpcState.getList("private_subnets");

Available methods include:

• get(outputName)
• getString(outputName)
• getNumber(outputName)
• getList(outputName)
• getBoolean(outputName)

Cross-Stack References

If you are managing multiple stacks within the same App, you can use app.crossStackReference() to automatically handle the dependency and state sharing.

const networkStack = new NetworkStack(app, "network");
const appStack = new AppStack(app, "app");

// Accessing an output from networkStack in appStack
const vpcId = app.crossStackReference(appStack, networkStack, "vpcId");

new Instance(appStack, "web", {
  vpcId: vpcId,
  // ...
});

This pattern simplifies the management of shared resources by abstracting away the manual configuration of remote state data sources and outputs.