Multi-Stack Projects

chant supports splitting resources across multiple stacks with automatic cross-stack reference resolution.

When resources in different stacks reference each other, chant generates cross-stack outputs and imports using the appropriate provider-specific mechanism.

Child projects (nested stacks)

chant supports child projects — subdirectories that build to separate, independently-valid templates. The parent references a child project via a lexicon-specific function, and cross-stack outputs are declared explicitly with stackOutput().

For example, the AWS lexicon’s nestedStack() function references a child project directory and produces separate CloudFormation child templates:

src/
  app.ts            # parent resources
  network/          # ← child project
    vpc.ts          # child resources
    outputs.ts      # stackOutput() declarations

src/network/outputs.ts

/**
 * Cross-stack outputs — values the parent can reference
 */

import { stackOutput } from "@intentius/chant";
import { vpc, subnet } from "./vpc";
import { lambdaSg } from "./security";

export const vpcId = stackOutput(vpc.VpcId, {
  description: "VPC ID",
});
export const subnetId = stackOutput(subnet.SubnetId, {
  description: "Public subnet ID",
});
export const lambdaSgId = stackOutput(lambdaSg.GroupId, {
  description: "Lambda security group ID",
});

src/app.ts

/**
 * App layer — Lambda function in the parent template that references
 * the network nested stack's outputs via cross-stack references
 */

import { Function, Sub, AWS, Ref, nestedStack } from "@intentius/chant-lexicon-aws";

// nestedStack() references a child project directory
const network = nestedStack("network", import.meta.dirname + "/network", {
  parameters: { Environment: "prod" },
});

export const handler = new Function({
  FunctionName: Sub`${AWS.StackName}-handler`,
  Runtime: "nodejs20.x",
  Handler: "index.handler",
  Role: Ref("LambdaExecutionRole"),
  Code: { ZipFile: "exports.handler = async () => ({ statusCode: 200 });" },
  VpcConfig: {
    SubnetIds: [network.outputs.subnetId],
    SecurityGroupIds: [network.outputs.lambdaSgId],
  },
});

// Re-export so discovery picks it up as an entity
export { network };

The child can be built independently (chant build src/network/), and the parent build produces multiple template files. See your lexicon’s documentation for details — for AWS, see the Nested Stacks guide.

For details on how multi-stack serialization works, see Multi-Stack Output.