Lambda

Lambda functions are created implicitly when you wire .fn.ts handlers to infrastructure.

Implicit creation

When you import from a .fn.ts file in your infrastructure code, the compiler transforms each handler export into a Lambda resource. A single import generates:

• Lambda function with bundled handler code
• IAM execution role with least-privilege permissions
• CloudWatch log group with 30-day retention
• Deterministic zip package of the handler code

import { api, router } from "@notation/aws/api-gateway";
import { getTodos } from "runtime/todos.fn";

const myApi = api({ name: "todo-api" });
const myRouter = router(myApi);

myRouter.get("/todos", getTodos);

The transformation

The function-infra-plugin intercepts .fn.ts imports and replaces handler exports with Lambda resource declarations:

import type { LambdaConfig } from "@notation/aws/lambda.fn";
import { handle, json } from "@notation/aws/lambda.fn";

export const getTodos = handle.apiRequest(() => {
  return json([{ id: 1, text: "Build with Notation" }]);
});

export const config: LambdaConfig = {
  service: "aws/lambda",
  timeout: 5,
  memory: 64,
};

export const getTodos = async () => {
  return { body: JSON.stringify({ id: 1, text: "Build with Notation" }), statusCode: 200 };
};

The plugin strips runtime-only code (imports, side effects) that would be unsafe in an infrastructure context, preserves the config object, and emits a lambda() call for each exported handler. Reserved exports like config and preload are excluded from the transform.

Configuration

Lambda settings are configured via the config export in .fn.ts files. See Lambda Config for details.

export const config: LambdaConfig = {
  service: "aws/lambda",
  memory: 256,
  timeout: 30,
};

Runtime defaults