@composurecdk/lambda

Lambda builders for ComposureCDK.

This package provides a fluent builder for AWS Lambda functions with secure, AWS-recommended defaults. It wraps the CDK Function construct — refer to the CDK documentation for the full set of configurable properties.

Function Builder

import { createFunctionBuilder } from "@composurecdk/lambda";

const handler = createFunctionBuilder()
  .runtime(Runtime.NODEJS_22_X)
  .handler("index.handler")
  .code(Code.fromAsset("lambda"))
  .build(stack, "MyFunction");

Every FunctionProps property is available as a fluent setter on the builder.

Secure Defaults

createFunctionBuilder applies the following defaults. Each can be overridden via the builder's fluent API.

| Property | Default | Rationale | | --------------- | -------- | ------------------------------------------------------------------------------------ | | tracing | ACTIVE | Enables X-Ray distributed tracing for observability. | | loggingFormat | JSON | Structured logs for CloudWatch Logs Insights auto-discovery and consistent querying. |

These defaults are guided by the AWS Well-Architected Serverless Applications Lens.

The defaults are exported as FUNCTION_DEFAULTS for visibility and testing:

import { FUNCTION_DEFAULTS } from "@composurecdk/lambda";

Overriding defaults

import { LoggingFormat, Tracing } from "aws-cdk-lib/aws-lambda";

const handler = createFunctionBuilder()
  .runtime(Runtime.NODEJS_22_X)
  .handler("index.handler")
  .code(Code.fromAsset("lambda"))
  .tracing(Tracing.PASS_THROUGH)
  .loggingFormat(LoggingFormat.TEXT)
  .build(stack, "MyFunction");

Examples

• LambdaApiStack — REST API backed by a Lambda function, wired with ref
• DualFunctionStack — Two Lambda functions with different configurations
• MultiStackApp — Lambda split across stacks via .withStacks()
• StrategyStackApp — Lambda split across stacks via .withStackStrategy()