@crvouga/mockingbird-service-lambda

Local emulators. Real API contracts. Part of Mockingbird.

Transport scaffold for Amazon Lambda. ESM; Node 22+ or Bun 1.2+.

Usage

import { ListFunctionsCommand, LambdaClient } from "@aws-sdk/client-lambda"
import { createServer } from "@crvouga/mockingbird-service-lambda/server"

// Test setup: the Lambda client your application already uses, pointed at the emulator.
const server = await createServer()
const lambda = new LambdaClient({
  endpoint: server.url,
  region: "us-east-1",
  credentials: { accessKeyId: "fixture", secretAccessKey: "fixture" },
})

// No Lambda operation is implemented yet, so every command rejects.
const outcome = await lambda.send(new ListFunctionsCommand({})).catch(() => "rejected")
// "rejected"

await server.close()

State lives in SQLite collections and participates in the shared runtime's namespace isolation, reset, timeline, clock, journal, metrics and fault controls. No AWS account is needed.

Planned, not implemented, AWS operations: CreateFunction, GetFunction, GetFunctionConfiguration, ListFunctions, UpdateFunctionConfiguration, UpdateFunctionCode, DeleteFunction, Invoke, PublishVersion, ListVersionsByFunction, CreateAlias, GetAlias, ListAliases, UpdateAlias, DeleteAlias, AddPermission, GetPolicy, RemovePermission, TagResource, UntagResource, ListTags, CreateEventSourceMapping, ListEventSourceMappings, DeleteEventSourceMapping.

Operations outside this list fail explicitly. This package emulates API state, not AWS infrastructure, production quotas, billing, IAM enforcement, or provider consoles. Service-specific omissions and oracle evidence are recorded in the AWS coverage ledger.

Run bun run parity with LocalStack on http://127.0.0.1:4566; an unavailable oracle fails the run. No LocalStack run is recorded for this integration. The parity command is a bounded read-only SDK envelope probe, not proof of full vendor equivalence.

Implementation status

No vendor operations are implemented. Requests fail explicitly with UnknownOperationException; transport tests cover this boundary and malformed input. This package is not a usable vendor replacement yet. No LocalStack or live AWS parity is claimed.

Install

bun add @crvouga/mockingbird-service-lambda

API

• LambdaAPI(options?): low-level AWS transport instance with fetch and reset.

• createRuntime(options?): in-process Fetch API and shared state controls.

• createServer(options?) from the /server entry: HTTP listener with url, runtime, and close().

• document, operationIds, and supportedOperationIds: generated transport contract metadata.