Skip to content

lambda.md

Latest commit

 

History

History
248 lines (200 loc) · 9.86 KB

lambda.md

File metadata and controls

248 lines (200 loc) · 9.86 KB

Lambda Service Guide

Lambda is a fully implemented service in LocalStack Explorer. It supports function management, code and configuration updates, synchronous invocation with log output, triggers, versions, and aliases.

Features

  • List, create, and delete Lambda functions
  • View function details (configuration, environment variables, layers, architectures)
  • Update function code (zip upload or S3 reference)
  • Update function configuration (handler, runtime, memory, timeout, environment, role)
  • Invoke functions synchronously with JSON payload
  • View invocation results: status code, response payload, function errors, and decoded CloudWatch logs
  • Triggers: view all trigger sources for a function
    • Resource-based policy triggers (S3, SNS, API Gateway, EventBridge, etc.) — detected from the function's resource policy via GetPolicy
    • Event source mappings (SQS, DynamoDB Streams, Kinesis, etc.) — with create and delete support
  • Browse function versions
  • Browse function aliases
  • Search/filter functions by name
  • Active service detection: Lambda appears greyed out in the UI when not running on LocalStack

API Endpoints

All endpoints are prefixed with /api/lambda.

Functions

Method Path Description Request Response
GET / List functions ?marker=string { functions: [...] }
POST / Create function CreateFunctionBody { message: string }
GET /:functionName Get function detail -- FunctionDetail
PUT /:functionName/code Update function code { zipFile?, s3Bucket?, s3Key? } { message: string }
PUT /:functionName/config Update function config UpdateFunctionConfigBody { message: string }
DELETE /:functionName Delete function -- { success: boolean }

Invocation

Method Path Description Request Response
POST /:functionName/invoke Invoke function { payload?, invocationType? } InvokeFunctionResponse

Triggers

Method Path Description Request Response
GET /:functionName/triggers List all triggers ?marker=string { eventSourceMappings, policyTriggers }
POST /:functionName/event-source-mappings Create event source mapping { eventSourceArn, batchSize?, enabled?, ... } { message, uuid }
DELETE /event-source-mappings/:uuid Delete event source mapping -- { success: boolean }

The GET /:functionName/triggers endpoint combines two data sources:

  • Event source mappings — Lambda's ListEventSourceMappings (SQS queues, DynamoDB Streams, Kinesis streams)
  • Policy triggers — parsed from the function's resource-based policy via GetPolicy (S3 bucket notifications, SNS topics, API Gateway, EventBridge rules, etc.)

Versions & Aliases

Method Path Description Request Response
GET /:functionName/versions List versions ?marker=string { versions: [...] }
GET /:functionName/aliases List aliases ?marker=string { aliases: [...] }

Request/Response Examples

List functions:

curl http://localhost:3001/api/lambda
{
  "functions": [
    {
      "functionName": "my-function",
      "functionArn": "arn:aws:lambda:us-east-1:000000000000:function:my-function",
      "runtime": "nodejs20.x",
      "handler": "index.handler",
      "codeSize": 284,
      "lastModified": "2024-01-15T10:30:00.000+0000",
      "memorySize": 128,
      "timeout": 30
    }
  ]
}

Create function:

curl -X POST http://localhost:3001/api/lambda \
  -H "Content-Type: application/json" \
  -d '{
    "functionName": "my-function",
    "runtime": "nodejs20.x",
    "handler": "index.handler",
    "role": "arn:aws:iam::000000000000:role/lambda-role",
    "code": { "zipFile": "<base64-encoded-zip>" },
    "memorySize": 128,
    "timeout": 30
  }'
{ "message": "Function 'my-function' created successfully" }

Invoke function:

curl -X POST http://localhost:3001/api/lambda/my-function/invoke \
  -H "Content-Type: application/json" \
  -d '{
    "payload": "{\"key\": \"value\"}",
    "invocationType": "RequestResponse"
  }'
{
  "statusCode": 200,
  "payload": "{\"statusCode\":200,\"body\":\"hello\"}",
  "logResult": "START RequestId: ...\nEND RequestId: ...\n"
}

Get function detail:

curl http://localhost:3001/api/lambda/my-function
{
  "functionName": "my-function",
  "functionArn": "arn:aws:lambda:us-east-1:000000000000:function:my-function",
  "runtime": "nodejs20.x",
  "handler": "index.handler",
  "role": "arn:aws:iam::000000000000:role/lambda-role",
  "codeSize": 284,
  "description": "My Lambda function",
  "timeout": 30,
  "memorySize": 128,
  "lastModified": "2024-01-15T10:30:00.000+0000",
  "codeSha256": "abc123...",
  "version": "$LATEST",
  "environment": { "NODE_ENV": "production" },
  "architectures": ["x86_64"],
  "layers": [],
  "packageType": "Zip"
}

List triggers:

curl http://localhost:3001/api/lambda/my-function/triggers
{
  "eventSourceMappings": [
    {
      "uuid": "abc-123",
      "eventSourceArn": "arn:aws:sqs:us-east-1:000000000000:my-queue",
      "state": "Enabled",
      "batchSize": 10
    }
  ],
  "policyTriggers": [
    {
      "sid": "AllowS3Invoke",
      "service": "s3.amazonaws.com",
      "sourceArn": "arn:aws:s3:::my-bucket"
    }
  ]
}

Create event source mapping:

curl -X POST http://localhost:3001/api/lambda/my-function/event-source-mappings \
  -H "Content-Type: application/json" \
  -d '{
    "eventSourceArn": "arn:aws:sqs:us-east-1:000000000000:my-queue",
    "batchSize": 10,
    "enabled": true
  }'
{ "message": "Event source mapping created successfully", "uuid": "abc-123" }

Delete function:

curl -X DELETE http://localhost:3001/api/lambda/my-function
{ "success": true }

Error Handling

Error HTTP Status Code
Function not found 404 FUNCTION_NOT_FOUND
Function already exists / in use 409 FUNCTION_CONFLICT
Event source mapping not found 404 EVENT_SOURCE_MAPPING_NOT_FOUND
Invalid parameter value 400 INVALID_PARAMETER
Rate limit exceeded 429 TOO_MANY_REQUESTS
AWS service error 502 SERVICE_ERROR

UI Components

Function List (/lambda)

  • Searchable table with columns: Name, Runtime, Memory, Timeout, Last Modified
  • Function name links to detail view
  • Create button opens a dialog with fields for name, runtime, handler, role, memory, timeout, and optional zip upload
  • Per-row delete button with confirmation dialog

Function Detail (/lambda/:functionName)

Five tabs:

  1. Configuration — attribute grid (runtime, handler, role, memory, timeout, code size, state, package type, architectures, SHA256) and environment variables table
  2. Invoke — JSON payload textarea, invocation type selector (RequestResponse, Event, DryRun), result panel with status code, payload, error, and decoded log output
  3. Triggers — two sections:
    • Resource-Based Policy Triggers — read-only table showing services (S3, SNS, API Gateway, etc.) authorized to invoke the function, with source ARN and policy statement ID. Detected automatically from the function's resource-based policy.
    • Event Source Mappings — table of SQS/DynamoDB Streams/Kinesis mappings with state, batch size, and last modified. Supports creating new mappings (event source ARN + batch size) and deleting existing ones with confirmation dialog.
  4. Versions — table of published versions with version number, ARN, runtime, and last modified date
  5. Aliases — table of aliases with name, ARN, function version, and description

Backend Architecture

The Lambda plugin follows the standard service plugin pattern:

packages/backend/src/plugins/lambda/
├── index.ts       # Plugin registration (5 lines)
├── routes.ts      # 12 Fastify routes
├── service.ts     # LambdaService class wrapping @aws-sdk/client-lambda
└── schemas.ts     # TypeBox request/response schemas

The LambdaService class maps AWS SDK exceptions to AppError instances with appropriate HTTP status codes via a centralized mapLambdaError function.