apex

README

Apex Golang

Golang runtime support for Apex/Lambda – providing handlers for Lambda sources, and runtime requirements such as implementing the Node.js shim stdio interface.

Features

Currently supports:

• Node.js shim
• Environment variable population
• Arbitrary JSON
• CloudWatch Logs
• Cognito
• Kinesis
• Dynamo
• S3
• SNS
• SES

Example

package main

import (
  "encoding/json"
  "strings"

  "github.com/apex/go-apex"
)

type message struct {
  Value string `json:"value"`
}

func main() {
  apex.HandleFunc(func(event json.RawMessage, ctx *apex.Context) (interface{}, error) {
    var m message

    if err := json.Unmarshal(event, &m); err != nil {
      return nil, err
    }

    m.Value = strings.ToUpper(m.Value)

    return m, nil
  })
}

Run the program:

echo '{"event":{"value":"Hello World!"}}' | go run main.go
{"value":{"value":"HELLO WORLD!"}}

Notes

Due to the Node.js shim required to run Go in Lambda, you must use stderr for logging – stdout is reserved for the shim.

Badges

---

tjholowaychuk.com  ·  GitHub @tj  ·  Twitter @tjholowaychuk

Documentation

Overview

Package apex provides Lambda support for Go via a Node.js shim and this package for operating over stdio.

Example

Example of a Lambda function handling arbitrary JSON input.

package main

import (
	"encoding/json"

	"github.com/apex/go-apex"
)

type Message struct {
	Hello string `json:"hello"`
}

// Example of a Lambda function handling arbitrary JSON input.
func main() {
	apex.HandleFunc(func(event json.RawMessage, ctx *apex.Context) (interface{}, error) {
		return &Message{"world"}, nil
	})
}

Index

• func Handle(h Handler)
• func HandleFunc(h HandlerFunc)
• type Context
• type Handler
• type HandlerFunc
  • func (h HandlerFunc) Handle(event json.RawMessage, ctx *Context) (interface{}, error)
• type Identity

Examples

• Package

Functions

func Handle

func Handle(h Handler)

Handle Lambda events with the given handler.

func HandleFunc

func HandleFunc(h HandlerFunc)

HandleFunc handles Lambda events with the given handler function.

Types

type Context

type Context struct {
	InvokeID                 string          `json:"invokeid"`
	RequestID                string          `json:"awsRequestId"`
	FunctionName             string          `json:"functionName"`
	FunctionVersion          string          `json:"functionVersion"`
	LogGroupName             string          `json:"logGroupName"`
	LogStreamName            string          `json:"logStreamName"`
	MemoryLimitInMB          string          `json:"memoryLimitInMB"`
	IsDefaultFunctionVersion bool            `json:"isDefaultFunctionVersion"`
	ClientContext            json.RawMessage `json:"clientContext"`
	Identity                 Identity        `json:"identity,omitempty"`
	InvokedFunctionARN       string          `json:"invokedFunctionArn"`
}

Context represents the context data provided by a Lambda invocation.

type Handler

type Handler interface {
	Handle(json.RawMessage, *Context) (interface{}, error)
}

Handler handles Lambda events.

type HandlerFunc

type HandlerFunc func(json.RawMessage, *Context) (interface{}, error)

HandlerFunc implements Handler.

func (HandlerFunc) Handle

func (h HandlerFunc) Handle(event json.RawMessage, ctx *Context) (interface{}, error)

Handle Lambda event.

type Identity

type Identity struct {
	CognitoIdentityID       string `json:"cognitoIdentityId"`
	CognitoIdentityIDPoolID string `json:"cognitoIdentityPoolId"`
}

Identity as defined in: http://docs.aws.amazon.com/mobile/sdkforandroid/developerguide/lambda.html#identity-context