LambdaからAPI Gateway(IAM認可)へのアクセス方法 [Node.js版]

const https = require("https")
const AWS = require("aws-sdk")

exports.handler = async (event) => {
  const HOST = "XXXXXXXXXX.execute-api.ap-northeast-1.amazonaws.com"
  const STAGE = "dev"
  const PATH = "/your/resource"

  const url = `https://${HOST}/${STAGE}${PATH}`
  const req = new AWS.HttpRequest(url, process.env.AWS_REGION)
  req.method = "GET"  // Default => "POST"
  req.headers.host = HOST

  // Sign
  const signer = new AWS.Signers.V4(req, "execute-api", true)
  signer.addAuthorization(AWS.config.credentials, AWS.util.date.getDate())

  // Request
  const res = await new Promise(resolve => https.get(req.endpoint.href, req, resolve))
  const body = await new Promise(resolve => res.on("data", resolve))

  // Do something 
}

{
  'X-Amz-Date': '20190628T180333Z',
  'x-amz-security-token': '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',
  Authorization: 'AWS4-HMAC-SHA256 Credential=ASIAVHFXXXXXXXXXXXXX/20190628/ap-northeast-1/execute-api/aws4_request, SignedHeaders=host;x-amz-date;x-amz-security-token, Signature=ac00aaab0b00fe0a000000e0fd0a00c00aab00000b0000a0a000bddb0b000d'
}