CDK Entest

Introduction#

Create signature v4
Send request to bedrock endpoint
Parse response chunk by chunk

Here is the full script

bedrock-wo-sdk.js

// https://blog.alu.ai/signing-aws-api-requests-in-node-js-2023-version/
// const { SignatureV4 } = require("@smithy/signature-v4");
import { SignatureV4 } from '@smithy/signature-v4'
import { Sha256 } from '@aws-crypto/sha256-js'
import { HttpRequest } from '@aws-sdk/protocol-http'

const decoder = new TextDecoder()

// const ENDPOINT = "https://bedrock-runtime.us-east-1.amazonaws.com/model/anthropic.claude-v2/invoke";

const ENDPOINT =
  'https://bedrock-runtime.us-east-1.amazonaws.com/model/anthropic.claude-v2/invoke-with-response-stream'

async function signRequest() {
  // create a http request
  // path: /BUCKET-NAME/web-css/osaka-street.jpeg
  // host: s3.us-east-1.amazonaws.com
  const request = new HttpRequest({
    path: new URL(ENDPOINT).pathname,
    hostname: new URL(ENDPOINT).hostname,
    protocol: 'https:',
    method: 'POST',
    headers: {
      host: new URL(ENDPOINT).hostname,
      Accept: 'application/vnd.amazon.eventstream',
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      prompt: '\n\nHuman: How to cook chicken soup? \n\nAssistant: ',
      max_tokens_to_sample: 128
    })
  })

  // create a signer using singnaturev4
  const signer = new SignatureV4({
    service: 'bedrock',
    region: 'us-east-1',
    credentials: {
      accessKeyId: '',
      secretAccessKey: '',
      sessionToken: ''
    },
    sha256: Sha256
  })

  const signedRequest = await signer.sign(request, {
    // signingRegion: "us-east-1",
    // signingService: "bedrock",
    // signingDate: new Date(),
    // date: new Date(),
    // expires: new Date(Date.now() + 15 * 60 * 1000), // 15 minutes
    // // list of headers used to compute signature
    // signedHeaders: "host;x-amz-date",
  })

  console.log(signedRequest)

  console.log(`https://${signedRequest.hostname}${signedRequest.path}`)

  const response = await fetch(
    `https://${signedRequest.hostname}${signedRequest.path}`,
    signedRequest
  )

  // const json = await response.json();
  // console.log(json);

  const reader = response.body.getReader()
  const decoder = new TextDecoder('utf-8')

  let answer = ''
  const regex = /\{(.*?)\}/g
  let match

  while (true) {
    const { done, value } = await reader.read()
    if (done) {
      console.log('Done with stream')
      break
    }

    const x = decoder.decode(value)

    try {
      while ((match = regex.exec(x)) !== null) {
        const y = '{' + match[1] + '}'
        const z = atob(JSON.parse(y).bytes)
        console.log(JSON.parse(z).completion)
        answer += JSON.parse(z).completion
      }
    } catch (error) {
      console.log(error)
      answer += 'ERROR'
    }
  }

  console.log(answer)

  // console.log(response.data);
  // fs.writeFileSync("./hehe.jpg", response.data);
  // console.log(signedRequest.headers);
  // console.log(response.data);

  // pipe stream to file
  // response.data.pipe(fs.createWriteStream("./hehe.jpg"));

  // response.data event emitter data chunk
  // response.data.on("data", (chunk) => {
  //   console.log(chunk.length);
  // });
}

// Example usage

const main = async () => {
  await signRequest()
}

main()

And here is package.json

package.json

{
  "name": "nodejs",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "type": "module",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "@aws-crypto/sha256-js": "^5.2.0",
    "@aws-sdk/credential-provider-ini": "^3.529.1",
    "@aws-sdk/protocol-http": "^3.374.0",
    "@smithy/signature-v4": "^2.1.4",
    "axios": "^1.6.7"
  }
}

Create Request#

Let create a request

const ENDPOINT =
  'https://bedrock-runtime.us-east-1.amazonaws.com/model/anthropic.claude-v2/invoke-with-response-stream'

const request = new HttpRequest({
  // path: /cdk-entest-videos/web-css/osaka-street.jpeg
  path: new URL(ENDPOINT).pathname,
  // host: s3.us-east-1.amazonaws.com
  hostname: new URL(ENDPOINT).hostname,
  protocol: 'https:',
  method: 'POST',
  headers: {
    host: new URL(ENDPOINT).hostname,
    Accept: 'application/vnd.amazon.eventstream',
    'Content-Type': 'application/json'
  },
  body: JSON.stringify({
    prompt: '\n\nHuman: How to cook chicken soup? \n\nAssistant: ',
    max_tokens_to_sample: 128
  })
})

Sign Request#

Let create a signature v4 and sign the request

// create a signer using singnaturev4
const signer = new SignatureV4({
  service: 'bedrock',
  region: 'us-east-1',
  credentials: {
    accessKeyId: '',
    secretAccessKey: '',
    sessionToken: ''
  },
  sha256: Sha256
})

const signedRequest = await signer.sign(request, {
  // signingRegion: "us-east-1",
  // signingService: "bedrock",
  // signingDate: new Date(),
  // date: new Date(),
  // expires: new Date(Date.now() + 15 * 60 * 1000), // 15 minutes
  // // list of headers used to compute signature
  // signedHeaders: "host;x-amz-date",
})

console.log(signedRequest)

Parse Response#

In case of streaming response, let parse it chunk by chunk, use regex to detect the completion, the decode the based64.

Parse chunk by chunk
Regex to capture answer
Base64 decode to string

const reader = response.body.getReader()
const decoder = new TextDecoder('utf-8')

let answer = ''
const regex = /\{(.*?)\}/g
let match

while (true) {
  const { done, value } = await reader.read()
  if (done) {
    console.log('Done with stream')
    break
  }

  const x = decoder.decode(value)

  try {
    while ((match = regex.exec(x)) !== null) {
      const y = '{' + match[1] + '}'
      const z = atob(JSON.parse(y).bytes)
      console.log(JSON.parse(z).completion)
      answer += JSON.parse(z).completion
    }
  } catch (error) {
    console.log(error)
    answer += 'ERROR'
  }
}

console.log(answer)

In case of normal response

const json = await response.json()
console.log(json)

Reference#

bedrock runtime api docs