AWS Lambda から AppSync の API を ぶん殴る https://blog.r3it.com/aws-lambda-to-appsync-1aa0c2f1da04

AppSyncQueryInAwsLambdaCognitoAuth.js

require('isomorphic-fetch');
const AUTH_TYPE = require('aws-appsync/lib/link/auth-link').AUTH_TYPE;
const AWSAppSyncClient = require('aws-appsync').default;
const AmazonCognitoIdentity = require('amazon-cognito-identity-js');
const gql = require('graphql-tag');

const listMessages = gql(`
  query getConversationMessages($conversationId: ID!, $after: String, $first: Int) {
    allMessageConnection(conversationId: $conversationId, after: $after, first: $first) {
      __typename
      nextToken,
      messages {
        __typename
        id
        conversationId
        content
        createdAt
        sender
        isSent
      }
    }
  }`);

exports.handler = async (event) => {
  const poolData = {
    UserPoolId: process.env['USERPOOL_ID'],
    ClientId: process.env['CLIENT_ID']
  };
  const userData = {
    Username: process.env['USERNAME'],
    Pool: new AmazonCognitoIdentity.CognitoUserPool(poolData)
  };
  const cognitoUser = new AmazonCognitoIdentity.CognitoUser(userData);

  const authenticationData = {
    Username: userData.Username,
    Password: process.env['PASSWORD']
  };
  const authenticationDetails = new AmazonCognitoIdentity.AuthenticationDetails(authenticationData);

  const authenticateUser = new Promise((resolve, reject) => {
    cognitoUser.authenticateUser(authenticationDetails, {
      onSuccess: (result) => {
        const idToken = result.getIdToken().getJwtToken();
        resolve(idToken);
      },
      onFailure: (err) => {
        reject(err);
      },
      newPasswordRequired: (userAttributes, requiredAttributes) => {
        const err = new Error("newPasswordRequired");
        reject(err);
      }
    });
  });

  return authenticateUser.then(async (idToken) => {
    const client = new AWSAppSyncClient({
      url: process.env['URL'],
      region: process.env['REGION'],
      auth: {
        type: AUTH_TYPE.AMAZON_COGNITO_USER_POOLS,
        jwtToken: idToken
      },
      disableOffline: true
    });

    const param = {
      conversationId: "hello",
      after: null,
      first: 20
    };

    const result = await client.query({
      query: listMessages,
      variables: param,
      fetchPolicy: 'network-only'
    });
    console.log(JSON.stringify(result));
    return result;
  }).catch((err) => {
    console.log(JSON.stringify(err));
    return err;
  });

};