无法从 Lambda 调用 AppSync GraphQL api：TypeError：无法读取 null 的属性“匹配”

Posted 2023-03-08

【中文标题】无法从 Lambda 调用 AppSync GraphQL api：TypeError：无法读取 null 的属性“匹配”

【英文标题】：Unable to call AppSync GraphQL api from Lambda: TypeError: Cannot read property 'match' of null

【发布时间】：2020-10-20 12:36:36

【问题描述】：

我正在尝试从 Lambda 调用我的 AWS AppSync graphQL API，但我遇到了一个我无法解决的错误，所以我想请你帮忙找出我做错了什么。

凭据似乎正确，查询应该正确（见下文）。

lambda 函数是使用无服务器框架部署的，我可以使用sls invoke --function <my_function_name> 调用它。

我一直在关注this article

我得到的错误是：

"errorType": "Runtime.UnhandledPromiseRejection",
"errorMessage": "TypeError: Cannot read property 'match' of null",
"trace": [
    "Runtime.UnhandledPromiseRejection: TypeError: Cannot read property 'match' of null",
    "    at process.<anonymous> (/var/runtime/index.js:35:15)",
    "    at process.emit (events.js:310:20)",
    "    at process.EventEmitter.emit (domain.js:482:12)",
    "    at processPromiseRejections (internal/process/promises.js:209:33)",
    "    at processTicksAndRejections (internal/process/task_queues.js:98:32)"
]


Error --------------------------------------------------

Error: Invoked function failed
  at AwsInvoke.log (/usr/local/lib/node_modules/serverless/lib/plugins/aws/invoke/index.js:101:31)
  at AwsInvoke.tryCatcher (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/util.js:16:23)
  at Promise._settlePromiseFromHandler (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/promise.js:517:31)
  at Promise._settlePromise (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/promise.js:574:18)
  at Promise._settlePromise0 (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/promise.js:619:10)
  at Promise._settlePromises (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/promise.js:699:18)
  at _drainQueueStep (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/async.js:138:12)
  at _drainQueue (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/async.js:131:9)
  at Async._drainQueues (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/async.js:147:5)
  at Immediate.Async.drainQueues [as _onImmediate] (/usr/local/lib/node_modules/serverless/node_modules/bluebird/js/release/async.js:17:14)
  at runCallback (timers.js:705:18)
  at tryOnImmediate (timers.js:676:5)
  at processImmediate (timers.js:658:5)
  at process.topLevelDomainCallback (domain.js:126:23)

这是我的完整 Lambda 函数：

'use strict'

const AWS = require('aws-sdk');
const gql = require('graphql-tag');
const AWSAppSyncClient = require('aws-appsync').default;
require('isomorphic-fetch');
require('es6-promise').polyfill();

module.exports.pushNotificationHandler = async (event, context, callback) => 

    const appsyncClient = new AWSAppSyncClient(
        url: process.env.GRAPHQL_API_ID,
        region: process.env.AWS_REGION,
        auth: 
            type: 'AWS_IAM',
            credentials: AWS.config.credentials
        ,
        disableOffline: true
    ,
        
            defaultOptions: 
                query: 
                    fetchPolicy: 'network-only',
                    errorPolicy: 'all',
                ,
            ,
        
    );

    const client = await appsyncClient.hydrated();

    try 

        const result = await client.query(
            query: gql`
                query GetUser 
                    getUser(id: "<A_VALID_USER_ID") 
                        firstname
                    
                
            `,
            variables: 
        );

        console.log(JSON.stringify(result));

        return result;

     catch (error) 
        console.log(JSON.stringify(error));
        return error;
    

    callback(null, event);

;

凭据

我通过简单地登录并签入CloudWatch 来检查凭据。有一个访问密钥和一个会话令牌，所以我会假设我的凭据是正确的。

查询

我通过从 AppSync 控制台执行它检查的查询。它应该可以工作。

IAM 权限

权限在Serverless配置文件中设置，但与以下相同：

    "Version": "2012-10-17",
    "Statement": [
        
            "Effect": "Allow",
            "Action": [
                "appsync:GraphQL"
            ],
            "Resource": [
                "arn:aws:appsync:<REGION>:<ACCOUNTID>:apis/<APIID>/*"
            ]
        
    ]

我做错了什么？

【参考方案1】：

尝试只使用return 而不是callback。使用 async 函数意味着您不需要使用回调，这可能是影响 Lambda 函数响应的原因。

【参考方案2】：

当输入不正确或 appSyncClient 未正确实例化时，通常会发生此错误。确保

GRAPHQL_API_ID AWS_REGION 具有合法的 graphQL 端点 credentials 存在

另外，我建议您转到 AppSync UI 控制台并请求相同的 Query 并查看它是否返回结果。如果有，那就是appSyncClient初始化的问题