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Lambda忘记了如何解释JavaScript?

aws-lambda typescript javascript

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GridDragon · 技术社区 · 6 年前

我在兰达发生了一件很奇怪的事。我有一个解释字符串输入的JS函数。单元测试将覆盖此代码,以确认验证逻辑是否按预期工作。但一旦部署到Lambda,我就会有不同的行为。我真的忽略了一个小错误吗。或者Lambda中有一些设置可以解释为什么我的代码被不同的解释。

以下是我的功能:

public async processMessage(message: string): Promise<void> {
    logger.info(`Message: ${message}`);
    const params = JSON.parse(message);


    if ('fileId' in params && 'location' in params && 'fileType' in params) {
        return this.fileLoader.load(params.fileId, params.location, fromString(params.fileType));
    } else {
        throw new InvalidArgumentError('A required field on the message is missing.');
    }
}

验证按预期工作,函数被正确调用。一切都很好! 然后我将它部署到lambda并调用它。我得到这个错误:

Cannot use 'in' operator to search for 'fileId' in {\"fileId\":\"1234\",\"fileType\": \"TEST_FILE\",\"location\": \"https://d4-file-proc-staging.s3.amazonaws.com/testFile.csv\"}

以下是CloudWatch日志:

Message: "{\"fileId\":\"1234\",\"fileType\": \"TEST_FILE\",\"location\": \"https://d4-file-proc-staging.s3.amazonaws.com/testFile.csv\"}"
ERROR   Unhandled Promise Rejection     
{
    "errorType": "Runtime.UnhandledPromiseRejection",
    "errorMessage": "TypeError: Cannot use 'in' operator to search for 'fileId' in {\"fileId\":\"1234\",\"fileType\": \"TEST_FILE\",\"location\": \"https://d4-file-proc-staging.s3.amazonaws.com/testFile.csv\"}",
    "reason": {
        "errorType": "TypeError",
        "errorMessage": "Cannot use 'in' operator to search for 'fileId' in {\"fileId\":\"1234\",\"fileType\": \"TEST_FILE\",\"location\": \"https://d4-file-proc-staging.s3.amazonaws.com/testFile.csv\"}",
        "stack": [
            "TypeError: Cannot use 'in' operator to search for 'fileId' in {\"fileId\":\"1234\",\"fileType\": \"TEST_FILE\",\"location\": \"https://d4-file-proc-staging.s3.amazonaws.com/testFile.csv\"}",
            "    at FileLoaderMessageHandler.processMessage (/var/task/dist/infrastructure/fileLoaderMessageHandler.js:14:22)",
            "    at /var/task/dist/aws/fileLoader.js:23:57",
            "    at Array.forEach (<anonymous>)",
            "    at Runtime.exports.handle [as handler] (/var/task/dist/aws/fileLoader.js:23:18)",
            "    at Runtime.handleOnce (/var/runtime/Runtime.js:66:25)"
        ]
    },
    "promise": {},
    "stack": [
        "Runtime.UnhandledPromiseRejection: TypeError: Cannot use 'in' operator to search for 'fileId' in {\"fileId\":\"1234\",\"fileType\": \"TEST_FILE\",\"location\": \"https://d4-file-proc-staging.s3.amazonaws.com/testFile.csv\"}",
        "    at process.<anonymous> (/var/runtime/index.js:35:15)",
        "    at process.emit (events.js:210:5)",
        "    at process.EventEmitter.emit (domain.js:476:20)",
        "    at processPromiseRejections (internal/process/promises.js:201:33)",
        "    at processTicksAndRejections (internal/process/task_queues.js:94:32)"
    ]
}

我尝试重构它以使用Object.keys。但它的表现还是很奇怪。

function isFileLoaderParams(params: any): params is FileLoaderParams {
    logger.info(`INPUT: ${params}`);

    if (!params.fileId) {
        logger.warn('FileId not found');
        logger.info(`DoubleCheck: ${JSON.stringify(params)}`);
        logger.info(`Value Is: ${JSON.stringify(params.fileId)}`);
        logger.info(`ArrayAccess?: ${JSON.stringify(params['fileId'])}`);
        return false;
    }

    if (!params.location) {
        logger.warn('Location not found');
        return false;
    }

    if (!params.fileType) {
        logger.warn('FileType not found');
        return false;
    }

    return true;
}

生成此输出的:

INPUT: {"fileId":"1234","fileType": "TEST_FILE","location": "https://d4-file-proc-staging.s3.amazonaws.com/testFile.csv"}
FileId not found
DoubleCheck: "{\"fileId\":\"1234\",\"fileType\": \"TEST_FILE\",\"location\": \"https://d4-file-proc-staging.s3.amazonaws.com/testFile.csv\"}"
Value Is: undefined
ArrayAccess?: undefined

配置/环境详细信息

手写体
由tsc使用Typescript 8.3.0编写
使用无服务器框架部署
Lambda Runtime:Node.js 12.x(也在Node 10中运行,但升级到12尝试修复此问题)

1 回复 | 直到 6 年前

1

3

Jacob 6 年前

这个错误意味着 params 是一个 String ,不是对象。也许你的 message 是双编码的JSON字符串(包含JSON字符串的JSON字符串)。我不知道它是怎么来的,但要找一个逻辑 JSON.stringify 关于已经是JSON的东西。或者如@Titus所说,做双重解码:

const params = JSON.parse(JSON.parse(message));