在异步 lambda 函数中被忽略的函数

Question

我正在创建一个系统，该系统使用 API 检查玩家数据，然后更新到我的 DynamoDB，但似乎它在中途停止了？因为 Let's scan our players & update stats! 从未显示在我的日志中？

exports.handler = async (event, context) => {

    var documentClient = new AWS.DynamoDB.DocumentClient();

    var params = {
        TableName: 'games',
        FilterExpression:'updated_at = :updated_at',
        ExpressionAttributeValues: {
            ":updated_at": 0,
        }
    };
    var rows = await documentClient.scan(params).promise();

    let gameAPI = new GameAPI();

    await gameAPI.login().then(function() {

        console.log("We have logged into our game!");

        rows.Items.forEach(function(match) {

            console.log("Let's look at our match! " + match.id);

            var player_params = {
                TableName: 'players',
                FilterExpression:'match_id = :match_id',
                ExpressionAttributeValues: {
                    ":match_id": match.id,
                }
            };

            documentClient.scan(player_params).promise().then(row => {

                console.log("Let's scan our players & update stats!");

            });

        });

    });

};

我假设这与我的 async & await 函数有关？有人能给我指出正确的方向吗？

Answer 1

您正在将 await 与 then 混合使用。

试试这个：

exports.handler = async (event, context) => {

    var documentClient = new AWS.DynamoDB.DocumentClient();

    var params = {
        TableName: 'games',
        FilterExpression:'updated_at = :updated_at',
        ExpressionAttributeValues: {
            ":updated_at": 0,
        }
    };
    var rows = await documentClient.scan(params).promise();

    let gameAPI = new GameAPI();

    await gameAPI.login();

    console.log("We have logged into our game!");

    for (let match of rows.Items) {

        console.log("Let's look at our match! " + match.id);

        var player_params = {
            TableName: 'players',
            FilterExpression:'match_id = :match_id',
            ExpressionAttributeValues: {
                ":match_id": match.id,
            }
        };

        let row = await documentClient.scan(player_params).promise();
        console.log("Let's scan our players & update stats!");
    }
};

then 的工作方式是基于回调的：

documentClient.scan(params).promise().then((rows) => {
    // do something with the rows
});

虽然 await / async 的工作原理是消除回调并使您的代码看起来同步且更具可读性。

const rows = await documentClient.scan(params).promise();
// do something with the rows

在异步 lambda 函数中被忽略的函数

functions being ignored inside async lambda function

node.js

asynchronous

lambda

amazon-dynamodb

async.js