【Azure 应用服务】Azure JS Function 异步方法中执行SQL查询后，Callback函数中日志无法输出问题

问题描述

开发 Azure JS Function(NodeJS)，使用 mssql 组件操作数据库。当SQL语句执行完成后，在Callback函数中执行日志输出 context.log(" ...") , 遇见如下错误：

Warning: Unexpected call to 'log' on the context object after function execution has completed.

Please check for asynchronous calls that are not awaited or calls to 'done' made before function execution completes. 

Function name: HttpTrigger1. Invocation Id: e8c69eb5-fcbc-451c-8ee6-c130ba86c0e9. Learn more: https://go.microsoft.com/fwlink/?linkid=2097909

错误截图

问题解答

JS 函数代码(日志无法正常输出)

var sql = require('mssql');
var config = {
    user: 'username',
    password: 'Password',
    server: '<server name>.database.chinacloudapi.cn', // You can use 'localhost\\instance' to connect to named instance
    database: 'db name',

    options: {
        encrypt: true // Use this if you're on Windows Azure
    }
}

module.exports = async function (context, req) {
    context.log('JavaScript HTTP trigger function processed a request.');
    
    await callDBtoOutput(context);

    context.log('################');
    //Default Code ...
    const name = (req.query.name || (req.body && req.body.name));
    const responseMessage = name
        ? "Hello, " + name + ". This HTTP triggered function executed successfully."
        : "This HTTP triggered function executed successfully. Pass a name in the query string or in the request body for a personalized response.";

    context.res = {
        // status: 200, /* Defaults to 200 */
        body: responseMessage
    };
}

async function callDBtoOutput(context) {
    try {
        context.log("Some Message from callDBtoOutput")

        var ps = new sql.PreparedStatement(await sql.connect(config))
        await ps.prepare('SELECT SUSER_SNAME() ', async function (err) {
            if (err) {
                context.log(err)
            }
            context.log("start to exec sql ...from callDBtoOutput")
            await ps.execute({}, async function (err, recordset) {
                // ... error checks
                context.log(recordset)
                context.log("Login SQL DB successfully....from callDBtoOutput")
                ps.unprepare(function (err) {
                    // ... error checks
                });
            });
        });
    } catch (error) {
        context.log(`Some Error Log: from callDBtoOutput`, error);
    }
}