How should I specify the arguments of getMetricData in AWS Lambda to get CloudFront metric for CloudWatch

Question

I am trying to get number of requests from my Cloudfront instance. Currently, I use function getMetricData provided by aws-sdk in Javascripts. However, I always get an response without any values when I use lambda to query for the metric data, while I can clearly see there are requests when I check the Metric page of CloudWatch on browser.

I already check CloudWatch API document . However, I am not 100% clear about the arguments that I need for getting the "requests" metric data. Here is some code similar to what I did.

const AWS = require('aws-sdk');

exports.handler = async(event) => {
    // TODO implement
    let endDate = "2020-03-04T13:14:18.546Z";
    let startDate = "2020-02-28T13:14:18.546Z";
    let cloudwatch = new AWS.CloudWatch();
    var params = {
        "StartTime": startDate,
        "EndTime": endDate,
        "MetricDataQueries": [{
            "Id": "m1",
            "MetricStat": {
                "Metric": {
                    "Namespace": "AWS/CloudFront",
                    "MetricName": "Requests",
                    "Dimensions": [{
                        "Name": "DistributionId",
                        "Value": "EG12345678" <-- I made this up
                    }]
                },
                "Period": 60,
                "Stat": "Sum",
                "Unit": "Count"
            }
        }]
    };
    const response = await cloudwatch.getMetricData(params).promise();
    return response
}

I am sure in between the start date and end data that there are more than 100 requests. However, the return values array is simply empty.

Thanks in advance

Answer 1

Ok, I just forget to specify region in the dimension field

here is a fixed one

const AWS = require('aws-sdk');

exports.checkHealth = async(event) => {
    // TODO implement
    let endDate = new Date;
    let startDate = new Date(endDate - 20 * 60 * 1000);
    let cloudwatch = new AWS.CloudWatch();
    //let startDate = "2020-02-28T13:00:00.000Z";
    //let endDate = "2020-02-28T15:30:00.000Z";
    var params = {
        "StartTime": startDate,
        "EndTime": endDate,
        "MetricDataQueries": [{
            "Id": "m1",
            "MetricStat": {
                "Metric": {
                    "Namespace": "AWS/CloudFront",
                    "MetricName": "TotalErrorRate",
                    "Dimensions": [{
                        "Name": "DistributionId",
                        "Value": "EG12345678"
                    },
                    {
                        "Name": "Region", // <------ this fix things
                        "Value": "Global" // <------ this fix things
                    }]
                },
                "Period":60,
                "Stat": "Average"
            }
        }]
    };
    const response = await cloudwatch.getMetricData(params).promise();
    return response;
}