Create a dashboard per asg that beats the 3hr aws CloudWatch Metrics Insights limit

CreateDashboard.cs

using Amazon.AutoScaling.Model;
using Amazon.AutoScaling;
using Amazon.CloudWatch.Model;
using Amazon;
using Amazon.CloudWatch;


const string Namespace = "CWAgent";
const string MetricName = "TCPv4 Connections Established";


var response = await GetMetrics();
var asgs = GetAsgForMetric(response);
var asgEnvTable = await GetAsgEbEnvs(asgs);
var asgInstanceDic = GetAsgInstanceDic(response);
var widgets = asgEnvTable.OrderByDescending(f=>f.EbEnv).Select((row, idx) => GetDashboardWidgetObj(asgInstanceDic[row.Asg], row.Asg, row.EbEnv, idx)).ToList();
var dashboardObj = GetDashboardObj(widgets);
var dashboardJsonString = System.Text.Json.JsonSerializer.Serialize(dashboardObj);
await CreateDashboard($"TCP_{DateTime.Now.ToString("yyyy-MM-dd")}", dashboardJsonString);


static async Task<IReadOnlyList<(string Asg, string EbEnv)>> GetAsgEbEnvs(IEnumerable<string> asgs)
{    
    var asgEbEnvs = await GetAsgEbEnvsByCurrentAsg();
    var table = asgs.Select(asg => (asg, asgEbEnvs.SingleOrDefault(ae => ae.Asg == asg).EbEnv)).ToList();
    return table;
}

static async Task<ListMetricsResponse> ListMetricsUntilDone(ListMetricsRequest req, AmazonCloudWatchClient client)
{
    ListMetricsResponse? mainRespone = null;

    while (true)
    {
        var response = await client.ListMetricsAsync(req);
        if (mainRespone == null)
        {
            mainRespone = response;
        }
        else
        {
            mainRespone.Metrics.AddRange(response.Metrics);
        }
        if (string.IsNullOrEmpty(response.NextToken))
        {
            return mainRespone;
        }
        req.NextToken = response.NextToken;
    }
}

static async Task<ListMetricsResponse> GetMetrics()
{
    using var client = new Amazon.CloudWatch.AmazonCloudWatchClient(RegionEndpoint.APSoutheast2);
    var request = new Amazon.CloudWatch.Model.ListMetricsRequest
    {
        Namespace = Namespace,
        MetricName = MetricName,

    };
    var response = await ListMetricsUntilDone(request, client);
    return response;
}

static IReadOnlyList<string> GetAsgForMetric(ListMetricsResponse response)
{    
    var asgs = response.Metrics.Select(m => m.Dimensions.Single(d => d.Name == "AutoScalingGroupName").Value).Distinct().ToList();
    return asgs;
}


static async Task<IReadOnlyList<(string Asg, string EbEnv)>> GetAsgEbEnvsByCurrentAsg()
{
    using var client = new AmazonAutoScalingClient(RegionEndpoint.APSoutheast2);
    var response = await client.DescribeAutoScalingGroupsAsync(new DescribeAutoScalingGroupsRequest());
    var asgEbEnvs = response.AutoScalingGroups.Select(asg => (asg.AutoScalingGroupName, asg.Tags.SingleOrDefault(t => t.Key == "elasticbeanstalk:environment-name")?.Value)).ToList();
    return asgEbEnvs;
}

static IReadOnlyDictionary<string, IEnumerable<string>> GetAsgInstanceDic(ListMetricsResponse response) => 
    response.Metrics.GroupBy(m => m.Dimensions.Single(d => d.Name == "AutoScalingGroupName").Value).ToDictionary(g => g.Key, g => g.Select(m => m.Dimensions.Single(d => d.Name == "InstanceId").Value));


static object GetDashboardObj(IEnumerable<object> widgets) => new { widgets };

static object GetDashboardWidgetObj(IEnumerable<string> instanceIds, string asg, string name, int idx)
{
    const int height = 10;
    var obj = new
    {
        metrics = instanceIds.Select(instanceId => new[] { "CWAgent", "TCPv4 Connections Established", "InstanceId", instanceId, "AutoScalingGroupName", asg, "objectname", "TCPv4" }),
        title = $"Max(TCPv4 Conn Est) {asg} {name}",
        stat = "Maximum",
        view = "timeSeries",
        stacked = false,
        region = "ap-southeast-2",
    };

    return new
    {
        properties = obj,
        type = "metric",
        x = 0,
        y = height * idx,
        width = 24,
        height = height
    };

}




static async Task CreateDashboard(string dashboardName, string dashboardBody)
{
    using var client = new AmazonCloudWatchClient(RegionEndpoint.APSoutheast2);
    var request = new PutDashboardRequest
    {
        DashboardName = dashboardName,
        DashboardBody = dashboardBody
    };
    var response = await client.PutDashboardAsync(request);
    Console.WriteLine(response);
}