AWS CloudWatchLogs do not return logs in Descending order using DescribeLogStreamsRequest

Question

I am using C# AWS SDK to retieve CloudWatch logs in (date-time) descending order (latest-first). So setting up the AmazonCloudWatchLogsClient as follows:

AmazonCloudWatchLogsConfig config = new AmazonCloudWatchLogsConfig {
    RegionEndpoint = Amazon.RegionEndpoint.GetBySystemName("<aws-region>")
};
AmazonCloudWatchLogsClient _client = new AmazonCloudWatchLogsClient(config);
_client.DescribeLogStreamsAsync(new DescribeLogStreamsRequest {
    LogGroupName = "logGroup",
    OrderBy = "LastEventTime",
    Descending = true,
});

And setting up cloud watch group and stream as follows:

_client.CreateLogGroupAsync(new CreateLogGroupRequest { LogGroupName = "logGroup" });
_client.CreateLogStreamAsync(new CreateLogStreamRequest {
    LogGroupName = "logGroup",
    LogStreamName = "logStream"
});

Than retrieving cloud watch logs as follows:

var request = new GetLogEventsRequest
{
    LogStreamName = "logStream",
    LogGroupName = "logGroup",
    StartTime = DateTime.UtcNow.AddDays(-1),
    EndTime = DateTime.UtcNow,
    Limit = 50,
    StartFromHead = false
};

var response = await GetLogEventsAsync(123, 456, 50, "000/f", "000/b");
var logs = response.Events;

The logs are received as always oldest-first, not the latest-first.

Please suggest any fixes.

Ref: https://docs.aws.amazon.com/sdkfornet/latest/apidocs/items/TCloudWatchLogsDescribeLogStreamsRequestNET45.html

Answer 1

Shakeel, I wondered if you had tried the extension method OrderByDescending? I was able to get this to work by using that:

returnValue.AddRange(logEventsResponse.Events.OrderByDescending(y => y.Timestamp).Select(x => new CloudWatchLogEvent { Message = x.Message, Timestamp = x.Timestamp.AddHours(-5), StreamName = stream.LogStreamName }));

returnValue is type List<CloudWatchLogEvent> and logEventsResponse is Task<GetLogEventsResponse> and CloudWatchLogEvent is a simple class I created:

public class CloudWatchLogEvent
{
    public string Message { get; set; }
    public DateTime Timestamp { get; set; }
    public string StreamName { get; set; }
}