How can I access AWS CloudWatch Custom Metrics via PHP SDK

Question

I'm able to retrieve metrics information for included metrics however for custom metrics, for example CPUUtilization on a per/instance basis, I cannot get the info. I'm not sure if I'm using the correct NameSpace, or perhaps I need to include additional information in the Dimensions field. Anyone know how to do this?

Here is my code:

<?php

date_default_timezone_set('America/New_York');

require 'vendor/autoload.php';

use Aws\CloudWatch\CloudWatchClient;
$cloudWatchClient = CloudWatchClient::factory(array(
    'profile' => 'my_profile',
    'region' => 'us-east-1',
));

$dimensions = array(
    array('Name' => 'InstanceId', 'Value' => 'i-0c0f546e4d1ef25e1'),
    array('Name' => 'ImageId', 'Value' => 'ami-9cdee48b'),
    array('Name' => 'AutoScalingGroupName', 'Value' => 'lc-wordpress-asg'),
);

$cpuResult = $cloudWatchClient->getMetricStatistics(array(
    'Namespace'  => 'AWS/EC2',
    'MetricName' => 'CPUUtilization',
    'Dimensions' => $dimensions,
    'StartTime'  => strtotime('-5 minutes'),
    'EndTime'    => strtotime('now'),
    'Period'     => 300,
    'Statistics' => array('Average'),
));

var_dump($cpuResult); 

$memoryResult = $cloudWatchClient->getMetricStatistics(array(
    'Namespace'  => 'Linux System',
    'MetricName' => 'MemoryUtilization',
    'Dimensions' => $dimensions,
    'StartTime'  => strtotime('-5 hours'),
    'EndTime'    => strtotime('now'),
    'Period'     => 60,
    'Statistics' => array('Average'),
));

var_dump($memoryResult);
?>

Running this code produces the following output. As you can see CPUUtilization returns the desired results however MemoryUtilization returns an empty array.

[ec2-user@ip-10-0-52-163 php-sdk]$ php get-cloudwatch-metrics.php 
object(Guzzle\Service\Resource\Model)#100 (2) {
  ["structure":protected]=>
  NULL
  ["data":protected]=>
  array(3) {
    ["Datapoints"]=>
    array(0) {
    }
    ["Label"]=>
    string(14) "CPUUtilization"
    ["ResponseMetadata"]=>
    array(1) {
      ["RequestId"]=>
      string(36) "63dc311e-bdaf-11e6-8143-f96eefa160b8"
    }
  }
}
object(Guzzle\Service\Resource\Model)#102 (2) {
  ["structure":protected]=>
  NULL
  ["data":protected]=>
  array(3) {
    ["Datapoints"]=>
    array(0) {
    }
    ["Label"]=>
    string(17) "MemoryUtilization"
    ["ResponseMetadata"]=>
    array(1) {
      ["RequestId"]=>
      string(36) "63dec890-bdaf-11e6-b04d-0707ed181fab"
    }
  }
}

Note, I'm using the typical AWS custom metric Perl scripts to send custom metrics to CloudWatch.

* * * * * ~/aws-scripts-mon/mon-put-instance-data.pl --mem-util --mem-used --mem-avail --disk-space-util --disk-path=/ --from-cron --aggregated --auto-scaling

Answer 1

I used to have same problem, Problem was in dimensions (I should use ClusterName)

 $dimensions = array(array('Name' => 'ClusterName', 'Value' => env('AWS_CLUSTER_NAME')));
 $metrics = $cloudWatch->GetMetricStatistics(['Namespace' => 'AWS/ECS',
                                              'MetricName' => "MemoryUtilization",
                                              'Period' => 60,
                                              'Dimensions' => $dimensions,
                                              'StartTime' => strtotime('-24 hours'),
                                              'EndTime' =>  strtotime('now'),
                                              'Statistics' => array('Maximum', 'Minimum', 'Average')]);

Answer 2

I figured it out. A quick check of my custom metric instance scripts that put metrics to CloudWatch show a namespace of "System/Linux", however in the CloudWatch Console it displays "Linux System". Switching the code to System/Linux produces the expected results!

$dimensions = array(
    array('Name' => 'InstanceId', 'Value' => 'i-0c0f546e4d1ef25e1'),
);

$memoryResult = $cloudWatchClient->getMetricStatistics(array(
    'Namespace'  => 'System/Linux',
    'MetricName' => 'MemoryUtilization',
    'Dimensions' => $dimensions,
    'StartTime'  => strtotime('-5 minutes'),
    'EndTime'    => strtotime('now'),
    'Period'     => 60,
    'Statistics' => array('Average'),
));

var_dump($memoryResult);

Output below:

[ec2-user@ip-10-0-52-163 php-sdk]$ php get-cloudwatch-metrics.php 
object(Guzzle\Service\Resource\Model)#100 (2) {
  ["structure":protected]=>
  NULL
  ["data":protected]=>
  array(3) {
    ["Datapoints"]=>
    array(5) {
      [0]=>
      array(3) {
        ["Average"]=>
        string(16) "50.1385233069785"
        ["Unit"]=>
        string(7) "Percent"
        ["Timestamp"]=>
        string(20) "2016-12-10T23:07:00Z"
      }
      [1]=>
      array(3) {
        ["Average"]=>
        string(16) "38.5987663771093"
        ["Unit"]=>
        string(7) "Percent"
        ["Timestamp"]=>
        string(20) "2016-12-10T23:08:00Z"
      }
      [2]=>
      array(3) {
        ["Average"]=>
        string(16) "41.5588687016341"
        ["Unit"]=>
        string(7) "Percent"
        ["Timestamp"]=>
        string(20) "2016-12-10T23:09:00Z"
      }
      [3]=>
      array(3) {
        ["Average"]=>
        string(16) "45.4270517993215"
        ["Unit"]=>
        string(7) "Percent"
        ["Timestamp"]=>
        string(20) "2016-12-10T23:10:00Z"
      }
      [4]=>
      array(3) {
        ["Average"]=>
        string(16) "46.4784461685095"
        ["Unit"]=>
        string(7) "Percent"
        ["Timestamp"]=>
        string(20) "2016-12-10T23:06:00Z"
      }
    }
    ["Label"]=>
    string(17) "MemoryUtilization"
    ["ResponseMetadata"]=>
    array(1) {
      ["RequestId"]=>
      string(36) "07c17abc-bf2e-11e6-a0ce-0f6cd308d7b2"
    }
  }
}