Working with Amazon CloudWatch Alarms with AWS SDK for PHP Version 3

An Amazon CloudWatch alarm watches a single metric over a time period you specify. It performs one or more actions based on the value of the metric relative to a given threshold over a number of time periods.

The following examples show how to:

All the example code for the AWS SDK for PHP Version 3 is available here on GitHub.

Credentials

Before running the example code, configure your AWS credentials, as described in Credentials for the AWS SDK for PHP Version 3. Then import the AWS SDK for PHP, as described in Basic Usage Patterns of the AWS SDK for PHP Version 3.

Describe Alarms

Imports

require 'vendor/autoload.php';

use Aws\CloudWatch\CloudWatchClient; 
use Aws\Exception\AwsException;

Sample Code

function describeAlarms($cloudWatchClient)
{
    try {
        $result = $cloudWatchClient->describeAlarms();

        $message = '';

        if (isset($result['@metadata']['effectiveUri']))
        {
            $message .= 'Alarms at the effective URI of ' . 
                $result['@metadata']['effectiveUri'] . "\n\n";

            if (isset($result['CompositeAlarms']))
            {
                $message .= "Composite alarms:\n";

                foreach ($result['CompositeAlarms'] as $alarm) {
                    $message .= $alarm['AlarmName'] . "\n";
                }
            } else {
                $message .= "No composite alarms found.\n";
            }
            
            if (isset($result['MetricAlarms']))
            {
                $message .= "Metric alarms:\n";

                foreach ($result['MetricAlarms'] as $alarm) {
                    $message .= $alarm['AlarmName'] . "\n";
                }
            } else {
                $message .= 'No metric alarms found.';
            }
        } else {
            $message .= 'No alarms found.';
        }
        
        return $message;
    } catch (AwsException $e) {
        return 'Error: ' . $e->getAwsErrorMessage();
    }
}

function describeTheAlarms()
{
    $cloudWatchClient = new CloudWatchClient([
        'profile' => 'default',
        'region' => 'us-east-1',
        'version' => '2010-08-01'
    ]);

    echo describeAlarms($cloudWatchClient);
}

// Uncomment the following line to run this code in an AWS account.
// describeTheAlarms();

Create an Alarm

Imports

require 'vendor/autoload.php';

use Aws\CloudWatch\CloudWatchClient; 
use Aws\Exception\AwsException;

Sample Code

function putMetricAlarm($cloudWatchClient, $cloudWatchRegion, 
    $alarmName, $namespace, $metricName, 
    $dimensions, $statistic, $period, $comparison, $threshold, 
    $evaluationPeriods)
{
    try {
        $result = $cloudWatchClient->putMetricAlarm([
            'AlarmName' => $alarmName,
            'Namespace' => $namespace,
            'MetricName' => $metricName,
            'Dimensions' => $dimensions,
            'Statistic' => $statistic,
            'Period' => $period,
            'ComparisonOperator' => $comparison,
            'Threshold' => $threshold,
            'EvaluationPeriods' => $evaluationPeriods
        ]);
        
        if (isset($result['@metadata']['effectiveUri']))
        {
            if ($result['@metadata']['effectiveUri'] == 
                'https://monitoring.' . $cloudWatchRegion . '.amazonaws.com')
            {
                return 'Successfully created or updated specified alarm.';
            } else {
                return 'Could not create or update specified alarm.';
            }
        } else {
            return 'Could not create or update specified alarm.';
        }
    } catch (AwsException $e) {
        return 'Error: ' . $e->getAwsErrorMessage();
    }
}

function putTheMetricAlarm()
{
    $alarmName = 'my-ec2-resources';
    $namespace = 'AWS/Usage';
    $metricName = 'ResourceCount';
    $dimensions = [
        [
            'Name' => 'Type',
            'Value' => 'Resource'
        ],
        [
            'Name' => 'Resource',
            'Value' => 'vCPU'
        ],
        [
            'Name' => 'Service',
            'Value' => 'EC2'
        ],
        [
            'Name' => 'Class',
            'Value' => 'Standard/OnDemand'
        ]
    ];
    $statistic = 'Average';
    $period = 300;
    $comparison = 'GreaterThanThreshold';
    $threshold = 1;
    $evaluationPeriods = 1;

    $cloudWatchRegion = 'us-east-1';
    $cloudWatchClient = new CloudWatchClient([
        'profile' => 'default',
        'region' => $cloudWatchRegion,
        'version' => '2010-08-01'
    ]);

    echo putMetricAlarm($cloudWatchClient, $cloudWatchRegion, 
        $alarmName, $namespace, $metricName, 
        $dimensions, $statistic, $period, $comparison, $threshold, 
        $evaluationPeriods);
}

// Uncomment the following line to run this code in an AWS account.
// putTheMetricAlarm();

Delete Alarms

Imports

require 'vendor/autoload.php';

use Aws\CloudWatch\CloudWatchClient; 
use Aws\Exception\AwsException;

Sample Code

function deleteAlarms($cloudWatchClient, $alarmNames)
{
    try {
        $result = $cloudWatchClient->deleteAlarms([
            'AlarmNames' => $alarmNames
        ]);

        return 'The specified alarms at the following effective URI have ' . 
            'been deleted or do not currently exist: ' . 
            $result['@metadata']['effectiveUri'];

    } catch (AwsException $e) {
        return 'Error: ' . $e->getAwsErrorMessage();
    }
}

function deleteTheAlarms()
{
    $alarmNames = array('my-alarm');
    
    $cloudWatchClient = new CloudWatchClient([
        'profile' => 'default',
        'region' => 'us-east-1',
        'version' => '2010-08-01'
    ]);

    echo deleteAlarms($cloudWatchClient, $alarmNames);
}

// Uncomment the following line to run this code in an AWS account.
// deleteTheAlarms();