How to count number of instances in AWS PHP SDK2 - php

Question

Assume composer is installed and you need to setup an ec2 client.

Answer 1

Suppose SDK setup with recommended method using Composer. First call aws_setupthen create an ec2 client object with security credentials. Since composer has been invoked, it will automatically load required libraries.
Then use DescribeInstances to get all running instances.
I packaged the function countInstances so it can be reused. You can call DescribeInstances with
with an array to filter results which is posted at the end.
Setup as follows:
require('/PATH/TO/MY/COMPOSER/vendor/autoload.php');
function aws_setup()
{
$conf_aws = array();
$conf_aws['key'] = 'MYKEY';
$conf_aws['secret'] = 'MYSECRET';
$conf_aws['region'] = 'us-east-1';
return $conf_aws;
}
function countInstances($list)
{
$count = 0;
foreach($list['Reservations'] as $instances)
{
foreach($instances['Instances'] as $instance)
{
$count++;
}
}
return $count;
}
$config = aws_setup();
$ec2Client = \Aws\Ec2\Ec2Client::factory($config);
$list = $ec2Client->DescribeInstances();
echo "Number of running instances: " . countInstances($list);
If you want to filter your results try something like this as a parameter to DescribeInstances:
array('Filters' => array(array('Name' => 'tag-value', 'Values' => array('MY_INSTANCE_TAG'))));
The code executes without error, but I had to adapt it to post it here.
EDIT: Added list of instances to countInstances function. Otherwise it wouldn't be visible.