PHP Classes

File: application/modules/extensions/aws/Aws/Credentials/InstanceProfileProvider.php

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File: application/modules/extensions/aws/Aws/Credentials/InstanceProfileProvider.php
Role: Application script
Content type: text/plain
Description: Application script
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<?php
namespace Aws\Credentials;

use
Aws\Exception\CredentialsException;
use
GuzzleHttp\Promise;
use
GuzzleHttp\Psr7\Request;
use
GuzzleHttp\Promise\PromiseInterface;
use
Psr\Http\Message\ResponseInterface;

/**
 * Credential provider that provides credentials from the EC2 metadata server.
 */
class InstanceProfileProvider
{
    const
SERVER_URI = 'http://169.254.169.254/latest/';
    const
CRED_PATH = 'meta-data/iam/security-credentials/';

   
/** @var string */
   
private $profile;

   
/** @var callable */
   
private $client;

   
/**
     * The constructor accepts the following options:
     *
     * - timeout: Connection timeout, in seconds.
     * - profile: Optional EC2 profile name, if known.
     *
     * @param array $config Configuration options.
     */
   
public function __construct(array $config = [])
    {
       
$this->timeout = isset($config['timeout']) ? $config['timeout'] : 1.0;
       
$this->profile = isset($config['profile']) ? $config['profile'] : null;
       
$this->client = isset($config['client'])
            ?
$config['client'] // internal use only
           
: \Aws\default_http_handler();
    }

   
/**
     * Loads instance profile credentials.
     *
     * @return PromiseInterface
     */
   
public function __invoke()
    {
        return
Promise\coroutine(function () {
            if (!
$this->profile) {
               
$this->profile = (yield $this->request(self::CRED_PATH));
            }
           
$json = (yield $this->request(self::CRED_PATH . $this->profile));
           
$result = $this->decodeResult($json);
            yield new
Credentials(
               
$result['AccessKeyId'],
               
$result['SecretAccessKey'],
               
$result['Token'],
               
strtotime($result['Expiration'])
            );
        });
    }

   
/**
     * @param string $url
     * @return PromiseInterface Returns a promise that is fulfilled with the
     * body of the response as a string.
     */
   
private function request($url)
    {
       
$fn = $this->client;
       
$request = new Request('GET', self::SERVER_URI . $url);

        return
$fn($request, ['timeout' => $this->timeout])
            ->
then(function (ResponseInterface $response) {
                return (string)
$response->getBody();
            })->
otherwise(function (array $reason) {
               
$reason = $reason['exception'];
               
$msg = $reason->getMessage();
                throw new
CredentialsException(
                   
$this->createErrorMessage($msg, 0, $reason)
                );
            });
    }

    private function
createErrorMessage($previous)
    {
        return
"Error retrieving credentials from the instance profile "
           
. "metadata server. ({$previous})";
    }

    private function
decodeResult($response)
    {
       
$result = json_decode($response, true);

        if (
$result['Code'] !== 'Success') {
            throw new
CredentialsException('Unexpected instance profile '
               
. 'response code: ' . $result['Code']);
        }

        return
$result;
    }
}