Simplistic GCP Secret Manager usage from PHP

composer.json

{
    "require": {
        "google/cloud": "^0.171.0"
    }
}

index.php

<?php

require __DIR__ . "/vendor/autoload.php";

use Google\Cloud\SecretManager\V1\Replication;
use Google\Cloud\SecretManager\V1\Replication\Automatic;
use Google\Cloud\SecretManager\V1\Secret;
use Google\Cloud\SecretManager\V1\SecretPayload;
use Google\Cloud\SecretManager\V1\SecretManagerServiceClient;

class SecretManager {
    private $client;

    public function __construct()
    {
        $this->client = new SecretManagerServiceClient();
    }

    public function __destruct()
    {
        $this->client->close();
    }

    public function createSecret($name, $value)
    {
        $secret = $this->client->createSecret(
            $this->client->projectName(
                $this->getProjectName()
            ),
            $name,
            new Secret([
                'replication' => new Replication([
                    'automatic' => new Automatic()
                ])
            ])
        );
        
        return $this->addSecretVersion($secret->getName(), $value);
    }

    public function accessSecret($name, $version = 'latest')
    {
        $formattedName = $this->client->secretVersionName($this->getProjectName(), $name, $version);
        $response = $this->client->accessSecretVersion($formattedName);
        return $response->getPayload()->getData();
    }

    public function rotateSecret($name, $value)
    {
        $secretName = $this->client->secretName($this->getProjectName(), $name);

        $newSecretVersion = $this->addSecretVersion(
            $secretName,
            $value
        );


        $pagedResponse = $this->client->listSecretVersions($secretName, [
            'filter' => 'state:ENABLED'
        ]);
        foreach ($pagedResponse->iteratePages() as $page) {
            foreach ($page as $element) {
                if ($element->getName() != $newSecretVersion->getName()) {
                    // If the version isn't our latest one, destroy it.
                    $this->client->destroySecretVersion($element->getName());
                }
            }
        }
    }

    private function addSecretVersion($name, $value)
    {
        $payload = new SecretPayload([
            'data' => $value
        ]);
        
        return $this->client->addSecretVersion($name, $payload);
    }

    private function getProjectName()
    {
        return "a1-alpha";
    }
}

function str_rand(int $length = 64){ // 64 = 32
    $length = ($length < 4) ? 4 : $length;
    return bin2hex(random_bytes(($length-($length%2))/2));
}

$client = new SecretManager();

$secretName = "testing-" . str_rand(6);
echo "Using secret name: " . $secretName . "\n";
$secretValue1 = str_rand(36);
echo "Using initial secret value: " . $secretValue1 . "\n";

echo "Creating secret...\n\n";
$client->createSecret($secretName, $secretValue1);

echo "Accessing secret...\n";
$returnedValue1 = $client->accessSecret($secretName);

if ($returnedValue1 !== $secretValue1) {
    die("Secret value returned doesn't match, got " . $returnedValue1 . "\n");
} else {
    echo "Secret returned ok\n\n";
}

for ($i = 0; $i < 3; $i++) {
    $secretValue = str_rand(36);
    echo "Using secret value " . ($i+2) . ": " . $secretValue . "\n";

    echo "Rotating Secret...\n\n";
    $client->rotateSecret($secretName, $secretValue);

    echo "Accessing secret...\n";
    $returnedValue = $client->accessSecret($secretName);

    if ($returnedValue !== $secretValue) {
        die("Secret value returned doesn't match, got " . $returnedValue . "\n");
    } else {
        echo "Secret returned ok\n\n";
    }
}

result.txt

iamacarpet@penguin:~/secret-manager-api$ php index.php 
Using secret name: testing-a0da94
Using initial secret value: a3bd90d8498d1b1078e4a22ea4f8a73b8d46
Creating secret...

Accessing secret...
Secret returned ok

Using secret value 2: afc261c9cb75bde343f1308402449969419f
Rotating Secret...

Accessing secret...
Secret returned ok

Using secret value 3: ff193fdbe301336babc66cb3b536c6987c50
Rotating Secret...

Accessing secret...
Secret returned ok

Using secret value 4: d512ffae4ed5bcaeb08c0e8bf418301000aa
Rotating Secret...

Accessing secret...
Secret returned ok