Created new env var to programatically provide an initial API key

module/Rest/src/ApiKey/InitialApiKeyDelegator.php

@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shlinkio\Shlink\Rest\ApiKey;
+
+use Doctrine\ORM\EntityManager;
+use Mezzio\Application;
+use Psr\Container\ContainerInterface;
+use Shlinkio\Shlink\Rest\ApiKey\Repository\ApiKeyRepositoryInterface;
+use Shlinkio\Shlink\Rest\Entity\ApiKey;
+
+class InitialApiKeyDelegator
+{
+    public function __invoke(ContainerInterface $container, string $serviceName, callable $callback): Application
+    {
+        $initialApiKey = $container->get('config')['initial_api_key'] ?? null;
+        if ($initialApiKey !== null) {
+            $this->createInitialApiKey($initialApiKey, $container);
+        }
+
+        return $callback();
+    }
+
+    private function createInitialApiKey(string $initialApiKey, ContainerInterface $container): void
+    {
+        /** @var ApiKeyRepositoryInterface $repo */
+        $repo = $container->get(EntityManager::class)->getRepository(ApiKey::class);
+        $repo->createInitialApiKey($initialApiKey);
+    }
+}

module/Rest/src/ApiKey/Repository/ApiKeyRepository.php

@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shlinkio\Shlink\Rest\ApiKey\Repository;
+
+use Doctrine\DBAL\LockMode;
+use Happyr\DoctrineSpecification\Repository\EntitySpecificationRepository;
+use Shlinkio\Shlink\Rest\Entity\ApiKey;
+
+class ApiKeyRepository extends EntitySpecificationRepository implements ApiKeyRepositoryInterface
+{
+    public function createInitialApiKey(string $apiKey): void
+    {
+        $this->getEntityManager()->wrapInTransaction(function () use ($apiKey): void {
+            $qb = $this->getEntityManager()->createQueryBuilder();
+            $amountOfApiKeys = $qb->select('COUNT(a.id)')
+                                  ->from(ApiKey::class, 'a')
+                                  ->getQuery()
+                                  ->setLockMode(LockMode::PESSIMISTIC_WRITE)
+                                  ->getSingleScalarResult();
+
+            if ($amountOfApiKeys === 0) {
+                $this->getEntityManager()->persist(ApiKey::fromKey($apiKey));
+                $this->getEntityManager()->flush();
+            }
+        });
+    }
+}

module/Rest/src/ApiKey/Repository/ApiKeyRepositoryInterface.php

@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Shlinkio\Shlink\Rest\ApiKey\Repository;
+
+use Doctrine\Persistence\ObjectRepository;
+use Happyr\DoctrineSpecification\Repository\EntitySpecificationRepositoryInterface;
+
+interface ApiKeyRepositoryInterface extends ObjectRepository, EntitySpecificationRepositoryInterface
+{
+    /**
+     * Will create provided API key only if there's no API keys yet
+     */
+    public function createInitialApiKey(string $apiKey): void;
+}