Begin work on cached lookup

src/StorageDrivers/Database/CachedTenantResolver.php

@@ -0,0 +1,45 @@
+<?php
+
+namespace Stancl\Tenancy\StorageDrivers\Database;
+
+use Closure;
+use Illuminate\Cache\CacheManager;
+use Illuminate\Config\Repository as ConfigRepository;
+use Illuminate\Cache\Repository as CacheRepository;
+use Illuminate\Contracts\Cache\Store;
+use Stancl\Tenancy\Tenant;
+
+class CachedTenantResolver
+{
+    /** @var CacheRepository */
+    protected $cache;
+
+    /** @var ConfigRepository */
+    protected $config;
+
+    public function __construct(CacheManager $cacheManager, ConfigRepository $config)
+    {
+        $this->cache = $cacheManager->store($config->get('tenancy.storage_drivers.db.cache_store'));
+        $this->config = $config;
+    }
+
+    protected function ttl(): int
+    {
+        return $this->config->get('tenancy.storage_drivers.db.cache_ttl');
+    }
+
+    public function getTenantIdByDomain(string $domain, Closure $query): string
+    {
+        return $this->cache->remember('_tenancy_domain_to_id:' . $domain, $this->ttl(), $query);
+    }
+
+    public function findById(string $id, Closure $dataQuery, Closure $domainsQuery): Tenant
+    {
+        $data = $this->cache->remember('_tenancy_id_to_data:' . $id, $this->ttl(), $dataQuery);
+        $domains = $this->cache->remember('_tenancy_id_to_domains:' . $id, $this->ttl(), $domainsQuery);
+
+        return Tenant::fromStorage($data)->withDomains($domains);
+    }
+
+    // todo update cache on writes to data & domains
+}

src/StorageDrivers/Database/DatabaseStorageDriver.php

@@ -32,12 +32,16 @@ class DatabaseStorageDriver implements StorageDriver, CanDeleteKeys, CanFindByAn
     /** @var DomainRepository */
     protected $domains;
 
+    /** @var CachedTenantResolver */
+    protected $cache;
+
     /** @var Tenant The default tenant. */
     protected $tenant;
 
-    public function __construct(Application $app, ConfigRepository $config)
+    public function __construct(Application $app, ConfigRepository $config, CachedTenantResolver $cache)
     {
         $this->app = $app;
+        $this->cache = $cache;
         $this->centralDatabase = $this->getCentralConnection();
         $this->tenants = new TenantRepository($config);
         $this->domains = new DomainRepository($config);
@@ -60,7 +64,16 @@ class DatabaseStorageDriver implements StorageDriver, CanDeleteKeys, CanFindByAn
 
     public function findByDomain(string $domain): Tenant
     {
-        $id = $this->domains->getTenantIdByDomain($domain);
+        $query = function () use ($domain) {
+            return $this->domains->getTenantIdByDomain($domain);
+        };
+
+        if ($this->usesCache()) {
+            $id = $this->cache->getTenantIdByDomain($domain, $query);
+        } else {
+            $id = $query();
+        }
+
         if (! $id) {
             throw new TenantCouldNotBeIdentifiedException($domain);
         }
@@ -70,14 +83,25 @@ class DatabaseStorageDriver implements StorageDriver, CanDeleteKeys, CanFindByAn
 
     public function findById(string $id): Tenant
     {
-        $tenant = $this->tenants->find($id);
+        $dataQuery = function () use ($id) {
+            return $this->tenants->decodeData($this->tenants->find($id));
+        };
+        $domainsQuery = function () use ($id) {
+            return $this->domains->getTenantDomains($id);
+        };
 
-        if (! $tenant) {
+        if ($this->usesCache()) {
+            return $this->cache->findById($id, $dataQuery, $domainsQuery);
+        } else {
+            $data = $dataQuery();
+        }
+
+        if (! $data) {
             throw new TenantDoesNotExistException($id);
         }
 
-        return Tenant::fromStorage($this->tenants->decodeData($tenant))
-            ->withDomains($this->domains->getTenantDomains($id));
+        return Tenant::fromStorage($data)
+            ->withDomains($domainsQuery());
     }
 
     /**
@@ -191,4 +215,10 @@ class DatabaseStorageDriver implements StorageDriver, CanDeleteKeys, CanFindByAn
     {
         $this->tenants->deleteMany($keys, $tenant ?? $this->currentTenant());
     }
+
+    public function usesCache(): bool
+    {
+        // null is also truthy here
+        return $this->app['config']['tenancy.storage_drivers.db.cache_store'] !== false;
+    }
 }