fix: fix memcache fortrabbit integration (monicahq/chandler#372)

Author: asbiin

config/cache.php

@@ -1,8 +1,9 @@
 <?php
 
+use Illuminate\Support\Arr;
 use Illuminate\Support\Str;
 
-return [
+$config = [
 
     /*
     |--------------------------------------------------------------------------
@@ -108,3 +109,53 @@
     'prefix' => env('CACHE_PREFIX', Str::slug(env('APP_NAME', 'laravel'), '_').'_cache'),
 
 ];
+
+// on fortrabbit: construct credentials from App secrets
+if (env('APP_SECRETS')) {
+    $secrets = json_decode(file_get_contents(env('APP_SECRETS')), true);
+    if (array_key_exists('MEMCACHE', $secrets)) {
+        $servers = [[
+            'host' => $secrets['MEMCACHE']['HOST1'],
+            'port' => $secrets['MEMCACHE']['PORT1'],
+            'weight' => 100,
+        ]];
+        if ($secrets['MEMCACHE']['COUNT'] > 1) {
+            $servers[] = [
+                'host' => $secrets['MEMCACHE']['HOST2'],
+                'port' => $secrets['MEMCACHE']['PORT2'],
+                'weight' => 100,
+            ];
+        }
+        Arr::set($config, 'stores.memcached.servers', $servers);
+    }
+}
+
+if (extension_loaded('memcached')) {
+    $timeout_ms = 50;
+    $options = [
+        // Assure that dead servers are properly removed and ...
+        \Memcached::OPT_REMOVE_FAILED_SERVERS => true,
+
+        // ... retried after a short while (here: 2 seconds)
+        \Memcached::OPT_RETRY_TIMEOUT => 2,
+
+        // KETAMA must be enabled so that replication can be used
+        \Memcached::OPT_LIBKETAMA_COMPATIBLE => true,
+
+        // Replicate the data, write it to both memcached servers
+        \Memcached::OPT_NUMBER_OF_REPLICAS => 1,
+
+        // Those values assure that a dead (due to increased latency or
+        // really unresponsive) memcached server is dropped fast
+        \Memcached::OPT_POLL_TIMEOUT => $timeout_ms,        // milliseconds
+        \Memcached::OPT_SEND_TIMEOUT => $timeout_ms * 1000, // microseconds
+        \Memcached::OPT_RECV_TIMEOUT => $timeout_ms * 1000, // microseconds
+        \Memcached::OPT_CONNECT_TIMEOUT => $timeout_ms,        // milliseconds
+
+        // Further performance tuning
+        \Memcached::OPT_NO_BLOCK => true,
+    ];
+    Arr::set($config, 'stores.memcached.options', $options);
+}
+
+return $config;