Issue #3279170 by mfb, zebda: No client interface set. in...

Issue #3279170 by mfb, zebda: No client interface set. in Drupal\redis\ClientFactory::getClientInterface()

src/CryptologMiddleware.php

@@ -192,7 +192,14 @@ class CryptologMiddleware implements HttpKernelInterface {
           $backend = $chained_fast;
       }
     }
-    $this->backend = $backend->get(self::BIN);
+    try {
+      $this->backend = $backend->get(self::BIN);
+    }
+    catch (\Exception $e) {
+      // Redis module is installed but a Redis client is not available.
+      $backend = $apcu ?: $chained_fast;
+      $this->backend = $backend->get(self::BIN);
+    }
   }
 
   /**