diff --git a/Clim/Builder.php b/Clim/Builder.php
index 0056a39..242c3ef 100644
--- a/Clim/Builder.php
+++ b/Clim/Builder.php
@@ -22,7 +22,9 @@ class Builder
     public function __construct(ContainerInterface $container)
     {
         $this->container = $container;
+
         $this->runner = new Runner();
+        $this->runner->setApp($this);
     }
 
     /**
@@ -94,7 +96,7 @@ public function dispatch($meta_var, $children)
      *
      * @since 1.1.0
      */
-    public function add(callable $callable)
+    public function add($callable)
     {
         $this->runner->pushMiddleware($this->containerBoundCallable($callable));
         return $this;
diff --git a/Clim/Context.php b/Clim/Context.php
index 83131ea..241e52e 100644
--- a/Clim/Context.php
+++ b/Clim/Context.php
@@ -21,6 +21,9 @@ class Context implements MiddlewareContextInterface
     /** @var string hold tentative value */
     protected $_tentative;
 
+    /** @var Builder */
+    protected $app;
+
     /**
      * hold result
      * @var string
@@ -110,6 +113,16 @@ public function tentative($value = null)
         }
     }
 
+    public function getApp()
+    {
+        return $this->app;
+    }
+
+    public function setApp(Builder $app)
+    {
+        $this->app = $app;
+    }
+
     public function getResult()
     {
         return $this->result;
diff --git a/Clim/Runner.php b/Clim/Runner.php
index 9d007e8..900fdb7 100644
--- a/Clim/Runner.php
+++ b/Clim/Runner.php
@@ -11,6 +11,9 @@
 
 class Runner
 {
+    /** @var Builder */
+    protected $app;
+
     /** @var array */
     private $options = [];
 
@@ -38,6 +41,11 @@ public function __construct(array $options = [], array $arguments = [])
         $this->arguments = $arguments;
     }
 
+    public function setApp(Builder $app)
+    {
+        $this->app = $app;
+    }
+
     public function addOption(Option $option)
     {
         $this->options[] = $option;
@@ -64,6 +72,8 @@ public function run($context)
             $context = new Context($context);
         }
 
+        if ($this->app) $context->setApp($this->app);
+
         return $this->task_middleware->run($context, function ($context) {
             if ($this->parse($context)) return $context;
 
diff --git a/examples/db.php b/examples/db.php
new file mode 100644
index 0000000..fdf72f6
--- /dev/null
+++ b/examples/db.php
@@ -0,0 +1,34 @@
+<?php
+
+require dirname(__DIR__). '/vendor/autoload.php';
+require __DIR__. '/middlewares/DatabaseMiddleware.php';
+
+$app = new Clim\App(['settings' => [
+    // default database connection parameter.
+    // it can be overwritten by '--dsn' option from cli.
+    // @see middlewares/DatabaseMiddleware.php
+
+    'dsn' => 'pgsql:host=localhost;dbname=sampledb;user=foobar',
+]]);
+
+$app->add('DatabaseMiddleware');
+$app->arg('sql');
+
+$app->task(function ($opts, $args) {
+    // database connection is supplied by service provier
+    $db = $this->db;
+
+    // what to execute is from command line argument
+    $sql = $args['sql'];
+
+    echo $sql . "\n";
+
+    foreach ($db->query($sql) as $row) {
+        foreach ($row as $key => $value) {
+            echo "{$key} = $value ";
+        }
+        echo "\n";
+    }
+});
+
+$app->run();
diff --git a/examples/middlewares/DatabaseMiddleware.php b/examples/middlewares/DatabaseMiddleware.php
new file mode 100644
index 0000000..c2e55e3
--- /dev/null
+++ b/examples/middlewares/DatabaseMiddleware.php
@@ -0,0 +1,33 @@
+<?php
+
+use Psr\Container\ContainerInterface;
+
+class DatabaseMiddleware
+{
+    private $container;
+
+    public function __construct(ContainerInterface $c)
+    {
+
+        $this->container = $c;
+    }
+
+    public function __invoke($context, $next)
+    {
+        $app = $context->getApp();
+
+        $app->opt('--dsn {DSN}');
+
+        $this->container['db'] = function($c) use ($context) {
+            $opt = $context->options();
+            $dsn = $opt['dsn'] ?: $c['settings']['dsn'];
+            echo $dsn . "\n";
+
+            $db = new PDO($dsn);
+            $db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
+
+            return $db;
+        };
+        return $next($context);
+    }
+}
\ No newline at end of file