TransportConfigForm: Use a select input for setting the instance

refs #9651

modules/monitoring/application/controllers/ConfigController.php

@@ -195,6 +195,7 @@ class Monitoring_ConfigController extends Controller
         $form->setRedirectUrl('monitoring/config');
         $form->setTitle(sprintf($this->translate('Edit Command Transport %s'), $transportName));
         $form->setIniConfig($this->Config('commandtransports'));
+        $form->setInstanceNames($this->backend->select()->from('instance', array('instance_name'))->fetchColumn());
         $form->setOnSuccess(function (TransportConfigForm $form) use ($transportName) {
             try {
                 $form->edit($transportName, array_map(
@@ -236,6 +237,7 @@ class Monitoring_ConfigController extends Controller
         $form->setRedirectUrl('monitoring/config');
         $form->setTitle($this->translate('Create New Command Transport'));
         $form->setIniConfig($this->Config('commandtransports'));
+        $form->setInstanceNames($this->backend->select()->from('instance', array('instance_name'))->fetchColumn());
         $form->setOnSuccess(function (TransportConfigForm $form) {
             try {
                 $form->add(array_filter($form->getValues()));

modules/monitoring/application/forms/Config/TransportConfigForm.php

@@ -24,6 +24,13 @@ class TransportConfigForm extends ConfigForm
      */
     protected $transportToLoad;
 
+    /**
+     * The names of all available Icinga instances
+     *
+     * @var array
+     */
+    protected $instanceNames;
+
     /**
      * Initialize this form
      */
@@ -33,6 +40,29 @@ class TransportConfigForm extends ConfigForm
         $this->setSubmitLabel($this->translate('Save Changes'));
     }
 
+    /**
+     * Set the names of all available Icinga instances
+     *
+     * @param   array   $names
+     *
+     * @return  $this
+     */
+    public function setInstanceNames(array $names)
+    {
+        $this->instanceNames = $names;
+        return $this;
+    }
+
+    /**
+     * Return the names of all available Icinga instances
+     *
+     * @return  array
+     */
+    public function getInstanceNames()
+    {
+        return $this->instanceNames ?: array();
+    }
+
     /**
      * Return a form object for the given transport type
      *
@@ -163,18 +193,21 @@ class TransportConfigForm extends ConfigForm
      */
     public function createElements(array $formData)
     {
-        $this->addElement(
+        $instanceNames = $this->getInstanceNames();
-            'text',
+        if (count($instanceNames) > 1) {
-            'instance',
+            $options = array('none' => $this->translate('None', 'command transport instance association'));
-            array(
+            $this->addElement(
-                'placeholder'   => 'default',
+                'select',
-                'label'         => $this->translate('Instance Name'),
+                'instance',
-                'description'   => $this->translate(
+                array(
-                    'The name of the Icinga instance this transport should transfer commands to. You do not '
+                    'label'         => $this->translate('Instance Link'),
-                    . 'need to adjust this if you\'re not using a different instance name than the default.'
+                    'description'   => $this->translate(
+                        'The name of the Icinga instance this transport should exclusively transfer commands to.'
+                    ),
+                    'multiOptions'  => array_merge($options, array_combine($instanceNames, $instanceNames))
                 )
-            )
+            );
-        );
+        }
 
         $this->addElement(
             'text',