From becd7d0504c09307ba7f0e6eae792c25742d2ce9 Mon Sep 17 00:00:00 2001
From: Eric Lippmann <eric.lippmann@icinga.com>
Date: Tue, 3 Jul 2018 14:41:55 +0200
Subject: [PATCH] Introduce monitoring/PluginOutputHook

refs #3257
---
 .../controllers/HostController.php            |   3 +-
 .../controllers/ListController.php            |   6 +-
 .../views/helpers/PluginOutput.php            |  14 ++-
 .../views/scripts/list/hosts.phtml            |   2 +-
 .../views/scripts/list/services.phtml         |   2 +-
 .../scripts/show/components/output.phtml      |   4 +-
 modules/monitoring/doc/20-Hooks.md            |  85 ++++++++++++++
 .../Monitoring/Hook/PluginOutputHook.php      |  46 ++++++++
 .../Web/Helper/PluginOutputHookRenderer.php   | 105 ++++++++++++++++++
 9 files changed, 259 insertions(+), 8 deletions(-)
 create mode 100644 modules/monitoring/library/Monitoring/Hook/PluginOutputHook.php
 create mode 100644 modules/monitoring/library/Monitoring/Web/Helper/PluginOutputHookRenderer.php

diff --git a/modules/monitoring/application/controllers/HostController.php b/modules/monitoring/application/controllers/HostController.php
index bb98b2a8f..b0cda11dd 100644
--- a/modules/monitoring/application/controllers/HostController.php
+++ b/modules/monitoring/application/controllers/HostController.php
@@ -100,7 +100,8 @@ class HostController extends MonitoredObjectController
             'service_active_checks_enabled',
             'service_passive_checks_enabled',
             'current_check_attempt' => 'service_current_check_attempt',
-            'max_check_attempts'    => 'service_max_check_attempts'
+            'max_check_attempts'    => 'service_max_check_attempts',
+            'service_check_command'
         ));
         $this->applyRestriction('monitoring/filter/objects', $query);
         $this->view->services = $query->where('host_name', $this->object->getName());
diff --git a/modules/monitoring/application/controllers/ListController.php b/modules/monitoring/application/controllers/ListController.php
index ccdb149d4..4bbb39fb5 100644
--- a/modules/monitoring/application/controllers/ListController.php
+++ b/modules/monitoring/application/controllers/ListController.php
@@ -76,7 +76,8 @@ class ListController extends Controller
             'host_last_state_change' => $stateChangeColumn,
             'host_notifications_enabled',
             'host_active_checks_enabled',
-            'host_passive_checks_enabled'
+            'host_passive_checks_enabled',
+            'host_check_command'
         ), $this->addColumns()));
         $this->applyRestriction('monitoring/filter/objects', $hosts);
 
@@ -156,7 +157,8 @@ class ListController extends Controller
             'service_severity',
             'service_notifications_enabled',
             'service_active_checks_enabled',
-            'service_passive_checks_enabled'
+            'service_passive_checks_enabled',
+            'service_check_command'
         ), $this->addColumns()));
         $this->applyRestriction('monitoring/filter/objects', $services);
 
diff --git a/modules/monitoring/application/views/helpers/PluginOutput.php b/modules/monitoring/application/views/helpers/PluginOutput.php
index 1c77b578d..f10e516ff 100644
--- a/modules/monitoring/application/views/helpers/PluginOutput.php
+++ b/modules/monitoring/application/views/helpers/PluginOutput.php
@@ -76,19 +76,31 @@ class Zend_View_Helper_PluginOutput extends Zend_View_Helper_Abstract
         '<table style="font-size: 0.75em"'
     );
 
+    /** @var \Icinga\Module\Monitoring\Web\Helper\PluginOutputHookRenderer */
+    protected $hookRenderer;
+
+    public function __construct()
+    {
+        $this->hookRenderer = (new \Icinga\Module\Monitoring\Web\Helper\PluginOutputHookRenderer())->registerHooks();
+    }
+
     /**
      * Render plugin output
      *
      * @param   string  $output
      * @param   bool    $raw
+     * @param   string  $command    Check command
      *
      * @return  string
      */
-    public function pluginOutput($output, $raw = false)
+    public function pluginOutput($output, $raw = false, $command = null)
     {
         if (empty($output)) {
             return '';
         }
+        if ($command !== null) {
+            $output = $this->hookRenderer->render($command, $output, ! $raw);
+        }
         $output = preg_replace('~<br[^>]*>~', "\n", $output);
         if (preg_match('~<[^>]*["/\'][^>]*>~', $output)) {
             // HTML
diff --git a/modules/monitoring/application/views/scripts/list/hosts.phtml b/modules/monitoring/application/views/scripts/list/hosts.phtml
index da00fccc6..e00038bf6 100644
--- a/modules/monitoring/application/views/scripts/list/hosts.phtml
+++ b/modules/monitoring/application/views/scripts/list/hosts.phtml
@@ -82,7 +82,7 @@ if (! $this->compact): ?>
                 <?php endif ?>
                     <span class="state-icons"><?= $this->hostFlags($host) ?></span>
                 </div>
-                <p class="overview-plugin-output"><?= $this->pluginOutput($this->ellipsis($host->host_output, 10000), true) ?></p>
+                <p class="overview-plugin-output"><?= $this->pluginOutput($this->ellipsis($host->host_output, 10000), true, $host->host_check_command) ?></p>
             </td>
         <?php foreach($this->addColumns as $col): ?>
             <td><?= $this->escape($host->$col) ?></td>
diff --git a/modules/monitoring/application/views/scripts/list/services.phtml b/modules/monitoring/application/views/scripts/list/services.phtml
index c9f1e855b..25a18781a 100644
--- a/modules/monitoring/application/views/scripts/list/services.phtml
+++ b/modules/monitoring/application/views/scripts/list/services.phtml
@@ -86,7 +86,7 @@ if (! $this->compact): ?>
                     <div class="overview-performance-data">
                         <?= $this->perfdata($service->service_perfdata, true, 5) ?>
                     </div>
-                    <p class="overview-plugin-output"><?= $this->pluginOutput($this->ellipsis($service->service_output, 10000), true) ?></p>
+                    <p class="overview-plugin-output"><?= $this->pluginOutput($this->ellipsis($service->service_output, 10000), true, $service->service_check_command) ?></p>
                 </div>
             </td>
         <?php foreach($this->addColumns as $col): ?>
diff --git a/modules/monitoring/application/views/scripts/show/components/output.phtml b/modules/monitoring/application/views/scripts/show/components/output.phtml
index e4c0fd0a8..c450319a1 100644
--- a/modules/monitoring/application/views/scripts/show/components/output.phtml
+++ b/modules/monitoring/application/views/scripts/show/components/output.phtml
@@ -1,3 +1,3 @@
 <h2><?= $this->translate('Plugin Output') ?></h2>
-<?= $this->pluginOutput($object->output) ?>
-<?= $this->pluginOutput($object->long_output) ?>
+<?= $this->pluginOutput($object->output, false, $object->check_command) ?>
+<?= $this->pluginOutput($object->long_output, false, $object->check_command) ?>
diff --git a/modules/monitoring/doc/20-Hooks.md b/modules/monitoring/doc/20-Hooks.md
index 373f7ebea..5d38843d6 100644
--- a/modules/monitoring/doc/20-Hooks.md
+++ b/modules/monitoring/doc/20-Hooks.md
@@ -74,3 +74,88 @@ class Simple extends DetailviewExtensionHook
 ### How it looks <a id="monitoring-module-hooks-detailviewextension-how-it-looks"></a>
 
 ![Screenshot](img/hooks-detailviewextension-01.png)
+
+## Plugin Output Hook <a id="monitoring-module-hooks-pluginoutput"></a>
+
+The Plugin Output Hook allows you to rewrite the plugin output based on check commands. You have to implement the
+following methods:
+
+* `getCommands()`
+* and `render()`
+
+With `getCommands()` you specify for which commands the provided hook is responsible for. You may return a single
+command as string or a list of commands as array. If you want your hook to be responsible for every command, you have to
+specify the `*`.
+
+In `render()` you rewrite the plugin output based on check commands. The parameter `$command` specifies the check
+command of the host or service and `$output` specifies the plugin output. The parameter `$detail` tells you
+whether the output is requested from the detail area of the host or service.
+
+Do not use complex logic for rewriting plugin output in list views because of the performance impact!
+
+You have to return the rewritten plugin output as string. It is also possible to return a HTML string here.
+Please refer to `\Icinga\Module\Monitoring\Web\Helper\PluginOutputPurifier` for a list of allowed tags.
+
+Please also have a look at the following examples.
+
+**Example hook which is responsible for disk checks:**
+
+```php
+<?php
+
+namespace Icinga\Module\Example\ProvidedHook\Monitoring;
+
+use Icinga\Module\Monitoring\Hook\PluginOutputHook;
+
+class PluginOutput extends PluginOutputHook
+{
+    public function getCommands()
+    {
+        return ['disk'];
+    }
+
+    public function render($command, $output, $detail)
+    {
+        if (! $detail) {
+            // Don't rewrite plugin output in list views
+            return $output;
+        }
+        return implode('<br>', explode(';', $output));
+    }
+}
+```
+
+**Example hook which is responsible for disk and procs checks:**
+
+```php
+<?php
+
+namespace Icinga\Module\Example\ProvidedHook\Monitoring;
+
+use Icinga\Module\Monitoring\Hook\PluginOutputHook;
+
+class PluginOutput extends PluginOutputHook
+{
+    public function getCommands()
+    {
+        return ['disk', 'procs'];
+    }
+
+    public function render($command, $output, $detail)
+    {
+        switch ($command) {
+            case 'disk':
+                if ($detail) {
+                    // Only rewrite plugin output in the detail area
+                    $output = implode('<br>', explode(';', $output));
+                }
+                break;
+            case 'procs':
+                $output = preg_replace('/(\d)+/', '<b>$1</b>', $output);
+                break;
+        }
+
+        return $output;
+    }
+}
+```
diff --git a/modules/monitoring/library/Monitoring/Hook/PluginOutputHook.php b/modules/monitoring/library/Monitoring/Hook/PluginOutputHook.php
new file mode 100644
index 000000000..52ecd0963
--- /dev/null
+++ b/modules/monitoring/library/Monitoring/Hook/PluginOutputHook.php
@@ -0,0 +1,46 @@
+<?php
+/* Icinga Web 2 | (c) 2018 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Module\Monitoring\Hook;
+
+/**
+ * Base class for plugin output hooks
+ *
+ * The Plugin Output Hook allows you to rewrite the plugin output based on check commands.
+ * You have to implement the following methods:
+ * * {@link getCommands()}
+ * * and {@link render()}
+ */
+abstract class PluginOutputHook
+{
+    /**
+     * Get the command or list of commands the hook is responsible for
+     *
+     * With this method you specify for which commands the provided hook is responsible for. You may return a single
+     * command as string or a list of commands as array.
+     * If you want your hook to be responsible for every command, you have to return the asterisk `'*'`.
+     *
+     * @return  string|array
+     */
+    abstract public function getCommands();
+
+    /**
+     * Render the given plugin output based on the specified check command
+     *
+     * With this method you rewrite the plugin output based on check commands. The parameter `$command` specifies the
+     * check command of the host or service and `$output` specifies the plugin output. The parameter `$detail` tells you
+     * whether the output is requested from the detail area of the host or service.
+     *
+     * Do not use complex logic for rewriting plugin output in list views because of the performance impact!
+     *
+     * You have to return the rewritten plugin output as string. It is also possible to return a HTML string here.
+     * Please refer to {@link \Icinga\Module\Monitoring\Web\Helper\PluginOutputPurifier} for a list of allowed tags.
+     *
+     * @param   string  $command    Check command
+     * @param   string  $output     Plugin output
+     * @param   bool    $detail     Whether the output is requested from the detail area
+     *
+     * @return  string              Rewritten plugin output
+     */
+    abstract public function render($command, $output, $detail);
+}
diff --git a/modules/monitoring/library/Monitoring/Web/Helper/PluginOutputHookRenderer.php b/modules/monitoring/library/Monitoring/Web/Helper/PluginOutputHookRenderer.php
new file mode 100644
index 000000000..50b6c6568
--- /dev/null
+++ b/modules/monitoring/library/Monitoring/Web/Helper/PluginOutputHookRenderer.php
@@ -0,0 +1,105 @@
+<?php
+/* Icinga Web 2 | (c) 2018 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Module\Monitoring\Web\Helper;
+
+use Icinga\Application\Logger;
+use Icinga\Web\Hook;
+
+/**
+ * Renderer for plugin output based on hooks
+ */
+class PluginOutputHookRenderer
+{
+    /** @var array */
+    protected $commandMap = [];
+
+    /**
+     * Register PluginOutput hooks
+     *
+     * Map PluginOutput hooks to their responsible commands.
+     *
+     * @return  $this
+     */
+    public function registerHooks()
+    {
+        if (! Hook::has('monitoring/PluginOutput')) {
+            return $this;
+        }
+
+        foreach (Hook::all('monitoring/PluginOutput') as $hook) {
+            /** @var \Icinga\Module\Monitoring\Hook\PluginOutputHook $hook */
+            try {
+                $commands = $hook->getCommands();
+            } catch (\Exception $e) {
+                Logger::error(
+                    'Failed to get applicable commands from hook "%s". An error occurred: %s',
+                    get_class($hook),
+                    $e
+                );
+
+                continue;
+            }
+
+            if (! is_array($commands)) {
+                $commands = [$commands];
+            }
+
+            foreach ($commands as $command) {
+                if (! isset($this->commandMap[$command])) {
+                    $this->commandMap[$command] = [];
+                }
+
+                $this->commandMap[$command][] = $hook;
+            }
+        }
+
+        return $this;
+    }
+
+    protected function renderCommand($command, $output, $detail)
+    {
+        if (isset($this->commandMap[$command])) {
+            foreach ($this->commandMap[$command] as $hook) {
+                /** @var \Icinga\Module\Monitoring\Hook\PluginOutputHook $hook */
+
+                try {
+                    $output = $hook->render($command, $output, $detail);
+                } catch (\Exception $e) {
+                    Logger::error(
+                        'Failed to render plugin output from hook "%s". An error occurred: %s',
+                        get_class($hook),
+                        $e
+                    );
+
+                    continue;
+                }
+            }
+        }
+
+        return $output;
+    }
+
+    /**
+     * Render the given plugin output based on the specified check command
+     *
+     * Traverse all hooks which are responsible for the specified check command and call their `render()` methods.
+     *
+     * @param   string  $command    Check command
+     * @param   string  $output     Plugin output
+     * @param   bool    $detail     Whether the output is requested from the detail area
+     *
+     * @return  string
+     */
+    public function render($command, $output, $detail)
+    {
+        if (empty($this->commandMap)) {
+            return $output;
+        }
+
+        $output = $this->renderCommand('*', $output, $detail);
+        $output = $this->renderCommand($command, $output, $detail);
+
+        return $output;
+    }
+}