Rework caching

- Rename indirectproxyrefresh to enablecaching, defaults to yes
- Calculate the cache time based on the check interval

Author: martialblog

application/controllers/IcingadbimgController.php

@@ -42,7 +42,7 @@ class IcingadbimgController extends IcingadbGrafanaController
     protected $SSLVerifyHost           = "0";
     protected $cacheTime;
     protected $defaultdashboarduid;
-    protected $refresh                 = "yes";
+    protected $enableCache             = "yes";
     protected $customVars;
     protected $timerangeto;
     protected $object;
@@ -68,6 +68,7 @@ public function init()
         } else {
             $this->timerangeto = strpos($this->timerange ?? '', '/') ? 'now-' . $this->timerange ?? '' : "now";
         }
+
         $this->cacheTime = $this->hasParam('cachetime') ? $this->getParam('cachetime') : 300;
 
         /* load global configuration */
@@ -97,7 +98,7 @@ public function init()
         $this->height = $this->myConfig->get('height', $this->height);
         $this->width = $this->myConfig->get('width', $this->width);
         $this->proxyTimeout = $this->myConfig->get('proxytimeout', $this->proxyTimeout);
-        $this->refresh = $this->myConfig->get('indirectproxyrefresh', $this->refresh);
+        $this->enableCache = $this->myConfig->get('enablecache', $this->enableCache);
         /**
          * Read the global default timerange
          */
@@ -214,21 +215,15 @@ public function indexAction()
         }
 
         $imageHtml = "";
-        $res = $this->getMyimageHtml($serviceName, $hostName, $imageHtml);
-        header('Pragma: public');
-        if ($this->refresh == "yes") {
-            header('Pragma: public');
-            header("Expires: ".gmdate("D, d M Y H:i:s", time() + $this->cacheTime)." GMT");
-            header('Cache-Control: max-age='.$this->cacheTime).', public';
-        } else {
-            header("Expires: ".gmdate("D, d M Y H:i:s", time() + 365*86440)." GMT");
-            header('Cache-Control: max-age='. (365*86440));
+        $result = $this->getMyimageHtml($serviceName, $hostName, $imageHtml);
+
+        if ($this->enableCache === 'yes') {
+            header('Cache-Control: public, max-age=' . $this->cacheTime);
         }
+
         header("Content-type: image/png");
-        if (! $res) {
-            // set expire to now and max age to 1 minute
-            header("Expires: ".gmdate("D, d M Y H:i:s", time())." GMT");
-            header('Cache-Control: max-age='. 120);
+
+        if (! $result) {
             $string = wordwrap($this->translate('Error'). ': ' . $imageHtml, 40, "\n");
             $lines = explode("\n", $string);
             $im = @imagecreate($this->width, $this->height);
@@ -368,11 +363,11 @@ private function getMyimageHtml($serviceName, $hostName, &$imageHtml)
         }
 
         curl_setopt_array($curl_handle, $curl_opts);
-        $res = curl_exec($curl_handle);
+        $result = curl_exec($curl_handle);
 
         $statusCode = curl_getinfo($curl_handle, CURLINFO_HTTP_CODE);
 
-        if ($res === false) {
+        if ($result === false) {
             $imageHtml .=$this->translate('Cannot fetch graph with curl') .': '. curl_error($curl_handle). '.';
 
             //provide a hint for 'Failed to connect to ...: Permission denied'
@@ -383,7 +378,7 @@ private function getMyimageHtml($serviceName, $hostName, &$imageHtml)
         }
 
         if ($statusCode > 299) {
-            $error = @json_decode($res);
+            $error = @json_decode($result);
             $imageHtml .= $this->translate('Cannot fetch Grafana graph')
                 . ": "
                 . Util::httpStatusCodeToString($statusCode)
@@ -395,7 +390,7 @@ private function getMyimageHtml($serviceName, $hostName, &$imageHtml)
         }
 
         curl_close($curl_handle);
-        $imageHtml = $res;
+        $imageHtml = $result;
         return true;
     }
 

application/forms/Config/GeneralConfigForm.php

@@ -236,15 +236,15 @@ public function createElements(array $formData)
         if (isset($formData['grafana_accessmode']) && $formData['grafana_accessmode'] === 'indirectproxy') {
             $this->addElement(
                 'select',
-                'grafana_indirectproxyrefresh',
+                'grafana_enablecache',
                 [
-                    'label' => $this->translate('Refresh on indirect proxy'),
+                    'label' => $this->translate('Enable cache'),
                     'value' => 'yes',
                     'multiOptions' => [
                         'yes' => $this->translate('Yes'),
                         'no' => $this->translate('No'),
                     ],
-                    'description' => $this->translate('Refresh graphs on indirect proxy mode.')
+                    'description' => $this->translate('Enable cache on indirect proxy mode.')
                 ]
             );
         }

doc/03-module-configuration.md

@@ -44,7 +44,7 @@ datasource = "influxdb"
 defaultdashboardstore = "db"
 accessmode = "proxy"
 timeout = "5"
-directrefresh = "no"
+enablecache = "no"
 usepublic = "no"
 publichost = "otherhost:3000"
 publicprotocol = "http"
@@ -80,7 +80,7 @@ ssl_verifyhost = "0"
 |username               | **Proxy with basic only** **Required** HTTP Basic Auth user name to access Grafana.|
 |password               | **Proxy with basic only** **Required** HTTP Basic Auth password to access Grafana. Requires the username setting.|
 |apitoken               | **Proxy with token only** **Required** Token of a Service Account to access Grafana.|
-|indirectproxyrefresh   | **Indirect Proxy Only** **Optional.** Refresh graphs on indirect proxy mode. Defaults to `yes`.|
+|enablecache            | **Indirect Proxy Only** **Optional.** Enables or disable caching graphs. Defaults to `yes`. |
 |usepublic              | **Optional** Enable usage of publichost/protocol. Defaults to `no`.|
 |publichost             | **Optional** Use a different host for the graph links.|
 |publicprotocol         | **Optional** Use a different protocol for the graph links.|
@@ -190,9 +190,8 @@ The password used to authenticate to Grafana server.
 For token access you need to create a Service Account and assign it a token.
 See the [Grafana Docs](https://grafana.com/docs/grafana/latest/administration/service-accounts/).
 
-### indirectproxyrefresh
-Only for `indirectproxy` access mode. Enables or disable graph refresh with an interval of the service interval.
-Defaults to `yes`.
+### enablecache
+Only for `indirectproxy` access mode. Enables or disable caching graphs. Defaults to `yes`.
 
 ### usepublic
 Enables/Disables the usage of a `public` URL to the Grafana server.

library/Grafana/ProvidedHook/Icingadb/IcingaDbGrapher.php

@@ -352,8 +352,8 @@ private function getMyPreviewHtml($serviceName, $hostName, HtmlDocument $preview
     public function getPreviewHtml(Model $object, $report = false)
     {
         $this->object = $object;
-        //$this->cacheTime = round($object->state->next_check - $object->state->last_update);
-                $this->cacheTime = 0;
+        // Calculate the cachetime based on the check intervals
+        $this->cacheTime = round($object->state->next_check->getTimestamp() - $object->state->last_update->getTimestamp());
 
         if ($object instanceof Host) {
             $serviceName = $object->checkcommand_name;