Simple linear port graph prediction (#10520)

* Simple linear port graph prediction
Simple linear prediction line for in and out if graph "to" value is in the future
Improve graph date handling

* thinner line

* Make test specify timezone

includes/html/functions.inc.php

@@ -1526,6 +1526,34 @@ function generate_stacked_graphs($transparency = '88')
     }
 }
 
+/**
+ * Parse AT time spec, does not handle the entire spec.
+ * @param string $time
+ * @return int
+ */
+function parse_at_time($time)
+{
+    if (is_numeric($time)) {
+        return $time < 0 ? time() + $time : intval($time);
+    }
+
+    if (preg_match('/^[+-]\d+[hdmy]$/', $time)) {
+        $units = [
+            'm' => 60,
+            'h' => 3600,
+            'd' => 86400,
+            'y' => 31557600,
+        ];
+        $value = substr($time, 1, -1);
+        $unit = substr($time, -1);
+
+        $offset = ($time[0] == '-' ? -1 : 1) * $units[$unit] * $value;
+        return time() + $offset;
+    }
+
+    return (int)strtotime($time);
+}
+
 /**
  * Get the ZFS pools for a device... just requires the device ID
  * an empty return means ZFS is not in use or there are currently no pools

includes/html/graphs/common.inc.php

@@ -2,13 +2,8 @@
 
 use LibreNMS\Util\Clean;
 
-if ($_GET['from']) {
-    $from = preg_match('/(-\d+[hdm]|now)/', $_GET['from']) ? $_GET['from'] : (int)$_GET['from'];
-}
-
-if ($_GET['to']) {
-    $to = preg_match('/(-?\d+[hdm]|now)/', $_GET['to']) ? $_GET['to'] : (int)$_GET['to'];
-}
+$from = parse_at_time($_GET['from']);
+$to = parse_at_time($_GET['to']);
 
 if ($_GET['width']) {
     $width = (int)$_GET['width'];

includes/html/graphs/generic_data.inc.php

@@ -137,8 +137,21 @@ $rrd_options .= " GPRINT:totout:'Out %6.2lf%sB)\\l'";
 $rrd_options .= ' LINE1:percentile_in#aa0000';
 $rrd_options .= ' LINE1:dpercentile_out#aa0000';
 
+// Linear prediction of trend
+if ($to > time()) {
+    $rrd_options .= ' VDEF:islope=inbits_max,LSLSLOPE';
+    $rrd_options .= ' VDEF:icons=inbits_max,LSLINT';
+    $rrd_options .= ' CDEF:ilsl=inbits_max,POP,islope,COUNT,*,icons,+ ';
+    $rrd_options .= " LINE2:ilsl#44aa55:'In Linear Prediction\\n':dashes=8";
+
+    $rrd_options .= ' VDEF:oslope=doutbits_max,LSLSLOPE';
+    $rrd_options .= ' VDEF:ocons=doutbits_max,LSLINT';
+    $rrd_options .= ' CDEF:olsl=doutbits_max,POP,oslope,COUNT,*,ocons,+ ';
+    $rrd_options .= " LINE2:olsl#4400dd:'Out Linear Prediction\\n':dashes=8";
+}
+
 if ($_GET['previous'] == 'yes') {
-    $rrd_options .= ' LINE1.25:in' . $format . "X#009900:'Prev In \\\\n'";
+    $rrd_options .= ' LINE1.25:in' . $format . "X#009900:'Prev In \\n'";
     $rrd_options .= ' LINE1.25:dout' . $format . "X#000099:'Prev Out'";
 }
 

includes/html/graphs/graph.inc.php

@@ -22,14 +22,10 @@ $title    = $vars['title'];
 $vertical = $vars['vertical'];
 $legend   = $vars['legend'];
 $output   = (!empty($vars['output']) ? $vars['output'] : 'default');
-$from = (isset($vars['from']) ? $vars['from'] : time() - 60 * 60 * 24);
-$to   = (isset($vars['to']) ? $vars['to'] : time());
+$from = parse_at_time($_GET['from']) ?: Config::get('time.day');
+$to   = parse_at_time($_GET['to']) ?: Config::get('time.now');
 $graph_type = (isset($vars['graph_type']) ? $vars['graph_type'] : Config::get('webui.graph_type'));
 
-if ($from < 0) {
-    $from = ($to + $from);
-}
-
 $period = ($to - $from);
 $base64_output = '';
 $prev_from = ($from - $period);

includes/html/pages/graphs.inc.php

@@ -14,12 +14,8 @@ if (session('widescreen')) {
     $thumb_width=113;
 }
 
-if (!is_numeric($vars['from'])) {
-    $vars['from'] = strtotime($vars['from']) ?: Config::get('time.day');
-}
-if (!is_numeric($vars['to'])) {
-    $vars['to'] = strtotime($vars['to']) ?: Config::get('time.now');
-}
+$vars['from'] = parse_at_time($vars['from']) ?: Config::get('time.day');
+$vars['to'] = parse_at_time($vars['to']) ?: Config::get('time.now');
 
 preg_match('/^(?P<type>[A-Za-z0-9]+)_(?P<subtype>.+)/', $vars['type'], $graphtype);