Graphing server log files

Maps, Graphics and Geographics example from a Well House Consultants training course
More on Maps, Graphics and Geographics [link]

This example is described in the following article(s):
• Server logs - drawing a graph of gathered data - [link]

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Source code: serverlog.php Module: H309


<?php
# Create a graph of system loading data from server log files

# Start with a blank canvas, 820 x 500 pixels

$image = ImageCreate(820,500);

# Choose your paint pallette

$black = ImageColorAllocate($image,0,0,0);
$grey = ImageColorAllocate($image,200,200,200);
$blue = ImageColorAllocate($image,0,0,255);
$red = ImageColorAllocate($image,255,0,0);
$green = ImageColorAllocate($image,0,255,0);
$yellow = ImageColorAllocate($image,255,255,0);
$orange = ImageColorAllocate($image,255,128,0);
$white = ImageColorAllocate($image,255,255,255);
# List of colours for each of the days
$cols = array($yellow, $red, $green, $orange, $black);

# Blue outline, Grey area for axes, White area for data

ImageFilledRectangle($image,0,0,819,499,$blue);
ImageFilledRectangle($image,1,1,818,498,$grey);
ImageFilledRectangle($image,50,50,769,449,$white);

# Draw and label the axes

$load = 3;
for ($y1 = 150; $y1 <= 350; $y1 += 100) {
        ImageLine($image,50,$y1,770,$y1,$grey);
        Imagettftext($image,8,0,40,$y1+4,$black,"ArialBold.ttf", $load);
        $load--;
 }

$hour = 0;
for ($x1 = 50; $x1 <= 770; $x1 += 30) {
        ImageLine($image,$x1,50,$x1,450,$grey);
        if ($hour % 3 == 0) {
                Imagettftext($image,8,0,$x1-15,465,$black,"ArialBold.ttf",
                        sprintf("%02d:00",$hour));
        }
        $hour ++;
 }

# Add in a box for labelling each curve

ImageFilledRectangle($image,55,145,240,55,$grey);
ImageFilledRectangle($image,56,144,239,56,$white);

# Title the graph and the axes

Imagettftext($image,16,0,250,30,$black,"ArialBold.ttf",
        "Server loading on www.wellho.net");

Imagettftext($image,12,0,350,490,$black,"ArialBold.ttf", "Time of day");
Imagettftext($image,12,90,20,400,$black,"ArialBold.ttf",
        "Server Load (last 5 minutes average)");

# Find the most recent five data files to graph

$statfiles = array();
$dh = opendir ("$_SERVER[DOCUMENT_ROOT]/../serverstatus");
while ($item = readdir($dh)) {
        if (! preg_match('/_statlog/',$item)) continue;
        array_push($statfiles, $item);
        }
sort($statfiles);
$week = array_slice($statfiles,-5);

# Loop through adding each line to the graph

$n=0;
foreach ($week as $daily) {
        $col = $cols[$n++];
        $records = file("$_SERVER[DOCUMENT_ROOT]/../serverstatus/$daily");

# Draw the line itself

        $oldx = -1;
        foreach ($records as $rec) {
                $parts = explode(" ",$rec);
                $y = $parts[13];
                $x = $oldx+1;
                if ($oldx >= 0) { # Skip drawing to very first point
                        $y1 = 450.0 - $oldy * 100.0 ;
                        $y2 = 450.0 - $y  * 100.0;
                        ImageLine($image,50+$oldx*2,$y1,50+ $x * 2,$y2,$col);
                }
                $oldx = $x;
                $oldy = $y;
        }

# Annotate the line just added - the date is based on the file name

        preg_match('/(....)(..)(..)/',$daily,$dp);
        $dtext = "$dp[3]/$dp[2]/$dp[1]";

        $yax = 150 - 15 * $n;
        ImageLine($image,60,$yax-4,160,$yax-4,$col);
        Imagettftext($image,8,0,170,$yax,$black,
                        "ArialBold.ttf", $dtext);
}

# Tell the browser that it will be receiving a jpg image rather than HTML!
header("Content-type: image/jpeg");

# Convert the canvas into a .jpg image and output it
ImageJpeg($image);

?>

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Other Examples

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