Generating Badges

Costa Tsaousis edited this page Jan 16, 2017 · 80 revisions

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Netdata badges

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Badges are cool!

Netdata can generate badges for any chart and any dimension at any time-frame. Badges come in SVG and can be added to any web page using an <IMG> HTML tag.

Netdata badges are powerful!

Given that netdata collects from 1.000 to 5.000 metrics per server (depending on the number of network interfaces, disks, cpu cores, applications running, users logged in, containers running, etc) and that netdata already has data reduction/aggregation functions embedded, the badges can be quite powerful.

For each metric/dimension and for arbitrary time-frames badges can show min, max or average value, but also sum or incremental-sum to have their volume.

For example, there is a chart in netdata that shows the current requests/s of nginx. Using this chart alone we can show the following badges (we could add more time-frames, like today, yesterday, etc):

Similarly, there is a chart that shows outbound bandwidth per class, using QoS data. So it shows kilobits/s per class. Using this chart we can show:

The right one is a volume calculation. Netdata calculated the total of the last 86.400 seconds (a day) which gives kilobits, then divided it by 8 to make it KB, then by 1024 to make it MB and then by 1024 to make it GB. Calculations like this are quite accurate, since for every value collected, every second, netdata interpolates it to second boundary using microsecond calculations.

Let's see a few more badge examples (they come from the netdata registry):

  • cpu usage of user root (you can pick any user; 100% = 1 core). This will be green <10%, yellow <20%, orange <50%, blue <100% (1 core), red otherwise (you define thresholds and colors on the URL).

  • mysql queries per second

    niche ones: mysql SELECT statements with JOIN, which did full table scans:

  • bind (ISC named) queries


So, every single line on the charts of a netdata dashboard, can become a badge and this badge can calculate average, min, max, or volume for any time-frame! And you can also vary the badge color using conditions on the calculated value.


How to create badges

The basic URL is http://your.netdata:19999/api/v1/badge.svg?option1&option2&option3&....

Here is what you can put for options (these are standard netdata API options):

  • chart=CHART.NAME

    The chart to get the values from.

    This is the only parameter required and with just this parameter, netdata will return the sum of the latest values of all chart dimensions.

    Example:

    <a href="#">
       <img src="http://registry.my-netdata.io/api/v1/badge.svg?chart=system.cpu"></img>
    </a>

    Which produces this:

  • alarm=NAME

    Render the current value and status of an alarm linked to the chart. This option can be ignored if the badge to be generated is not related to an alarm.

    The current value of the alarm will be rendered. The color of the badge will indicate the status of the alarm.

    For alarm badges, both chart and alarm parameters are required.

  • dimensions=DIMENSION1|DIMENSION2|...

    The dimensions of the chart to use. If you don't set any dimension, all will be used. When multiple dimensions are used, netdata will sum their values. You can append options=absolute if you want this sum to convert all values to positive before adding them.

    Pipes in HTML have to escaped with %7C.

    Example:

    <a href="#">
       <img src="http://registry.my-netdata.io/api/v1/badge.svg?chart=system.cpu&dimensions=system%7Cnice"></img>
    </a>

    Which produces this:

  • before=SECONDS and after=SECONDS

    The timeframe. These can be absolute unix timestamps, or relative to now, number of seconds. By default before=0 and after=-1 (1 second in the past).

    To get the last minute set after=-60. This will give the average of the last complete minute (XX:XX:00 - XX:XX:59).

    To get the max of the last hour set after=-3600&group=max. This will give the maximum value of the last complete hour (XX:00:00 - XX:59:59)

    Example:

    <a href="#">
       <img src="http://registry.my-netdata.io/api/v1/badge.svg?chart=system.cpu&after=-60"></img>
    </a>

    Which produces the average of last complete minute (XX:XX:00 - XX:XX:59):

    While this is the previous minute (one minute before the last one, again aligned XX:XX:00 - XX:XX:59):

    <a href="#">
       <img src="http://registry.my-netdata.io/api/v1/badge.svg?chart=system.cpu&before=-60&after=-60"></img>
    </a>

    It produces this:

  • group=min or group=max or group=average (the default) or group=sum or group=incremental-sum

    If netdata will have to reduce (aggregate) the data to calculate the value, which aggregation method to use.

    • max will find the max value for the timeframe. This works on both positive and negative dimensions. It will find the most extreme value.

    • min will find the min value for the timeframe. This works on both positive and negative dimensions. It will find the number closest to zero.

    • average will calculate the average value for the timeframe.

    • sum will sum all the values for the timeframe. This is nice for finding the volume of dimensions for a timeframe. So if you have a dimension that reports X per second, you can find the volume of the dimension in a timeframe, by adding its values in that timeframe.

    • incremental-sum will sum the difference of each value to its next. Let's assume you have a dimension that does not measure the rate of something, but the absolute value of it. So it has values like this "1, 5, 3, 7, 4". incremental-sum will calculate the difference of adjacent values. In this example, they will be (5 - 1) + (3 - 5) + (7 - 3) + (4 - 7) = 3 (which is equal to the last value minus the first = 4 - 1).

  • options=opt1|opt2|opt3|...

    These fine tune various options of the API. Here is what you can use for badges (the API has more option, but only these are useful for badges):

    • percentage, instead of returning the value, calculate the percentage of the sum of the selected dimensions, versus the sum of all the dimensions of the chart. This also sets the units to %.

    • absolute or abs, turn all values positive and then sum them.

    • min2max, when multiple dimensions are given, do not sum them, but take their max - min.

    • unaligned, when data are reduced / aggregated (e.g. the request is about the average of the last minute, or hour), netdata by default aligns them so that the charts will have a constant shape (so average per minute returns always XX:XX:00 - XX:XX:59). Setting the unaligned option, netdata will aggregate data without any alignment, so if the request is for 60 seconds, it will aggregate the latest 60 seconds of collected data.

These are options dedicated to badges:

  • label=TEXT

    The label of the badge.

  • units=TEXT

    The units of the badge. If you want to put a /, please put a \. This is because netdata allows badges parameters to be given as path in URL, instead of query string. You can also use null or empty to show it without any units.

    The units seconds, minutes and hours trigger special formatting. The value has to be in this unit, and netdata will automatically change it to show a more pretty duration.

  • multiply=NUMBER

    Multiply the value with this number. The default is 1.

  • divide=NUMBER

    Divide the value with this number. The default is 1.

  • label_color=COLOR

    The color of the label (the left part). You can use any HTML color, include #NNN and #NNNNNN. The following colors are defined in netdata (and you can use them by name): green, brightgreen, yellow, yellowgreen, orange, red, blue, grey, gray, lightgrey, lightgray. These are taken from https://github.com/badges/shields so they are compatible with standard badges.

  • value_color=COLOR:null|COLOR<VALUE|COLOR>VALUE|COLOR>=VALUE|COLOR<=VALUE|...

    You can add a pipe delimited list of conditions to pick the color. The first matching (left to right) will be used.

    Example: value_color=grey:null|green<10|yellow<100|orange<1000|blue<10000|red

    The above will set grey if no value exists (not collected within the gap when lost iterations above in netdata.conf for the chart), green if the value is less than 10, yellow if the value is less than 100, etc up to red which will be used if no other conditions match.

    The supported operators are <, >, <=, >=, =.

  • precision=NUMBER

    The number of decimal digits of the value. By default netdata will add:

    • no decimal digits for values > 1000
    • 1 decimal digit for values > 100
    • 2 decimal digits for values > 1
    • 3 decimal digits for values > 0.1
    • 4 decimal digits for values <= 0.1

    Using the precision=NUMBER you can set your preference per badge.

  • refresh=auto or refresh=SECONDS

    This option enables auto-refreshing of images. netdata will send the HTTP header Refresh: SECONDS to the web browser, thus requesting automatic refresh of the images at regular intervals.

    auto will calculate the proper SECONDS to avoid unnecessary refreshes. If SECONDS is zero, this feature is disabled (it is also disabled by default).

    Auto-refreshing like this, works only if you access the badge directly. So, you may have to put it an embed or iframe for it to be auto-refreshed. Use something like this:

    <embed src="BADGE_URL" type="image/svg+xml" height="20" />

    Another way is to use javascript to auto-refresh them. You can auto-refresh all the netdata badges on a page using javascript. You have to add a class to all the netdata badges, like this <img class="netdata-badge" src="..."/>. Then add this javascript code to your page (it requires jquery):

    <script>
    var NETDATA_BADGES_AUTOREFRESH_SECONDS = 5;
    function refreshNetdataBadges() {
      var now = new Date().getTime().toString();
      $('.netdata-badge').each(function() {
        this.src = this.src.replace(/\&_=\d*/, '') + '&_=' + now;
      });
      setTimeout(refreshNetdataBadges, NETDATA_BADGES_AUTOREFRESH_SECONDS * 1000);
    }
    setTimeout(refreshNetdataBadges, NETDATA_BADGES_AUTOREFRESH_SECONDS * 1000);
    </script>

Escaping URLs

Keep in mind that if you add badge URLs to your HTML pages you have to escape the special characters:

character name escape sequence
space (in labels and units) %20
# hash (for colors) %23
% percent (in units) %25
< less than %3C
> greater than %3E
\ backslash (when you need a /) %5C
| pipe (delimiting parameters) %7C

Using the path instead of the query string

The badges can also be generated using the URL path for passing parameters. The format is exactly the same.

So instead of:

http://your.netdata:19999/api/v1/badge.svg?option1&option2&option3&...

you can write:

http://your.netdata:19999/api/v1/badge.svg/option1/option2/option3/...

You can also append anything else you like, like this:

http://your.netdata:19999/api/v1/badge.svg/option1/option2/option3/my-super-badge.svg

FAQ

Is it fast?

On modern hardware, netdata can generate about 2.000 badges per second per core, before noticing any delays. It generates a badge in about half a millisecond!

Of course these timing are for badges that use recent data. If you need badges that do calculations over long durations (a day, or more), timing will differ. netdata logs its timings at its access.log, so take a look there before adding a heavy badge on a busy web site. Of course, you can cache such badges or have a cron job get them from netdata and save them at your web server at regular intervals.

Embedding badges in github

You have 2 options a) SVG images with markdown and b) SVG images with HTML (directly in .md files).

For example, this is the cpu badge shown above:

  • Markdown example:

    [![A nice name](https://registry.my-netdata.io/api/v1/badge.svg?chart=users.cpu&dimensions=root&value_color=grey:null%7Cgreen%3C10%7Cyellow%3C20%7Corange%3C50%7Cblue%3C100%7Cred&label=root%20user%20cpu%20now&units=%25)](https://registry.my-netdata.io/#apps_cpu)
  • HTML example:

    <a href="https://registry.my-netdata.io/#apps_cpu">
    <img src="https://registry.my-netdata.io/api/v1/badge.svg?chart=users.cpu&dimensions=root&value_color=grey:null%7Cgreen%3C10%7Cyellow%3C20%7Corange%3C50%7Cblue%3C100%7Cred&label=root%20user%20cpu%20now&units=%25"></img>
    </a>

Both produce this:

auto-refreshing badges in github

Unfortunately it cannot be done. Github fetches all the images using a proxy and rewrites all the URLs to be served by the proxy.

You can refresh them from your browser console though. Press F12 to open the web browser console (switch to the console too), paste the following and press enter. They will refresh:

var len = document.images.length; while(len--) { document.images[len].src = document.images[len].src.replace(/\?cacheBuster=\d*/, "") + "?cacheBuster=" + new Date().getTime().toString(); };