NDepend Status Badges

How I used C# and Maui.Graphics to generate status badges for NDepend static analysis metrics

October 17, 2021

csharp maui

Many project websites and readmes have status badges that display build status, project details, or code metrics. badgen.net and shields.io are popular services for dynamically generating status badges as SVG files using HTTP requests. This article demonstrates how I use C# and Microsoft.Maui.Graphics to build status badges from NDepend static analysis reports. Source code for this project is available on GitHub.

NDepend Trend Data XML

NDepend can analyze a code base at different points in time and display code metric trends. See NDepend: Trend Monitoring for a full description. These metrics are stored in an XML file available in the HTML build folder.

Metric Index

The XML file contains many Root/MetricIndex/Metric elements that describe each metric and its units. This can be parsed to obtain the Name and Unit for each metric.

<Root>
  <MetricIndex>
    <Metric Name="# New Issues since Baseline" Unit="issues" />
    <Metric Name="# Issues Fixed since Baseline" Unit="issues" />
    <Metric Name="# Issues Worsened since Baseline" Unit="issues" />
    <Metric Name="# Issues with severity Blocker" Unit="issues" />
    <Metric Name="# Issues with severity Critical" Unit="issues" />
    <Metric Name="# Issues with severity High" Unit="issues" />
    <Metric Name="# Issues with severity Medium" Unit="issues" />
    ...
  </MetricIndex>
</Root>

Metrics by DateTime

The XML file contains multiple Root/M/R elements that contain the value of each metric at a distinct time point. Numerical metrics have been converted to strings separated by the | character. Metric values for each time point are in the same order as the metric index.

<Root>
  <M>
    <R D="10/16/2021 11:58:04 AM" V="0|0|0|0|1|598|2177|...|19|133" />
    <R D="10/03/2021 04:15:24 PM" V="0|0|0|0|1|593|2160|...|19|132" />
	...
  </M>
</Root>

Read NDepend Trend XML with C#

To read timestamped metrics from the NDepend XML I started by creating a C# record to hold an individual timestamped metric:

public record Metric
{
    public DateTime DateTime { get; init; }
    public string Name { get; init; }
    public string Unit { get; init; }
    public string Value { get; init; }
}

I then reached for using System.Xml.Linq and using System.Xml.XPath to extract a big list of timestamped metrics from the NDepend XML file:

Metric[] GetMetricsFromXML(string xmlFilePath)
{
    XDocument doc = XDocument.Load(xmlFilePath);
    List<Metric> baseMetrics = new();
    foreach (var el in doc.XPathSelectElement("/Root/MetricIndex").Elements())
    {
        string name = el.Attribute("Name").Value;
        string unit = el.Attribute("Unit").Value;
        baseMetrics.Add(new Metric() { Name = name, Unit = unit });
    }

    List<Metric> allMetrics = new();
    foreach (var runElement in doc.XPathSelectElement("/Root/M").Elements())
    {
        DateTime runDateTime = DateTime.Parse(runElement.Attribute("D").Value);
        string[] values = runElement.Attribute("V").Value.Split("|");

        List<Metric> runMetrics = new();
        for (int i = 0; i < baseMetrics.Count; i++)
            runMetrics.Add(baseMetrics[i] with { DateTime = runDateTime, Value = values[i] });

        allMetrics.AddRange(runMetrics);
    }

    return allMetrics.ToArray();
}

I found it convenient to make a helper function to get only the latest metrics:

Metric[] GetLatestMetrics(Metric[] metrics)
{
    DateTime latestDateTime = metrics.Select(x => x.DateTime).Distinct().OrderBy(x => x).Last();
    return metrics.Where(x => x.DateTime == latestDateTime).ToArray();
}

Generate NDepend Status Badges

I’ve already written how to make status badges with C# and Maui.Graphics, but that strategy only generates PNG files. For this project I also chose to generate SVG files. Rather than discuss that in detail, I’ll just show to the source code for an example SVG file.

It is important to note that in order to know the image width I must measure the string width. In HTML environments this could be done with vanilla Javascript, but in a C# environment I reached for Microsoft.Maui.Graphics (see how to MeasureString() with Maui.Graphics).

<svg xmlns='http://www.w3.org/2000/svg'
    xmlns:xlink='http://www.w3.org/1999/xlink' width='237' height='20' role='img' aria-label='languages: 5'>
    <title>Average # Lines of Code for Types: 25.96</title>
    <linearGradient id='s' x2='0' y2='100%'>
        <!-- linear gradient to use for the background shadow -->
        <stop offset='0' stop-color='#bbb' stop-opacity='.1'/>
        <stop offset='1' stop-opacity='.1'/>
    </linearGradient>
    <clipPath id='r'>
        <!-- clip to a rectangle with rounded edges -->
        <rect width='237' height='20' rx='3' fill='#fff'/>
    </clipPath>
    <g clip-path='url(#r)'>
        <!-- left background -->
        <rect width='195' height='20' fill='#555'/>
        <!-- right background -->
        <rect x='195' width='42' height='20' fill='#007ec6'/>
        <!-- background shadow -->
        <rect width='237' height='20' fill='url(#s)'/>
    </g>
    <g fill='#FFF' text-anchor='center' font-family='Verdana,Geneva,DejaVu Sans,sans-serif' text-rendering='geometricPrecision' font-size='110'>
        <!-- left text semitransparent shadow then white text -->
        <text aria-hidden='true' x='40' y='150' fill='#010101' fill-opacity='.3' transform='scale(.1)' textLength='1854'>Average # Lines of Code for Types</text>
        <text x='40' y='140' transform='scale(.1)' fill='#FFF' textLength='1854'>Average # Lines of Code for Types</text>
        <!-- right text semitransparent shadow then white text -->
        <text aria-hidden='true' x='1994' y='150' fill='#010101' fill-opacity='.3' transform='scale(.1)' textLength='300'>25.96</text>
        <text x='1994' y='140' transform='scale(.1)' fill='#FFF' textLength='300'>25.96</text>
    </g>
</svg>