yq can parse XML, including JaCoCo coverage reports

2026-03-06 (7m ago)13 views

I wanted a quick way to print JaCoCo coverage numbers from the terminal without opening the HTML report or writing a Python script. I knew yq handles YAML and JSON but wasn't sure about XML — turns out it does, with -p xml.

JaCoCo generates target/site/jacoco/jacoco.xml after a test run. The root <report> element has a bunch of <counter> children with type, covered, and missed attributes. To get coverage percentages:

yq -p xml -oy '.report.counter[] | . as $r |
  ($r."+@covered" | tonumber) as $c |
  ($r."+@missed" | tonumber) as $m |
  $r."+@type" + ": " + ($c | tostring) + "/" + (($c + $m) | tostring) + " (" + (($c * 100 / ($c + $m)) | tostring | split(".")[0]) + "%)"' \
  target/site/jacoco/jacoco.xml

Output:

INSTRUCTION: 14913/17724 (84%)
BRANCH: 1027/1516 (67%)
LINE: 3068/3585 (85%)
COMPLEXITY: 809/1227 (65%)
METHOD: 408/460 (88%)
CLASS: 83/91 (91%)

A few things worth noting:

XML attributes are accessed with the "+@attrname" syntax in yq — the + prefix and quotes are required
-p xml sets the input format, -oy forces YAML output (without it yq warns about format ambiguity since the file ends in .xml)
tonumber is needed because all attribute values come in as strings
I truncate the decimal with split(".")[0] since yq doesn't have a floor or round built-in (at least not one I could find)

I wrapped this plus ./mvnw test -q into a script at ~/.local/bin/jacoco so I can just run jacoco from any Maven project root.