Add a utility to prune junit xml files

Signed-off-by: Davanum Srinivas <davanum@gmail.com>

cmd/prune-junit-xml/prunexml.go

@@ -0,0 +1,145 @@
+/*
+Copyright 2022 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"encoding/xml"
+	"flag"
+	"io"
+	"os"
+)
+
+// JUnitTestSuites is a collection of JUnit test suites.
+type JUnitTestSuites struct {
+	XMLName xml.Name         `xml:"testsuites"`
+	Suites  []JUnitTestSuite `xml:"testsuite"`
+}
+
+// JUnitTestSuite is a single JUnit test suite which may contain many
+// testcases.
+type JUnitTestSuite struct {
+	XMLName    xml.Name        `xml:"testsuite"`
+	Tests      int             `xml:"tests,attr"`
+	Failures   int             `xml:"failures,attr"`
+	Time       string          `xml:"time,attr"`
+	Name       string          `xml:"name,attr"`
+	Properties []JUnitProperty `xml:"properties>property,omitempty"`
+	TestCases  []JUnitTestCase `xml:"testcase"`
+	Timestamp  string          `xml:"timestamp,attr"`
+}
+
+// JUnitTestCase is a single test case with its result.
+type JUnitTestCase struct {
+	XMLName     xml.Name          `xml:"testcase"`
+	Classname   string            `xml:"classname,attr"`
+	Name        string            `xml:"name,attr"`
+	Time        string            `xml:"time,attr"`
+	SkipMessage *JUnitSkipMessage `xml:"skipped,omitempty"`
+	Failure     *JUnitFailure     `xml:"failure,omitempty"`
+}
+
+// JUnitSkipMessage contains the reason why a testcase was skipped.
+type JUnitSkipMessage struct {
+	Message string `xml:"message,attr"`
+}
+
+// JUnitProperty represents a key/value pair used to define properties.
+type JUnitProperty struct {
+	Name  string `xml:"name,attr"`
+	Value string `xml:"value,attr"`
+}
+
+// JUnitFailure contains data related to a failed test.
+type JUnitFailure struct {
+	Message  string `xml:"message,attr"`
+	Type     string `xml:"type,attr"`
+	Contents string `xml:",chardata"`
+}
+
+func main() {
+	maxTextSize := flag.Int("max-text-size", 1, "maximum size of attribute or text (in MB)")
+	flag.Parse()
+
+	if flag.NArg() > 0 {
+		for _, path := range flag.Args() {
+			xmlReader, err := os.Open(path)
+			if err != nil {
+				panic(err)
+			}
+			defer xmlReader.Close()
+			suites, err := fetchXML(xmlReader) // convert MB into bytes (roughly!)
+			if err != nil {
+				panic(err)
+			}
+
+			pruneXML(suites, *maxTextSize*1e6) // convert MB into bytes (roughly!)
+
+			xmlWriter, err := os.OpenFile(path, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0666)
+			if err != nil {
+				panic(err)
+			}
+			defer xmlWriter.Close()
+			err = streamXML(xmlWriter, suites)
+			if err != nil {
+				panic(err)
+			}
+		}
+	}
+}
+
+func pruneXML(suites *JUnitTestSuites, maxBytes int) {
+	for _, suite := range suites.Suites {
+		for _, testcase := range suite.TestCases {
+			if testcase.SkipMessage != nil {
+				if len(testcase.SkipMessage.Message) > maxBytes {
+					testcase.SkipMessage.Message = "[... clipped...]" +
+						testcase.SkipMessage.Message[len(testcase.SkipMessage.Message)-maxBytes:]
+				}
+			}
+			if testcase.Failure != nil {
+				if len(testcase.Failure.Contents) > maxBytes {
+					testcase.Failure.Contents = "[... clipped...]" +
+						testcase.Failure.Contents[len(testcase.Failure.Contents)-maxBytes:]
+				}
+			}
+		}
+	}
+}
+
+func fetchXML(xmlReader io.Reader) (*JUnitTestSuites, error) {
+	decoder := xml.NewDecoder(xmlReader)
+	var suites JUnitTestSuites
+	err := decoder.Decode(&suites)
+	if err != nil {
+		return nil, err
+	}
+	return &suites, nil
+}
+
+func streamXML(writer io.Writer, in *JUnitTestSuites) error {
+	_, err := writer.Write([]byte("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n"))
+	if err != nil {
+		return err
+	}
+	encoder := xml.NewEncoder(writer)
+	encoder.Indent("", "\t")
+	err = encoder.Encode(in)
+	if err != nil {
+		return err
+	}
+	return encoder.Flush()
+}