Parsing an XML file within a Jenkins pipeline - jenkins

Question

Note:
I posted this question back when I only had a master node in my Jenkins environment. This made serialization a lesser issue as there were no other nodes to communicate with, thus the code here will not run as expected on a multi-node environment (for instance, readFile will only read files from the master node).
In my experience it's better to have your configuration written in other formats (JSON, YAML, Groovy which are all supported natively in Jenkins), or use external tools (such as xmllint on Linux) if you don't have control over the file's format.
Original question:
I have an XML file which I'd like to use as input for a pipeline script. Problem is the XMLParser isn't serializable so I put it in a NonCPS function, but I lost the Node object because of that.
This is the pipeline script:
def buildPlanPath = 'C:\\buildPlan_test.xml'
#NonCPS
groovy.util.Node getBuildPlan(path) {
new XmlParser().parseText(readFile(path))
}
node {
//def buildPlan = new XmlParser().parseText(readFile(buildPlanPath))
groovy.util.Node buildPlan = getBuildPlan(buildPlanPath)
println buildPlan.getClass()
println buildPlan
println buildPlan.branch
}
This is an input sample:
<branch name='mybranch'>
<stage>
<job name='job11' />
<job name='job12' />
</stage>
<stage>
<job name='job21' />
<job name='job22' />
<job name='job23' />
</stage>
<stage>
<job name='job31' />
</stage>
</branch>
This is the result:
Started by user admin
[Pipeline] node
Running on master in C:\Jenkins\workspace\pipeline-develop
[Pipeline] {
[Pipeline] readFile
[Pipeline] echo
class java.lang.String
[Pipeline] echo
<branch name='mybranch'>
<stage>
<job name='job11' />
<job name='job12' />
</stage>
<stage>
<job name='job21' />
<job name='job22' />
<job name='job23' />
</stage>
<stage>
<job name='job31' />
</stage>
</branch>
[Pipeline] }
[Pipeline] // node
[Pipeline] End of Pipeline
groovy.lang.MissingPropertyException: No such property: branch for class: java.lang.String
at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.unwrap(ScriptBytecodeAdapter.java:53)
at org.codehaus.groovy.runtime.ScriptBytecodeAdapter.getProperty(ScriptBytecodeAdapter.java:458)
at com.cloudbees.groovy.cps.sandbox.DefaultInvoker.getProperty(DefaultInvoker.java:25)
at com.cloudbees.groovy.cps.impl.PropertyAccessBlock.rawGet(PropertyAccessBlock.java:17)
at WorkflowScript.run(WorkflowScript:16)
at ___cps.transform___(Native Method)
at com.cloudbees.groovy.cps.impl.PropertyishBlock$ContinuationImpl.get(PropertyishBlock.java:62)
at com.cloudbees.groovy.cps.LValueBlock$GetAdapter.receive(LValueBlock.java:30)
at com.cloudbees.groovy.cps.impl.PropertyishBlock$ContinuationImpl.fixName(PropertyishBlock.java:54)
at sun.reflect.GeneratedMethodAccessor327.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.cloudbees.groovy.cps.impl.ContinuationPtr$ContinuationImpl.receive(ContinuationPtr.java:72)
at com.cloudbees.groovy.cps.impl.ConstantBlock.eval(ConstantBlock.java:21)
at com.cloudbees.groovy.cps.Next.step(Next.java:58)
at com.cloudbees.groovy.cps.Continuable.run0(Continuable.java:154)
at org.jenkinsci.plugins.workflow.cps.CpsThread.runNextChunk(CpsThread.java:164)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.run(CpsThreadGroup.java:276)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.access$000(CpsThreadGroup.java:78)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:185)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:183)
at org.jenkinsci.plugins.workflow.cps.CpsVmExecutorService$2.call(CpsVmExecutorService.java:47)
at java.util.concurrent.FutureTask.run(Unknown Source)
at hudson.remoting.SingleLaneExecutorService$1.run(SingleLaneExecutorService.java:112)
at jenkins.util.ContextResettingExecutorService$1.run(ContextResettingExecutorService.java:28)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Finished: FAILURE
I'm using Jenkins 2.7 with pipeline 2.1, which are currently the latest.

Answer 1

You could use XmlSlurper, it works for me.
def xmlText = new XmlSlurper().parse(MyURL)
xmlText.data.artifact.each {******

Answer 2

As branch is the root element, you don't need to explicitly specify it when accessing your parsed nodes
Try changing
println buildPlan.branch
To
println buildPlan.stage
To print out the stage nodes

Answer 3

A #NonCPS method should only accept or return Serializable types. Try returning .branch from the method.

Answer 4

May I recommend a shared library. That will allow you to
centralize logic
write unit tests - via jenkins pipeline unit and perhaps Spock
use this kind of approach
Src dir
class PipelineSupport {
PipelineSupport(def env, def jenkinsStepAccess) {
this.env = env
this.jenkinsStepAccess = jenkinsStepAccess
}
def readXml(def path) {
def text = jenkinsStepAccess.readFile(path)
def parser = new XmlParser()
def xml = parser.parseText(text.toString())
return xml
}
}
vars dir var/foo.groovy
import ...PipelineSupport
Map readXml(def path) {
// pass env and "this" access point to jenkins DSL to calls
return new PipelineSupport(env, this).readXml(path)
}
use in a build
library "mylib"
def xmlData = foo.readXml('path/to/bar.xml')

Answer 5

In the end I think my approach was wrong: I decided to convert the XML file into a separate groovy script and load it within the pipeline
Update: Recently people started editing my answer for clarity, but the fact is that I just ditched storing my configuration in XML files and opted for groovy scripts, which gave me more flexibility. I understand it may not be a common practice, but it suits my needs.
For example - instead of:
config.xml:
<settings>
<floopi>2</floopi>
</settings>
I used:
config.groovy:
[
floopi: 2
]
And in the pipeline script:
stage('init') {
def settings = load('config.groovy')
echo "floopi: ${settings.floopi}"
}
I hope that's a better answer :)