"java.io.NotSerializableException: java.io.PrintWriter" when writing file - jenkins workflow

Question

We have a piece of workflow code that does these things:

1 Loads some files from disk

2.Renders their contents using a SimpleTemplateEngine and bindings

3.Writes their result to another files.

def renderTemplates(binding) {
  //stage "Render templates"
  sh "find $infraDir/*.tpl -printf '%f\n' > result"
  def files = readFile('result').split('\n')
  println("Found tpl files -> $files")
  sh "rm result"  //Remove the result file

  for(int i=0; i<files.size(); i++){
    def tpl = files[i]
    println("Process tpl file ${tpl}")
    renderTemplate(readFile("${infraDir}/${tpl}"), tpl, binding)
  }
}

@NonCPS
def renderTemplate(String input,String tpl, binding){
  def template = new groovy.text.SimpleTemplateEngine().createTemplate(input).make(binding)
  def rendered = template.toString()
  def newFileName = "$infraDir/${tpl.replaceFirst(/\.tpl$/, "")}"
  //sh "echo ${rendered} > ${newFileName}" //--> GIVES ERROR
  writeFile file: newFileName, text: rendered // --> ERROR AS WELL
}

However, the workflow fails everytime with this error:

java.io.NotSerializableException: java.io.PrintWriter
at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:860)
at org.jboss.marshalling.river.BlockMarshaller.doWriteObject(BlockMarshaller.java:65)
at org.jboss.marshalling.river.BlockMarshaller.writeObject(BlockMarshaller.java:56)
at org.jboss.marshalling.MarshallerObjectOutputStream.writeObjectOverride(MarshallerObjectOutputStream.java:50)
at org.jboss.marshalling.river.RiverObjectOutputStream.writeObjectOverride(RiverObjectOutputStream.java:179)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:344)
at java.util.LinkedHashMap.internalWriteEntries(LinkedHashMap.java:333)
at java.util.HashMap.writeObject(HashMap.java:1354)
at sun.reflect.GeneratedMethodAccessor97.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.jboss.marshalling.reflect.SerializableClass.callWriteObject(SerializableClass.java:271)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:976)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:967)
at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
at org.jboss.marshalling.river.BlockMarshaller.doWriteObject(BlockMarshaller.java:65)
at org.jboss.marshalling.river.BlockMarshaller.writeObject(BlockMarshaller.java:56)
at org.jboss.marshalling.MarshallerObjectOutputStream.writeObjectOverride(MarshallerObjectOutputStream.java:50)
at org.jboss.marshalling.river.RiverObjectOutputStream.writeObjectOverride(RiverObjectOutputStream.java:179)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:344)
at java.util.HashMap.internalWriteEntries(HashMap.java:1777)
at java.util.HashMap.writeObject(HashMap.java:1354)
at sun.reflect.GeneratedMethodAccessor97.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.jboss.marshalling.reflect.SerializableClass.callWriteObject(SerializableClass.java:271)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:976)
at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
at org.jboss.marshalling.river.RiverMarshaller.doWriteFields(RiverMarshaller.java:1032)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:988)
at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
at org.jboss.marshalling.river.RiverMarshaller.doWriteFields(RiverMarshaller.java:1032)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:988)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:967)
at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
at org.jboss.marshalling.river.RiverMarshaller.doWriteFields(RiverMarshaller.java:1032)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:988)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:967)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:967)
at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
at org.jboss.marshalling.river.RiverMarshaller.doWriteFields(RiverMarshaller.java:1032)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:988)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:967)
at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
at org.jboss.marshalling.river.RiverMarshaller.doWriteFields(RiverMarshaller.java:1032)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:988)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:967)
at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
at org.jboss.marshalling.river.RiverMarshaller.doWriteFields(RiverMarshaller.java:1032)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:988)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:967)
at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
at org.jboss.marshalling.river.RiverMarshaller.doWriteFields(RiverMarshaller.java:1032)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:988)
at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
at org.jboss.marshalling.river.BlockMarshaller.doWriteObject(BlockMarshaller.java:65)
at org.jboss.marshalling.river.BlockMarshaller.writeObject(BlockMarshaller.java:56)
at org.jboss.marshalling.MarshallerObjectOutputStream.writeObjectOverride(MarshallerObjectOutputStream.java:50)
at org.jboss.marshalling.river.RiverObjectOutputStream.writeObjectOverride(RiverObjectOutputStream.java:179)
at java.io.ObjectOutputStream.writeObject(ObjectOutputStream.java:344)
at java.util.TreeMap.writeObject(TreeMap.java:2434)
at sun.reflect.GeneratedMethodAccessor394.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.jboss.marshalling.reflect.SerializableClass.callWriteObject(SerializableClass.java:271)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:976)
at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
at org.jboss.marshalling.river.RiverMarshaller.doWriteFields(RiverMarshaller.java:1032)
at org.jboss.marshalling.river.RiverMarshaller.doWriteSerializableObject(RiverMarshaller.java:988)
at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:854)
at org.jboss.marshalling.AbstractObjectOutput.writeObject(AbstractObjectOutput.java:58)
at org.jboss.marshalling.AbstractMarshaller.writeObject(AbstractMarshaller.java:111)
at org.jenkinsci.plugins.workflow.support.pickles.serialization.RiverWriter.writeObject(RiverWriter.java:132)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.saveProgram(CpsThreadGroup.java:371)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.saveProgram(CpsThreadGroup.java:355)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.run(CpsThreadGroup.java:309)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.access$000(CpsThreadGroup.java:77)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:186)
at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:184)
at org.jenkinsci.plugins.workflow.cps.CpsVmExecutorService$2.call(CpsVmExecutorService.java:47)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
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(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: an exception which occurred:
in field locals
in field parent
in field parent
in field parent
in field caller
in field e
in field program
in field threads
in object org.jenkinsci.plugins.workflow.cps.CpsThreadGroup@5fc05e47
Finished: FAILURE

I tried using sh to echo to a file, but that fails too. Tried removing @NonCPS, that too an error.

If I comment out the writeFile and sh lines, the workflow succeeds, but obviously the file is not written.

Not sure what I am doing wrong.

Any advice?

Answer 1

You can use org.apache.commons.lang3.text.StrSubstitutor instead, e.g :

// vars/tokenize.groovy

def call(String text, Map binding) {
    _tokenize(text, binding)
}

@NonCPS
def _tokenize(String text, Map binding){
    def engine = new org.apache.commons.lang3.text.StrSubstitutor(binding)
    def s = engine.replace(text)
    engine = null
    return s
}

// in Jenkinsfile or another .groovy

def binding = [:]
binding.veggie = 'Carrot'

def text = "${veggie}"

writeFile file: 'veggie.txt', text: tokenize(text, binding)