Writing Pipeline steps - Help

[sohl]

I'm following https://github.com/jenkinsci/workflow-step-api-plugin/#writing-pipeline-steps

It advises the following implementation:

class MyStep extends Step {

@Extension

public static final class DescriptorImpl extends StepDescriptor {

@Override

public Set<? extends Class<?>> getRequiredContext() { return set; }

}

private static class Execution extends SynchronousNonBlockingStepExecution<Object> {

@Override

protected Object run() throws Exception { return object; }

}

@Override

public StepExecution start(StepContext context) throws Exception {

return new StepExecution(context); 

}

}

Some of the questions I'm struggling to figure out:

MyStep.start

is this method invoked automatically by Jenkins? If Yes, then

Why to use Execution when all the logic of the plugin can be done here?

MyStep.DescriptorImpl.getRequiredContext

What has to go here? Set of what classes needs to be provided?

MyStep.Execution    Note 'private static'

how is this supposed to be instantiated?.

how to pass handle of this to Jenkins?.

how to pass/get parameters from MyStep to Execution?

MyStep.Execution.run

Is this method called automatically by Jenkins (through SynchronousNonBlockingStepExecution.start)?

Note that all the existing plugins I checked so far use deprecated API, so not much help.

Advise is highly appreciated.

[sohl]

Figured out some of the questions

MyStep.start   is invoked automatically

MyStep.Execution   apparently has to be instantiated from the outer class:

@Override

public StepExecution start(StepContext context) throws Exception {

return new Execution(context);    // here also other paramters could be supplied by modifying the Execution constructor correspondingly e.g.

//  return new Execution (context, this);

}

MyStep.Execution.run is called automatically after the above instantiation.

Now the remaining problems:

MyStep.DescriptorImpl.getRequiredContext      how to implement?

With the naive implementation

Execution.run () {

     return "Run OK"

}

The following ERROR is thrown:

-------------------------------------------

Feb 23, 2017 4:07:31 PM org.jenkinsci.plugins.workflow.cps.CpsThreadGroup saveProgramIfPossible

WARNING: program state save failed

java.io.IOException: Failed to persist C:\a02_projects\jenkins\saltapi-step\work\jobs\xx_pipe\builds\11\program.dat

        at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.saveProgram(CpsThreadGroup.java:466)

        at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.saveProgram(CpsThreadGroup.java:427)

        at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.saveProgramIfPossible(CpsThreadGroup.java:415)

        at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.run(CpsThreadGroup.java:360)

        at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup.access$100(CpsThreadGroup.java:80)

        at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:240)

        at org.jenkinsci.plugins.workflow.cps.CpsThreadGroup$2.call(CpsThreadGroup.java:228)

        at org.jenkinsci.plugins.workflow.cps.CpsVmExecutorService$2.call(CpsVmExecutorService.java:64)

        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:744)

Caused by: java.io.NotSerializableException: org.jenkinsci.plugins.workflow.job.WorkflowRun

        at org.jboss.marshalling.river.RiverMarshaller.doWriteObject(RiverMarshaller.java:860)

        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.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:2433)

        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)

        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)

        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)

        at java.lang.reflect.Method.invoke(Method.java:483)

        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:452)

        ... 15 more

Caused by: an exception which occurred:

        in field build

        in field step

        in field threads

        in object org.jenkinsci.plugins.workflow.cps.CpsThreadGroup@1af4f1a7

-------------------------------------------

Suggestions?

[Jesse Glick]

On Thu, Feb 23, 2017 at 4:25 PM, sohl <mahr...@gmail.com> wrote:
> MyStep.DescriptorImpl.getRequiredContext how to implement?

For any usages of `StepContext.get(Class)` from your `StepExecution`,
list that class—unless you can handle a null return value.

> java.io.NotSerializableException: org.jenkinsci.plugins.workflow.job.WorkflowRun

Presumably you had a non-`transient` field of type `Run` somewhere. Do
not store it; use `context.get(Run.class)` whenever required.

[sohl]

That was it! Indeed I saved Run as a private variable in Execution.run. Removed and everything worked!

Thanks a lot for the help.