No httpclient implementations found on the context classloader in Groovy 3.0.11 in JMeter 5.5

Describe the bug

Below is my code where I am trying to get the list of pods from the default namespace in Groovy 3.0.11 in JMeter 5.5.

But it is throwing the No httpclient implementations found on the context classloader, please ensure your classpath includes an implementation jar error. Please see the below error for more details.

import io.fabric8.kubernetes.client.KubernetesClient;
import io.fabric8.kubernetes.client.KubernetesClientBuilder;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@Grab(group='io.fabric8', module='kubernetes-client', version='6.0.0-RC1')
@Grab(group='io.fabric8', module='knative-client', version='6.0.0-RC1')
@Grab(group='io.fabric8', module='kubernetes-client-api', version='6.0.0-RC1')
@Grab(group='org.slf4j', module='slf4j-api', version='2.0.0-alpha7')

Logger logger = LoggerFactory.getLogger(this.class);

KubernetesClient k8s = new KubernetesClientBuilder().build()

k8s.pods().inNamespace("default").list().getItems()
.forEach(pod ->
        println pod.getMetadata().getName()
)

Error

javax.script.ScriptException: io.fabric8.kubernetes.client.KubernetesClientException: An error has occurred.
javax.script.ScriptException: io.fabric8.kubernetes.client.KubernetesClientException: An error has occurred.
	at org.codehaus.groovy.jsr223.GroovyScriptEngineImpl.eval(GroovyScriptEngineImpl.java:320) ~[groovy-jsr223-3.0.11.jar:3.0.11]
	at org.codehaus.groovy.jsr223.GroovyCompiledScript.eval(GroovyCompiledScript.java:71) ~[groovy-jsr223-3.0.11.jar:3.0.11]
	at javax.script.CompiledScript.eval(CompiledScript.java:93) ~[java.scripting:?]
	at org.apache.jmeter.util.JSR223TestElement.processFileOrScript(JSR223TestElement.java:217) ~[ApacheJMeter_core.jar:5.5]
	at org.apache.jmeter.protocol.java.sampler.JSR223Sampler.sample(JSR223Sampler.java:72) ~[ApacheJMeter_java.jar:5.5]
	at org.apache.jmeter.threads.JMeterThread.doSampling(JMeterThread.java:651) ~[ApacheJMeter_core.jar:5.5]
	at org.apache.jmeter.threads.JMeterThread.executeSamplePackage(JMeterThread.java:570) ~[ApacheJMeter_core.jar:5.5]
	at org.apache.jmeter.threads.JMeterThread.processSampler(JMeterThread.java:501) ~[ApacheJMeter_core.jar:5.5]
	at org.apache.jmeter.threads.JMeterThread.run(JMeterThread.java:268) ~[ApacheJMeter_core.jar:5.5]
	at java.lang.Thread.run(Thread.java:833) ~[?:?]
Caused by: io.fabric8.kubernetes.client.KubernetesClientException: An error has occurred.
	at io.fabric8.kubernetes.client.KubernetesClientException.launderThrowable(KubernetesClientException.java:103) ~[?:?]
	at io.fabric8.kubernetes.client.KubernetesClientException.launderThrowable(KubernetesClientException.java:97) ~[?:?]
	at io.fabric8.kubernetes.client.KubernetesClientBuilder.build(KubernetesClientBuilder.java:76) ~[?:?]
	at io.fabric8.kubernetes.client.KubernetesClientBuilder$build.call(Unknown Source) ~[?:?]
	at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:47) ~[groovy-3.0.11.jar:3.0.11]
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125) ~[groovy-3.0.11.jar:3.0.11]
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:130) ~[groovy-3.0.11.jar:3.0.11]
	at Script7.run(Script7.groovy:13) ~[?:?]
	at org.codehaus.groovy.jsr223.GroovyScriptEngineImpl.eval(GroovyScriptEngineImpl.java:317) ~[groovy-jsr223-3.0.11.jar:3.0.11]
	... 9 more
Caused by: java.lang.reflect.InvocationTargetException
	at jdk.internal.reflect.DirectConstructorHandleAccessor.newInstance(DirectConstructorHandleAccessor.java:79) ~[?:?]
	at java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499) ~[?:?]
	at java.lang.reflect.Constructor.newInstance(Constructor.java:483) ~[?:?]
	at io.fabric8.kubernetes.client.KubernetesClientBuilder.build(KubernetesClientBuilder.java:69) ~[?:?]
	at io.fabric8.kubernetes.client.KubernetesClientBuilder$build.call(Unknown Source) ~[?:?]
	at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:47) ~[groovy-3.0.11.jar:3.0.11]
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125) ~[groovy-3.0.11.jar:3.0.11]
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:130) ~[groovy-3.0.11.jar:3.0.11]
	at Script7.run(Script7.groovy:13) ~[?:?]
	at org.codehaus.groovy.jsr223.GroovyScriptEngineImpl.eval(GroovyScriptEngineImpl.java:317) ~[groovy-jsr223-3.0.11.jar:3.0.11]
	... 9 more
Caused by: io.fabric8.kubernetes.client.KubernetesClientException: No httpclient implementations found on the context classloader, please ensure your classpath includes an implementation jar
	at io.fabric8.kubernetes.client.utils.HttpClientUtils.createHttpClient(HttpClientUtils.java:171) ~[?:?]
	at io.fabric8.kubernetes.client.DefaultKubernetesClient.<init>(DefaultKubernetesClient.java:153) ~[?:?]
	at jdk.internal.reflect.DirectConstructorHandleAccessor.newInstance(DirectConstructorHandleAccessor.java:67) ~[?:?]
	at java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499) ~[?:?]
	at java.lang.reflect.Constructor.newInstance(Constructor.java:483) ~[?:?]
	at io.fabric8.kubernetes.client.KubernetesClientBuilder.build(KubernetesClientBuilder.java:69) ~[?:?]
	at io.fabric8.kubernetes.client.KubernetesClientBuilder$build.call(Unknown Source) ~[?:?]
	at org.codehaus.groovy.runtime.callsite.CallSiteArray.defaultCall(CallSiteArray.java:47) ~[groovy-3.0.11.jar:3.0.11]
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:125) ~[groovy-3.0.11.jar:3.0.11]
	at org.codehaus.groovy.runtime.callsite.AbstractCallSite.call(AbstractCallSite.java:130) ~[groovy-3.0.11.jar:3.0.11]
	at Script7.run(Script7.groovy:13) ~[?:?]
	at org.codehaus.groovy.jsr223.GroovyScriptEngineImpl.eval(GroovyScriptEngineImpl.java:317) ~[groovy-jsr223-3.0.11.jar:3.0.11]
	... 9 more

Fabric8 Kubernetes Client version

6.0.0-RC1

Steps to reproduce

1. import the fabric8 directives
2. Execute the above code in JMeter 5.5, which has Groovy 3.0.11
3. Exceptions can be seen.

Expected behavior

No errors.

Runtime

Kubernetes (vanilla)

Kubernetes API Server version

other (please specify in additional context)

Environment

Windows, Linux, other (please specify in additional context)

Fabric8 Kubernetes Client Logs

No response

Additional context

• tried in 5.12.2 as well, same issue

[iocanel]

In other words, yeah I think that the issue will be solved by leveraging TCL / current class classloader.

[manusa]

I’m testing this with Groovy (4.0.3 ), and it works for me.

Tested Script:

@Grab(group='io.fabric8', module='kubernetes-client', version='6.0.0-RC1')
@Grab(group='io.fabric8', module='kubernetes-client-api', version='6.0.0-RC1')

import io.fabric8.kubernetes.client.KubernetesClient
import io.fabric8.kubernetes.client.KubernetesClientBuilder

try (KubernetesClient client = new KubernetesClientBuilder().build()) {

    client.pods().inNamespace("default").list().getItems()
        .forEach(pod ->
            println pod.getMetadata().getName()
        )
}

The same script on JMeter fails. However, note that JMeter is using Groovy 3.0.11. I’m not sure if the classloader issues are caused by the groovy engine or JMeter itself when invoking the scripts.