Cassandra integration seems to crash the agent when driver not available

[fmonniot]

Hello there,

I tried to update my kamon-bundle to version 2.1.2 and in doing so I encounter the error java.lang.NoClassDefFoundError: com/datastax/driver/core/Session (complete stack trace below) on startup. As my application does not use Cassandra, it seems pretty logical that the class was not found. It's less logical that kanela try to load it by default :)

Complete stack trace

Unable to start Kanela Agent. Please remove -javaagent from your startup arguments and contact Kanela support.:
java.lang.NoClassDefFoundError: com/datastax/driver/core/Session
	at kamon.instrumentation.cassandra.driver.DriverInstrumentation.<init>(DriverInstrumentation.scala:35)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500)
	at java.base/java.lang.reflect.ReflectAccess.newInstance(ReflectAccess.java:166)
	at java.base/jdk.internal.reflect.ReflectionFactory.newInstance(ReflectionFactory.java:404)
	at java.base/java.lang.Class.newInstance(Class.java:591)
	at kanela.agent.InstrumentationLoader.lambda$loadInstrumentation$b85f757d$1(InstrumentationLoader.java:58)
	at kanela.agent.libs.io.vavr.control.Try.of(Try.java:75)
	at kanela.agent.InstrumentationLoader.loadInstrumentation(InstrumentationLoader.java:56)
	at kanela.agent.InstrumentationLoader.lambda$null$1(InstrumentationLoader.java:46)
	at kanela.agent.libs.io.vavr.collection.List.flatMap(List.java:898)
	at kanela.agent.InstrumentationLoader.lambda$load$4(InstrumentationLoader.java:46)
	at kanela.agent.libs.io.vavr.collection.List.map(List.java:1038)
	at kanela.agent.InstrumentationLoader.load(InstrumentationLoader.java:43)
	at kanela.agent.Kanela.lambda$null$0(Kanela.java:79)
	at kanela.agent.util.classloader.InstrumentationClassPath.use(InstrumentationClassPath.java:84)
	at kanela.agent.Kanela.lambda$start$1(Kanela.java:68)
	at kanela.agent.util.Execution.timed(Execution.java:32)
	at kanela.agent.util.Execution.runWithTimeSpent(Execution.java:41)
	at kanela.agent.Kanela.start(Kanela.java:67)
	at kanela.agent.Kanela.agentmain(Kanela.java:54)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:567)
	at java.instrument/sun.instrument.InstrumentationImpl.loadClassAndStartAgent(InstrumentationImpl.java:513)
	at java.instrument/sun.instrument.InstrumentationImpl.loadClassAndCallAgentmain(InstrumentationImpl.java:535)
Caused by: java.lang.ClassNotFoundException: com.datastax.driver.core.Session
	at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:602)
	at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:521)
	at kamon.instrumentation.cassandra.driver.DriverInstrumentation.<init>(DriverInstrumentation.scala:35)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500)
	at java.base/java.lang.reflect.ReflectAccess.newInstance(ReflectAccess.java:166)
	at java.base/jdk.internal.reflect.ReflectionFactory.newInstance(ReflectionFactory.java:404)
	at java.base/java.lang.Class.newInstance(Class.java:591)
	at kanela.agent.InstrumentationLoader.lambda$loadInstrumentation$b85f757d$1(InstrumentationLoader.java:58)
	at kanela.agent.libs.io.vavr.control.Try.of(Try.java:75)
	at kanela.agent.InstrumentationLoader.loadInstrumentation(InstrumentationLoader.java:56)
	at kanela.agent.InstrumentationLoader.lambda$null$1(InstrumentationLoader.java:46)
	at kanela.agent.libs.io.vavr.collection.List.flatMap(List.java:898)
	at kanela.agent.InstrumentationLoader.lambda$load$4(InstrumentationLoader.java:46)
	at kanela.agent.libs.io.vavr.collection.List.map(List.java:1038)
	at kanela.agent.InstrumentationLoader.load(InstrumentationLoader.java:43)
	at kanela.agent.Kanela.lambda$null$0(Kanela.java:79)
	at kanela.agent.util.classloader.InstrumentationClassPath.use(InstrumentationClassPath.java:84)
	at kanela.agent.Kanela.lambda$start$1(Kanela.java:68)
	at kanela.agent.util.Execution.timed(Execution.java:32)
	at kanela.agent.util.Execution.runWithTimeSpent(Execution.java:41)
	at kanela.agent.Kanela.start(Kanela.java:67)
	at kanela.agent.Kanela.agentmain(Kanela.java:54)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:567)
	at java.instrument/sun.instrument.InstrumentationImpl.loadClassAndStartAgent(InstrumentationImpl.java:513)
	at java.instrument/sun.instrument.InstrumentationImpl.loadClassAndCallAgentmain(InstrumentationImpl.java:535) 

[fmonniot]

Thanks for the quick fix !