Yes, we look a bit at osgi but seems overkill for what we need. I can understand our simple implementation and seems to work for now. A more complex framework will require more time and is not even clear that is the right solution. Next JDK will support modular loading so it is probably a good idea to wait if we can. Let's see if this works for what we need and we can revisit later. However, if you have a good alternative to suggest alternatives, please do so.
Our requirements are very constrained because we only need to load subclasses of App. This seems to simplify the problem quite a bit. Because apps have their own CL, we can easily de-reference the loaded app and have the CL + loaded classes get GCed. This seems to satisfies our loading/unloading of apps requirement. For inter-app communication we only use the EventSource API. -leo On Oct 24, 2011, at 11:35 AM, kishore g wrote: > I know you have tried lot of alternatives for dynamic app/module deployment. > Just wanted to confirm if we tried Apache Felix. > > On Mon, Oct 24, 2011 at 11:00 AM, Leo Neumeyer <[email protected]>wrote: > >> Nice! >> >> any thoughts on what will it take to include the dependent jars in the s4r >> package? >> >> talk tomorrow, >> -leo >> >> On Oct 24, 2011, at 10:29 AM, Matthieu Morel wrote: >> >>> Hi, >>> >>> I had a look into that, and the solution boils down to using the same >>> classloader for classes loaded from s4r archives and for classes >> dynamically >>> generated. >>> The JarLoader needs a small modification to handle that. >>> It is now possible to load several apps concurrently, including apps from >>> the s4-example subproject. >>> >>> I'll share my changes tomorrow so we can discuss and see what the next >> steps >>> are. >>> >>> Matthieu >>> >>> >>> On Sun, Oct 23, 2011 at 4:53 AM, Leo Neumeyer <[email protected]> >> wrote: >>> >>>> I made some progress getting the app to load. The problem was a >>>> missing no-args constructor to get the newInstance method to work. >>>> (Apps will be required to have a no-args constructor.) Once the app >>>> starts, there is an exception because the CounterPE is not found. It >>>> looks like a conflict between dynamic app loading and dynamic >>>> dispatching. More debugging needed, here is the trace: >>>> >>>> comm.module=org.apache.s4.comm.Module >>>> s4.logger_level=TRACE >>>> comm.queue_emmiter_size=8000 >>>> comm.queue_listener_size=8000 >>>> cluster.hosts=localhost >>>> cluster.ports=5077 >>>> cluster.lock_dir=/tmp >>>> cluster.isCluster=true >>>> 19:43:53.281 [main] TRACE org.apache.s4.core.Server - Read: >>>> >>>> >> file:/Users/leo/Projects/s4project/s4-piper/subprojects/s4-core/bin/apps/CounterExample.s4r >>>> 19:43:53.297 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: >>>> org.apache.s4.example.counter.MyApp, resolveIt: true >>>> 19:43:53.297 [main] DEBUG o.a.s4.base.util.MultiClassLoader - Not a >>>> system class. >>>> 19:43:53.297 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: org.apache.s4.core.App, >>>> resolveIt: true >>>> 19:43:53.298 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.298 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning newly loaded class. >>>> 19:43:53.298 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: org.apache.s4.core.KeyFinder, >>>> resolveIt: true >>>> 19:43:53.298 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.299 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: java.lang.Throwable, >>>> resolveIt: true >>>> 19:43:53.299 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.299 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: >>>> java.lang.InterruptedException, resolveIt: true >>>> 19:43:53.299 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.303 [main] INFO org.apache.s4.comm.topology.Cluster - Added >>>> cluster node: localhost:5077 >>>> 19:43:53.336 [main] INFO o.a.s.c.topology.AssignmentFromFile - Host >>>> Name: 10.0.1.97 >>>> 19:43:53.336 [main] INFO o.a.s.c.topology.AssignmentFromFile - >>>> Partition available: true >>>> 19:43:53.352 [main] INFO o.a.s.c.topology.AssignmentFromFile - >>>> Partition acquired by PID:16610 HOST:Leos-MacBook-Air.local Lock File >>>> location: /tmp/s4-0.lock >>>> 19:43:53.352 [main] INFO o.a.s.c.topology.AssignmentFromFile - >>>> Acquire partition:success. >>>> 19:43:53.354 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: >>>> org.apache.s4.example.counter.PrintPE, resolveIt: true >>>> 19:43:53.355 [main] DEBUG o.a.s4.base.util.MultiClassLoader - Not a >>>> system class. >>>> 19:43:53.355 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: >>>> org.apache.s4.core.ProcessingElement, resolveIt: true >>>> 19:43:53.356 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.356 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning newly loaded class. >>>> 19:43:53.359 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: java.lang.Object, resolveIt: >>>> true >>>> 19:43:53.359 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.360 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: org.apache.s4.base.Event, >>>> resolveIt: true >>>> 19:43:53.360 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.401 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: >>>> org.apache.s4.example.counter.CountKeyFinder, resolveIt: true >>>> 19:43:53.401 [main] DEBUG o.a.s4.base.util.MultiClassLoader - Not a >>>> system class. >>>> 19:43:53.402 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning newly loaded class. >>>> 19:43:53.402 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: java.util.List, resolveIt: >>>> true >>>> 19:43:53.402 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.404 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: >>>> org.apache.s4.example.counter.CounterPE, resolveIt: true >>>> 19:43:53.404 [main] DEBUG o.a.s4.base.util.MultiClassLoader - Not a >>>> system class. >>>> 19:43:53.404 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning newly loaded class. >>>> 19:43:53.404 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: >>>> org.apache.s4.example.counter.CountEvent, resolveIt: true >>>> 19:43:53.405 [main] DEBUG o.a.s4.base.util.MultiClassLoader - Not a >>>> system class. >>>> 19:43:53.405 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning newly loaded class. >>>> 19:43:53.405 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: org.apache.s4.core.Stream, >>>> resolveIt: true >>>> 19:43:53.405 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.407 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: java.util.concurrent.TimeUnit, >>>> resolveIt: true >>>> 19:43:53.408 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.413 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: >>>> org.apache.s4.example.counter.UserIDKeyFinder, resolveIt: true >>>> 19:43:53.414 [main] DEBUG o.a.s4.base.util.MultiClassLoader - Not a >>>> system class. >>>> 19:43:53.414 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning newly loaded class. >>>> 19:43:53.414 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: >>>> org.apache.s4.example.counter.GenderKeyFinder, resolveIt: true >>>> 19:43:53.415 [main] DEBUG o.a.s4.base.util.MultiClassLoader - Not a >>>> system class. >>>> 19:43:53.415 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning newly loaded class. >>>> 19:43:53.415 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: >>>> org.apache.s4.example.counter.AgeKeyFinder, resolveIt: true >>>> 19:43:53.416 [main] DEBUG o.a.s4.base.util.MultiClassLoader - Not a >>>> system class. >>>> 19:43:53.416 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning newly loaded class. >>>> 19:43:53.416 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: >>>> org.apache.s4.example.counter.GenerateUserEventPE, resolveIt: true >>>> 19:43:53.417 [main] DEBUG o.a.s4.base.util.MultiClassLoader - Not a >>>> system class. >>>> 19:43:53.417 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: >>>> org.apache.s4.core.SingletonPE, resolveIt: true >>>> 19:43:53.417 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.418 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning newly loaded class. >>>> 19:43:53.418 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: >>>> org.apache.s4.example.counter.UserEvent, resolveIt: true >>>> 19:43:53.418 [main] DEBUG o.a.s4.base.util.MultiClassLoader - Not a >>>> system class. >>>> 19:43:53.418 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning newly loaded class. >>>> 19:43:53.418 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: java.lang.String, resolveIt: >>>> true >>>> 19:43:53.418 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.420 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: java.util.Random, resolveIt: >>>> true >>>> 19:43:53.420 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.420 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: java.util.ArrayList, >>>> resolveIt: true >>>> 19:43:53.420 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.420 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: java.lang.Character, >>>> resolveIt: true >>>> 19:43:53.420 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.421 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: java.lang.Integer, resolveIt: >>>> true >>>> 19:43:53.421 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.423 [User Stream] TRACE org.apache.s4.core.ProcessingElement >>>> - OnCreateInternal >>>> 19:43:53.423 [Gender Stream] TRACE >>>> org.apache.s4.core.ProcessingElement - OnCreateInternal >>>> 19:43:53.423 [Age Stream] TRACE org.apache.s4.core.ProcessingElement - >>>> OnCreateInternal >>>> 19:43:53.428 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: java.lang.Thread, resolveIt: >>>> true >>>> 19:43:53.428 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:53.430 [Gender Stream] TRACE >>>> org.apache.s4.core.ProcessingElement - Num PE instances: 0. >>>> 19:43:53.430 [User Stream] TRACE org.apache.s4.core.ProcessingElement >>>> - Num PE instances: 0. >>>> 19:43:53.430 [Age Stream] TRACE org.apache.s4.core.ProcessingElement - >>>> Num PE instances: 0. >>>> Exception in thread "Age Stream" java.lang.NoClassDefFoundError: >>>> org/apache/s4/example/counter/CounterPE >>>> at OverloadDispatcher847.dispatchEvent(Unknown Source) >>>> at >>>> >> org.apache.s4.core.ProcessingElement.handleInputEvent(ProcessingElement.java:376) >>>> at org.apache.s4.core.Stream.run(Stream.java:272) >>>> at java.lang.Thread.run(Thread.java:680) >>>> Caused by: java.lang.ClassNotFoundException: >>>> org.apache.s4.example.counter.CounterPE >>>> at java.net.URLClassLoader$1.run(URLClassLoader.java:202) >>>> at java.security.AccessController.doPrivileged(Native Method) >>>> at java.net.URLClassLoader.findClass(URLClassLoader.java:190) >>>> at java.lang.ClassLoader.loadClass(ClassLoader.java:306) >>>> at java.lang.ClassLoader.loadClass(ClassLoader.java:247) >>>> ... 4 more >>>> Exception in thread "Gender Stream" java.lang.NoClassDefFoundError: >>>> org/apache/s4/example/counter/CounterPE >>>> at OverloadDispatcher3022.dispatchEvent(Unknown Source) >>>> at >>>> >> org.apache.s4.core.ProcessingElement.handleInputEvent(ProcessingElement.java:376) >>>> at org.apache.s4.core.Stream.run(Stream.java:272) >>>> at java.lang.Thread.run(Thread.java:680) >>>> Caused by: java.lang.ClassNotFoundException: >>>> org.apache.s4.example.counter.CounterPE >>>> at java.net.URLClassLoader$1.run(URLClassLoader.java:202) >>>> at java.security.AccessController.doPrivileged(Native Method) >>>> at java.net.URLClassLoader.findClass(URLClassLoader.java:190) >>>> at java.lang.ClassLoader.loadClass(ClassLoader.java:306) >>>> at java.lang.ClassLoader.loadClass(ClassLoader.java:247) >>>> ... 4 more >>>> Exception in thread "User Stream" java.lang.NoClassDefFoundError: >>>> org/apache/s4/example/counter/CounterPE >>>> at OverloadDispatcher2958.dispatchEvent(Unknown Source) >>>> at >>>> >> org.apache.s4.core.ProcessingElement.handleInputEvent(ProcessingElement.java:376) >>>> at org.apache.s4.core.Stream.run(Stream.java:272) >>>> at java.lang.Thread.run(Thread.java:680) >>>> Caused by: java.lang.ClassNotFoundException: >>>> org.apache.s4.example.counter.CounterPE >>>> at java.net.URLClassLoader$1.run(URLClassLoader.java:202) >>>> at java.security.AccessController.doPrivileged(Native Method) >>>> at java.net.URLClassLoader.findClass(URLClassLoader.java:190) >>>> at java.lang.ClassLoader.loadClass(ClassLoader.java:306) >>>> at java.lang.ClassLoader.loadClass(ClassLoader.java:247) >>>> ... 4 more >>>> 19:43:58.429 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: java.lang.System, resolveIt: >>>> true >>>> 19:43:58.429 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> 19:43:58.429 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> MultiClassLoader loadClass - className: java.io.PrintStream, >>>> resolveIt: true >>>> 19:43:58.429 [main] DEBUG o.a.s4.base.util.MultiClassLoader - >>>> Returning system class (in CLASSPATH). >>>> Done. Closing... >>>> Bye. >>>> 19:43:58.430 [Age Count Stream] INFO org.apache.s4.core.Stream - >>>> Closing stream Age Count Stream. >>>> 19:43:58.430 [Gender Count Stream] INFO org.apache.s4.core.Stream - >>>> Closing stream Gender Count Stream. >>>> 19:43:58.430 [User Count Stream] INFO org.apache.s4.core.Stream - >>>> Closing stream User Count Stream. >>>> >>>> >>>> >>>> On Tue, Oct 18, 2011 at 11:00 PM, Leo Neumeyer <[email protected]> >>>> wrote: >>>>> Matthieu, please check my *modules* branch. >>>>> I packaged the counter example in a *.s4r file (a jar with a different >>>>> extension name). Here is how: >>>>> https://github.com/leoneu/s4-piper/blob/modules/NOTES.md >>>>> I fixed the code so we can read the jar as a resource from the >> classpath. >>>>> The HelloApp example works fine but there is an exception when trying >> to >>>>> load the counter app. The MyApp class should load as is, I think. You >>>> will >>>>> probably find the bug by the time I wake up :-) The good side of being >> 9 >>>>> time zones apart. >>>>> -leo >>>>> >>>> >>>> >>>> >>>> -- >>>> >>>> -leo >>>> >> >>
