Corda - Passing Anonymous Implementations Over RPC - corda

Is it possible to pass anonymous object implementations over Corda's RPC interface? - For example:
Workflow
#CordaSerializable
interface ExampleInterface {
val number: Int
}
#StartableByRPC
class SquareFlow(private val example: ExampleInterface) : FlowLogic<Int>() {
#Suspendable
override fun call(): Int = example.number * example.number
}
RPC Client
val value = object : ExampleInterface {
override val number: Int = 5
}
return rpc.startFlowDynamic(SquareFlow::class.java, value).returnValue.getOrThrow()
Exception
net.corda.client.rpc.RPCException: java.util.List<*> -> Unable to create an object serializer for type class com.example.client.ExampleService$square$value$1: No unique deserialization constructor can be identified
Either annotate a constructor for this type with #ConstructorForDeserialization, or provide a custom serializer for it
Whilst this is an example, what I actually want to do is pass object : TypeReference<SomeType>(){} over RPC.

As per Corda's docs anonymous objects are not supported by their AMQP
serialization which is used in the RPC client which you can read here. This is likely due to a public constructor being needed for serialization and deserialization I imagine.
Additionally I assume you are referencing Jackson's TypeReference class which uses generics which are only available at compile time. Due to how Corda's serialization works the generic won't be available at runtime so when the TypeReference is passed from the rpc application to the corda node the corda node will not know what the generic is. I haven't tried this myself but I believe some exception will be thrown whenever the flow attempts to suspend or possibly before in the RPC client.
You can probably pass a jackson JavaType class to a flow without a problem as I believe it is whitelisted as serializable in Corda by default, if not look at how to whitelist the class here using the SerializationWhitelist. You can obtain the JavaType by instantiating a TypeFactory and calling constructType(new TypeReference<SomeType> {}). then just pass the JavaType to your flows constructor.

Related

Vimeo Networking Library Crash for Android 10 platform (api29)

I implemented vimeo networking using vimeo networking library(https://github.com/vimeo/vimeo-networking-java), exoplayer and explained in this post https://stackoverflow.com/a/65737556/8814924
Now the problem is when I was checking with API 30 it was getting error
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.emergingit.emergingstudy/com.emergingit.emergingstudy.activities.course.ExoPlayerActivity}: java.lang.IllegalStateException: Unable to extract the trust manager on Android10Platform, sslSocketFactory is class com.android.org.conscrypt.OpenSSLSocketFactoryImpl
Caused by: java.lang.IllegalStateException: Unable to extract the trust manager on Android10Platform, sslSocketFactory is class com.android.org.conscrypt.OpenSSLSocketFactoryImpl
which indicates the error on
VimeoClient.initialize(configuration);
which issue is dicscussed here : https://github.com/square/okhttp/issues/5878 , issue discussion :
I assume you are calling the deprecated form of sslSocketFactory, which is broken on newer Android versions. https://github.com/square/okhttp/blob/master/okhttp/src/main/java/okhttp3/OkHttpClient.kt#L719
/**
* Sets the socket factory used to secure HTTPS connections. If unset, the system default will
* be used.
*
* #deprecated [SSLSocketFactory] does not expose its [X509TrustManager], which is a field that
* OkHttp needs to build a clean certificate chain. This method instead must use reflection
* to extract the trust manager. Applications should prefer to call
* `sslSocketFactory(SSLSocketFactory, X509TrustManager)`, which avoids such reflection.
*/
#Deprecated(
message = "Use the sslSocketFactory overload that accepts a X509TrustManager.",
level = DeprecationLevel.ERROR
)
fun sslSocketFactory(sslSocketFactory: SSLSocketFactory) = apply {
if (sslSocketFactory != this.sslSocketFactoryOrNull) {
this.routeDatabase = null
}
this.sslSocketFactoryOrNull = sslSocketFactory
this.certificateChainCleaner = Platform.get().buildCertificateChainCleaner(sslSocketFactory)
}
is there any solution possible with using the current version "1.1.3" of networking library for this or I have to wait till the library update ?
I primarily Solved the problem for Vimeo video streaming on the Android 10 platform using the Vimeo-Networking library (v1.1.3).
as the main problem is in the OkHttpClient build method
builder.sslSocketFactory(sSLSocketFactory);
//RetrofitClientBuilder.java#186
where with 1 parameter version is depricated and I needed to pass X509TTrustManager as 2nd parameter like this :
builder.sslSocketFactory(sSLSocketFactory, new X509TrustManager() {
#Override
public void checkClientTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {
}
#Override
public void checkServerTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {
}
#Override
public X509Certificate[] getAcceptedIssuers() {
return new X509Certificate[0];
}
});
So it solved my problem till this update comes in the stable version of this library. How I implemented this is described below :
Error was showing on VimeoClient.initialize(accessToken); line and I searched about the error and find out that it is caused because of this OkHttpClient method deprecation (with 1 parameter).
So I went into VimeoClient.java and saw in its constructor private Retrofit createRetrofit() was called and inside it private OkHttpClient createOkHttpClient() was called. and there public class RetrofitClientBuilder object was created and it's problemetic method was public OkHttpClient build() in which : if (sSLSocketFactory != null) { builder.sslSocketFactory(sSLSocketFactory); }
this deprecated method was called.
So I just had to create 2 new java file with name VimeoClientUpdated.java and RetrofitClientBuilderUpdated.java which is just a renamed copy of VimeoClient.java and RetrofitClientBuilder.java and now my RetrofitClientBuilderUpdated.java has no deprecated method rather the correct and VimeoClientUpdated.java is calling RetrofitClientBuilderUpdated.java
(I couldn't extend because of the final class and couldn't even wrap the class as to the gateway to that solution, I had to face the private method which wasn't possible to alter in wrapper class)
and finally just instead of calling VimeoClient.initialize(accessToken) I am calling my newly created VimeoClientUpdated(accessToken) which won't crash while playing Vimeo video on Android 10.
Suggest me if there is a better way of serving my purpose (solving deprecated library method calling from the android activity).
Cheers..!!

Spring Cloud Stream Kafka : How to access recordMetadata of kafka headers after producing a message to a kafka topic

I want get the offset and partition information after i produce a message to kafka topic.
I read through spring cloud stream kafka binding document and found that that can be achieved by fecthing RECORD_METADATA kafka header.
From Spring documentation: (https://cloud.spring.io/spring-cloud-static/spring-cloud-stream-binder-kafka/3.0.0.RELEASE/reference/html/spring-cloud-stream-binder-kafka.html#kafka-producer-properties)
recordMetadataChannel
The bean name of a MessageChannel to which successful send results should be sent; the bean must exist in the application context. The message sent to the channel is the sent message (after conversion, if any) with an additional header KafkaHeaders.RECORD_METADATA. The header contains a RecordMetadata object provided by the Kafka client; it includes the partition and offset where the record was written in the topic.
ResultMetadata meta = sendResultMsg.getHeaders().get(KafkaHeaders.RECORD_METADATA, RecordMetadata.class)
I have configured my output topic bean name as message channel in the property file
spring.cloud.stream.kafka.bindings.acknowledgement-out.producer.record-metadata-channel = acknowledgement-out
my customized interface and producer class as below:
public interface OutputAcknowledgement {
#Output("acknowledgement-out")
MessageChannel output();
}
Producer class:
#EnableBinding(OutputAcknowledgement.class)
public class AcknowledgementProducer {
#Autowired
OutputAcknowledgement outputAcknowledgement;
public Boolean produce(Acknowledgement acknowledgement) {
Message msg = MessageBuilder.withPayload(acknowledgement).build();
boolean val = outputAcknowledgement.output().send(msg);
RecordMetadata recordMetadata = msg.getHeaders().get(KafkaHeaders.RECORD_METADATA, RecordMetadata.class);
Getting null for recordMetadata.
Please suggest whether my approach is correct?
You're getting null because it doesn't exist in that message object at the time you're accessing it. According to the docs the metadata is only provided after successful publish. See this answer on how to get record metadata by providing a handler/consumer for the record metadata channel.

JpaSagaStore in conjunction with Jackson unable to properly store state

In a SpringBoot application, I have the following configuration:
axon:
axonserver:
servers: "${AXON_SERVER:localhost}"
serializer:
general: jackson
messages: jackson
events: jackson
logging.level:
org.axonframework.modelling.saga: debug
Downsizing the scenario to bare minimum, the relevant portion of Saga class:
#Slf4j
#Saga
#ProcessingGroup("AuctionEventManager")
public class AuctionEventManagerSaga {
#Autowired
private transient EventScheduler eventScheduler;
private ScheduleToken scheduleToken;
private Instant auctionTimerStart;
#StartSaga
#SagaEventHandler(associationProperty = "auctionEventId")
protected void on(final AuctionEventScheduled event) {
this.auctionTimerStart = event.getTimerStart();
// Cancel any pre-existing previous job, since the scheduling thread might be lost upon a crash/restart of JVM.
if (this.scheduleToken != null) {
this.eventScheduler.cancelSchedule(this.scheduleToken);
}
this.scheduleToken = this.eventScheduler.schedule(
this.auctionTimerStart,
AuctionEventStarted.builder()
.auctionEventId(event.getAuctionEventId())
.build()
);
}
#EndSaga
#SagaEventHandler(associationProperty = "auctionEventId")
protected void on(final AuctionEventStarted event) {
log.info(
"[AuctionEventManagerSaga] Current state: {scheduleToken={}, auctionTimerStart={}}",
this.scheduleToken,
this.auctionTimerStart
);
}
}
In the final compiled class, we will end up having 4 properties: log (from #Slf4j), eventScheduler (transient, #Autowired), scheduleToken and auctionTimerStart.
For reference information, here is a sample of the general approach I've been using for both Command and Event classes:
#Value
#Builder
#JsonDeserialize(builder = AuctionEventStarted.AuctionEventStartedBuilder.class)
public class AuctionEventStarted {
AuctionEventId auctionEventId;
#JsonPOJOBuilder(withPrefix = "")
public static final class AuctionEventStartedBuilder {}
}
When executing the code, you get the following output:
2020-05-12 15:40:01.180 DEBUG 1 --- [mandProcessor-4] o.a.m.saga.repository.jpa.JpaSagaStore : Updating saga id c8aff7f7-d47f-4616-8a96-a40044cb7e3b as {}
As soon as the general serializer is changed to xstream, the content is serialized properly, but I face another issue during deserialization, since I have private static final class Builder classes using Lombok.
So is there a way for Axon to handle these scenarios:
1- Axon to safely manage Jackson to ignore #Autowired, transient and static properties from #Saga classes? I've attempted to manually define #JsonIgnore at non-state properties and it still didn't work.
2- Axon to safely configure XStream to ignore inner classes (mostly Builder classes implemented as private static final)?
Thanks in advance,
EDIT: I'm pursuing a resolution using my preferred serializer: JSON. I attempted to modify the saga class and extend JsonSerializer<AuctionEventManagerSaga>. For that I implemented the methods:
#Override
public Class<AuctionEventManagerSaga> handledType() {
return AuctionEventManagerSaga.class;
}
#Override
public void serialize(
final AuctionEventManagerSaga value,
final JsonGenerator gen,
final SerializerProvider serializers
) throws IOException {
gen.writeStartObject();
gen.writeObjectField("scheduleToken", value.eventScheduler);
gen.writeObjectField("auctionTimerStart", value.auctionTimerStart);
gen.writeEndObject();
}
Right now, I have something being serialized, but it has nothing to do with the properties I've defined:
2020-05-12 16:20:01.322 DEBUG 1 --- [mandProcessor-0] o.a.m.saga.repository.jpa.JpaSagaStore : Storing saga id c4b5d94c-7251-40a5-accf-332768b1cacd as {"delegatee":null,"unwrappingSerializer":false}
EDIT 2 Decided to add more insight into the issue I experience when I switch general to use XStream (even though it's somewhat unrelated to the main issue described in the title).
Here is the issue it complains to me:
2020-05-12 17:08:06.495 DEBUG 1 --- [ault-executor-0] o.a.a.c.command.AxonServerCommandBus : Received command response [message_identifier: "79631ffb-9a87-4224-bed3-a957730dced7"
error_code: "AXONIQ-4002"
error_message {
message: "No converter available\n---- Debugging information ----\nmessage : No converter available\ntype : jdk.internal.misc.InnocuousThread\nconverter : com.thoughtworks.xstream.converters.reflection.ReflectionConverter\nmessage[1] : Unable to make field private static final jdk.internal.misc.Unsafe jdk.internal.misc.InnocuousThread.UNSAFE accessible: module java.base does not \"opens jdk.internal.misc\" to unnamed module #7728643a\n-------------------------------"
location: "1#600b5b87a922"
details: "No converter available\n---- Debugging information ----\nmessage : No converter available\ntype : jdk.internal.misc.InnocuousThread\nconverter : com.thoughtworks.xstream.converters.reflection.ReflectionConverter\nmessage[1] : Unable to make field private static final jdk.internal.misc.Unsafe jdk.internal.misc.InnocuousThread.UNSAFE accessible: module java.base does not \"opens jdk.internal.misc\" to unnamed module #7728643a\n-------------------------------"
}
request_identifier: "2f7020b1-f655-4649-bbe0-d6f458b3c2f3"
]
2020-05-12 17:08:06.505 WARN 1 --- [ault-executor-0] o.a.c.gateway.DefaultCommandGateway : Command 'ACommandClassDispatchedFromSaga' resulted in org.axonframework.commandhandling.CommandExecutionException(No converter available
---- Debugging information ----
message : No converter available
type : jdk.internal.misc.InnocuousThread
converter : com.thoughtworks.xstream.converters.reflection.ReflectionConverter
message[1] : Unable to make field private static final jdk.internal.misc.Unsafe jdk.internal.misc.InnocuousThread.UNSAFE accessible: module java.base does not "opens jdk.internal.misc" to unnamed module #7728643a
-------------------------------)
Still no luck on resolving this...
I've worked on Axon systems where the only used Serializer implementation was the JacksonSerializer too. Mind you though, this is not what the Axon team recommends. For messages (i.e. commands, events and queries) it makes perfect sense to use JSON as the serialized format. But switching the general Serializer to jackson means you have to litter your domain logic (e.g. your Saga) with Jackson specifics "to make it work".
Regardless, backtracking to my successful use case of jackson-serialized-sagas. In this case we used the correct match of JSON annotations on the fields we desired to take into account (the actual state) and to ignore the one's we didn't want deserialized (with either transient or #JsonIgnore). Why both do not seem to work in your scenario is not entirely clear at this stage.
What I do recall is that the referenced project's team very clearly decided against Lombok due to "overall weirdnes" when it comes to de-/serialization. As a trial it thus might be worth to not use any Lombok annotations/logic in the Saga class and see if you can de-/serialize it correctly in such a state.
If it does work at that moment, I think you have found your culprit for diving in further search.
I know this isn't an exact answer, but I hope it helps you regardless!
Might be worthwhile to share the repository where this problems occurs in; might make the problem clearer for others too.
I was able to resolve the issue #2 when using XStream as general serializer.
One of the Sagas had an #Autowired dependency property that was not transient.
XStream was throwing some cryptic message, but we managed to track the problem and address it.
As for JSON support, we had no luck. We ended up switched everything to XStream for now, as the company only uses Java and it would be ok to decode the events using XStream.
Not the greatest solution, as we really wanted (and hoped) JSON would be supported properly out of the box. Mind you, this is in conjunction with using Lombok which caused for the nuisance in this case.

How to prevent Corda Service auto-initialisation in MockNetwork flow tests?

As of Corda 2.0, constructors of classes annotated with #CordaService are automatically invoked during node start. Corda Service original class implementations may, for example, initialise network connections in their constructors, which may not be desirable in unit tests.
My current workaround is to use a boolean flag (set from an environment variable) that marks whether to run or skip Corda Service initialisation code. Is there a better way to do this (e.g. inject a mock Corda Service class instance into MockNetwork.MockNode without using PowerMock and the like)?
Your workaround is currently the best way to handle this. See https://r3-cev.atlassian.net/browse/CORDA-989.
In your approach, you might define your service as follows:
#CordaService
class MyService(services: ServiceHub) : SingletonSerializeAsToken() {
private companion object {
val logger = loggerFor<MyService>()
val load = System.getenv("enable-my-service")
}
init {
if (load == "false") {
logger.warn("Not loading service")
} else {
logger.info("Loading service")
}
}
}
And then you can toggle your service off in tests using an environment variable.

JBoss AS 7, EJB3 cast to interface

I'm facing weird behavior with JBoss AS 7 and my application which uses EJB3.1.
I successfully lookup bean but when Im trying to cast it to its interface, exception is thrown.
Code in short:
#Local
public interface BusinessObjectsFactory { ... }
#Stateless
#Local(BusinessObjectsFactory.class)
public class JPABusinessObjectsFactory implements BusinessObjectsFactory { ... }
...
Object obj = ctx.lookup("java:app/moduleName/" +
"JPABusinessObjectsFactory!pckg.BusinessObjectsFactory");
Class c = obj.getClass();
System.out.println(c.getName()); // pckg.BusinessObjectsFactory$$$view36
System.out.println(c.getInterfaces()[0].getName()); // BusinessObjectsFactory
BusinessObjectsFactory bof = (BusinessObjectsFactory) obj; //cast exception
Any ideas? Note that interface is needed (which implementation is looked up is read from configuration file and might change)
I switched to another lookup strategy while this is no longer issue for me. I'm not sure if this is still present in newest versions of JBoss/Wildfly AS. That's why I'm closing this question.

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