No handler was subscribed to command. Axon 3.3 - spring-boot

Question

I'm attempting to create basic Axon/Spring application by tutorial, but faced with strange error like: NoHandlerForCommandException: No handler was subscribed to command. It seems that Axon can't see #CommandHandler annotation.
Here my files:
aggregate
#Aggregate
#NoArgsConstructor
public class Account {
#AggregateIdentifier
private UUID accountId;
private Double balance;
#CommandHandler
public Account(CreateAccountCommand command) {
apply(new AccountCreatedEvent(command.getAccountId(), command.getName()));
}
#EventSourcingHandler
protected void on(AccountCreatedEvent event) {
this.accountId = event.getAccountId();
this.balance = 0.0;
}
}
event
#AllArgsConstructor
#Getter
public class AccountCreatedEvent {
private UUID accountId;
private String name;
}
command
#Getter
public class CreateAccountCommand {
#TargetAggregateIdentifier
private UUID accountId;
private String name;
public CreateAccountCommand(UUID accountId, String name) {
this.accountId = accountId;
this.name = name;
}
}
spring boot conf
#SpringBootApplication
public class App {
#Configuration
public static class TestConfiguration {
#Bean
public EventStorageEngine inMemoryEventStorageEngine() {
return new InMemoryEventStorageEngine();
}
}
public static void main(String[] args) {
SpringApplication.run(App.class, args);
}
}
this is how i send cmd
#Component
public class AppLoader {
#Autowired
private CommandGateway cmdGateway;
#PostConstruct
public void init() {
cmdGateway.send(new CreateAccountCommand(UUID.randomUUID(), "test"));
}
}
my build.gradle
buildscript {
ext {
springBootVersion = '2.0.5.RELEASE'
}
repositories {
mavenCentral()
}
dependencies {
classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
}
}
apply plugin: 'java'
apply plugin: 'eclipse'
apply plugin: 'org.springframework.boot'
apply plugin: 'io.spring.dependency-management'
group = 'io.yourpoint.nettnews'
version = '0.0.1-SNAPSHOT'
sourceCompatibility = 1.8
repositories {
mavenCentral()
}
dependencies {
testCompile group: 'org.axonframework', name: 'axon-test', version: '3.3.5'
compile group: 'org.axonframework', name: 'axon-spring-boot-starter', version: '3.3.5'
compile('org.springframework.boot:spring-boot-starter-webflux')
compileOnly('org.projectlombok:lombok')
testCompile('org.springframework.boot:spring-boot-starter-test')
testCompile('io.projectreactor:reactor-test')
}

Answer 1

It is very likely that performing the CommandGateway#send() call in a #PostConstruct is to early for Axon..
As it currently stands, all the command, event and query handlers typically get registered after all your beans have been initialized.
Moving the CommandGateway#send() behind a REST endpoint should give you a big enough time frame to ensure all the handlers have been registered.
So in short, it's a timing issues why you get the NoHandlerForCommandException.
We (at AxonIQ) see benefit in sending some sort of application events as soon as all the handlers have been registered. That's a thing for the future though.
Hope this helps you out #Benjamin!