I'm using Spring Boot 1.4.0.RELEASE, Spring Integration 4.3.1.RELEASE, Spring Integration DSL 1.2.0.M1.
What I'm trying to do:
I'm writing an application that will read files from FTP and local file system (using inbound channel adapters), transfer the files to a local working directory (using file outbound gateways), process, then move them to a final destination (file outbound gateway/adapters).
I'm running into an issue with 'Dispatcher has no subscribers for channel' errors. I believe this probably means something in the context is broken and the Integration components are not starting. The Context itself says it is active when I debug.
My actual configuration is fairly large, so I'm not looking for someone to find the solution for me. I'm looking for some guidance on where to look and how to figure out what component is complaining.
The actual error is below.
DEBUG [integration.channel.ExecutorChannel] [task-scheduler-1] preSend on channel 'errorChannel', message: ErrorMessage [payload=org.springframework.messaging.MessageDeliveryException: Dispatcher has no subscribers for channel 'application:test.fileReadingFlow.channel#1'.
The fileReadingFlow is an InboundChannelAdapter which reads files from a directory (basically, what I asked about here. There is nothing complex in it. The adapter sends the message to a .log() handler, enriches headers, sends it to a handler (Files.outboundgateway), and finally a MessageChannel.
What I've tried:
- I've walked through the chain of
MessageChannels and things line up (no misspellings, allBeanexist). - I've added more
LoggingHandlers in thefileReadingFlowto identify where the message errors. - I've removed portions of the
fileReadingFlowto see if I could get the message farther along. - I've removed some
Components to see if I could find the problem. - I added debug logging for
org.springframework.integrationand nothing resembling an error or warning appears.
What I found was that the first time the flow tried to do something other than logging (even enrichHeaders), the Dispatcher error occurred, and the message ended up in the errorChannel. When I changed the fileReadingFlow to only read the file, log a message, and terminate with an empty Handler, I got the Dispatcher error. Thus, I'm fairly certain the issue is not with the fileReadingFlow itself.
Other than removing each Component one by one, is there a way to track down what is causing the error?
EDIT:
Source:
@Bean(name = "fileReadingFlow")
@Scope("prototype")
@Profile("test")
public IntegrationFlow testFileReadingFlow(MyEntity entity) {
return IntegrationFlows.from(s -> s.file(new File("someFolder")))
.filter(fileListFilterBuilder.buildFileListFilter(File.class))
, endpointConfigurer -> endpointConfigurer.poller(poller)
)
.log(DEBUG, "com.myco.testFileReadingFlow")
.enrichHeaders(h ->
h.header("entity", entity)
.header(FOLDER_NAME, entity.getFolder())
)
.log(DEBUG, "com.myco.testFileReadingFlow", message -> "after headers")
.handle(Files.outboundGateway("workingFolder").deleteSourceFiles(true).autoCreateDirectory(true))
.log(DEBUG, "com.myco.testFileReadingFLow", message -> "sending message to aggregatingFileChannel " + message)
.channel("aggregatingFileChannel")
.get();
}
@Bean
public MessageChannel aggregatingFileChannel() {
return MessageChannels.executor(Executors.newCachedThreadPool()).get();
}
@Bean
public IntegrationFlow aggregatingFlow() {
// Read from the aggregatingFileChannel
return from("aggregatingFileChannel")
<...>
.get();
}
Application:
@SpringBootApplication
@EnableConfigurationProperties
@EntityScan(
basePackages = { "com.myco.model" }
)
@EnableJpaRepositories(basePackages = {"com.myco.rest"})
public class Application {
public static void main(String[] args) {
ConfigurableApplicationContext context = new SpringApplicationBuilder(Application.class).web(false).run(args);
MyEntitySvc entitySvc = context.getBean(MyEntitySvc.class);
List<MyEntity> entities = entitySvc.findAllActive();
AutowireCapableBeanFactory beanFactory = context.getBeanFactory();
entities.forEach(entity -> {
IntegrationFlow flow = (IntegrationFlow) context.getBean("fileReadingFlow", entity);
beanFactory.getBean(entity.getFolder() + MyConstants.ADAPTER, Lifecycle.class).start();
}
Solution:
Per my comments below, the @Prototype method did work at some point, but I broke it and could not easily rollback the change. Using Gary and Artem's suggestions, I tried changed to using the IntegrationFlowContext method. In order to retain the runtime startup, profile driven injection, etc. I had originally, I moved the definition of my IntegrationFlow from a @Configuration class to a @Service class. That way I can inject the IntegrationFlowContext into the Service, and implement different versions of the Service for my different profiles without requiring my Application to know about the Profile. The main method goes from extracting a Bean from Context and manually starting it to retrieving a Service and calling a method.
@Service
@Profile("test")
public class TestFlowSvc implements FlowSvc {
public IntegrationFlow testFileReadingFlow(Vendor vendor) {
return // As previous Flow
}
public void startFileReadingFlow(MyEntity entity) {
IntegrationFlow flow = testFileReadingFlow(entity);
integrationFlowContext.register(flow, true);
}
}
Application:
@SpringBootApplication
@EnableConfigurationProperties
@EntityScan(
basePackages = { "com.myco.model" }
)
@EnableJpaRepositories(basePackages = {"com.myco.rest"})
public class Application {
public static void main(String[] args) {
ConfigurableApplicationContext context = new SpringApplicationBuilder(Application.class).web(false).run(args);
MyEntitySvc entitySvc = context.getBean(MyEntitySvc.class);
FlowSvc flowSvc = context.getBean(FlowSvc.class);
List<MyEntity> entities = entitySvc.findAllActive();
entities.forEach(entity -> {
flowSvc.startFileReadingFlow(entity);
}
