Error Handling

[amin]

Hi

I am currently trying to work on an error handling mechanism using Spring Integration. I have defined the following error handling and I was wondering if I could get some input on whether it is the correct way of doing it. Essentially when an error occurs I would like to send an email. Any help would be appreciated:

 	
 	<channel id="errorChannel">
     <queue capacity="500"/>
 	</channel>
	
	<beans:bean id="errorTransformer" class="com.amin.app.index.integration.transformer.ErrorTransformer"/>
	
	<chain input-channel="errorChannel">
		<transformer ref="errorTransformer" method="transformError" />
		<service-activator ref="errorHandler" method="sendEmail" />
	</chain>
	
	<beans:bean id="errorHandler" class="com.amin.app.index.integration.error.handling.ErrorHandler">
		<beans:constructor-arg ref="mailSender" />
	</beans:bean>
 	
	<!-- Mail sending error -->

	<beans:bean id="mailSender" class="org.springframework.mail.javamail.JavaMailSenderImpl">
  		<beans:property name="host" value="localhost" />
  		<beans:property name="port" value="22" />
	</beans:bean>

Also I was wondering whether I should use the mail support from Spring Integration rather than creating a service activator. I wasn't sure how to configure the error handling with the mail support (I was using the sample from the distribution).

[Mark Fisher]

I think what you're doing makes sense. You might consider using a synchronous hand-off for the errorChannel (i.e. no queue) but there's a tradeoff in that case: the original thread that created the error will block for the mail-sending, but less likely to result in lost error messages.

You could use the outbound-channel-adapter in the Spring Integration mail module. It basically expects a MailMessage or String as its payload. In the simplest case, you can just pass a String and then add some headers as necessary with the mail namespace's 'header-enricher' element.

[amin]

Thanks Mark for your response. I have updated accordingly and have the following (which works):

<channel id="errorChannel" />
 	
 	<channel id="errorOutChannel" />
	
	<beans:bean id="errorTransformer" class="com.amin.app.index.integration.transformer.ErrorTransformer"/>
	
	<chain input-channel="errorChannel" output-channel="errorOutChannel">
		<transformer ref="errorTransformer" method="transformError" />
	</chain>
	
	<!-- Mail sending error -->
	<mail:outbound-channel-adapter channel="errorOutChannel" mail-sender="mailSender" />

Cheers

[amin]

Hi again

I've been looking back at what i've done and decided to make some improvements to the error mail handling. I decided to add a header-enricher rather than adding to the mail creation class. However the error handling does not seem to work. I was wondering if someone could tell me whether I am on the right path:

<chain input-channel="errorChannel" output-channel="errorOutChannel">
		<transformer ref="errorTransformer" method="transformError" />
        <mail:header-enricher from="${mailFrom}" to="{mailTo}" subject="${mail.subject}" overwrite="false" />

	</chain>

Should it be:

<channel id="errorChannel" />
 	
 	<channel id="errorOutChannel" />

    <channel id="errorMailOutChannel" />
	
	<beans:bean id="errorTransformer" class="com.amin.luceneindexsi.index.integration.transformer.ErrorTransformer" />
        
	
	<chain input-channel="errorChannel" output-channel="errorOutChannel">
		<transformer ref="errorTransformer" method="transformError" />

	</chain>

     <mail:header-enricher from="${mailFrom}" to="{mailTo}" subject="${mail.subject}" overwrite="false" input-channel="errorOutChannel" output-channel="errorMailOutChannel"/>

	<!-- Mail sending error -->
	<mail:outbound-channel-adapter channel="errorMailOutChannel" mail-sender="mailSender" />

Any help would be appreciated.

Cheers

[Mark Fisher]

If you copied this directly, it looks like you are missing the $ for your "mailTo" value.

[amin]

Hi Mark

oh boy so sorry for posting that mistake! Thanks for pointing out user error.

Cheers

amin

[Mark Fisher]

No problem. If that's all that was causing you trouble, then I'm happy.

Cheers,
Mark

[amin]

Hi Mark

Unfortunately it is still not working. I have done:

<chain input-channel="errorChannel" output-channel="errorOutChannel">
		<transformer ref="errorTransformer" method="transformError" />

     </chain>

       <mail:header-enricher from="${mailFrom}" to="${mailTo}" subject="${mail.subject}" overwrite="false" input-channel="errorOutChannel" output-channel="errorMailOutChannel"/>
	<!-- Mail sending error -->
	<mail:outbound-channel-adapter channel="errorMailOutChannel" mail-sender="mailSender" />

and tried

	<beans:bean id="errorTransformer" class="com.amin.luceneindexsi.index.integration.transformer.ErrorTransformer" />
        
	
	<chain input-channel="errorChannel" output-channel="errorOutChannel">
		<transformer ref="errorTransformer" method="transformError" />
        <mail:header-enricher from="${mailFrom}" to="${mailTo}" subject="${mail.subject}" overwrite="false"/>
     </chain>

But both do not work. I'm not sure which one is the best approach to be honest. My error to mail transformer has the following:

public class ErrorTransformer {
	
	public MailMessage transformError(ErrorMessage errorMessage) {
		Message<?> failedMessage = ((MessagingException) errorMessage.getPayload()).getFailedMessage();
		Throwable cause = ((MessagingException) errorMessage.getPayload()).getCause();
		IndexingException indexingException = new IndexingException(cause,failedMessage.getPayload());
		SimpleMailMessage mailMessage = new SimpleMailMessage();
		message.append("An exception occured while performing an index operation").append(", the following provides more details:\n");
		message.append("Exception message:\n").append(indexingException.getExceptionThrown().getMessage() + "\n");
		message.append("\n\n");
		message.append("Exception occured:\n");
		message.append(indexingException.getExceptionThrown().getStackTrace()[0].toString());
		message.append("\n\n");
		message.append("Message failed:\n").append(indexingException.getPayLoad().toString());
		mailMessage.setText(message.toString());
		return mailMessage;
	}

I presume the enricher should add the to and from settings to the mailMessage.

The process only works when I add the "to" and "from" the mail message itself.

Any help would be appreciated.

Cheers

[Mark Fisher]

Where are you configuring the mailFrom and mailTo properties? I assume you have a property-placeholder-configurer element as well?

[amin]

Yep. I even tried hard coding the values as well. The properties file is in the classpath as well. The only time it works is when I had the "to" and "from" in the mail message in the transformer and remove the mail enricher from the config.

Cheers
Amin