I am new to using Camel. I am getting expected response from the url i hit - which i have logged. But after receiving the message I get the error following error while unmarshalling it:
On delivery attempt: 0 caught: com.fasterxml.json.databind.JsonMappingException: no content to map due to end-of-input
Maybe its due to streaming - can only read once problem, and since you logged it, its empty. See this FAQ: http://camel.apache.org/why-is-my-message-body-empty.html
How I solved this issue:
I autowired the DefaultCamelContext bean in my routeBuilder class and set the stream caching to true. This will set stream caching to true globally.
#Autowired
DefaultCamelContext camelContext;
Then set stream caching to true:
camelContext.setStreamCaching(true);
Alternatively you can also set stream caching true for a single router as follows:
from("jbi:service:http://myService.org")
.streamCaching(true)
.to("jbi:service:http://myOtherService.org");
Related
I have implemented a retry functionality in my code using camel retry. It will retry a maximum of five times.
onException(Exception.class)
.maximumRedeliveries(5)
.retryAttemptedLogLevel(LoggingLevel.WARN)
.backOffMultiplier(5)
.maximumRedeliveryDelay(5)
.useExponentialBackOff();
Now I want to call a custom method if the threshold has been reached instead of throwing an exception. How can I achieve this?
This is exact use-case for Dead Letter Channel EIP pattern. I would suggest converting your onException block to errorHandler and use deadLetterChannel builder.
errorHandler(
deadLetterChannel("direct:redeliveryExhausted")
.maximumRedeliveries(5)
.retryAttemptedLogLevel(LoggingLevel.WARN)
.backOffMultiplier(5)
.maximumRedeliveryDelay(5)
.useExponentialBackOff()
);
from("direct:redeliveryExhausted")
.log("I am going to handle non-deliverable message")
.log("Because of this exception: ${exception}")
.to("log:failed");
You can set the handled-flagto true and then call your custom bean.
onException(Exception.class)
.maximumRedeliveries(5)
.retryAttemptedLogLevel(LoggingLevel.WARN)
.backOffMultiplier(5)
.maximumRedeliveryDelay(5)
.useExponentialBackOff()
.handled(true)
.to("bean:myCustomBean");
I have a Camel rest endpoint (Jetty) which validates and processes incoming requests. Besides specific Exception handlers (onException) it uses a DLQ error handler (errorHandler(deadLetterChannel...)) which is setup to retry 3 times - if unsuccessful the message is moved to the DLQ.
My question is, how do I still return a user friendly error message back to the client if an unexpected Exception occurs rather than the full Exception body? Is there some config I'm missing on the errorHandler?
I've tried to find some examples on the camel unit tests (DeadLetterChannelHandledExampleTest) and camel in action 2 (Chapter 11) but none seemed to have specific examples for this scenario.
Code is:
.from(ROUTE_URI)
.errorHandler(deadLetterChannel("{{activemq.webhook.dlq.queue}}")
.onPrepareFailure(new FailureProcessor())
.maximumRedeliveries(3)
.redeliveryDelay(1000))
.bean(ParcelProcessor.class, "process");
Thank you for your help!
Use a 2nd route as the DLQ, eg direct:dead and then send the message first to the real DLQ, and then do the message transformation afterwards to return a friendly response.
errorHandler(deadLetterChannel("direct:dead")
from("direct:dead")
.to("{{activemq.webhook.dlq.queue}}")
.transform(constant("Sorry something was wrong"));
I'd like to wrap the result of a processed message into some reply-object to answer a webservice. This is my test-route:
this.from("cxf:someEndpoint")
.process(new SomeProcessorThatMightThrowAnException())
.process(new SomeOtherProcessorThatMightThrowAnException())
.log("normal end of route");
Nevermind if there was an exception or not, the result should be wrapped in some object, that is given back to the caller of my ws.
In camel 2.13.x I did this by adding an other processor to the end of the route and to do the same in 'onException'.
Now I tried to simplify this (technical thing and handle it outside of the 'functional route') in camel 2.14 (2.14 because of 'modeBeforeConsumer'), and added this to my routebuilder:
onCompletion()
.modeBeforeConsumer()
.process(new ConvertToWsReplyProcessor());
This ConvertToWsReplyProcessor should handle an Exception, but I found no way to see, if there was an Exception, because exchange.getProperty(Exchange.EXCEPTION_CAUGHT, Throwable.class) is allways null.
Questions:
1) Is there a way to find out if there was an excetion in onCompletion()?
2) The only way I found to prevent camel from dumping a stacktrace is to use onException(Ex...).handled(true), are there others?
3) How are these onXY processed? Do they get a copy of the exchange? And is onCompletion called last?
OnCompletionProcessor just remove some exchange properties before processing the exchange, that could explain why you cannot fine the exception here.
As camel use onException to handle the exception, I'm afraid you have to do it that way.
I'm using camel 2.14.0 with netty4-http
and I get the following exception.
the scenario is this:
I have a route that sends a request, waits for the response (inOut) and then sends another request.
the first request works, and then the second one fails.
also, if I do it quickly enough after the failure - the first request will also fail.
while debugging a bit (HttpObjectEncoder) - I saw that in the working flow the state of the request is: state = ST_INIT (0)
and in the request that failed it is: ST_CONTENT_NON_CHUNK (1)
which causes the illegal state when the type of message is HttpMessage
is this a bug or is there anything I can configure to fix it?
Caused by: io.netty.handler.codec.EncoderException: java.lang.IllegalStateException: unexpected message type: DefaultFullHttpRequest
at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:107)
at io.netty.channel.CombinedChannelDuplexHandler.write(CombinedChannelDuplexHandler.java:192)
at io.netty.channel.AbstractChannelHandlerContext.invokeWrite(AbstractChannelHandlerContext.java:658)
at io.netty.channel.AbstractChannelHandlerContext.access$2000(AbstractChannelHandlerContext.java:32)
at io.netty.channel.AbstractChannelHandlerContext$AbstractWriteTask.write(AbstractChannelHandlerContext.java:939)
at io.netty.channel.AbstractChannelHandlerContext$WriteAndFlushTask.write(AbstractChannelHandlerContext.java:991)
at io.netty.channel.AbstractChannelHandlerContext$AbstractWriteTask.run(AbstractChannelHandlerContext.java:924)
at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:380)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:357)
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116)
at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalStateException: unexpected message type: DefaultFullHttpRequest
at io.netty.handler.codec.http.HttpObjectEncoder.encode(HttpObjectEncoder.java:63)
at io.netty.handler.codec.http.HttpClientCodec$Encoder.encode(HttpClientCodec.java:106)
at io.netty.handler.codec.MessageToMessageEncoder.write(MessageToMessageEncoder.java:89)
... 10 more
I managed to identify the problem:
the first request I sent was a GET request with null body.
in the class org.apache.camel.component.netty4.http.NettyHttpProducer -
the method getRequestBody(Exchange exchange) is creating the actual request object from the exchange.
in it - the method "toNettyRequest" in class org.apache.camel.component.netty4.http.DefaultNettyHttpBinding
checks if the body is null, and if so - it is creating a DefaultHttpRequest, and not DefaultHttpFullRequest
when the request reaches the encoder as a result of a writeAndFlush call - the encoder does not clean its state because of this part of the code:
if (msg instanceof LastHttpContent) {
state = ST_INIT;
}
the DefaultHttpRequest is not instanceof LastHttpContent, so the state remains ST_CONTENT_NON_CHUNK and the next request will get an IllegalStateException because the state is not ST_INIT
this bug did not exist in netty-http, it only happened when I moved to use netty4-http
the workaround is simple - use an empty String ("") as body
I created a camel route without INOUT exchange pattern and the route looks like
direct:start > bean:myBean?method=handle
I'm sending payload using ProducerTemplate's send method
Exchange response = producerTemplate.send(endpointUri, exchange);
I set the exception on exchange in the bean's handle method, but its not retained in the response.
Is there something I'm missing.
You should throw an exception from the bean if you want to signal an exception.
I found where camel's hiding the exception. Since I marked the exchange as handled and marked for rollback, camel is setting the exception to null and moved it to properties.
I was able to retrieve it using
result.getProperty(Exchange.EXCEPTION_CAUGHT)