How to use Apache Camel exchange messages? - apache-camel

I am newcomer in Apache Camel. Please have a look to my code bellow:
I have a service which exposed as cxf webservice:
interface CxfService{
public OutputType hello(InputType input);
}
This is my route:
from("cxf:/test?serviceClass=" + CxfService.class.getName())
.to("log:cxfLog1")
.recipientList(simple("direct:${header.operationName}"));
from("direct:hello")
.process(new Processor(){
public void process(Exchange exchange) throws Exception {
InputType file = exchange.getIn().getBody(InputType.class);
exchange.getOut().setBody(new OutputType());
}
});
The code works as expected, it consume InputType and produce OutputType.
I want to borrow my body to do another stuffs, so i rewrite that like this:
from("cxf:/test?serviceClass=" + CxfService.class.getName())
.to("log:cxfLog1")
.recipientList(simple("direct:${header.operationName}"));
from("direct:hello")
.process(new Processor(){
public void process(Exchange exchange) throws Exception {
InputType file = exchange.getIn().getBody(InputType.class);
exchange.getOut().setHeader("header.temporary", new OutputType());
}
})
.to("some endpoint")
.setBody(simple("${header.temporary}"));
This webservice consume InputType and produce nothing. What wrong with that?

In your second piece of code, when setting the header.temporary, you should change two things:
setHeader("temporary", new OutputType()) - the 'header' prefix isn't
needed - you're addressing headers directly via the method call.
Use getIn() instead of getOut(). The input will get copied to the
output. You may want to do some research into the procedure for
Camel building the out message for details - I'm not 100% sure of
this one.

Change
exchange.getOut().setHeader("header.temporary", new OutputType());
To
exchange.getIn().setHeader("temporary"), new OutputType());
.setHeader() is when you use the simple language. In 99% of the cases getIn() is sufficient.

Related

Camel ProducerTemplate and ActiveMQ message and persistence issues

Issue:
I have multiple route sending messages to an ActiveMQ queue which later gets processed by a processor to save status information
The same message sending from ProducerTemplate to ActiveMQ queue somehow breakes the same code by not triggering logs on console, and saving status information to a randomly generated file name.
Desired Behavior:
Both sending method gets the messages processed the same way
Code Explanation:
On below codes the Save processor is the one producing the weird behavior where logs dont show up on console and writes to some random file, file name is basically the clientID from ActiveMQ
StartRoute calling the activemq:save works correctly
Code:
public class Save implements Processor {
public void process(Exchange exchange) throws Exception {
try {
Map<String, Object> map = new HashMap<String, Object>() {};
map.put(".....", ".....");
map.put(".....", ".....");
map.put(".....", ".....");
map.put(".....", ".....");
ProducerTemplate template = exchange.getContext().createProducerTemplate();
String response = template.requestBodyAndHeaders("activemq:save", "Batch Job Started", map, String.class);
FluentProducerTemplate FluentTemplate = exchange.getContext().createFluentProducerTemplate();
String result = FluentTemplate
.withHeader(".....", ".....")
.withHeader(".....", ".....")
.withHeader(".....", ".....")
.withHeader(".....", ".....")
.withHeader(".....", ".....")
.to("activemq:save")
.request(String.class);
} catch (Exception e) {
.....
}
}
}
public class StartRoute extends RouteBuilder {
restConfiguration()
.component("servlet")
.enableCORS(true);
rest("/start").id("start")
.post("/{filename}")
.route()
.....
.process(new Save())
.wireTap(startBackgroundProcessRoute)
.to("activemq:save")
.endRest();
}
public class SaveRoute extends RouteBuilder {
from("activemq:save")
.log("started saving")
.process(new FormatText())
.to("file:///status");
}
This question came from my original problem described here:
Camel Multicast Route call order
Solution can be found also there:
Camel Multicast Route call order
However to satisfy this question:
It seems Camel have few bugs regarding producer templates and maybe ActiveMQ, this is my initial conclusion.
The Only way i was able to use ProducerTemplate without issue is to use the send function with Exchanges, send() sends the messages correctly to the ActiveMQ same way as the to() however for whatever reason the content was still not written to the file.
After I dropped the ActiveMQ between the routes, everything started to work consistently. So possible miss configuration on ActiveMQ component or possible another camel framework bug.
If anyone knows the exact answer i would be happy to hear / see the reason for this behavior.
Code example:
public class SaveProcessor implements Processor {
public void process(Exchange exchange) throws Exception {
ProducerTemplate template = exchange.getContext().createProducerTemplate();
template.send(Utilities.trackBatchJobStatus, exchange);
/** NOTE
* DO NOT USE any other functions which are not working with EXCHANGES.
* Functions that uses body, header values and such are bugged
*/
}
}

Unit testing with Apache Camel

I want to test below camel route. All the example which i find online has route starting with file, where as in my case i have a spring bean method which is getting called every few minutes and finally message is transformed and moved to jms as well as audit directory.
I am clue less on write test for this route.
All i have currently in my test case is
Mockito.when(tradeService.searchTransaction()).thenReturn(dataWithSingleTransaction);
from("quartz2://tsTimer?cron=0/20+*+8-18+?+*+MON,TUE,WED,THU,FRI+*")
.bean(TradeService.class)
.marshal()
.jacksonxml(true)
.to("jms:queue:out-test")
.to("file:data/test/audit")
.end();
Testing with Apache Camel and Spring-Boot is really easy.
Just do the following (the example below is an abstract example just to give you a hint how you can do it):
Write a Testclass
Use the Spring-Boot Annotations to configure the test class.
#SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.NONE)
#RunWith(SpringRunner.class)
public class MyRouteTest {
#EndpointInject(uri = "{{sourceEndpoint}}")
private ProducerTemplate sourceEndpoint;
....
public void test() {
// send your body to the endpoint. See other provided methods too.
sourceEndpoint.sendBody([your input]);
}
}
In the src/test/application.properties:
Configure your Camel-Endpoints like the source and the target:
sourceEndpoint=direct:myTestSource
Hints:
It's good not to hardwire your start-Endpoint in the route directly when using spring-boot but to use the application.properties. That way it is easier to mock your endpoints for unit tests because you can change to the direct-Component without changing your source code.
This means instead of:
from("quartz2://tsTimer?cron=0/20+*+8-18+?+*+MON,TUE,WED,THU,FRI+*")
you should write:
from("{{sourceEndpoint}}")
and configure the sourceEndpoint in your application.properties:
sourceEndpoint=quartz2://tsTimer?cron=0/20+*+8-18+?+*+MON,TUE,WED,THU,FRI+*
That way you are also able to use your route for different situations.
Documentation
A good documentation about how to test with spring-boot can be found here: https://docs.spring.io/spring-boot/docs/current/reference/html/boot-features-testing.html
For Apache Camel: http://camel.apache.org/testing.html
#the hand of NOD Thanks for your hints, i was going into completely wrong direction. After reading your answer i was able to write the basic test and from this i think i can take it forward.
Appreciate your time, however i see that based on my route it should drop an XML file to audit directory which is not happening.
Look like intermediate steps are also getting mocked, without I specifying anything.
InterceptSendToMockEndpointStrategy - Adviced endpoint [xslt://trans.xslt] with mock endpoint [mock:xslt:trans.xslt]
INFO o.a.c.i.InterceptSendToMockEndpointStrategy - Adviced endpoint [file://test/data/audit/?fileName=%24%7Bheader.outFileName%7D] with mock endpoint [mock:file:test/data/audit/]
INFO o.a.camel.spring.SpringCamelContext - StreamCaching is not in use. If using streams then its recommended to enable stream caching. See more details at http://camel.apache.org/stream-caching.html
TradePublisherRoute.java
#Override
public void configure() throws Exception {
logger.info("TradePublisherRoute.configure() : trade-publisher started configuring camel route.");
from("{{trade-publisher.sourceEndpoint}}")
.doTry()
.bean(tradeService)
.process(new Processor() {
#Override
public void process(Exchange exchange) throws Exception {
String dateStr = Constant.dateFormatForFileName.format(new Date());
logger.info("this is getting executed : " + dateStr);
exchange.setProperty(Constant.KEY_INCOMING_XML_FILE_NAME, "REQ-" + dateStr + Constant.AUDIT_FILE_EXTENSION);
exchange.setProperty(Constant.KEY_OUTGOING_XML_FILE_NAME, "RESP-" + dateStr + Constant.AUDIT_FILE_EXTENSION);
}
})
.marshal()
.jacksonxml(true)
.wireTap("{{trade-publisher.requestAuditDir}}" + "${header.inFileName}")
.to("{{trade-publisher.xsltFile}}")
.to("{{trade-publisher.outboundQueue}}")
.to("{{trade-publisher.responseAuditDir}}" + "${header.outFileName}")
.bean(txnService, "markSuccess")
.endDoTry()
.doCatch(Exception.class)
.bean(txnService, "markFailure")
.log(LoggingLevel.ERROR, "EXCEPTION: ${exception.stacktrace}")
.end();
TradePublisherRouteTest.java
#ActiveProfiles("test")
#RunWith(CamelSpringBootRunner.class)
#SpringBootTest(classes = TradePublisherApplication.class)
#MockEndpoints
public class TradePublisherRouteTest {
#EndpointInject(uri = "{{trade-publisher.outboundQueue}}")
private MockEndpoint mockQueue;
#EndpointInject(uri = "{{trade-publisher.sourceEndpoint}}")
private ProducerTemplate producerTemplate;
#MockBean
TradeService tradeService;
private List<Transaction> transactions = new ArrayList<>();
#BeforeClass
public static void beforeClass() {
}
#Before
public void before() throws Exception {
Transaction txn = new Transaction("TEST001", "C001", "100", "JPM", new BigDecimal(100.50), new Date(), new Date(), 1000, "P");
transactions.add(txn);
}
#Test
public void testRouteConfiguration() throws Exception {
Mockito.when(tradeService.searchTransaction()).thenReturn(new Data(transactions));
producerTemplate.sendBody(transactions);
mockQueue.expectedMessageCount(1);
mockQueue.assertIsSatisfied(2000);
}
Please correct me if i am doing something wrong!

filter messages coming from a specific type of camel endpoint

lets say, I have
from("direct:start").filter("...")
How can I filter out messages coming from an endpoint like smtp? Is there a way to check the type of the previous endpoint?
Edit: As per advice from vikingsteve, I have implemented the code this way:
from("direct:source")
.process(new Processor() {
#Override
public void process(Exchange exchange) throws Exception {
exchange.setProperty("source", "smtps");
}
})
.to("direct:start");
from("direct:start").filter(
new Predicate() {
#Override
public boolean matches(Exchange exchange) {
if(exchange.getProperty("source") == "smtps")
return true;
else
return false;
}}));
You would normally set an exchange property if you need to identify some information about the original message (such as where it came from, or some other metadata not contained in the body).
from("smtp:...").setProperty("source", "smtp").to("...")
edit: here's a simpler version of your solution, I havent tested it, but it might work like this:
from("direct:source")
.setProperty("source", "smtps")
.to("direct:start");
from("direct:start")
.filter(exchangeProperty("source").isEqualTo("smtp"))

Can we provide a processor before onFallbackViaNetwork() in camel-hystrix-eip

I'm using camel-hystrix-eip in my project, I want a processor before my fallback, but it's not working
from("direct:sample").id("id:direct:sample").process(requestProcessor)
.hystrix()
.to(endPoint)
.onFallbackViaNetwork()
.to(fallback_endPoint)
I want to alter my fallback_endpoint using a processor, but seems like after onFallbackViaNetwork() we have to immediately provide to().
please suggest if there any way to do so.
I tried something like below, but it's not working.
from("direct:sample").id("id:direct:sample").process(requestProcessor)
.hystrix()
.to(endPoint)
.onFallbackViaNetwork()
.process(fallbackProcessor)
.to(fallback_endPoint)
Actually, I'm using requestProcessor to override the actual endpoint, and in case of a fallback, fallback_endPoint is also getting overridden, is there any way to avoid this.
You can have a processor after onFallbackViaNetwork(). You can also use the toD EIP to send the message to a dynamic endpoint.
Based on your code, you could set a Header MyEndpoint which contains your new endpoint string, and then reference it using .toD("${header.MyEndpoint}"). Repeat this pattern whenever you need to set a dynamic endpoint.
For example:
from("direct:sample")
.process(new Processor() {
#Override
public void process(Exchange exchange) throws Exception {
// do something
exchange.getIn().setHeader("EndpointHystrix", "mock:hystrix");
}
})
.hystrix()
.toD("${header.EndpointHystrix}")
.onFallbackViaNetwork()
.process(new Processor() {
#Override
public void process(Exchange exchange) throws Exception {
// do something more
exchange.getIn().setHeader("EndpointFallback", "mock:fallback");
}
})
.toD("${header.EndpointFallback}")
.end()
.to("...");
I've tested this in Camel 2.20.0 and 2.21.0.

Correlating messages on two Camel Routes

In my application I have a generic Camel Route such as the following
from("direct:something").to("direct:outgoing")
and then dynamically in my code I deploy another route:
from("direct:outgoing").process(processor)
When flowing from route 1 to route 2 a new Exchange will be created. Is there an idiomatic way to correlate both? Should I set EXCHANGE.Correlation_ID header on the first route before sending it out?
This should definitely all be processed on the one exchange. Run this test and you'll see the same camel Exchange, with the same properties, etc.
public class CamelExchangeTest {
public static void main(String[] args) throws Exception {
final Processor showExchangeIdProcessor = new Processor() {
#Override
public void process(Exchange exchange) throws Exception {
System.out.println(exchange.getExchangeId());
}
};
Main camelMain = new Main();
camelMain.addRouteBuilder(new RouteBuilder() {
#Override
public void configure() throws Exception {
from("timer:foo?period=1s&repeatCount=1")
.log("excgabge created!")
.process(showExchangeIdProcessor)
.to("direct:outgoing")
;
from("direct:outgoing")
.log("outgoing!")
.process(showExchangeIdProcessor)
;
}
});
camelMain.run();
}
}
Output:
ID-MYPC-55760-1411129552791-0-2
ID-MYPC-55760-1411129552791-0-2
So something else is going on. When you say "direct:outgoing", do you mean exactly that or is it something different - a different component perhaps?
When you say the route is created dynamically, how exactly is that done, and when (and why?)
From the Camel doc:
Some EIP patterns will spin off a sub message, and in those cases, Camel will add a correlation id on the Exchange as a property with they key Exchange.CORRELATION_ID, which links back to the source Exchange. For example the Splitter, Multicast, Recipient List, and Wire Tap EIP does this.
Thus, Exchange.CORRELATION_ID is set by Camel and should not be set by your application. But feel free to set a custom header or property if you need to such as:
exchange.getIn().setProperty("myProperty", myIdentifier);

Resources