I'm working on a camel prototype which uses two start points in the same camel context.
The first route consumes messages which are used to "configure" the application. Messages are loaded in a configuration repository through a configService bean:
// read configuration files
from("file:data/config?noop=true&include=.*.xml")
.startupOrder(1)
.to("bean:configService?method=loadConfiguration")
.log("Configuration loaded");
The second route implements a recipient list eip pattern, delivering a different kind of input messages to a number of recipients, which are read dinamically from the same configuration repository:
// process some source files (using configuration)
from("file:data/source?noop=true")
.startupOrder(2)
.unmarshal()
.to("setupProcessor") // set "recipients" header
.recipientList(header("recipients"))
// ...
The question that arises now is how to synchronize them, so the second route "waits" if the first is processing new data.
I'm new to Apache Camel and pretty lost on how to approach such a problem, any suggestion would be appreciated.
Use aggregate in combination with the possibility to start and stop routes dynamically:
from("file:data/config?noop=true&include=.*.xml")
.id("route-config")
.aggregate(constant(true), new MyAggregationStrategy()).completionSize(2).completionTimeout(2000)
.process(new Processor() {
#Override
public void process(final Exchange exchange) throws Exception {
exchange.getContext().startRoute("route-source");
}
});
from("file:data/source?noop=true&idempotent=false")
.id("route-source") // the id is needed so that the route is found by the start and stop processors
.autoStartup(false) // this route is only started at runtime
.aggregate(constant(true), new MyAggregationStrategy()).completionSize(2).completionTimeout(2000)
.setHeader("recipients", constant("direct:end")) // this would be done in a separate processor
.recipientList(header("recipients"))
.to("seda:shutdown"); // shutdown asynchronously or the route would be waiting for pending exchanges
from("seda:shutdown")
.process(new Processor() {
#Override
public void process(final Exchange exchange) throws Exception {
exchange.getContext().stopRoute("route-source");
}
});
from("direct:end")
.log("End");
That way, route-source is only started when route-config is completed. route-config and consequently route-source are restarted if new files are found in the config directory.
You can also place an "on completion" http://camel.apache.org/oncompletion.html in the first route that activates the second one.
Apache camel File will create a lock for the file that being processed. Any other File process on this file will not pool on if there is a lock (except if you put consumer.exclusiveReadLock=false)
source :
http://camel.apache.org/file.html => URI Options => consumer.exclusiveReadLock
Related
I want to run a processor upon file appearance in a directory. My file url is like this:
file:{{file.root}}in?include=.*\.csv&charset=windows-1251&move=../out/done
A procedure that associates an url with a processor is like this:
MessageProcessor getOrCreateConsumer(CamelContext context, String uri) {
Endpoint endpoint = context.getEndpoint(uri);
endpoint.setCamelContext(context); // added this out of desperation, doesn't help
processor = new MessageProcessor();
try {
Consumer consumer = endpoint.createConsumer(processor);
endpoint.start(); // do we need this at all? works the same without it
consumer.start();
} catch (Exception e) {
throw new RuntimeException(e);
}
return processor;
}
}
MessageProcessor is a processor that does some things to an exchange.
Everything seems to work except the file doesn't get moved to the ../out/done directory. While debugging I can't get when the endpoint is configured to provide the file message exchange with this post operation.
I think I am missing some magic call that is normally invoked by a RouteBuilder and that will fully configure the file endpoint. Can you please help me out?
I have written a camel route which polls a folder and sends it to Azure Blob Container
I followed the example mentioned in the Azure document page
https://github.com/apache/camel/blob/master/components/camel-azure/src/main/docs/azure-blob-component.adoc
I am reversing the route. Instead of a consumer, I am using the Azure Blob Producer.
This is my route. I have used Java DSL.
from("file://C:/camel/source1").to("azure-blob://datastorage/container1/BLOB1?credentials=#credentials&operation=updateBlockBlob")
When I placed a file, I got the following error.
**java.lang.IllegalArgumentException: Unsupported blob type:org.apache.camel.component.file.GenericFile
at org.apache.camel.component.azure.blob.BlobServiceProducer.getInputStreamFromExchange(BlobServiceProducer.java:474) ~[camel-azure-2.19.2.jar:2.19.2]
at org.apache.camel.component.azure.blob.BlobServiceProducer.updateBlockBlob(BlobServiceProducer.java:143) ~[camel-azure-2.19.2.jar:2.19.2]
at org.apache.camel.component.azure.blob.BlobServiceProducer.process(BlobServiceProducer.java:79) ~[camel-azure-2.19.2.jar:2.19.2]**
I was able to fix this. I rewrote my route as.
from("file://C:/camel/source1")
.process(new Processor() {
#Override
public void process(Exchange exchange) throws Exception {
Object file = exchange.getIn().getMandatoryBody();
exchange.getOut().setBody(
GenericFileConverter.genericFileToInputStream(
(GenericFile<?>) file, exchange));
}
})
.to("azure-blob://datastorage/container1/BLOB1?credentials=#credentials&operation=updateBlockBlob")
.to("mock:Result");
My Question is, do I need to really write the processor? Shouldn't the camel component be receiving a stream or a File Object?
Yeah this is a little bug. I have logged a ticket: https://issues.apache.org/jira/browse/CAMEL-11844
You can do the workaround you did, or you can add a .convertBodyTo and convert to a FileInputStream, String etc.
from("file://C:/camel/source1")
.convertBodyTo(String.class)
...
I would like to write a Camel Route that gets in a URI (can be http, ftp, file, ...) and then fetches the data and stores it locally in a file.
This URI-String could be, for example:
"ftp://localhost/example.txt"
"file://tmp/example.txt"
"jms:queue:dataInputQueue"
...
Based on this string, the correct Camel Component should be used to access the data. Something like a case/switch in Java:
(1) Receive URI (from uri="vm:incomingUri")
(2) Chose "right" Camel Component
switch(URI)
case HTTP: use Camel HTTP component
case FTP: use Camel FTP component
case JMS: use Camel JMS component
...
(3) Read data from that URI, using the "right" Camel component
(4) Store file locally (to uri="file://...)
Example:
From "vm:incomingUri" I read a String "ftp://localhost/example.txt". That what finally needs to happen now should be equivalent to this:
<route>
<from uri="ftp://localhost/example.txt"/>
<to uri="file://tmpDir/example.txt"/>
</route>
How would this look like in Camel?
I believe one difficulty will be that, for the components you mention (HTTP, FTP, file, JMS), you may want to use either a producer or a consumer:
FTP, File: definitely a consumer to read a file.
HTTP (or HTTP4): definitely a producer, to send a request to the server (the server's reply will by the new message body)
JMS: depends on wether you want to read from a queue (consumer), or send a message to a queue with a ReplyTo header, then wait for the answer (producer).
Producers :
If you are using Camel 2.16+, you can use the new "dynamic to" syntax. It's basically the same as a regular "to", except that the endpoint uri can be evaluated dynamically using a simple expression (or, optionnaly, another type of expression). Alternatively, you can use the enrich flavor of the content-enricher pattern, wich also supports dynamic uris starting with Camel 2.16.
If you are using an older version of Camel, or if you need to dynamically route to several endpoints (not just one), you can use the recipient list pattern.
Here's an exemple. We will transform the message body by calling an endpoint; the uri for that endpoint will be found in a header named TargetUri and will be evaluated dynamically for each message.
// An instance of this class is registered as 'testbean' in the registry. Instead of
// sending to this bean, I could send to a FTP or HTTP endpoint, or whatever.
public class TestBean {
public String toUpperCase(final String str) {
return str.toUpperCase();
}
}
// This route sends a message to our example route for testing purpose. Of course, we
// could send any message as long as the 'TargetUri' header contains a valid endpoint uri
from("file:inbox?move=done&moveFailed=failed")
.setHeader("TargetUri").constant("bean:testbean?method=toUpperCase")
.setBody().constant("foo")
.to("direct:test");
// 1. The toD example :
from("direct:test")
.toD("${header.TargetUri}")
.to("log:myRoute");
// 2. The recipient list example :
from("direct:test")
.recipientList(header("TargetUri"))
.to("log:myRoute");
// 3. The enrich example :
from("direct:test")
.enrich().simple("${header.TargetUri}") // add an AggregationStrategy if necessary
.to("log:myRoute");
Consumers :
With Camel 2.16+, you can use the pollEnrich flavor of the content-enricher pattern.
For older versions of Camel, you can use a ConsumerTemplate in a processor.
// 4. The pollEnrich example (assuming the TargetUri header contains, e.g., a file
// or ftp uri) :
from("direct:test")
.pollEnrich().simple("${header.TargetUri}") // add an AggregationStrategy if necessary
.to("log:myRoute");
// 5. The ConsumerTemplate example (same assumption as above)
from("direct:test")
.process(new Processor() {
#Override
public void process(Exchange exchange) throws Exception {
String uri = exchange.getIn().getHeader("TargetUri", String.class);
ConsumerTemplate consumer = exchange.getContext().createConsumerTemplate();
final Object data = consumer.receiveBody(uri);
exchange.getIn().setBody(data);
}
})
.to("log:myRoute");
Producer or consumer?
Sadly, I can't think of any really elegant solution to handle both - I think you will have to route to two branches based on the uri and known components... Here's the sort of thing I might do (with Camel 2.16+), it's not very pretty:
// This example only handles http and ftp endpoints properly
from("direct:test")
.choice()
.when(header("TargetUri").startsWith("http"))
.enrich().simple("${header.TargetUri}")
.endChoice()
.when(header("TargetUri").startsWith("ftp"))
.pollEnrich().simple("${header.TargetUri}")
.endChoice()
.end()
.to("log:myRoute");
It is possible by using
<to uri="{{some.endpoint}}"/>
But you would require to add it in property .
<cm:property name="some.endpoint" value="SomeEndPoint"/>
And you can add any endpoint you want http, ftp, file, log, jms, vm etc.
Value of SomeEndPoint.
Log Component: log:mock
JMS Component: activemq:someQueueName
File Component: file://someFileShare
VMComponent: vm:toSomeRoute
I would like to run a route once and stop the context when the route is completed. Currently I do the usual Thread.sleep(3000) in the main Java class to leave some time for the route to finish but it's obviously not accurate, my route may take 1 second or 20 seconds I can not know in advance.
The Java class:
public static void main(String[] args) throws Exception {
try (ClassPathXmlApplicationContext context = new ClassPathXmlApplicationContext("camel-context.xml")) {
CamelContext camelContext = SpringCamelContext.springCamelContext(context);
// context.start(); // apparently not necessary
camelContext.startRoute("route1");
try { Thread.sleep(3000); } catch (InterruptedException e) { e.printStackTrace(); }
// context.stop(); // apparently not necessary
}
}
The Spring xml:
<route id="route1" autoStartup="false">
<from uri="timer://runOnce?repeatCount=1&delay=3000" />
...
</route>
After reading http://camel.465427.n5.nabble.com/Need-control-back-in-the-Main-routine-so-that-we-can-terminate-JVM-td4483312.html#a4484845 especially the 4th post, from Claus Ibsen, I was thinking of using camelContext.getRouteStatus() in a loop with a Thread.sleep() but wherever I try to get the route status in the code (even after the Thread.sleep(3000)), the status is always "started". I don't know any other way to detect when the route is done.
What is the recommended way to stop the Camel context when a/all route(s) is/are completed, using Spring?
The route will never stop because routes do not have complete state. They can just be started, stopped or paused. A route will always be running if it's in the started state unless you do something to change that.
To accomplish what you are looking for, you can do a couple of things:
You can use the controlbus component and stop the route in the last step of your route. That way you can check (for example the way you mentioned checking for camelContext.getRouteStatus()) when you should stop the context as well.
You can write a small Processor that whenever it receives an Exchange it will stop the camelContext. Once ready, you will add it to the last step of your route.
Camel supports onCompletion callbacks, which can be equivalent to the option above. See the camel page.
Probably, the first option is the easiest for your use case, however I would go for the second option. It seems cleaner to me.
A more elegant way would be to use a synchronisation mechanism provided by Java like CountDownLatch. Main thread will wait for the latch to be opened by the Route thread. Something like :
CountDownLatch latch = new CountDownLatch(1);
camelContext.addRoutes(createRoute(latch));
and somewhere in the createRoute Method add a processor at the end of the route to open the latch. This worked perfectly for me.
.process(new Processor() {
#Override
public void process(Exchange exchange) throws Exception {
latch.countDown();
}
});
From a programming point of view, I have a very simple business case. However, I can't figure out how to implement it using Apache Camel... Well, I have 2 JMS queues: one to receive commands, another - to store large number of message which should be delivered to external system in a batches of 1000 or less.
Here is the concept message exchange algorithm:
upon receiving a command message in 1st JMS queue I prepare XML
message
Send the XML message to external SOAP Web Service to obtain a usertoken
Using the usertoken, prepare another XML message and send it to a REST service to obtain jobToken
loop:
4.1. aggregate messages from 2nd JMS queue in batches of 1000, stop aggregation at timeout
4.2. for every batch, convert it to CSV file
4.3. send csv via HTTP Post to a REST service
4.4. retain batchtoken assigned to each batch
using the jobtoken prepare XML message and send to REST service to commit the batches
using batchtoken check execution status of each batch via XML message to REST service
While looking at Camel I could create a sample project where I can model out the exchange 1-3, 5:
from("file:src/data?noop=true")
.setHeader("sfUsername", constant("a#fd.com"))
.setHeader("sfPwd", constant("12345"))
.to("velocity:com/eip/vm/bulkPreLogin.vm?contentCache=false")
.setHeader(Exchange.CONTENT_TYPE, constant("text/xml; charset=UTF-8"))
.setHeader("SOAPAction", constant("login"))
.setHeader("CamelHttpMethod", constant("POST"))
.to("http4://bulklogin") // send login
.to("xslt:com/eip/xslt/bulkLogin.xsl") //xslt transformation to retrieve userToken
.process(new Processor() {
#Override
public void process(Exchange exchange) throws Exception {
String body = (String) exchange.getIn().getBody();
String[] bodyParts = body.split(",");
exchange.getProperties().put("userToken", bodyParts[0]);
.....
}
})
.to("velocity:com/eip/vm/jobInsertTeamOppStart.vm")
.setHeader(Exchange.CONTENT_TYPE, constant("application/xml; charset=UTF-8"))
.setHeader("X-Session", property("userToken"))
.setHeader("CamelHttpMethod", constant("POST"))
.to("http4://scheduleJob") //schedule job
.to("xslt:com//eip/xslt/jobInfoTransform.xsl")
.process(new Processor() {
#Override
public void process(Exchange exchange) throws Exception {
String body = (String) exchange.getIn().getBody();
exchange.getProperties().put("jobToken",body.trim());
}
})
//add batches in a loop ???
.to("velocity:com/eip/vm/jobInsertTeamOppEnd.vm")
.setHeader(Exchange.HTTP_URI, simple("https://na15.com/services/async/job/${property.jobToken}"))
.setHeader(Exchange.CONTENT_TYPE, constant("application/xml; charset=UTF-8"))
.setHeader("X-ID-Session", property("userToken"))
.setHeader("CamelHttpMethod", constant("POST"))
.to("http4://closeJob") //schedule job
//check batch?
.bean(new SomeBean());
So, my question is:
How can I read messages from my 2nd JMS queue?
This doesn't strike me as a very good use-case for a single camel route. I think you should implement the main functionality in a POJO and use Camels Bean Integration for consuming and producing messages. This will result in much more easy to maintain code, and also for easier Exception handling.
See https://camel.apache.org/pojo-consuming.html