Add camel route at runtime in Java - spring

How can I add a camel route at run-time in Java? I have found a Grails example but I have implement it in Java.
My applicationContext.xml already has some predefined static routes and I want to add some dynamic routes to it at run time.
Is it possible?
Because the only way to include dynamic route is to write the route.xml and then load the route definition to context. How will it work on existing static routes?
Route at runtime

you can simply call a few different APIs on the CamelContext to add routes...something like this
context.addRoutes(new MyDynamcRouteBuilder(context, "direct:foo", "mock:foo"));
....
private static final class MyDynamcRouteBuilder extends RouteBuilder {
private final String from;
private final String to;
private MyDynamcRouteBuilder(CamelContext context, String from, String to) {
super(context);
this.from = from;
this.to = to;
}
#Override
public void configure() throws Exception {
from(from).to(to);
}
}
see this unit test for the complete example...
https://svn.apache.org/repos/asf/camel/trunk/camel-core/src/test/java/org/apache/camel/builder/AddRoutesAtRuntimeTest.java

#Himanshu,
Please take a look at dynamicroute options (in other words routing slip) that may help you dynamically route to different 'destinations' based on certain condition.
Check the dynamic router help link in camel site;
http://camel.apache.org/dynamic-router.html
from("direct:start")
// use a bean as the dynamic router
.dynamicRouter(method(DynamicRouterTest.class, "slip"));
And within the slip method;
/**
* Use this method to compute dynamic where we should route next.
*
* #param body the message body
* #return endpoints to go, or <tt>null</tt> to indicate the end
*/
public String slip(String body) {
bodies.add(body);
invoked++;
if (invoked == 1) {
return "mock:a";
} else if (invoked == 2) {
return "mock:b,mock:c";
} else if (invoked == 3) {
return "direct:foo";
} else if (invoked == 4) {
return "mock:result";
}
// no more so return null
return null;
}
Hope it helps...
Thanks.

One such solution could be:
Define route:
private RouteDefinition buildRouteDefinition() {
RouteDefinition routeDefinition = new RouteDefinition();
routeDefinition.from(XX).to(ZZ); // define any route you want
return routeDefinition;
}
Get Model Context and create route:
CamelContext context = getContext();
ModelCamelContext modelContext = context.adapt(ModelCamelContext.class);
modelContext.addRouteDefinition(routeDefinition);
There are more way of getting camel context. To name few:
In processor, you can use exchange.getContext()
Through RouteBuilder reference, you can use routeBuilder.getContext()

Related

Spring WebFlux: How to route to a different handler function based on query parameters?

I am writing a person API using Spring WebFlux functional programming, how to route to different handler functions based on the query param names?
#Bean
public RouterFunction<ServerResponse> route(PersonHandler personHandler) {
return RouterFunctions.route(GET("/people/{id}").and(accept(APPLICATION_JSON)), personHandler::get)
.andRoute(GET("/people").and(accept(APPLICATION_JSON)), personHandler::all)
.andRoute(GET("/people/country/{country}").and(accept(APPLICATION_JSON)), personHandler::getByCountry)
// .andRoute(GET("/people?name={name}").and(accept(APPLICATION_JSON)), personHandler::searchByName)
// .andRoute(GET("/people?age={age}").and(accept(APPLICATION_JSON)), personHandler::searchByAge)
// I am expecting to do something like this
;
}
Or do I need to handle it in the handler function?
like
public Mono<ServerResponse> searchPeople(ServerRequest serverRequest) {
final Optional<String> name = serverRequest.queryParam("name");
final Optional<String> age = serverRequest.queryParam("age");
Flux<People> result;
if(name.isPresent()){
result = name.map(peopleRepository::searchByName)
.orElseThrow();
} else if(age.isPresent()){
result = name.map(peopleRepository::searchByage)
.orElseThrow();
}
return ok().contentType(MediaType.APPLICATION_JSON).body(result, People.class);
}
What is the best way to do it?
Thanks
You can create your own RequestPredicate and use the existing infrastructure (by plugging it into a and()):
public static RequestPredicate hasQueryParam(String name) {
return RequestPredicates.queryParam(name, p -> StringUtils.hasText(p));
}

Logging with XQuery

I'm using XQuery 3.0 to transform an incoming message to fit my system.
The XQuery is called from an Apache Camel Route via the transform EIP.
Example:
transform().xquery("resource:classpath:xquery/myxquery.xquery",String.class)
While the transformation works without problems it would be nice, since it's partly very complex, to be able to log some informations directly during the transformation process.
So I wanted to ask if it is possible to log "into" logback directly from XQuery?
I already searched stackoverflow and of course https://www.w3.org/TR/xquery-30-use-cases/ and other sources, but I just couldn't find any information about how to log in Xquery.
My project structure is:
Spring-Boot 2 application
Apache-Camel as Routing framework
Logback as Logging framework
Update: For the integration of XQuery in the Apache-Camel Framework I use the org.apache.camel:camel-saxon-starter:2.22.2.
Update: Because the use of fn:trace was kind of ugly I searched further and now I use the extension mechanism from Saxon to provide different logging functions which can be accessed via xquery:
For more information see the documentation: http://www.saxonica.com/documentation/#!extensibility/integratedfunctions/ext-full-J
Here is what I did for logging (tested with Saxon-HE, Camel is not mandatory, I just use it by coincidence):
First step:
Extend the class net.sf.saxon.lib.ExtensionFunctionDefinition
public class XQueryInfoLogFunctionDefinition extends ExtensionFunctionDefinition{
private static final Logger log = LoggerFactory.getLogger(XQueryInfoLogFunctionDefinition.class);
private final XQueryInfoExtensionFunctionCall functionCall = new XQueryInfoExtensionFunctionCall();
private static final String PREFIX = "log";
#Override
public StructuredQName getFunctionQName() {
return new StructuredQName(PREFIX, "http://thehandofnod.com/saxon-extension", "info");
}
#Override
public SequenceType[] getArgumentTypes() {
return new SequenceType[] { SequenceType.SINGLE_STRING };
}
#Override
public SequenceType getResultType(SequenceType[] suppliedArgumentTypes) {
return SequenceType.VOID;
}
#Override
public ExtensionFunctionCall makeCallExpression() {
return functionCall;
}
}
Second step:
Implement the FunctionCall class
public class XQueryInfoExtensionFunctionCall extends ExtensionFunctionCall {
private static final Logger log = LoggerFactory.getLogger(XQueryInfoLogFunctionDefinition.class);
#Override
public Sequence call(XPathContext context, Sequence[] arguments) throws XPathException {
if (arguments != null && arguments.length > 0) {
log.info(((StringValue) arguments[0]).getStringValue());
} else
throw new IllegalArgumentException("We need a message");
return EmptySequence.getInstance();
}
}
Third step:
Configure the SaxonConfiguration and bind it into the camel context:
public static void main(String... args) throws Exception {
Main main = new Main();
Configuration saxonConfig = Configuration.newConfiguration();
saxonConfig.registerExtensionFunction(new XQueryInfoLogFunctionDefinition());
main.bind("saxonConfig", saxonConfig);
main.addRouteBuilder(new MyRouteBuilder());
main.run(args);
}
Fourth step:
Define the SaxonConfig in your XQueryEndpoint:
.to("xquery:test.xquery?configuration=#saxonConfig");
Fifth step:
Call it in your xquery:
declare namespace log="http://thehandofnod.com/saxon-extension";
log:info("Das ist ein INFO test")
Original post a.k.a How to overwrite the fn:trace Funktion:
Thanks to Martin Honnen I tried the fn:trace function. Problem was that by default it logs into the System.err Printstream and that's not what I wanted, because I wanted to combine the fn:trace function with the Logback Logging-Framework.
So I debugged the net.sf.saxon.functions.Trace methods and came to the following solution for my project setup.
Write a custom TraceListener which extends from net.sf.saxon.trace.XQueryTraceListener and implement the methods enter and leave in a way that the InstructionInfo with constructType == 2041 (for user-trace) is forwarded to the SLF4J-API. Example (for only logging the message):
#Override
public void enter(InstructionInfo info, XPathContext context) {
// no call to super to keep it simple.
String nachricht = (String) info.getProperty("label");
if (info.getConstructType() == 2041 && StringUtils.hasText(nachricht)) {
getLogger().info(nachricht);
}
}
#Override
public void leave(InstructionInfo info) {
// no call to super to keep it simple.
}
set the custom trace listener into your net.sf.saxon.Configuration Bean via setTraceListener
Call your xquery file from camel via the XQueryEndpoint because only there it is possible to overwrite the Configuration with an option: .to("xquery:/xquery/myxquery.xquery?configuration=#saxonConf"). Unfortunately the transform().xquery(...) uses it's own objects without the possibility to configure them.
call {fn:trace($element/text(),"Das ist ein Tracing Test")} in your xquery and see the message in your log.

Add camel route at runtime using end points configured in property file

I own a spring application and want to add camel routes dynamically during my application startup.End points are configured in property file and are loaded at run time.
Using Java DSL, i am using for loop to create all routes,
for(int i=0;i<allEndPoints;i++)
{
DynamcRouteBuilder route = new
DynamcRouteBuilder(context,fromUri,toUri)
camelContext.addRoutes(route)
}
private class DynamcRouteBuilder extends RouteBuilder {
private final String from;
private final String to;
private MyDynamcRouteBuilder(CamelContext context, String from, String to) {
super(context);
this.from = from;
this.to = to;
}
#Override
public void configure() throws Exception {
from(from).to(to);
}
}
but getting below exception while creating first route itself
Failed to create route file_routedirect: at: >>> OnException[[class org.apache.camel.component.file.GenericFileOperationFailedException] -> [Log[Exception trapped ${exception.class}], process[Processor#0x0]]] <<< in route: Route(file_routedirect:)[[From[direct:... because of ref must be specified on: process[Processor#0x0]\n\ta
Not sure about it- what is the issue ? Can someone has any suggestion or fix for this. Thanks
Well, to create routes in an iteration it is nice to have some object that holds the different values for one route. Let's call this RouteConfiguration, a simple POJO with String fields for from, to and routeId.
We are using YAML files to configure such things because you have a real List format instead of using "flat lists" in property files (route[0].from, route[0].to).
If you use Spring you can directly transform such a "list of object configurations" into a Collection of objects using #ConfigurationProperties
When you are able to create such a Collection of value objects, you can simply iterate over it. Here is a strongly simplified example.
#Override
public void configure() {
createConfiguredRoutes();
}
void createConfiguredRoutes() {
configuration.getRoutes().forEach(this::addRouteToContext);
}
// Implement route that is added in an iteration
private void addRouteToContext(final RouteConfiguration routeConfiguration) throws Exception {
this.camelContext.addRoutes(new RouteBuilder() {
#Override
public void configure() throws Exception {
from(routeConfiguration.getFrom())
.routeId(routeConfiguration.getRouteId())
...
.to(routeConfiguration.getTo());
}
});
}

How to do URL Rewrite in Zuul Proxy?

One of the request that comes to my Zuul Filter is of URI /hello/World which i want to redirect to /myapp/test. This /myapp/test is a service that is registered in Eureka.
zuul:
routes:
xyz:
path: /hello/World
url: http://localhost:1234/myapp/test
stripPrefix: true
When i try the above configuration, the incoming URI is suffixed to the configured URL like http://localhost:1234/myapp/test/World . Few of the links which i came across seem to be stating that URL Rewrite feature is not yet available in Zuul.
Is there any other way this can be done at the Zuul Layer ?
Note: At this point of time, i cannot do this reverse proxying in the Webserver or any other layer since, my Zuul filter is the one that is receiving the request directly.
Using #Adelin solution, with little improvements
Use 'url' property as path to prepend for customizing the Url rewriting (I have disabled Eureka in my example) :
ribbon.eureka.enabled=false
zuul.routes.route1.path=/route1/**
zuul.routes.route1.serviceId=service1
zuul.routes.route1.url=/path/to/prepend
service1.ribbon.listOfServers=http://server1
Then implement the following filter :
/**
* Fixing missing URL rewriting when using ribbon
*/
#Component
public class CustomPathZuulFilter extends ZuulFilter {
#Autowired
private ZuulProperties zuulProperties;
#Override
public String filterType() {
return FilterConstants.PRE_TYPE;
}
#Override
public int filterOrder() {
return FilterConstants.PRE_DECORATION_FILTER_ORDER + 1;
}
#Override
public boolean shouldFilter() {
// override PreDecorationFilter only if executed previously successfully
return RequestContext.getCurrentContext().getFilterExecutionSummary().toString()
.contains("PreDecorationFilter[SUCCESS]");
}
#Override
public Object run() {
final RequestContext context = RequestContext.getCurrentContext();
if (context.get(FilterConstants.SERVICE_ID_KEY) == null || context.getRouteHost() != null) {
// not a Ribbon route
return null;
}
// get current ZuulRoute
final String proxy = (String) context.get(FilterConstants.PROXY_KEY);
final ZuulRoute zuulRoute = this.zuulProperties.getRoutes().get(proxy);
// patch URL by prefixing it with zuulRoute.url
final Object originalRequestPath = context.get(FilterConstants.REQUEST_URI_KEY);
final String modifiedRequestPath = zuulRoute.getUrl() + originalRequestPath;
context.put(FilterConstants.REQUEST_URI_KEY, modifiedRequestPath);
// patch serviceId because :
// - has been set to route.location in PreDecorationFilter
// - route.location has been set to zuulRoute.location in SimpleRouteLocator
// - zuulRoute.location return zuulRoute.url if set
context.set(FilterConstants.SERVICE_ID_KEY, zuulRoute.getServiceId());
return null;
}
}
Now calls to /route1 will be proxified to http://server1/path/to/prepend
This solution is also compatible with co-existing routes not using Ribbon.
Example of a co-existing route not using Ribbon :
zuul.routes.route2.path=/route2/**
zuul.routes.route2.url=http://server2/some/path
Calls to /route2 will be proxified to http://server2/some/path by SimpleHostRoutingFilter (if not disabled)
Here is a posted solution in the link by #Vikash
#Component
public class CustomPathZuulFilter extends ZuulFilter
{
#Override
public String filterType() {
return "pre";
}
#Override
public int filterOrder() {
return PreDecorationFilter.FILTER_ORDER + 1;
}
#Override
public boolean shouldFilter() {
return true;
}
#Override
public Object run() {
RequestContext context = RequestContext.getCurrentContext();
Object originalRequestPath = context.get(REQUEST_URI_KEY);
String modifiedRequestPath = "/api/microservicePath" + originalRequestPath;
context.put(REQUEST_URI_KEY, modifiedRequestPath);
return null;
}
}
Have you tried creating a preFilter or even a routeFilter ?
That way you can intercept the request, and change the routing.
See Zuul Filters

Get resteasy servlet context without annotation params

Quick project explanation: We have a built application based on JSF2 + Spring with Dynamic data sources. The data reference control is made with a spring-config:
<bean id="dataSource" class="com.xxxx.xxxx.CustomerRoutingDataSource">
....
and a class (referenced above):
public class CustomerRoutingDataSource extends AbstractRoutingDataSource {
#Override
protected Object determineCurrentLookupKey() {
return CustomerContextHolder.getCustomerType();
}
public Logger getParentLogger() throws SQLFeatureNotSupportedException {
return null;
}
}
the CustomerContextHolder called above is as follows:
public class CustomerContextHolder {
private static final ThreadLocal<String> contextHolder = new ThreadLocal<String>();
public static void setCustomerType(String customerType) {
contextHolder.set(customerType);
}
public static String getCustomerType() {
String manager = (String)FacesContext.getCurrentInstance().getExternalContext().getSessionMap().get("dataBaseManager");
if (manager != null) {
contextHolder.set(manager);
FacesContext.getCurrentInstance().getExternalContext().getSessionMap().put("dataBaseManager", null);
} else {
String base = (String)FacesContext.getCurrentInstance().getExternalContext().getSessionMap().get("currentDatabBase");
if (base != null)
contextHolder.set(base);
}
return (String) contextHolder.get();
}
public static void clearCustomerType() {
contextHolder.remove();
}
}
The problem is that the last guy is calling FacesContext.getCurrentInstance() to get the servlet context. Just to explain, it uses the session Attribute dataBaseManager to tell which base it should use.
For the actual solution it was working fine, but with the implementation of a RESTEASY web service, when we make a get request the FacesContext.getCurrentInstance() is obviously returning null and crashing.
I searched a lot and could not find a way of getting the servlet-context from outside of the #GET params. I would like to know if is there any way of getting it, or if there is another solution for my dynamic datasource problem.
Thanks!
Like magic and probably not much people know.
I searched deep into the Resteasy documentation, and found a part of springmvc plugin that comes with the resteasy jars, that has a class called RequestUtil.class.
With that I was able to use the method getRequest() without the "#Context HttpServletRequest req" param.
Using that I was able to set the desired database on the request attributes, and from another thread (called by spring) get it and load the stuff from the right place!
I'm using it for a week now and it works like a charm. Only thing that I needed to do is change the determineLookupKey() above to this:
#Override
protected String determineCurrentLookupKey() {
if (FacesContext.getCurrentInstance() == null) {
//RESTEASY
HttpServletRequest hsr = RequestUtil.getRequest();
String lookUpKey = (String) hsr.getAttribute("dataBaseManager");
return lookUpKey;
}else{
//JSF
return CustomerContextHolder.getCustomerType();
}
}
Hope this helps other people!
Thiago

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