Making REST calls in parallel in Apache Camel - spring-boot

I am using Apache Camel Java DSL in a Spring Boot project. In the Camel route, I am calling two rest services sequentially, combining their outputs and sending to another application from the Camel route. Now we are trying to call the REST services in parallel. We were able to call the REST services in parallel by implementing the following steps:
In the route, first storing the two URLs of the two REST services in a list within an exchange.
Applying Splitter EIP and parallelProcessing() on that EIP to call two differrent Camel routes in parallel which calls the REST service.
Unmarshalling the response of the services from JSON to POJO
The problem is if I use an aggregationStrategy to aggregate the responses, how canI handlethe scenarion when the two REST services will return two different objects after unmarshalling the response? Also please suggest any better approach of calling the REST services in parallel and consolidating their responses.

Related

How to consume REST API and SOAP endpoint using one rest API?

We have an application that uses both rest API and soap API. At a time we use either of them, but the requirement is to change it when needed. So, the question is there a way to use a single API that can handle REST and SOAP requests, so that we can use either of them depending on our condition in spring boot?
I have tried to call using single rest API. My expectation is to find a mechanism that can handle both soap and rest requests.

Integrating hundres of SOAP services - Spring boot

I have a system (kind of aggregator) that integrates with hundreds of different SOAP services - most of them do the same business functionality, but each service having different data structure in SOAP request & very few having 2 API calls to complete one transaction.
The present service integration workflow is
create stubs from WSDL
map data to the generated stub api
setup a new endpoint to fire this api
I see this a repeated, unintelligent work & requires development effort for every new service integration.
Was there different approaches to integrate with lot many systems? Any libraries that can generate soap requests based on configurations, or I have to rely on some Java SOAP, Spring lirbaries to create custom SOAP xml request from my own configurations? I see Spring's WebServiceGatewaySupport for webservice client but requires stubs created from wsdl?
Is it wise to define soap request xml as templates for every service, generate xml with input data?
Other ways I thought was to develop each integrations as independent microservice layered under an API gateway that routes each requests to specific service. But this design approach will have hundreds of services running, consuming more resources (in case of Spring boot).
Generate stubs & deposit the jar to disk, load this jar with a classloader & use the stubs using reflection - not so simple, I believe.
Use of serverless looks promising but is not possible immediately.

REST api for processing parallel HTTP GET requests

My question might be quite basic.
I have a Spring MVC (Spring Boot) REST api, and multiple Spark workers that send parallel HTTP GET requests to this REST api (e.g. 4 workers on different nodes -> 4 parallel HTTP requests). I want my REST api be able to process these requests in parallel.
How can I do it? Should I use callbacks and DeferredResult inside my REST api? Any example would be really helpful.
Take a look at AsyncRestTemplate.
AsyncRestTemplate is deprecated. Take a look at WebClient instead.

Dynamically register hystrix commands without javanica annotations in spring boot

We have developed a software proxy based on spring boot and zuul, that is meant to govern services within our integration layer. We do not own the systems consuming the various services, nor do we own the actual services themselves. The services are SOAP based webservices at present. We make use of pre, post , error and route filters. Validations are database driven, including which client is allowed to call what webservice. All service definitions reside in the database (request endpoint, request xsd, response xsd, which clients are allowed to invoke, etc.).
The aim now is to add hystrix commands to handle service failures, as well as a hystrix dashboard.
The standard way to use hystrix commands involves annotating service methods with javanica. Is there a way to dynamically declare/register hystrix commands for these webservices at runtime after reading the configurations from the database? The hystrix interception will need to happen based on the multiple webservice endpoints being invoked from a single point.
Hoping this is achievable ...if not, I would really appreciate any alternative proposals for how hystrix commands could be declared in this way.
Thanks!
You're saying that you are already using Spring Boot and Zuul. How are you mapping the routes? Through the url param? Then you'll have to enroll your own. But if you define the routes as ribbon services and pass the routes as ribbon servers as described in the documentation you will get Hystrix for free.

Rest-SOAP gateaway for external services (Spring + Camel)

I need to build REST-SOAP gateaway between 2 external services
First web services makes SOAP requests and awaits SOAP response. Second service (mine, written in Play Framework 1.2.4) works only using RESTful approach. I don`t want to integrate SOAP related things with second service for many reasons. So I need some third service to act between them.
I have looked into using Spring web-app with Apache Camel, but still can't get the full picture because there are so many modules for Camel. CXF-RS and SOAP components looks promissing, but I can't figure out how to implement proxying using them.
First of all, how to make Camel listen for the specified SOAP request. And then, how to route response from RESTful service back to calling service.
I tried to do it using only spring configuration.
Camel CXF will do the trick for your soap endpoint.
First you need to write an endpoint
#WebService
public interface QuoteInEndpoint {
#WebResult(name = "quote")
public Quote price(#WebParam(name = "symbol") String symbol);
}
Then you need to declare it
<cxf:cxfEndpoint id="quoteIn" address="http://localhost:9002" serviceClass="my.package.QuoteInEndpoint" />
You can then build a route from this endpoint
from("cxf:bean:quoteIn")//
.process(new Processor() {
#Override
public void process(Exchange exchange) throws Exception {
//do whatever you need to get your object and transform it for your rest service
}
})//
.to("http://myplayframeworkserver/myservice")//
Camel will start the route, expose the wsdl of your soap service at localhost:9002, and every soap request will be send to your rest server. The process method can be use to shape your objects to the correct format for your rest service (I assume json). Instead of using a processor, you might use another Camel component to do the job (Camel JSON if you need json)
There is no straight forward way to simply proxy between soap and rest. REST services, is all about resources and CRUD - create/read/update/delete. The payload can be whatever, often JSON, but XML, plain text or any orther format is valid. SOAP is XML only with custom definied methods.
I understand the confusion about all the components related to this in Camel.
There are a few aspects you need to have in mind, while chosing your approach.
How much of the SOAP stack do you really need? Most likely you only want the basic featuers, such as receiving a simple soap-envelope and extract the payload without WS-addressing, ws-security etc. etc.
Do you have a contract first or code first approach? That is, do you have your soap service already definied by java classes/interfaces or do you have a WSDL?
Do you have your camel instance deployed inside a servlet container (which is quite common), such as Tomcat, Jetty or a JavaEE app server? If you, you might need to use that servlet container to handle requests by some reason (to get all requests from the same port/server/Domain name by some reason such as web server virtual host, firewalls etc). Then CXF might ge a bit tricky. Otherwise, camel can put up listeners with the built-in jetty core.
So:
Contract first and camel inside serverletcontainer - I prefer spring-ws, since it's very easy to get started with. spring-ws component. Just do the initial wireing in spring and you do not even need to generate things from a WSDL, just simply point out which soap-action, uri or rootq name to get messages from:
from("spring-ws:soapaction:http://example.com/GetFoo?endpointMapping=#endpointMapping")
then you have the XML.
If you need to host the web service from camel, CXF in payload mode is quite decent and will behave pretty much the same.
from("cxf:somename:http://localhost:8765?wsdl=somewsdlfile.wsdl&dataFormat=PAYLOAD")
If you have the service definied in Java already, you could use the SOAP dataformat with the Jetty component to get a very lightweight solution.
SoapJaxbDataFormat soap = new SoapJaxbDataFormat("com.example.customerservice", new ServiceInterfaceStrategy(CustomerService.class));
from("jetty:http://localhost:9832/soapsrv")
.marshal(soap) // and other transforms here
.to("http://somerestservicehost/srv");
Or. go with the full CXF solution with CXF or CXF-bean. There are plenty of examples on the camel website. But the component is rather large and can be somewhat tricky.
For rest, there are also choices, but that part is more straight forward. Rest is very much about creating some content (by extracting it from the soap message, and perhaps map xml to json), which might be easiest to achieve with some plain old java code. Then just invoke a HTTP endpoint towards your rest server. The HTTP4 or HTTP component will do a lot of this for you.
CXFRS is good if you like CXF, and can provide some help, specifically if you want to model your rest service with classes

Resources