Configuring apache-camel route to external URL with JavaDSL - rest

Question

I'm developing 'proxy' service using apache-camel.
There is my pom file
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.comapany</groupId>
<artifactId>proxy</artifactId>
<version>1.0-SNAPSHOT</version>
<name>Fabric8 :: Quickstarts :: Spring-Boot :: Camel</name>
<description>Spring Boot example running a Camel route</description>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<!-- configure the versions you want to use here -->
<fabric8.version>3.0.11.fuse-000039-redhat-1</fabric8.version>
<spring-boot.version>1.5.12.RELEASE</spring-boot.version>
<arquillian-cube.version>1.9.0</arquillian-cube.version>
<assertj.version>2.4.1</assertj.version>
<!-- maven plugin versions -->
<fabric8.maven.plugin.version>3.5.33.fuse-000067-redhat-1</fabric8.maven.plugin.version>
<maven-compiler-plugin.version>3.6.0</maven-compiler-plugin.version>
<maven-surefire-plugin.version>2.19.1</maven-surefire-plugin.version>
</properties>
<dependencyManagement>
<dependencies>
<dependency>
<groupId>io.fabric8</groupId>
<artifactId>fabric8-project-bom-camel-spring-boot</artifactId>
<version>${fabric8.version}</version>
<type>pom</type>
<scope>import</scope>
</dependency>
</dependencies>
</dependencyManagement>
<dependencies>
<!-- Enabling health checks -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-actuator</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-undertow</artifactId>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-servlet</artifactId>
</dependency>
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-http</artifactId>
<version>2.22.0</version>
</dependency>
<!-- testing -->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.jboss.arquillian.junit</groupId>
<artifactId>arquillian-junit-container</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.arquillian.cube</groupId>
<artifactId>arquillian-cube-openshift</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>io.fabric8</groupId>
<artifactId>kubernetes-assertions</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<defaultGoal>spring-boot:run</defaultGoal>
<plugins>
<plugin>
<artifactId>maven-compiler-plugin</artifactId>
<version>${maven-compiler-plugin.version}</version>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-surefire-plugin</artifactId>
<version>${maven-surefire-plugin.version}</version>
<inherited>true</inherited>
<configuration>
<argLine>-DenableImageStreamDetection=true</argLine>
<excludes>
<exclude>**/*KT.java</exclude>
</excludes>
</configuration>
</plugin>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<version>${spring-boot.version}</version>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
</execution>
</executions>
</plugin>
<plugin>
<groupId>io.fabric8</groupId>
<artifactId>fabric8-maven-plugin</artifactId>
<version>${fabric8.maven.plugin.version}</version>
<executions>
<execution>
<goals>
<goal>resource</goal>
<goal>build</goal>
</goals>
</execution>
</executions>
</plugin>
</plugins>
</build>
</project>
there is my Application.java:
#SpringBootApplication
#Configuration
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
#Bean
public ServletRegistrationBean camelServletRegistrationBean() {
ServletRegistrationBean registration = new ServletRegistrationBean(new CamelHttpTransportServlet(), "/proxy/*");
registration.setName("CamelServlet");
return registration;
}
}
and there is my routing component:
#Component
public class Router extends RouteBuilder {
#Value("${remote.base.url}")
private String baseUrl;
#Override
public void configure() throws Exception {
restConfiguration().component("servlet").bindingMode(RestBindingMode.auto);
rest()
.get("/users/{id}")
.to("direct:user_id/${header.id}");
from("direct:user_id/${header.id}")
.log(LoggingLevel.INFO, "request for users/id has been received")
.toD(baseUrl + "/redirect/${header.id}/?bridgeEndpoint=true")
.convertBodyTo(String.class);
}
}
Basically what I'm trying to achive: stand rest endpoint, log received request, redirect it to external url.
When I'm testing it with postman I got this:
org.apache.camel.http.common.HttpOperationFailedException: HTTP operation failed invoking http://localhost:8090/redirect/M70%20KEP/users/M70%20KEP with statusCode: 404
at org.apache.camel.component.http.HttpProducer.populateHttpOperationFailedException(HttpProducer.java:273)
at org.apache.camel.component.http.HttpProducer.process(HttpProducer.java:182)
at org.apache.camel.util.AsyncProcessorConverterHelper$ProcessorToAsyncProcessorBridge.process(AsyncProcessorConverterHelper.java:61)
at org.apache.camel.processor.SendDynamicProcessor$1.doInAsyncProducer(SendDynamicProcessor.java:132)
at org.apache.camel.impl.ProducerCache.doInAsyncProducer(ProducerCache.java:445)
at org.apache.camel.processor.SendDynamicProcessor.process(SendDynamicProcessor.java:127)
at org.apache.camel.processor.RedeliveryErrorHandler.process(RedeliveryErrorHandler.java:548)
at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:201)
at org.apache.camel.processor.Pipeline.process(Pipeline.java:138)
at org.apache.camel.processor.Pipeline.process(Pipeline.java:101)
at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:201)
at org.apache.camel.component.direct.DirectBlockingProducer.process(DirectBlockingProducer.java:53)
at org.apache.camel.processor.SendProcessor.process(SendProcessor.java:148)
at org.apache.camel.processor.RedeliveryErrorHandler.process(RedeliveryErrorHandler.java:548)
at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:201)
at org.apache.camel.processor.CamelInternalProcessor.process(CamelInternalProcessor.java:201)
at org.apache.camel.processor.DelegateAsyncProcessor.process(DelegateAsyncProcessor.java:97)
at org.apache.camel.http.common.CamelServlet.doService(CamelServlet.java:208)
at org.apache.camel.http.common.CamelServlet.service(CamelServlet.java:78)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:74)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129)
at org.springframework.boot.web.filter.ApplicationContextHeaderFilter.doFilterInternal(ApplicationContextHeaderFilter.java:55)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at org.springframework.boot.actuate.trace.WebRequestTraceFilter.doFilterInternal(WebRequestTraceFilter.java:111)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:99)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at org.springframework.web.filter.HttpPutFormContentFilter.doFilterInternal(HttpPutFormContentFilter.java:109)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:81)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at org.springframework.boot.actuate.autoconfigure.MetricsFilter.doFilterInternal(MetricsFilter.java:106)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:61)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84)
at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
at io.undertow.servlet.handlers.ServletChain$1.handleRequest(ServletChain.java:64)
at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:131)
at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:292)
at io.undertow.servlet.handlers.ServletInitialHandler.access$100(ServletInitialHandler.java:81)
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:138)
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:135)
at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48)
at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:272)
at io.undertow.servlet.handlers.ServletInitialHandler.access$000(ServletInitialHandler.java:81)
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:104)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:330)
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:812)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
I would be extremenly thankful if someone would explain why my intended url is appended with my rest mapping?
As well if there is an example of case I'm trying to achieve - pointing to right blog or github/gitlab/bitbucket repo would be greatly apprecited.
Thansks

Answer 1

To finalize this camel setup (and make life easier for other developers who come across the same issue).
Thanks to #Bedla for help with bridge endpoint - I wouldn't guess it without your help.
To overcome BindingException I had to add another dependency into pom file (but the error message in original exception doesn't help at all)
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-jackson</artifactId>
</dependency>
But it is not the end of the story. It happens that after removing HttpCamel headers you also remove CamelHttpMethod header, and after some time debugging I found this in code: HttpHelper -> createMethod:
// compute what method to use either GET or POST (header take precedence)
HttpMethods m = exchange.getIn().getHeader(Exchange.HTTP_METHOD, HttpMethods.class);
if (m != null) {
// always use what end-user provides in a header
answer = m;
} else if (queryString != null) {
// if a query string is provided then use GET
answer = HttpMethods.GET;
} else {
// fallback to POST if we have payload, otherwise GET
answer = hasPayload ? HttpMethods.POST : HttpMethods.GET;
}
}
So, unless you have a query string that automatically you will be using POST (which was an issue in my case).
At the end I end up with this routing configuration:
#Component
public class EmailRouter extends RouteBuilder {
#Value("${remote.base.url}")
private String baseUrl;
#Override
public void configure() throws Exception {
restConfiguration().component("servlet").bindingMode(RestBindingMode.json);
rest()
.get("/users/{id}")
.to("direct:user_id");
from("direct:user_id")
.log(LoggingLevel.INFO, "request for users/id has been received")
.removeHeaders("CamelHttp*")
.setHeader("CamelHttpMethod", constant("GET"))
.toD(baseUrl + "/redirect/${header.id}")
.convertBodyTo(String.class);
}
}