Provide better error handling for invalid hostnames. Fixes #159.

spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/LoadBalancerInterceptor.java

@@ -23,6 +23,7 @@
 import org.springframework.http.client.ClientHttpRequestExecution;
 import org.springframework.http.client.ClientHttpRequestInterceptor;
 import org.springframework.http.client.ClientHttpResponse;
+import org.springframework.util.Assert;
 
 /**
  * @author Spencer Gibb
@@ -42,6 +43,7 @@ public ClientHttpResponse intercept(final HttpRequest request, final byte[] body
 			final ClientHttpRequestExecution execution) throws IOException {
 		final URI originalUri = request.getURI();
 		String serviceName = originalUri.getHost();
+		Assert.state(serviceName != null, "Request URI does not contain a valid hostname: " + originalUri);
 		return this.loadBalancer.execute(serviceName,
 				new LoadBalancerRequest<ClientHttpResponse>() {
 					@Override

spring-cloud-commons/src/main/java/org/springframework/cloud/client/loadbalancer/RetryLoadBalancerInterceptor.java

@@ -12,6 +12,7 @@
 import org.springframework.retry.RetryContext;
 import org.springframework.retry.policy.NeverRetryPolicy;
 import org.springframework.retry.support.RetryTemplate;
+import org.springframework.util.Assert;
 
 /**
  * @author Ryan Baxter
@@ -38,6 +39,7 @@ public ClientHttpResponse intercept(final HttpRequest request, final byte[] body
 										final ClientHttpRequestExecution execution) throws IOException {
 		final URI originalUri = request.getURI();
 		final String serviceName = originalUri.getHost();
+		Assert.state(serviceName != null, "Request URI does not contain a valid hostname: " + originalUri);
 		LoadBalancedRetryPolicy retryPolicy = lbRetryPolicyFactory.create(serviceName,
 				loadBalancer);
 		retryTemplate.setRetryPolicy(

spring-cloud-commons/src/test/java/org/springframework/cloud/client/loadbalancer/RetryLoadBalancerInterceptorTest.java

@@ -16,6 +16,7 @@
 import org.springframework.retry.policy.NeverRetryPolicy;
 import org.springframework.retry.support.RetryTemplate;
 
+import static org.bouncycastle.crypto.tls.ConnectionEnd.client;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.Matchers.is;
 import static org.mockito.Matchers.any;
@@ -69,6 +70,25 @@ public void interceptDisableRetry() throws Throwable {
         verify(retryTemplate, times(1)).setRetryPolicy(any(NeverRetryPolicy.class));
     }
 
+    @Test(expected = IllegalStateException.class)
+    public void interceptInvalidHost() throws Throwable {
+        HttpRequest request = mock(HttpRequest.class);
+        when(request.getURI()).thenReturn(new URI("http://foo_underscore"));
+        ClientHttpResponse clientHttpResponse = new MockClientHttpResponse(new byte[]{}, HttpStatus.OK);
+        LoadBalancedRetryPolicy policy = mock(LoadBalancedRetryPolicy.class);
+        InterceptorRetryPolicy interceptorRetryPolicy = new InterceptorRetryPolicy(request, policy, client,"foo");
+        LoadBalancedRetryPolicyFactory lbRetryPolicyFactory = mock(LoadBalancedRetryPolicyFactory.class);
+        when(lbRetryPolicyFactory.create(eq("foo_underscore"), any(ServiceInstanceChooser.class))).thenReturn(policy);
+        ServiceInstance serviceInstance = mock(ServiceInstance.class);
+        when(client.choose(eq("foo_underscore"))).thenReturn(serviceInstance);
+        when(client.execute(eq("foo_underscore"), eq(serviceInstance), any(LoadBalancerRequest.class))).thenReturn(clientHttpResponse);
+        lbProperties.setEnabled(true);
+        RetryLoadBalancerInterceptor interceptor = new RetryLoadBalancerInterceptor(client, retryTemplate, lbProperties, lbRetryPolicyFactory);
+        byte[] body = new byte[]{};
+        ClientHttpRequestExecution execution = mock(ClientHttpRequestExecution.class);
+        ClientHttpResponse rsp = interceptor.intercept(request, body, execution);
+    }
+
     @Test
     public void interceptNeverRetry() throws Throwable {
         HttpRequest request = mock(HttpRequest.class);