Only set ribbon properties if they are not already set.

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/ribbon/eureka/EurekaRibbonClientPreprocessor.java

@@ -6,6 +6,8 @@ import static com.netflix.client.config.CommonClientConfigKey.NFLoadBalancerRule
 import static com.netflix.client.config.CommonClientConfigKey.NIWSServerListClassName;
 import static com.netflix.client.config.CommonClientConfigKey.NIWSServerListFilterClassName;
 
+import com.netflix.config.DynamicPropertyFactory;
+import com.netflix.config.DynamicStringProperty;
 import org.springframework.cloud.netflix.ribbon.RibbonClientPreprocessor;
 import org.springframework.cloud.netflix.ribbon.SpringClientFactory;
 
@@ -29,7 +31,10 @@ import com.netflix.niws.loadbalancer.DiscoveryEnabledNIWSServerList;
  */
 public class EurekaRibbonClientPreprocessor implements RibbonClientPreprocessor {
 
-	private EurekaClientConfig clientConfig;
+    protected static final String VALUE_NOT_SET = "__not__set__";
+    protected static final String DEFAULT_NAMESPACE = "ribbon";
+
+    private EurekaClientConfig clientConfig;
     private SpringClientFactory clientFactory;
 
     public EurekaRibbonClientPreprocessor(EurekaClientConfig clientConfig, SpringClientFactory clientFactory) {
@@ -83,9 +88,19 @@ public class EurekaRibbonClientPreprocessor implements RibbonClientPreprocessor
 
 	protected void setProp(String serviceId, String suffix, String value) {
 		// how to set the namespace properly?
-		String namespace = "ribbon";
-		ConfigurationManager.getConfigInstance().setProperty(
-				serviceId + "." + namespace + "." + suffix, value);
+        String key = getKey(serviceId, suffix);
+        DynamicStringProperty property = getProperty(key);
+        if (property.get().equals(VALUE_NOT_SET)) {
+            ConfigurationManager.getConfigInstance().setProperty(key, value);
+        }
 	}
 
+    protected DynamicStringProperty getProperty(String key) {
+        return DynamicPropertyFactory.getInstance().getStringProperty(key, VALUE_NOT_SET);
+    }
+
+    protected String getKey(String serviceId, String suffix) {
+        return serviceId + "." + DEFAULT_NAMESPACE + "." + suffix;
+    }
+
 }

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/ribbon/eureka/EurekaRibbonClientPreprocessorTests.java

@@ -18,7 +18,9 @@ package org.springframework.cloud.netflix.ribbon.eureka;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
+import static org.springframework.cloud.netflix.ribbon.eureka.EurekaRibbonClientPreprocessor.*;
 
+import com.netflix.config.DynamicStringProperty;
 import org.junit.After;
 import org.junit.Test;
 import org.springframework.cloud.netflix.ribbon.SpringClientFactory;
@@ -57,4 +59,28 @@ public class EurekaRibbonClientPreprocessorTests {
 		assertEquals("foo", ConfigurationManager.getDeploymentContext().getValue(ContextKey.zone));
 	}
 
+    @Test
+    public void testSetProp() {
+        EurekaClientConfigBean client = new EurekaClientConfigBean();
+        SpringClientFactory clientFactory = new SpringClientFactory();
+        EurekaRibbonClientPreprocessor preprocessor = new EurekaRibbonClientPreprocessor(
+                client, clientFactory);
+
+        String serviceId = "myService";
+        String suffix = "mySuffix";
+        String value = "myValue";
+
+        DynamicStringProperty property = preprocessor.getProperty(preprocessor.getKey(serviceId, suffix));
+
+        assertEquals("property doesn't have default value", VALUE_NOT_SET, property.get());
+
+        preprocessor.setProp(serviceId, suffix, value);
+
+        assertEquals("property has wrong value", value, property.get());
+
+        preprocessor.setProp(serviceId, suffix, value);
+
+        assertEquals("property has wrong value", value, property.get());
+    }
+
 }