add a config adjust the property source overriden behavior

apollo-client/src/main/java/com/ctrip/framework/apollo/spring/boot/ApolloApplicationContextInitializer.java

@@ -39,6 +39,7 @@
 import org.springframework.core.Ordered;
 import org.springframework.core.env.CompositePropertySource;
 import org.springframework.core.env.ConfigurableEnvironment;
+import org.springframework.core.env.StandardEnvironment;
 
 /**
  * Initialize apollo system properties and inject the Apollo config in Spring Boot bootstrap phase
@@ -140,7 +141,12 @@ protected void initialize(ConfigurableEnvironment environment) {
 
       composite.addPropertySource(configPropertySourceFactory.getConfigPropertySource(namespace, config));
     }
-
+    if (environment.getPropertySources().contains(StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME)) {
+      if (!isOverrideSystemProperties(environment)) {
+        environment.getPropertySources().addAfter(StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME, composite);
+        return;
+      }
+    }
     environment.getPropertySources().addFirst(composite);
   }
 
@@ -215,4 +221,9 @@ public int getOrder() {
   public void setOrder(int order) {
     this.order = order;
   }
+
+
+  private boolean isOverrideSystemProperties(ConfigurableEnvironment environment) {
+    return environment.getProperty(PropertySourcesConstants.APOLLO_OVERRIDE_SYSTEM_PROPERTIES, Boolean.class, true);
+  }
 }

apollo-client/src/main/java/com/ctrip/framework/apollo/spring/config/PropertySourcesConstants.java

@@ -22,4 +22,5 @@ public interface PropertySourcesConstants {
   String APOLLO_BOOTSTRAP_ENABLED = "apollo.bootstrap.enabled";
   String APOLLO_BOOTSTRAP_EAGER_LOAD_ENABLED = "apollo.bootstrap.eagerLoad.enabled";
   String APOLLO_BOOTSTRAP_NAMESPACES = "apollo.bootstrap.namespaces";
+  String APOLLO_OVERRIDE_SYSTEM_PROPERTIES = "apollo.bootstrap.overrideSystemProperties";
 }

apollo-client/src/main/java/com/ctrip/framework/apollo/spring/config/PropertySourcesProcessor.java

@@ -40,11 +40,7 @@
 import org.springframework.context.EnvironmentAware;
 import org.springframework.core.Ordered;
 import org.springframework.core.PriorityOrdered;
-import org.springframework.core.env.CompositePropertySource;
-import org.springframework.core.env.ConfigurableEnvironment;
-import org.springframework.core.env.Environment;
-import org.springframework.core.env.MutablePropertySources;
-import org.springframework.core.env.PropertySource;
+import org.springframework.core.env.*;
 
 /**
  * Apollo Property Sources processor for Spring Annotation Based Application. <br /> <br />
@@ -110,12 +106,20 @@ private void initializePropertySources() {
     if (environment.getPropertySources()
         .contains(PropertySourcesConstants.APOLLO_BOOTSTRAP_PROPERTY_SOURCE_NAME)) {
 
-      // ensure ApolloBootstrapPropertySources is still the first
-      ensureBootstrapPropertyPrecedence(environment);
+      if (isOverrideSystemProperties(environment)) {
+        // ensure ApolloBootstrapPropertySources is still the first
+        ensureBootstrapPropertyPrecedence(environment);
+      }
 
       environment.getPropertySources()
           .addAfter(PropertySourcesConstants.APOLLO_BOOTSTRAP_PROPERTY_SOURCE_NAME, composite);
     } else {
+      if (environment.getPropertySources().contains(StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME)) {
+        if (!isOverrideSystemProperties(environment)) {
+          environment.getPropertySources().addAfter(StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME, composite);
+          return;
+        }
+      }
       environment.getPropertySources().addFirst(composite);
     }
   }
@@ -149,6 +153,10 @@ private void initializeAutoUpdatePropertiesFeature(ConfigurableListableBeanFacto
     }
   }
 
+  private Boolean isOverrideSystemProperties(ConfigurableEnvironment environment) {
+    return environment.getProperty(PropertySourcesConstants.APOLLO_OVERRIDE_SYSTEM_PROPERTIES, Boolean.class, true);
+  }
+
   @Override
   public void setEnvironment(Environment environment) {
     //it is safe enough to cast as all known environment is derived from ConfigurableEnvironment

apollo-client/src/main/resources/META-INF/additional-spring-configuration-metadata.json

@@ -35,6 +35,13 @@
       "description": "enable apollo initialization before logging system initialization.",
       "defaultValue": false
     },
+    {
+      "name": "apollo.bootstrap.overrideSystemProperties",
+      "type": "java.lang.Boolean",
+      "sourceType": "com.ctrip.framework.apollo.spring.config.PropertySourcesConstants",
+      "description": "enable apollo server config override system properties.",
+      "defaultValue": true
+    },
     {
       "name": "apollo.cache-dir",
       "type": "java.lang.String",

apollo-client/src/test/java/com/ctrip/framework/apollo/spring/boot/ApolloApplicationContextInitializerTest.java

@@ -32,6 +32,10 @@
 import org.junit.Test;
 import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.env.MutablePropertySources;
+import org.springframework.core.env.PropertiesPropertySource;
+import org.springframework.core.env.StandardEnvironment;
+
+import java.util.Properties;
 
 public class ApolloApplicationContextInitializerTest {
 
@@ -143,4 +147,24 @@ public void testPropertyNamesCacheEnabled() {
     assertTrue(propertySources.contains(PropertySourcesConstants.APOLLO_BOOTSTRAP_PROPERTY_SOURCE_NAME));
     assertTrue(propertySources.iterator().next() instanceof CachedCompositePropertySource);
   }
+
+  @Test
+  public void testOverrideSystemProperties() {
+    Properties properties = new Properties();
+    properties.setProperty("server.port", "8080");
+    ConfigurableEnvironment environment = mock(ConfigurableEnvironment.class);
+
+    MutablePropertySources propertySources = new MutablePropertySources();
+    propertySources.addLast(new PropertiesPropertySource(StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME, properties));
+
+    when(environment.getPropertySources()).thenReturn(propertySources);
+    when(environment.getProperty(PropertySourcesConstants.APOLLO_OVERRIDE_SYSTEM_PROPERTIES, Boolean.class, true)).thenReturn(false);
+    when(environment.getProperty(PropertySourcesConstants.APOLLO_BOOTSTRAP_NAMESPACES,
+            ConfigConsts.NAMESPACE_APPLICATION)).thenReturn("");
+
+    apolloApplicationContextInitializer.initialize(environment);
+
+    assertTrue(propertySources.contains(PropertySourcesConstants.APOLLO_BOOTSTRAP_PROPERTY_SOURCE_NAME));
+    assertEquals(propertySources.iterator().next().getName(), StandardEnvironment.SYSTEM_ENVIRONMENT_PROPERTY_SOURCE_NAME);
+  }
 }