feat: support portal restTemplate Client connection pool config

CHANGES.md

@@ -14,6 +14,7 @@ Apollo 2.3.0
 * [Fix the role permission deletion issue when appid contains '_'](https://github.com/apolloconfig/apollo/pull/5150)
 * [fix: -XX:HeapDumpPath doesn't ready when meet OOM](https://github.com/apolloconfig/apollo/pull/5157)
 * [Fix the error occurred when using configuration retention feature](https://github.com/apolloconfig/apollo/pull/5162)
+* [Feature support portal restTemplate Client connection pool config](https://github.com/apolloconfig/apollo/pull/5200)
 
 ------------------
 All issues and pull requests are [here](https://github.com/apolloconfig/apollo/milestone/14?closed=1)

apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/component/RestTemplateFactory.java

@@ -20,6 +20,7 @@
 import com.ctrip.framework.apollo.portal.component.config.PortalConfig;
 import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClientBuilder;
+import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
@@ -59,8 +60,14 @@ public boolean isSingleton() {
   }
 
   public void afterPropertiesSet() throws UnsupportedEncodingException {
+
+    PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager();
+    connectionManager.setMaxTotal(portalConfig.connectPoolMaxTotal());
+    connectionManager.setDefaultMaxPerRoute(portalConfig.connectPoolMaxPerRoute());
+
     CloseableHttpClient httpClient = HttpClientBuilder.create()
         .setConnectionTimeToLive(portalConfig.connectionTimeToLive(), TimeUnit.MILLISECONDS)
+        .setConnectionManager(connectionManager)
         .build();
 
     restTemplate = new RestTemplate(httpMessageConverters.getConverters());

apollo-portal/src/main/java/com/ctrip/framework/apollo/portal/component/config/PortalConfig.java

@@ -173,6 +173,14 @@ public int connectionTimeToLive() {
     return getIntProperty("api.connectionTimeToLive", -1);
   }
 
+  public int connectPoolMaxTotal() {
+    return getIntProperty("api.pool.max.total", 20);
+  }
+
+  public int connectPoolMaxPerRoute() {
+    return getIntProperty("api.pool.max.per.route", 2);
+  }
+
   public List<Organization> organizations() {
 
     String organizations = getValue("organizations");