added ability to configure maxConnections in TbHttpClient using env TB_POOL_MAX_CONNECTIONS

rule-engine/rule-engine-components/src/main/java/org/thingsboard/rule/engine/rest/TbHttpClient.java

@@ -42,6 +42,7 @@ import org.thingsboard.server.common.data.StringUtils;
 import org.thingsboard.server.common.msg.TbMsg;
 import org.thingsboard.server.common.msg.TbMsgMetaData;
 import reactor.netty.http.client.HttpClient;
+import reactor.netty.resources.ConnectionProvider;
 import reactor.netty.transport.ProxyProvider;
 
 import javax.net.ssl.SSLException;
@@ -95,7 +96,12 @@ public class TbHttpClient {
                 semaphore = new Semaphore(config.getMaxParallelRequestsCount());
             }
 
-            HttpClient httpClient = HttpClient.create()
+            ConnectionProvider connectionProvider = ConnectionProvider
+                    .builder("http")
+                    .maxConnections(getPoolMaxConnections())
+                    .build();
+
+            HttpClient httpClient = HttpClient.create(connectionProvider)
                     .runOn(getSharedOrCreateEventLoopGroup(eventLoopGroupShared))
                     .doOnConnected(c ->
                             c.addHandlerLast(new ReadTimeoutHandler(config.getReadTimeoutMs(), TimeUnit.MILLISECONDS)));
@@ -143,6 +149,18 @@ public class TbHttpClient {
         }
     }
 
+    private int getPoolMaxConnections() {
+        String poolMaxConnectionsEnv = System.getenv("TB_POOL_MAX_CONNECTIONS");
+
+        int poolMaxConnections;
+        if (poolMaxConnectionsEnv != null) {
+            poolMaxConnections = Integer.parseInt(poolMaxConnectionsEnv);
+        } else {
+            poolMaxConnections = ConnectionProvider.DEFAULT_POOL_MAX_CONNECTIONS;
+        }
+        return poolMaxConnections;
+    }
+
     private void validateMaxInMemoryBufferSize(TbRestApiCallNodeConfiguration config) throws TbNodeException {
         int systemMaxInMemoryBufferSizeInKb = 25000;
         try {