31.8. Script Execution Using the Hot Rod C# Client

The Hot Rod C# client allows tasks to be executed directly on JBoss Data Grid servers via Remote Execution. This feature executes logic close to the data, utilizing the resources of all nodes in the cluster. Tasks may be deployed to the server instances, and may then be executed programmatically.

Important

Remote Execution is a Technology Preview feature of the Hot Rod C# client in JBoss Data Grid 7.0.0.
Installing a Task

Tasks may be installed on the server by being using the Put(string name, string script) method of the ___script_cache. The extension of the script name determines the engine used to execute the script; however, this may be overridden by metadata in the script itself.

The following example demonstrates installing scripts: 
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Infinispan.HotRod;
using Infinispan.HotRod.Config;

namespace RemoteExec
{
    /// <summary>
    /// This sample code shows how to perform a server remote execution using the C# client
    /// </summary>
    class RemoteExec
    {
        static void Main(string[] args)
        {
            // Cache manager setup
            RemoteCacheManager remoteManager;
            IMarshaller marshaller;
            ConfigurationBuilder conf = new ConfigurationBuilder();
            conf.AddServer().Host("127.0.0.1").Port(11222).ConnectionTimeout(90000).SocketTimeout(6000);
            marshaller = new JBasicMarshaller();
            conf.Marshaller(marshaller);
            remoteManager = new RemoteCacheManager(conf.Build(), true);

            // Install the .js code into the Infinispan __script_cache
            const string PROTOBUF_SCRIPT_CACHE_NAME = "___script_cache";
            string valueScriptName = "getValue.js";
            string valueScript = "// mode=local,language=javascript\n "
                 + "var cache = cacheManager.getCache(\"namedCache\");\n "
                 + "var ct = cache.get(\"accessCounter\");\n "
                 + "var c = ct==null ? 0 : parseInt(ct);\n "
                 + "cache.put(\"accessCounter\",(++c).toString());\n "
                 + "cache.get(\"privateValue\") ";
            string accessScriptName = "getAccess.js";
            string accessScript = "// mode=local,language=javascript\n "
                + "var cache = cacheManager.getCache(\"namedCache\");\n "
                + "cache.get(\"accessCounter\")";
            IRemoteCache<string, string> scriptCache = remoteManager.GetCache<string, string>(PROTOBUF_SCRIPT_CACHE_NAME);
            IRemoteCache<string, string> testCache = remoteManager.GetCache<string, string>("namedCache");
            scriptCache.Put(valueScriptName, valueScript);
            scriptCache.Put(accessScriptName, accessScript);
Executing a Task

Once installed, a task may be executed by using the execute(string name, Dictionary<string, string> scriptArgs method, passing in the name of the script to execute, along with any arguments that are required for execution.

The following example demonstrates installing scripts: 
            // This example continues the previous codeblock
            testCache.Put("privateValue", "Counted Access Value");
            Dictionary<string, string> scriptArgs = new Dictionary<string, string>();
            byte[] ret1 = testCache.Execute(valueScriptName, scriptArgs);
            string value = (string)marshaller.ObjectFromByteBuffer(ret1);
            byte[] ret2 = testCache.Execute(accessScriptName, scriptArgs);
            string accessCount = (string)marshaller.ObjectFromByteBuffer(ret2);
            Console.Write("Return value is '" + value + "' and has been accessed '" + accessCount + "' times.");

        }
    }
}
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