Chapter 31. Scripting
JBoss Data Grid includes a method of storing scripts on servers, allowing remote clients to execute scripts locally with the JDK's
javax.script.ScriptEngines. By default the JDK comes with Nashorn, capable of running JavaScript; however, this may be extended to run any JVM language that offers their own ScriptEngine.
31.1. Accessing the Script Cache
Scripts are stored in a special, protected cache entitled
___script_cache. As this is a protected cache only loopback requests or connections with authorization enabled will be allowed to access the cache.
The following requirements must be met to connect to the
___script_cache remotely:
- A user has been defined with the
___script_managerrole. - The client has a secure connection to the server; this may be attained by following the instructions in Section 20.7, “Securing Interfaces”.
- Authorization has been enabled on the cache-container.
Example 31.1. Configuring the Server for Access the Script Cache
The following example covers configuring the server to access the script cache, using the
DIGEST-MD5 method of securing the Hot Rod connector.
- Add a user to the server as follows:
- Execute the
$JDG_HOME/bin/add-user.sh(Linux) or$JDG_HOME\bin\add-user.bat(Windows) script. - Enter
bat the first prompt to create anApplicationRealmuser.What type of user do you wish to add? a) Management User (mgmt-users.properties) b) Application User (application-users.properties) (a): b
- Follow the prompts to define the desired username and password for the user.
- When prompted for the groups enter
___script_managerfor this user:What groups do you want this user to belong to? (Please enter a comma separated list, or leave blank for none)[ ]: ___script_manager
- Secure the communication between the client and server. As this example is using
DIGEST-MD5the instructions in will be followed. The following snippet demonstrates the necessary xml configuration:<cache-container name="local" default-cache="default" statistics="true"> <security> <authorization> <identity-role-mapper /> <role name="admin" permissions="ALL" /> <role name="reader" permissions="READ" /> <role name="writer" permissions="WRITE" /> <role name="supervisor" permissions="READ WRITE EXEC BULK" /> </authorization> </security> [...] <cache-container> [...] <hotrod-connector socket-binding="hotrod" cache-container="local"> <authentication security-realm="ApplicationRealm"> <sasl server-name="scriptserver" mechanisms="DIGEST-MD5" qop="auth" /> </authentication> </hotrod-connector> - Create the cache manager using the secured connection, as seen in the following code snippet:
Configuration config = new ConfigurationBuilder() .addServer() .host("localhost") .port(11222) .security() .authentication() .enable() .saslMechanism("DIGEST-MD5") .serverName("scriptserver") .callbackHandler(new MyCallbackHandler("user", "ApplicationRealm", "password".toCharArray())) .build(); cacheManager = new RemoteCacheManager(config);
