Package com.scivicslab.turingworkflow.plugins.ssh.mixin

Interface CommandExecutable

public interface CommandExecutable
Mixin interface providing command execution actions via @Action annotations.

This interface demonstrates the mixin pattern in Java using interface default methods with Action annotations. Classes implementing this interface automatically gain the ability to execute commands from workflow YAML without duplicating code.

Usage

Implement this interface and provide a CommandExecutor:


 public class NodeInterpreter extends Interpreter implements CommandExecutable {
     private final CommandExecutor executor;

     public NodeInterpreter(Node node, IIActorSystem system) {
         this.executor = new SshCommandExecutor(node);
     }

     @Override
     public CommandExecutor getCommandExecutor() {
         return executor;
     }
 }

Workflow YAML

Once implemented, the following actions become available in workflow YAML:


 steps:
   - states: ["0", "1"]
     actions:
       - actor: this
         method: executeCommand
         arguments: ["ls -la"]

   - states: ["1", "2"]
     actions:
       - actor: this
         method: executeSudoCommand
         arguments: ["apt-get update"]

Design Rationale

This interface solves the problem of code duplication between NodeInterpreter and NodeGroupInterpreter. Previously, each class needed its own implementation of command execution actions. With this mixin approach:

  • Both classes implement the same interface
  • The @Action methods are defined once in the interface
  • Each class provides its own CommandExecutor (SSH or local)
  • IIActorRef discovers the @Action methods via reflection
Since:
2.15.0
Author:
devteam@scivicslab.com
See Also:

  • Method Summary

    Modifier and Type
    Method
    Description
    default com.scivicslab.pojoactor.core.ActionResult
    doExecuteCommand(String args)
    Executes a command and returns the result (action handler).
    default com.scivicslab.pojoactor.core.ActionResult
    doExecuteSudoCommand(String args)
    Executes a command with sudo privileges (action handler).
    CommandExecutor
    getCommandExecutor()
    Returns the command executor for this instance.
    default Node.OutputCallback
    getOutputCallback()
    Returns an optional output callback for command execution.

  • Method Details

    • getCommandExecutor

      CommandExecutor getCommandExecutor()
      Returns the command executor for this instance.

      Implementing classes must provide an appropriate executor:

      Returns:
      the command executor

    • getOutputCallback

      default Node.OutputCallback getOutputCallback()
      Returns an optional output callback for command execution.

      When not null, command output is streamed to this callback in real-time. Default implementation returns null (no streaming).

      Returns:
      the output callback, or null

    • doExecuteCommand

      default com.scivicslab.pojoactor.core.ActionResult doExecuteCommand(String args)
      Executes a command and returns the result (action handler).

      This action is callable from workflow YAML as:

      
 - actor: this
   method: executeCommand
   arguments: ["your-command-here"]

      Note: The Java method name is different from the action name to avoid conflicts with existing methods on implementing classes that have different return types.

      Parameters:
      args - JSON array containing the command as the first element
      Returns:
      ActionResult with success status and command output

    • doExecuteSudoCommand

      default com.scivicslab.pojoactor.core.ActionResult doExecuteSudoCommand(String args)
      Executes a command with sudo privileges (action handler).

      This action is callable from workflow YAML as:

      
 - actor: this
   method: executeSudoCommand
   arguments: ["your-command-here"]

      Requires SUDO_PASSWORD environment variable to be set.

      Note: The Java method name is different from the action name to avoid conflicts with existing methods on implementing classes that have different return types.

      Parameters:
      args - JSON array containing the command as the first element
      Returns:
      ActionResult with success status and command output