Node palette (drag & drop)

[ralyodio]

📋 Product Requirements Document

PRD: Node palette (drag & drop)

Issue: #121
Milestone: Phase 3: Frontend (SvelteKit)
Labels: workflow-builder, hacktoberfest

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PRD: Node Palette (Drag & Drop)

Overview

This task focuses on enhancing the visual workflow builder within the MeshHook project by implementing a node palette that supports drag-and-drop functionality. This feature is pivotal for MeshHook's objective to provide a user-friendly, visually intuitive workflow engine, akin to n8n's ease of use but with the robust, deterministic execution model inspired by Temporal. The drag-and-drop node palette will allow users to easily construct and modify workflows by dragging nodes from the palette into the DAG (Directed Acyclic Graph) builder interface. This capability aligns with our goals to enhance user experience and efficiency in workflow creation and modification.

Functional Requirements

1. Node Palette UI: Develop a user interface for the node palette that lists available workflow nodes (e.g., transform, http_call, branch, delay, terminate).
2. Drag-and-Drop Mechanism: Implement a mechanism that allows users to drag nodes from the palette and drop them into the DAG builder area.
3. Node Placement Validation: Ensure that nodes dropped into the DAG builder are validated for correct placement within the workflow structure.
4. State Management: Update the workflow's state in real-time as nodes are added or repositioned within the DAG builder.
5. Visual Feedback: Provide visual feedback during drag operations to indicate valid drop zones within the DAG builder.

Non-Functional Requirements

• Performance: The drag-and-drop operations must be smooth and responsive, with no perceptible lag to the user.
• Usability: The UI/UX design of the node palette and drag-and-drop functionality should be intuitive, requiring minimal instruction for new users.
• Reliability: The feature should function consistently across different browsers and devices.
• Scalability: The implementation must be able to handle an expanding library of nodes as new types are added to the system.

Technical Specifications

Architecture Context

• Frontend: SvelteKit/Svelte 5 for the DAG builder UI.
• State Management: Local component state and/or global state management (e.g., Svelte stores) to handle the drag-and-drop operations and workflow modifications.

Implementation Approach

1. UI Design: Sketch the node palette UI and drag-and-drop interactions, focusing on usability and simplicity.
2. Frontend Implementation:
   • Develop the node palette component with a list of available nodes.
   • Implement the drag-and-drop functionality using Svelte's action and store mechanisms to manage state during drag operations.
   • Validate node placements within the DAG builder to ensure logical workflow construction.
3. State Management: Utilize Svelte stores to manage and update the workflow state as nodes are added or moved.
4. Integration Testing: Ensure the new feature integrates seamlessly with existing workflow builder components, maintaining state consistency and performance.

Data Model

No changes to the backend data model are required for this feature. The focus is on frontend enhancements to improve the user experience in workflow construction.

API Endpoints

No new API endpoints are required. This feature operates within the frontend, utilizing existing endpoints for workflow state management and persistence.

Acceptance Criteria

• Node palette UI is implemented and visually aligns with the existing design language of MeshHook.
• Users can drag nodes from the palette and drop them into the DAG builder.
• Drag-and-drop operations provide real-time visual feedback and validation.
• Workflow state updates accurately reflect changes made through the drag-and-drop interface.
• The feature works reliably across supported browsers and devices.
• Performance benchmarks are met, ensuring smooth and responsive interactions.
• Integration tests confirm that the feature integrates well with existing components.

Dependencies

• SvelteKit/Svelte 5 for frontend development.
• Existing workflow builder components and state management logic.

Implementation Notes

Development Guidelines

• Utilize Svelte's reactivity model and stores for efficient state management during drag-and-drop operations.
• Adhere to the project's coding standards and best practices for Svelte and JavaScript development.
• Prioritize accessibility and usability in UI design and interaction patterns.

Testing Strategy

• Unit Tests: Cover drag-and-drop logic and state updates with unit tests.
• Integration Tests: Test the integration of the node palette with the existing DAG builder and workflow state management system.
• User Acceptance Testing (UAT): Conduct UAT to gather feedback on the usability and functionality of the drag-and-drop feature.

Security Considerations

• Ensure that client-side operations do not expose or allow manipulation of workflow data beyond the user's permissions.

Monitoring & Observability

• Instrument frontend performance monitoring to track the responsiveness and efficiency of the drag-and-drop operations.

This PRD aligns the node palette (drag & drop) feature with the overarching goals of the MeshHook project, focusing on enhancing the user experience in workflow creation and modification while adhering to the project's technical and architectural standards.

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This PRD was AI-generated using gpt-4-turbo-preview from GitHub issue #121
Generated: 2025-10-10

📎 Generated Documentation

• 📄 PRD Document: 121-node-palette-drag-drop.md
• 🎨 PlantUML Diagram: 121-node-palette-drag-drop.puml
• 🖼️ Diagram Image: 121-node-palette-drag-drop.png

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This issue body was auto-generated from the PRD. Original issue content is preserved in the PRD document.
Last updated: 2025-10-10