pocketflow/cookbook/pocketflow-node

PocketFlow Summarize

A practical example demonstrating how to use PocketFlow to build a robust text summarization tool with error handling and retries. This example showcases core PocketFlow concepts in a real-world application.

Features

• Text summarization using LLMs (Large Language Models)
• Automatic retry mechanism (up to 3 attempts) on API failures
• Graceful error handling with fallback responses
• Clean separation of concerns using PocketFlow's Node architecture

Project Structure

.
├── docs/          # Documentation files
├── utils/         # Utility functions (LLM API wrapper)
├── flow.py        # PocketFlow implementation with Summarize Node
├── main.py        # Main application entry point
└── README.md      # Project documentation

Implementation Details

The example implements a simple but robust text summarization workflow:

1. Summarize Node (flow.py):

   • prep(): Retrieves text from the shared store
   • exec(): Calls LLM to summarize text in 10 words
   • exec_fallback(): Provides graceful error handling
   • post(): Stores the summary back in shared store

2. Flow Structure:

   • Single node flow for demonstration
   • Configured with 3 retries for reliability
   • Uses shared store for data passing

Setup

1. Create a virtual environment:

python -m venv venv
source venv/bin/activate  # On Windows: venv\Scripts\activate

2. Install dependencies:

pip install -r requirements.txt

3. Configure your environment:

   • Set up your LLM API key (check utils/call_llm.py for configuration)

4. Run the example:

python main.py

Example Usage

The example comes with a sample text about PocketFlow, but you can modify main.py to summarize your own text:

shared = {"data": "Your text to summarize here..."}
flow.run(shared)
print("Summary:", shared["summary"])

What You'll Learn

This example demonstrates several key PocketFlow concepts:

• Node Architecture: How to structure LLM tasks using prep/exec/post pattern
• Error Handling: Implementing retry mechanisms and fallbacks
• Shared Store: Using shared storage for data flow between steps
• Flow Creation: Setting up a basic PocketFlow workflow

Additional Resources

• PocketFlow Documentation
• Node Concept Guide
• Flow Design Patterns