hakoniwa-pdu 1.1.3

Hakoniwa PDU communication library for Python

hakoniwa-pdu-python

Python PDU communication library for the Hakoniwa simulator. Provides a unified transport layer where RPC and Pub/Sub (topics) run seamlessly over WebSocket. For high-speed use cases, a Shared Memory (SHM) backend is also available. The architecture is extensible to Zenoh, enabling scalable and distributed systems. Binary ⇔ JSON ⇔ Python type conversion is built-in, reducing boilerplate to a minimum.

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✨ Features

• Unified layer: RPC and Pub/Sub integrated on top of WebSocket
• Automatic type conversion: safely convert between binary, JSON, and Python types with offset definitions
• Transport flexibility: choose between WebSocket, Shared Memory (SHM), and extensible backends such as Zenoh
• Explicit & secure connections: WebSocket URIs (ws://...) clearly define communication scope
• Event-driven & polling support: register handlers or poll buffers as needed
• Ready-to-run samples: minimal examples for Twist (topic) and AddTwoInts (RPC) included

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📦 Installation

pip install hakoniwa-pdu
pip show hakoniwa-pdu   # check version

Environment Variables

Specify the directory containing .offset files for PDU conversion:

export HAKO_BINARY_PATH=/your/path/to/offset

Default path if unset:

/usr/local/lib/hakoniwa/hako_binary/offset

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🚀 Quick Start (3 commands)

Example 1: WebSocket Topic (geometry_msgs/Twist publish → subscribe)

1. Publisher (server)

python examples/topic/websocket/remote_publisher.py \
  --uri ws://localhost:8080 \
  --pdu-config examples/pdu_config.json \
  --service-config examples/service.json

2. Subscriber (client)

python examples/topic/websocket/remote_subscriber.py \
  --uri ws://localhost:8080 \
  --pdu-config examples/pdu_config.json \
  --service-config examples/service.json

3. Output

[INFO] Received Twist: linear.x=0 angular.z=0
[INFO] Received Twist: linear.x=1 angular.z=1

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Example 2: WebSocket RPC (AddTwoInts service)

1. RPC Server

python examples/rpc/websocket/remote_rpc_server.py \
  --uri ws://localhost:8080 \
  --pdu-config examples/pdu_config.json \
  --service-config examples/service.json

2. RPC Client

python examples/rpc/websocket/remote_rpc_client.py \
  --uri ws://localhost:8080 \
  --pdu-config examples/pdu_config.json \
  --service-config examples/service.json

3. Output

Response: 3

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📡 Event-Driven PDU Handling

Server:

server_manager.register_handler_pdu_data(on_pdu)

def on_pdu(client_id, packet):
    ...

Client:

client_manager.register_handler_pdu_data(on_pdu)

def on_pdu(packet):
    ...

Polling via contains_buffer() / get_buffer() is also available.

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📁 Project Structure

hakoniwa_pdu/
├── pdu_manager.py
├── impl/
│   ├── icommunication_service.py
│   ├── websocket_communication_service.py
│   ├── websocket_server_communication_service.py
│   ├── shm_communication_service.py
│   ├── pdu_convertor.py
│   └── hako_binary/
├── rpc/
│   ├── ipdu_service_manager.py
│   ├── protocol_client.py
│   ├── protocol_server.py
│   ├── auto_wire.py
│   ├── remote/
│   └── shm/
├── resources/
│   └── offset/
└── examples/

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🧭 Class Overview

PduManager

• Orchestrates PDU buffers and delegates to a transport (ICommunicationService).
• Direct I/O: declare_pdu_for_read/write → flush_pdu_raw_data() / read_pdu_raw_data().
• For RPC: extended via rpc.IPduServiceManager (handles register_client, start_rpc_service, etc.).

Transport Implementations (impl/)

• ICommunicationService defines the transport API.
• WebSocketCommunicationService / WebSocketServerCommunicationService: WebSocket backend (explicit URI-based connection, simple & secure).
• ShmCommunicationService: high-speed shared memory backend.
• Pluggable design: additional transports (e.g., Zenoh) can be integrated without changing application code.

RPC Layer (rpc/)

• IPduServiceManager family provides RPC APIs (client/server).
• protocol_client.py / protocol_server.py: user-friendly helpers.
• auto_wire.py: auto-loads generated converters.
• remote/: WebSocket managers.
• shm/: SHM managers.

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🧩 Class Diagram (Mermaid)

classDiagram
    class PduManager
    PduManager --> ICommunicationService : uses
    PduManager --> CommunicationBuffer
    PduManager --> PduConvertor
    PduManager --> PduChannelConfig

    class ICommunicationService {
        <<interface>>
    }
    class WebSocketCommunicationService
    class WebSocketServerCommunicationService
    class ShmCommunicationService
    ICommunicationService <|.. WebSocketCommunicationService
    ICommunicationService <|.. WebSocketServerCommunicationService
    ICommunicationService <|.. ShmCommunicationService

    class IPduServiceManager {
        <<abstract>>
    }
    PduManager <|-- IPduServiceManager
    class IPduServiceClientManager
    class IPduServiceServerManager
    IPduServiceManager <|-- IPduServiceClientManager
    IPduServiceManager <|-- IPduServiceServerManager

    class RemotePduServiceBaseManager
    RemotePduServiceBaseManager <|-- RemotePduServiceClientManager
    RemotePduServiceBaseManager <|-- RemotePduServiceServerManager
    IPduServiceManager <|-- RemotePduServiceBaseManager

    class ShmPduServiceBaseManager
    ShmPduServiceBaseManager <|-- ShmPduServiceClientManager
    ShmPduServiceBaseManager <|-- ShmPduServiceServerManager
    IPduServiceManager <|-- ShmPduServiceBaseManager

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🔗 Links

• 📘 GitHub: https://github.com/hakoniwalab/hakoniwa-pdu-python
• 🌐 Hakoniwa Lab: https://hakoniwa-lab.net

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📚 Documentation

For detailed API usage: ➡️ API Reference (api-doc.md)

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📜 License

MIT License — see LICENSE