linuxcnc-grpc

gRPC interface for LinuxCNC machine control and HAL (Hardware Abstraction Layer).

Why gRPC?

LinuxCNC's native Python API only works locally. This project exposes it over gRPC, enabling:

• Remote monitoring - Build web dashboards, mobile apps, or desktop GUIs
• Multi-machine management - Monitor a fleet of CNC machines from one place
• Any-language integration - Use Go, Node.js, Rust, or any gRPC-supported language
• Real-time streaming - Subscribe to status updates instead of polling

Running the Server

The server runs on your LinuxCNC machine and exposes the gRPC interface.

Basic Usage

pip install linuxcnc-grpc
# or with uv
uv pip install linuxcnc-grpc

linuxcnc-grpc --host 0.0.0.0 --port 50051

LinuxCNC must already be running before starting the server.

Auto-start with LinuxCNC

To start the gRPC server automatically when LinuxCNC launches, add to your machine's HAL file:

# Start gRPC server (runs until LinuxCNC exits)
loadusr linuxcnc-grpc --host 0.0.0.0 --port 50051

Or use a dedicated HAL file via your INI:

[HAL]
POSTGUI_HALFILE = grpc-server.hal

Quick Start

Python

pip install linuxcnc-grpc

PyPI package

import grpc
from linuxcnc_pb import linuxcnc_pb2, linuxcnc_pb2_grpc

channel = grpc.insecure_channel("localhost:50051")
stub = linuxcnc_pb2_grpc.LinuxCNCServiceStub(channel)

status = stub.GetStatus(linuxcnc_pb2.GetStatusRequest())
print(f"Position: X={status.position.x:.3f} Y={status.position.y:.3f} Z={status.position.z:.3f}")

Go

go get github.com/dougcalobrisi/linuxcnc-grpc

pkg.go.dev

import (
    pb "github.com/dougcalobrisi/linuxcnc-grpc/packages/go"
    "google.golang.org/grpc"
    "google.golang.org/grpc/credentials/insecure"
)

conn, _ := grpc.NewClient("localhost:50051", grpc.WithTransportCredentials(insecure.NewCredentials()))
client := pb.NewLinuxCNCServiceClient(conn)

status, _ := client.GetStatus(context.Background(), &pb.GetStatusRequest{})
fmt.Printf("Position: X=%.3f Y=%.3f Z=%.3f\n", status.Position.X, status.Position.Y, status.Position.Z)

Node.js / TypeScript

npm install linuxcnc-grpc

npm package

import * as grpc from "@grpc/grpc-js";
import { LinuxCNCServiceClient, GetStatusRequest } from "linuxcnc-grpc";

const client = new LinuxCNCServiceClient("localhost:50051", grpc.credentials.createInsecure());

client.getStatus(GetStatusRequest.create(), (err, status) => {
  console.log(`Position: X=${status.position.x.toFixed(3)} Y=${status.position.y.toFixed(3)}`);
});

Rust

crates.io

[dependencies]
linuxcnc-grpc = "1.0"
tokio = { version = "1", features = ["full"] }
tonic = "0.12"

use linuxcnc_grpc::linuxcnc::linux_cnc_service_client::LinuxCncServiceClient;
use linuxcnc_grpc::linuxcnc::GetStatusRequest;

let mut client = LinuxCncServiceClient::connect("http://localhost:50051").await?;
let status = client.get_status(GetStatusRequest {}).await?.into_inner();
println!("Position: X={:.3} Y={:.3}", status.position.unwrap().x, status.position.unwrap().y);

Examples

Complete examples for all supported languages:

Example	Description	Python	Go	Node.js	Rust
get_status	Poll machine status	view	view	view	view
stream_status	Real-time status streaming	view	view	view	view
jog_axis	Jog axes with keyboard	view	view	view	view
mdi_command	Execute G-code via MDI	view	view	view	view
hal_query	Query HAL pins/signals	view	view	view	view
upload_file	Upload, list, delete G-code files	view	view	view	view

See examples/README.md for setup instructions.

Services

• LinuxCNCService - Machine control: status, jogging, MDI, program execution, file management
• HalService - HAL introspection: query pins, signals, parameters (read-only)

File Management

The server provides UploadFile, ListFiles, and DeleteFile RPCs for remote G-code file management. Files are stored in the NC files directory (default: /home/linuxcnc/linuxcnc/nc_files).

Configure the directory with --nc-files or the LINUXCNC_NC_FILES environment variable:

linuxcnc-grpc --host 0.0.0.0 --nc-files /path/to/nc_files

Safety Warning

This server provides remote control of CNC machinery. Ensure proper safety measures:

• Use only on trusted networks
• Implement authentication in production (gRPC supports TLS/mTLS)
• Never leave machines unattended during remote operation
• Verify E-stop and safety systems are functional

Production Deployment

For production use, enable TLS authentication:

# Server with TLS
credentials = grpc.ssl_server_credentials([(private_key, certificate)])
server.add_secure_port('[::]:50051', credentials)

# Client with TLS
credentials = grpc.ssl_channel_credentials(root_certificates)
channel = grpc.secure_channel('your-machine:50051', credentials)

See Server Configuration for complete TLS setup instructions.

Development

Requires uv for Python dependency management:

# Install dev dependencies
make setup

# Run tests
make test          # Python tests
make test-all      # All languages

# Generate proto code
make proto-all     # Regenerate for all languages

See CLAUDE.md for detailed development documentation.

License

MIT