ctrlxutils

Go ctrlX Data Layer Utilities

This Go library provides utilities to simplify interaction with the Bosch Rexroth ctrlX Data Layer. It offers a high-level manager to handle the lifecycle of data layer providers and includes a generic node provider for easily exposing values.

Core Components

• DataLayerProviderManager: Manages the data layer connection and runs one or more providers in the background. It handles the creation and teardown of the datalayer.System and datalayer.Provider instances.
• IDataLayerProvider: An interface that allows for the creation of modular, custom providers. Any struct that implements the Name() and Run() methods can be managed by the DataLayerProviderManager.
• DataLayerProviderNode: A generic provider for exposing a single value of any type (T) as a node in the data layer. It automatically handles data layer events like read, write, create, and remove requests for the specified path.

Installation

To use this library, add it to your Go project.

go github.com/iotwin-at/ctrlxutils

Example Usage

The following example demonstrates how to create a custom DataLayerProviderNode and configure it using settings, that are stored to ctrlX appdata. Logs are written to jounald, such that they will be visible in CtrlX-UI's Logbook.

package main

import (
	"context"
	"os/signal"
	"syscall"
	"time"

	"github.com/boschrexroth/ctrlx-datalayer-golang/v2/pkg/datalayer"
	"github.com/iotwin-at/ctrlxutils"
	"github.com/uoul/go-common/log"
	"github.com/uoul/go-common/serialization"
)

// ---------------------------------------------------------------------------------
// Example AppConfig
// ---------------------------------------------------------------------------------
type AppConfig struct {
	UpdateRate int
}

// ---------------------------------------------------------------------------------
// Example Datalayer Provider implementation
// ---------------------------------------------------------------------------------

type CounterProvider struct {
	updateRate int
}

// Name implements ctrlxutils.IDataLayerProvider.
func (c *CounterProvider) Name() string {
	return "CounterProvider"
}

// Run implements ctrlxutils.IDataLayerProvider.
func (c *CounterProvider) Run(ctx context.Context, provider *datalayer.Provider, dlRootPath string) error {
	// Create nodes (here just one for demonstration purpose - in general a provider can host multiple nodes)
	counterNode := ctrlxutils.NewDataLayerProviderNode[int](ctx, provider, ctrlxutils.DataLayerProviderNodeConfig{
		Path:    "Counter", // Will be visible at Datalayer under <dlRootPath>/<ProviderName>/Counter
		Unit:    "inc.",
		Desc:    "Incrementing counter example",
		DescUrl: "",
	})
	// Init. value
	counterNode.SetValue(0)
	// Run Provider
	for {
		select {
		case <-time.Tick(time.Duration(c.updateRate) * time.Second):
			// Increment counter by 1
			counterNode.SetValue(counterNode.GetValue() + 1)
		case <-ctx.Done():
			return nil
		}
	}
}

// Use constructor to ensure provider implements interface
func NewCounterProvider(updateRate int) ctrlxutils.IDataLayerProvider {
	return &CounterProvider{
		updateRate: updateRate,
	}
}

// ---------------------------------------------------------------------------------
// Setup Application
// ---------------------------------------------------------------------------------

func main() {
	// Create Application Context
	ctx, cancel := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM, syscall.SIGABRT)
	defer cancel()

	// Load AppConfig from file (you need to make sure, that the corresponding entries in snapcraft.yaml and manifest.json exists!)
	appConfig, _ := ctrlxutils.UnmarshalAppdata[AppConfig]( // Ignore Errors - do not do this in your code!
		serialization.NewJSONSerializer(),
		"properties.json",
	)

	// Create Logger for Ctrlx Logbook
	logger, _ := ctrlxutils.NewJournaldLogger(ctx, "", log.INFO)

	// Create provider manager
	ctrlxutils.NewDataLayerProviderManager(
		ctx,
		logger,
		"ipc://",     // Datalayer interface (for local deployment as snap always ips://)
		"MyFancyApp", // Datalayer RootPath
		ctrlxutils.WithProvider(NewCounterProvider(appConfig.UpdateRate)), // Register our CounterProvider from above (you can register multiple providers here)
	)

	// Wait for termination
	<-ctx.Done()
}