PKGBUILD/pkg/daemon/daemon.go

package daemon

import (
	"context"
	"net/url"
	"os"
	"os/signal"
	"syscall"

	"github.com/volker-raschek/flucky/pkg/config"
	"github.com/volker-raschek/flucky/pkg/repository"
	"github.com/volker-raschek/flucky/pkg/sensor"
	"github.com/volker-raschek/flucky/pkg/types"
	"github.com/volker-raschek/go-logger/pkg/logger"
)

func Start(cnf *config.Config, flogger logger.Logger) error {

	measuredValueChannel := make(chan *types.MeasuredValue, 0)

	// load storage endpoint
	storageEndpointURL, err := url.Parse(cnf.StorageEndpoint)
	if err != nil {
		return err
	}

	repo, err := repository.New(storageEndpointURL, flogger)
	if err != nil {
		return err
	}

	repoSensors, err := repo.GetSensors()
	if err != nil {
		return err
	}

	sensors := make([]sensor.Sensor, 0)
	for _, repoSensor := range repoSensors {
		if !repoSensor.Enabled {
			continue
		}

		sensor, err := sensor.New(repoSensor)
		if err != nil {
			return err
		}
		sensors = append(sensors, sensor)
	}

	interruptChannel := make(chan os.Signal, 1)
	signal.Notify(interruptChannel, os.Kill, syscall.SIGTERM)

	// Collection
	parentCtx := context.Background()
	ctx, cancel := context.WithCancel(parentCtx)

	for _, s := range sensors {
		go func(sensor sensor.Sensor) {
			for {
				select {
				case <-ctx.Done():
					return
				case <-sensor.GetTicker().C:
					measuredValues, err := sensor.Read()
					if err != nil {
						flogger.Error("%v", err)
						continue
					}
					for _, measuredValue := range measuredValues {
						measuredValueChannel <- measuredValue
					}
				}
			}
		}(s)
	}

	measuredValues := make([]*types.MeasuredValue, 0, 10)
	for {
		select {
		case measuredValue := <-measuredValueChannel:
			flogger.Debug("%v\t%v\t%v", measuredValue.ID, measuredValue.ValueType, measuredValue.Value)
			measuredValues = append(measuredValues, measuredValue)

			if cap(measuredValues) == len(measuredValues) {
				flogger.Debug("Flush cache")
				err := repo.AddMeasuredValues(measuredValues...)
				if err != nil {
					flogger.Error("%v", err)
				}
				measuredValues = make([]*types.MeasuredValue, 0, 10)
			}

		case <-interruptChannel:
			cancel()
			close(measuredValueChannel)

			err := repo.AddMeasuredValues(measuredValues...)
			if err != nil {
				flogger.Error("%v", err)
			}

			break
		}
	}
}