PKGBUILD/pkg/daemon/daemon.go

package daemon

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

	"github.com/Masterminds/semver"
	"github.com/go-flucky/flucky/pkg/config"
	"github.com/go-flucky/flucky/pkg/sensor"
	"github.com/go-flucky/flucky/pkg/storage"
	"github.com/go-flucky/flucky/pkg/storage/db"
	"github.com/go-flucky/flucky/pkg/types"
	"github.com/volker-raschek/go-logger/pkg/logger"
)

var (
	postgresHost     = "markus-pc.trier.cryptic.systems"
	postgresPort     = "5432"
	postgresDatabase = "postgres"
	postgresUser     = "postgres"
	postgresPassword = "postgres"

	flogger = logger.NewSilentLogger()
)

func SetLogger(logger logger.Logger) {
	flogger = logger
}

// Start the daemon
func Start(cnf *config.Configuration, cleanCacheInterval time.Duration, compression bool, round float64, version *semver.Version) {

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

	// Ticker
	// saveTicker := time.Tick(cleanCacheInterval)

	// channels
	debugChannel := make(chan string, 0)
	infoChannel := make(chan string, 0)
	warnChannel := make(chan string, 0)
	errorChannel := make(chan error, 0)
	fatalChannel := make(chan error, 1)
	interruptChannel := make(chan os.Signal, 1)
	signal.Notify(interruptChannel, os.Interrupt, os.Kill, syscall.SIGTERM)
	measuredValueChannel := make(chan *types.MeasuredValue, 0)

	// Info
	flogger.Info("Use clean-cache-interval: %v", cleanCacheInterval.String())
	flogger.Info("Use compression: %v", compression)
	flogger.Info("Round: %v", round)

	ticker := time.Tick(cleanCacheInterval)
	measuredValuesCache := make([]*types.MeasuredValue, 0)
	// measuredValuesLogfile := logfile.New(cnf.Logfile)

	// Init semaphoreChannel
	semaphoreChannels := make(map[string]chan struct{})
	for _, sensor := range cnf.GetSensors(config.ENABLED) {
		semaphoreChannels[sensor.GetID()] = make(chan struct{}, 1)
	}

	// Start producers
	for _, s := range cnf.GetSensors(config.ENABLED) {

		// start go routine for each sensor
		go func(sensor sensor.Sensor) {
			// run forever
			for {
				select {
				case <-ctx.Done():
					errorChannel <- fmt.Errorf("Closed context: %v", ctx.Err().Error())
					return
				case <-semaphoreChannels[sensor.GetID()]:
					measuredValues, err := sensor.Read()
					if err != nil {
						errorChannel <- err
						return
					}
					for _, measmeasuredValue := range measuredValues {
						measuredValueChannel <- measmeasuredValue
					}
				}
			}
		}(s)

		// start ticker for each sensor
		go func(sensor sensor.Sensor) {
			for {
				select {
				case <-ctx.Done():
					errorChannel <- fmt.Errorf("Closed context: %v", ctx.Err().Error())
					return
				case <-sensor.GetTicker().C:
					semaphoreChannels[sensor.GetID()] <- struct{}{}
				}
			}
		}(s)
	}

	// Distributor
	//measuredValueChannels := distribute.MeasuredValues(ctx, 5, measuredValueChannel)

	for {
		select {
		case debug, _ := <-debugChannel:
			flogger.Debug("%v", debug)
		case info, _ := <-infoChannel:
			flogger.Info("%v", info)
		case warn, _ := <-warnChannel:
			flogger.Warn("%v", warn)
		case err, _ := <-errorChannel:
			flogger.Error("%v", err)
		case fatal, _ := <-fatalChannel:
			flogger.Fatal("Received a fatal error: %v", fatal)
		case interrupt := <-interruptChannel:
			flogger.Info("Received OS Signal: %v", interrupt)
			flogger.Info("Close context")
			cancel()
			flogger.Info("Close channels")
			close(debugChannel)
			close(infoChannel)
			close(warnChannel)
			close(errorChannel)
			close(interruptChannel)
			return

		case <-ticker:

			if round != 0 {
				storage.Round(measuredValuesCache, round)
			}

			if compression {
				measuredValuesCache = storage.Compression(measuredValuesCache)
			}

			// if err := logfile.Append(measuredValuesLogfile, measuredValuesCache); err != nil {
			// 	flogger.Error("Can not save caches measured values in logfile: %v", err)
			// }

			measuredValuesCache = make([]*types.MeasuredValue, 0)

		case measuredValue, open := <-measuredValueChannel:
			if !open {
				errorChannel <- fmt.Errorf("MeasuredValue channel closed")
				cancel()
			}
			measuredValuesCache = append(measuredValuesCache, measuredValue)
		}
	}
}

func checkDeviceInDatabase(ctx context.Context, device *types.Device, database db.Database) {
	_, err := database.SelectDeviceByID(ctx, device.ID)
	if err != nil {
		flogger.Debug("It's seems the current device is not registered in the database. Register the device now")
		err2 := database.InsertDevices(ctx, []*types.Device{device})
		if err2 != nil {
			flogger.Fatal("Can not register device into database: %v", err2)
		}
		flogger.Debug("Device successfully registered into the database")
		return
	}
	flogger.Debug("Device already registered into the database")
}

func checkSensorsInDatabase(ctx context.Context, sensors []*types.Sensor, database db.Database) {
	for _, sensor := range sensors {
		_, err := database.SelectSensorByID(ctx, sensor.ID)
		if err != nil {
			flogger.Debug("It's seems the sensor %v is not registered in the database. Register the sensor now", sensor.Name)
			err2 := database.InsertSensors(ctx, []*types.Sensor{sensor})
			if err2 != nil {
				flogger.Fatal("Can not register sensor %v into database: %v", sensor.Name, err2)
			}
			flogger.Debug("Sensor %v successfully registered into the database", sensor.Name)
			continue
		}
		flogger.Debug("Sensor %v is already registered into the database", sensor.Name)
	}
}