fix(pkg/sensor): reduce interface functions for better error handling

pkg/sensor/sensor.go

@@ -1,58 +1,46 @@
 package sensor
 
 import (
-	"context"
-	"fmt"
-	"sync"
-
-	"github.com/go-flucky/flucky/pkg/internal/collect"
-	"github.com/go-flucky/flucky/pkg/internal/prittyprint"
-
 	"github.com/go-flucky/flucky/pkg/types"
 )
 
-// Read measured values from sensors
-func Read(ctx context.Context, sensors []Sensor) ([]*types.MeasuredValue, error) {
+func Read(sensors []Sensor, measuredValueType types.MeasuredValueType) ([]*types.MeasuredValue, error) {
 
-	measuredValueChannel := make(chan *types.MeasuredValue, len(sensors))
-	errorChannel := make(chan error, len(sensors))
-
-	ReadChannel(ctx, sensors, measuredValueChannel, errorChannel)
-
-	errors := collect.Errors(errorChannel)
-	if len(errors) > 0 {
-		return nil, prittyprint.FormatErrors(errors)
+	type result struct {
+		measuredValues []*types.MeasuredValue
+		err            error
 	}
 
-	measuredValues := collect.MeasuredValues(measuredValueChannel)
+	resultChannel := make(chan *result, len(sensors))
 
-	return measuredValues, nil
-}
-
-// ReadChannel reads the measured values from sensors and writes them to a
-// channel.
-func ReadChannel(ctx context.Context, sensors []Sensor, measuredValueChannel chan<- *types.MeasuredValue, errorChannel chan<- error) {
-
-	wg := new(sync.WaitGroup)
-	wg.Add(len(sensors))
-
-	for _, sensor := range sensors {
-		go sensor.ReadChannel(measuredValueChannel, errorChannel, wg)
+	// producers
+	// read measured values
+	for _, s := range sensors {
+		go func(s Sensor) {
+			measuredValues, err := s.Read()
+			resultChannel <- &result{
+				measuredValues: measuredValues,
+				err:            err,
+			}
+		}(s)
 	}
 
-	wg.Wait()
-}
-
-// ReadContinuously reads the measured values continously from sensors and writes
-// them to a channel.
-func ReadContinuously(ctx context.Context, sensors []Sensor, measuredValueChannel chan<- *types.MeasuredValue, errorChannel chan<- error) {
+	// consumer
+	measuredValues := make([]*types.MeasuredValue, 0)
+	counter := len(sensors)
 	for {
+		if counter == 0 {
+			break
+		}
 		select {
-		case <-ctx.Done():
-			errorChannel <- fmt.Errorf("Context closed: %v", ctx.Err())
-			return
-		default:
-			ReadChannel(ctx, sensors, measuredValueChannel, errorChannel)
+		case result := <-resultChannel:
+			counter--
+			if result.err != nil {
+				return nil, result.err
+			}
+			measuredValues = append(measuredValues, result.measuredValues...)
 		}
 	}
+
+	return types.SelectMeasuredValues(measuredValueType, measuredValues), nil
 }