fix(pkg/config): use storage endpoints

changes:
- Only one storage endpoint can be defined. This consists of a URL which
  can be used to specify whether the data is to be stored in a file or
  in a database.

pkg/storage/storage.go

@@ -1,10 +1,15 @@
 package storage
 
 import (
+	"context"
+	"fmt"
 	"math"
+	"net/url"
 	"sort"
 
 	"github.com/go-flucky/flucky/pkg/internal/format"
+	"github.com/go-flucky/flucky/pkg/storage/db"
+	"github.com/go-flucky/flucky/pkg/storage/logfile"
 	"github.com/go-flucky/flucky/pkg/types"
 )
 
@@ -63,8 +68,49 @@ func Compression(measuredValues []*types.MeasuredValue) []*types.MeasuredValue {
 	return compressedMeasuredValues
 }
 
+// Read measured values from the given storage endpoint url. The scheme must be
+// matched to a provider, if the scheme is not implemented, the function
+// returns an error
+func Read(ctx context.Context, storageEndpoint *url.URL) ([]*types.MeasuredValue, error) {
+	switch storageEndpoint.Scheme {
+	case "file":
+		measuredValueLogfile := logfile.New(storageEndpoint.Path)
+		return measuredValueLogfile.Read()
+	case "postgres":
+		database, err := db.New(storageEndpoint)
+		if err != nil {
+			return nil, err
+		}
+		defer database.Close()
+		return database.SelectMeasuredValues(ctx)
+	}
+	return nil, fmt.Errorf("No supported scheme")
+}
+
 func Round(measuredValues []*types.MeasuredValue, round float64) {
 	for _, measuredValue := range measuredValues {
 		measuredValue.Value = math.Round(measuredValue.Value/round) * round
 	}
 }
+
+// Write measured values to the given storage endpoint url. The scheme must be
+// matched to a provider, if the scheme is not implemented, the function
+// returns an error
+func Write(ctx context.Context, measuredValues []*types.MeasuredValue, storageEndpoint *url.URL) error {
+	switch storageEndpoint.Scheme {
+	case "file":
+		measuredValueLogfile := logfile.New(storageEndpoint.Path)
+		return measuredValueLogfile.Write(measuredValues)
+	case "postgres":
+		database, err := db.New(storageEndpoint)
+		if err != nil {
+			return err
+		}
+		defer database.Close()
+
+		if err := database.InsertMeasuredValues(ctx, measuredValues); err != nil {
+			return err
+		}
+	}
+	return fmt.Errorf("No supported scheme")
+}