chore: refactor plugin structure (#18335)

plugin/getter.go

@@ -0,0 +1,72 @@
+package plugin
+
+import (
+	"strconv"
+
+	"github.com/spf13/cast"
+)
+
+type getter struct {
+	get   StringGetter
+	scale float64
+}
+
+func defaultGetters(get StringGetter, scale float64) *getter {
+	return &getter{
+		get:   get,
+		scale: scale,
+	}
+}
+
+var _ FloatGetter = (*getter)(nil)
+
+// FloatGetter parses float from exec result
+func (p *getter) FloatGetter() (func() (float64, error), error) {
+	g, err := p.get.StringGetter()
+
+	return func() (float64, error) {
+		s, err := g()
+		if err != nil {
+			return 0, err
+		}
+
+		f, err := strconv.ParseFloat(s, 64)
+		if err != nil {
+			return 0, err
+		}
+
+		return f * p.scale, nil
+	}, err
+}
+
+var _ IntGetter = (*getter)(nil)
+
+// IntGetter parses int64 from exec result
+func (p *getter) IntGetter() (func() (int64, error), error) {
+	g, err := p.FloatGetter()
+
+	return func() (int64, error) {
+		f, err := g()
+		if err != nil {
+			return 0, err
+		}
+
+		return int64(f), nil
+	}, err
+}
+
+var _ BoolGetter = (*getter)(nil)
+
+// BoolGetter parses bool from exec result. "on", "true" and 1 are considered truish.
+func (p *getter) BoolGetter() (func() (bool, error), error) {
+	g, err := p.get.StringGetter()
+
+	return func() (bool, error) {
+		s, err := g()
+		if err != nil {
+			return false, err
+		}
+
+		return cast.ToBoolE(s)
+	}, err
+}