RCT: add retry (evcc-io#9231)

go.mod

@@ -66,7 +66,7 @@ require (
 	github.com/mergermarket/go-pkcs7 v0.0.0-20170926155232-153b18ea13c9
 	github.com/mitchellh/go-homedir v1.1.0
 	github.com/mitchellh/mapstructure v1.5.0
-	github.com/mlnoga/rct v0.1.2-0.20230227143934-71af1fb7dfa1
+	github.com/mlnoga/rct v0.1.2-0.20230731074838-03eacb926f99
 	github.com/muka/go-bluetooth v0.0.0-20221213043340-85dc80edc4e1
 	github.com/mxschmitt/golang-combinations v1.1.0
 	github.com/nicksnyder/go-i18n/v2 v2.2.1

go.sum

@@ -822,8 +822,8 @@ github.com/mitchellh/mapstructure v1.5.0/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RR
 github.com/mitchellh/reflectwalk v1.0.0/go.mod h1:mSTlrgnPZtwu0c4WaC2kGObEpuNDbx0jmZXqmk4esnw=
 github.com/mitchellh/reflectwalk v1.0.2 h1:G2LzWKi524PWgd3mLHV8Y5k7s6XUvT0Gef6zxSIeXaQ=
 github.com/mitchellh/reflectwalk v1.0.2/go.mod h1:mSTlrgnPZtwu0c4WaC2kGObEpuNDbx0jmZXqmk4esnw=
-github.com/mlnoga/rct v0.1.2-0.20230227143934-71af1fb7dfa1 h1:+OVWP3tJu+en06qieaXY/pcX+1qKp4X1oX9g3hMgOCk=
-github.com/mlnoga/rct v0.1.2-0.20230227143934-71af1fb7dfa1/go.mod h1:0lfd2mmBnBzIvuzYtdhG+2371u+cUfIxsYErm4P9KRI=
+github.com/mlnoga/rct v0.1.2-0.20230731074838-03eacb926f99 h1:sX4VwA7zgImnMqRgEkzP+3oKCgUHRF0OvHghFJ0pntY=
+github.com/mlnoga/rct v0.1.2-0.20230731074838-03eacb926f99/go.mod h1:0lfd2mmBnBzIvuzYtdhG+2371u+cUfIxsYErm4P9KRI=
 github.com/modern-go/concurrent v0.0.0-20180228061459-e0a39a4cb421/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=
 github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd h1:TRLaZ9cD/w8PVh93nsPXa1VrQ6jlwL5oN8l14QlcNfg=
 github.com/modern-go/concurrent v0.0.0-20180306012644-bacd9c7ef1dd/go.mod h1:6dJC0mAP4ikYIbvyc7fijjWJddQyLn8Ig3JB5CqoB9Q=

meter/rct.go

@@ -6,6 +6,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/cenkalti/backoff/v4"
 	"github.com/evcc-io/evcc/api"
 	"github.com/evcc-io/evcc/util"
 
@@ -42,6 +43,7 @@ meters:
 
 // RCT implements the api.Meter interface
 type RCT struct {
+	bo    *backoff.ExponentialBackOff
 	conn  *rct.Connection // connection with the RCT device
 	usage string          // grid, pv, battery
 }
@@ -80,9 +82,14 @@ func NewRCT(uri, usage string, cache time.Duration, capacity func() float64) (ap
 		return nil, err
 	}
 
+	bo := backoff.NewExponentialBackOff()
+	bo.MaxElapsedTime = time.Second
+	bo.InitialInterval = 10 * time.Millisecond
+
 	m := &RCT{
 		usage: strings.ToLower(usage),
 		conn:  conn,
+		bo:    bo,
 	}
 
 	// decorate api.MeterEnergy
@@ -104,24 +111,24 @@ func NewRCT(uri, usage string, cache time.Duration, capacity func() float64) (ap
 func (m *RCT) CurrentPower() (float64, error) {
 	switch m.usage {
 	case "grid":
-		res, err := m.conn.QueryFloat32(rct.TotalGridPowerW)
-		return float64(res), err
+		res, err := m.queryFloat(rct.TotalGridPowerW)
+		return res, err
 
 	case "pv":
-		a, err := m.conn.QueryFloat32(rct.SolarGenAPowerW)
+		a, err := m.queryFloat(rct.SolarGenAPowerW)
 		if err != nil {
 			return 0, err
 		}
-		b, err := m.conn.QueryFloat32(rct.SolarGenBPowerW)
+		b, err := m.queryFloat(rct.SolarGenBPowerW)
 		if err != nil {
 			return 0, err
 		}
-		c, err := m.conn.QueryFloat32(rct.S0ExternalPowerW)
-		return float64(a + b + c), err
+		c, err := m.queryFloat(rct.S0ExternalPowerW)
+		return a + b + c, err
 
 	case "battery":
-		res, err := m.conn.QueryFloat32(rct.BatteryPowerW)
-		return float64(res), err
+		res, err := m.queryFloat(rct.BatteryPowerW)
+		return res, err
 
 	default:
 		return 0, fmt.Errorf("invalid usage: %s", m.usage)
@@ -132,24 +139,24 @@ func (m *RCT) CurrentPower() (float64, error) {
 func (m *RCT) totalEnergy() (float64, error) {
 	switch m.usage {
 	case "grid":
-		res, err := m.conn.QueryFloat32(rct.TotalEnergyGridWh)
-		return float64(res / 1000), err
+		res, err := m.queryFloat(rct.TotalEnergyGridWh)
+		return res / 1000, err
 
 	case "pv":
-		a, err := m.conn.QueryFloat32(rct.TotalEnergySolarGenAWh)
+		a, err := m.queryFloat(rct.TotalEnergySolarGenAWh)
 		if err != nil {
 			return 0, err
 		}
-		b, err := m.conn.QueryFloat32(rct.TotalEnergySolarGenBWh)
-		return float64((a + b) / 1000), err
+		b, err := m.queryFloat(rct.TotalEnergySolarGenBWh)
+		return (a + b) / 1000, err
 
 	case "battery":
-		in, err := m.conn.QueryFloat32(rct.TotalEnergyBattInWh)
+		in, err := m.queryFloat(rct.TotalEnergyBattInWh)
 		if err != nil {
 			return 0, err
 		}
-		out, err := m.conn.QueryFloat32(rct.TotalEnergyBattOutWh)
-		return float64((in - out) / 1000), err
+		out, err := m.queryFloat(rct.TotalEnergyBattOutWh)
+		return (in - out) / 1000, err
 
 	default:
 		return 0, fmt.Errorf("invalid usage: %s", m.usage)
@@ -158,6 +165,23 @@ func (m *RCT) totalEnergy() (float64, error) {
 
 // batterySoc implements the api.Battery interface
 func (m *RCT) batterySoc() (float64, error) {
-	res, err := m.conn.QueryFloat32(rct.BatterySoC)
-	return float64(res * 100), err
+	res, err := m.queryFloat(rct.BatterySoC)
+	return res * 100, err
+}
+
+// queryFloat adds retry logic of recoverable errors to QueryFloat32
+func (m *RCT) queryFloat(id rct.Identifier) (float64, error) {
+	started := time.Now()
+	m.bo.Reset()
+
+	for {
+		next := m.bo.NextBackOff()
+
+		res, err := m.conn.QueryFloat32(id)
+		if err == nil || !errors.Is(err, &rct.RecoverableError{}) || time.Since(started)+next > m.bo.MaxElapsedTime {
+			return float64(res), err
+		}
+
+		time.Sleep(next)
+	}
 }