From 36e8dce048b0ecac0b8a9270d90cd88f8abc5d46 Mon Sep 17 00:00:00 2001
From: andig <andi@evcc.io>
Date: Thu, 27 Mar 2025 09:01:15 +0100
Subject: [PATCH] Circuit: add retry (#20151)

---
 core/circuit/circuit.go | 22 ++++++++++++++--------
 core/circuit/helper.go  | 12 ++++++++++++
 2 files changed, 26 insertions(+), 8 deletions(-)
 create mode 100644 core/circuit/helper.go

diff --git a/core/circuit/circuit.go b/core/circuit/circuit.go
index 76fd821f1..051fef087 100644
--- a/core/circuit/circuit.go
+++ b/core/circuit/circuit.go
@@ -7,6 +7,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/cenkalti/backoff/v4"
 	"github.com/evcc-io/evcc/api"
 	"github.com/evcc-io/evcc/plugin"
 	"github.com/evcc-io/evcc/util"
@@ -234,7 +235,7 @@ func (c *Circuit) overloadOnError(t time.Time, val *float64) {
 }
 
 func (c *Circuit) updateMeters() error {
-	if f, err := c.meter.CurrentPower(); err == nil {
+	if f, err := backoff.RetryWithData(c.meter.CurrentPower, bo()); err == nil {
 		c.power = f
 		c.powerUpdated = time.Now()
 	} else {
@@ -243,6 +244,16 @@ func (c *Circuit) updateMeters() error {
 	}
 
 	if phaseMeter, ok := c.meter.(api.PhaseCurrents); ok {
+		var i1, i2, i3 float64
+		if err := backoff.Retry(func() error {
+			var err error
+			i1, i2, i3, err = phaseMeter.Currents()
+			return err
+		}, bo()); err != nil {
+			c.overloadOnError(c.currentUpdated, &c.current)
+			return fmt.Errorf("circuit currents: %w", err)
+		}
+
 		var p1, p2, p3 float64
 		if phaseMeter, ok := c.meter.(api.PhasePowers); ok {
 			var err error // phases needed for signed currents
@@ -251,13 +262,8 @@ func (c *Circuit) updateMeters() error {
 			}
 		}
 
-		if i1, i2, i3, err := phaseMeter.Currents(); err == nil {
-			c.current = max(util.SignFromPower(i1, p1), util.SignFromPower(i2, p2), util.SignFromPower(i3, p3))
-			c.currentUpdated = time.Now()
-		} else {
-			c.overloadOnError(c.currentUpdated, &c.current)
-			return fmt.Errorf("circuit currents: %w", err)
-		}
+		c.current = max(util.SignFromPower(i1, p1), util.SignFromPower(i2, p2), util.SignFromPower(i3, p3))
+		c.currentUpdated = time.Now()
 	}
 
 	return nil
diff --git a/core/circuit/helper.go b/core/circuit/helper.go
new file mode 100644
index 000000000..77c88c8b4
--- /dev/null
+++ b/core/circuit/helper.go
@@ -0,0 +1,12 @@
+package circuit
+
+import (
+	"time"
+
+	"github.com/cenkalti/backoff/v4"
+)
+
+// bo returns an exponential backoff for reading meter power quickly
+func bo() *backoff.ExponentialBackOff {
+	return backoff.NewExponentialBackOff(backoff.WithInitialInterval(20*time.Millisecond), backoff.WithMaxElapsedTime(time.Second))
+}