Add option to preread device tree (#349)

go.mod

@@ -61,4 +61,4 @@ require (
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
 
-replace github.com/grid-x/modbus => github.com/evcc-io/modbus v0.0.0-20240419133105-829633e7c6b0
+replace github.com/grid-x/modbus => github.com/evcc-io/modbus v0.0.0-20240915144537-980a0405c373

go.sum

@@ -15,8 +15,8 @@ github.com/dmarkham/enumer v1.5.9 h1:NM/1ma/AUNieHZg74w67GkHFBNB15muOt3sj486QVZk
 github.com/dmarkham/enumer v1.5.9/go.mod h1:e4VILe2b1nYK3JKJpRmNdl5xbDQvELc6tQ8b+GsGk6E=
 github.com/eclipse/paho.mqtt.golang v1.4.3 h1:2kwcUGn8seMUfWndX0hGbvH8r7crgcJguQNCyp70xik=
 github.com/eclipse/paho.mqtt.golang v1.4.3/go.mod h1:CSYvoAlsMkhYOXh/oKyxa8EcBci6dVkLCbo5tTC1RIE=
-github.com/evcc-io/modbus v0.0.0-20240419133105-829633e7c6b0 h1:TRyQYvEfiVsQup88bfboOmFy8bPYltAFJfzeS6JcSP4=
-github.com/evcc-io/modbus v0.0.0-20240419133105-829633e7c6b0/go.mod h1:ei49YhPP0v5cVJZAX9k/VdqQakUYNKOEvKB/6vnkZaU=
+github.com/evcc-io/modbus v0.0.0-20240915144537-980a0405c373 h1:+LFx0Rik2XlqQM8sq3VW3c8DbxN2hKBkjjusniBSsAs=
+github.com/evcc-io/modbus v0.0.0-20240915144537-980a0405c373/go.mod h1:WpbUAyptAAi0VAriSRopZa6uhiJOJCTz7KFvgGtNRXc=
 github.com/fatih/camelcase v1.0.0/go.mod h1:yN2Sb0lFhZJUdVvtELVWefmrXpuZESvPmqwoZc+/fpc=
 github.com/felixge/httpsnoop v1.0.4 h1:NFTV2Zj1bL4mc9sqWACXbQFVBBg2W3GPvqp8/ESS2Wg=
 github.com/felixge/httpsnoop v1.0.4/go.mod h1:m8KPJKqk1gH5J9DgRY2ASl2lWCfGKXixSwevea8zH2U=
@@ -25,9 +25,8 @@ github.com/frankban/quicktest v1.14.6/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7z
 github.com/fsnotify/fsnotify v1.7.0 h1:8JEhPFa5W2WU7YfeZzPNqzMP6Lwt7L2715Ggo0nosvA=
 github.com/fsnotify/fsnotify v1.7.0/go.mod h1:40Bi/Hjc2AVfZrqy+aj+yEI+/bRxZnMJyTJwOpGvigM=
 github.com/google/go-cmp v0.5.2/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
-github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
+github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/go-github v17.0.0+incompatible h1:N0LgJ1j65A7kfXrZnUDaYCs/Sf4rEjNlfyDHW9dolSY=
 github.com/google/go-github v17.0.0+incompatible/go.mod h1:zLgOLi98H3fifZn+44m+umXrS52loVEgC2AApnigrVQ=
 github.com/google/go-querystring v1.1.0 h1:AnCroh3fv4ZBgVIf1Iwtovgjaw/GiKJo8M8yD/fhyJ8=
@@ -40,7 +39,6 @@ github.com/gorilla/mux v1.8.1 h1:TuBL49tXwgrFYWhqrNgrUNEY92u81SPhu7sTdzQEiWY=
 github.com/gorilla/mux v1.8.1/go.mod h1:AKf9I4AEqPTmMytcMc0KkNouC66V3BtZ4qD5fmWSiMQ=
 github.com/gorilla/websocket v1.5.1 h1:gmztn0JnHVt9JZquRuzLw3g4wouNVzKL15iLr/zn/QY=
 github.com/gorilla/websocket v1.5.1/go.mod h1:x3kM2JMyaluk02fnUJpQuwD2dCS5NDG2ZHL0uE0tcaY=
-github.com/grid-x/serial v0.0.0-20191104121038-e24bc9bf6f08/go.mod h1:kdOd86/VGFWRrtkNwf1MPk0u1gIjc4Y7R2j7nhwc7Rk=
 github.com/grid-x/serial v0.0.0-20211107191517-583c7356b3aa h1:Rsn6ARgNkXrsXJIzhkE4vQr5Gbx2LvtEMv4BJOK4LyU=
 github.com/grid-x/serial v0.0.0-20211107191517-583c7356b3aa/go.mod h1:kdOd86/VGFWRrtkNwf1MPk0u1gIjc4Y7R2j7nhwc7Rk=
 github.com/hashicorp/go-version v1.6.0 h1:feTTfFNnjP967rlCxM/I9g701jU+RN74YKx2mOkIeek=
@@ -135,5 +133,5 @@ gopkg.in/ini.v1 v1.67.0/go.mod h1:pNLf8WUiyNEtQjuu5G5vTm06TEv9tsIgeAvK8hOrP4k=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-pgregory.net/rapid v0.4.7 h1:MTNRktPuv5FNqOO151TM9mDTa+XHcX6ypYeISDVD14g=
-pgregory.net/rapid v0.4.7/go.mod h1:UYpPVyjFHzYBGHIxLFoupi8vwk6rXNzRY9OMvVxFIOU=
+pgregory.net/rapid v1.1.0 h1:CMa0sjHSru3puNx+J0MIAuiiEV4N0qj8/cMWGBBCsjw=
+pgregory.net/rapid v1.1.0/go.mod h1:PY5XlDGj0+V1FCq0o192FdRhpKHGTRIWBgqjDBTrq04=

meters/sunspec/sunspec.go

@@ -39,6 +39,25 @@ func FixKostal(p sunspec.Point) {
 	}
 }
 
+// Initialize reads the device tree
+func DeviceTree(client modbus.Client) ([]sunspec.Device, error) {
+	in, err := sunspecbus.Open(client)
+	if err != nil {
+		if in == nil {
+			return nil, err
+		}
+
+		err = meters.ErrPartiallyOpened
+	}
+
+	devices := in.Collect(sunspec.AllDevices)
+	if len(devices) == 0 {
+		return nil, errors.New("sunspec: device not found")
+	}
+
+	return devices, err
+}
+
 // NewDevice creates a Sunspec device
 func NewDevice(meterType string, subdevice ...int) *SunSpec {
 	var dev int
@@ -58,20 +77,20 @@ func NewDevice(meterType string, subdevice ...int) *SunSpec {
 
 // Initialize implements the Device interface
 func (d *SunSpec) Initialize(client modbus.Client) error {
-	var partiallyOpen bool
-	in, err := sunspecbus.Open(client)
-	if err != nil {
-		if in == nil {
-			return err
-		}
-
-		partiallyOpen = true
+	devices, err := DeviceTree(client)
+	if err != nil && !errors.Is(err, meters.ErrPartiallyOpened) {
+		return err
 	}
 
-	devices := in.Collect(sunspec.AllDevices)
-	if len(devices) == 0 {
-		return errors.New("sunspec: device not found")
+	if err := d.InitializeWithTree(devices); err != nil {
+		return err
 	}
+
+	// this may be ErrPartiallyOpened
+	return err
+}
+
+func (d *SunSpec) InitializeWithTree(devices []sunspec.Device) error {
 	if len(devices) <= d.subdevice {
 		return fmt.Errorf("sunspec: subdevice %d not found", d.subdevice)
 	}
@@ -84,16 +103,7 @@ func (d *SunSpec) Initialize(client modbus.Client) error {
 	}
 
 	// collect relevant models
-	if err := d.collectModels(device); err != nil {
-		return err
-	}
-
-	// return partial open error if everything else went fine
-	if partiallyOpen {
-		err = fmt.Errorf("%w", meters.ErrPartiallyOpened)
-	}
-
-	return err
+	return d.collectModels(device)
 }
 
 func stringVal(b sunspec.Block, point string) string {