HEMS: add templates (#25832)

Co-authored-by: Michael Geers <michael@geers.tv>
Co-authored-by: premultiply <4681172+premultiply@users.noreply.github.com>

hems/config.go

@@ -6,24 +6,26 @@ import (
 	"strings"
 
 	"github.com/evcc-io/evcc/core/site"
-	"github.com/evcc-io/evcc/hems/eebus"
-	"github.com/evcc-io/evcc/hems/fnn"
+	"github.com/evcc-io/evcc/hems/config"
+	_ "github.com/evcc-io/evcc/hems/eebus"
+	_ "github.com/evcc-io/evcc/hems/fnn"
 	"github.com/evcc-io/evcc/hems/hems"
-	"github.com/evcc-io/evcc/hems/relay"
+	_ "github.com/evcc-io/evcc/hems/relay"
 )
 
-// NewFromConfig creates new HEMS from config
+var registry = config.Registry
+
+// Types returns the list of types
+func Types() []string {
+	return registry.Types()
+}
+
+// NewFromConfig creates hems from configuration
 func NewFromConfig(ctx context.Context, typ string, other map[string]any, site site.API) (hems.API, error) {
 	switch strings.ToLower(typ) {
 	case "sma", "shm", "semp":
 		return nil, errors.New("breaking change: Sunny Home Manager integration is always on. See https://github.com/evcc-io/evcc/releases and https://docs.evcc.io/en/docs/integrations/sma-sunny-home-manager")
-	case "eebus":
-		return eebus.NewFromConfig(ctx, other, site)
-	case "fnn", "fnn-3":
-		return fnn.NewFromConfig(ctx, other, site)
-	case "relay":
-		return relay.NewFromConfig(ctx, other, site)
 	default:
-		return nil, errors.New("unknown hems: " + typ)
+		return config.NewFromConfig(ctx, typ, other, site)
 	}
 }

hems/config/config.go

@@ -0,0 +1,35 @@
+package config
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"github.com/evcc-io/evcc/core/site"
+	"github.com/evcc-io/evcc/hems/hems"
+	reg "github.com/evcc-io/evcc/hems/registry"
+)
+
+var Registry = reg.New[hems.API]("hems")
+
+// AddCtx registers a factory returning a concrete type that implements hems.API
+func AddCtx[T hems.API](name string, factory func(context.Context, map[string]any, site.API) (T, error)) {
+	Registry.AddCtx(name, func(ctx context.Context, other map[string]any, site site.API) (hems.API, error) {
+		return factory(ctx, other, site)
+	})
+}
+
+// NewFromConfig creates hems from configuration
+func NewFromConfig(ctx context.Context, typ string, other map[string]any, site site.API) (hems.API, error) {
+	factory, err := Registry.Get(strings.ToLower(typ))
+	if err != nil {
+		return nil, err
+	}
+
+	v, err := factory(ctx, other, site)
+	if err != nil {
+		return nil, fmt.Errorf("cannot create hems type '%s': %w", typ, err)
+	}
+
+	return v, nil
+}

hems/eebus/eebus.go

@@ -8,12 +8,17 @@ import (
 	ucapi "github.com/enbility/eebus-go/usecases/api"
 	"github.com/evcc-io/evcc/api"
 	"github.com/evcc-io/evcc/core/site"
+	"github.com/evcc-io/evcc/hems/config"
 	"github.com/evcc-io/evcc/hems/smartgrid"
 	"github.com/evcc-io/evcc/plugin"
 	"github.com/evcc-io/evcc/server/eebus"
 	"github.com/evcc-io/evcc/util"
 )
 
+func init() {
+	config.AddCtx("eebus", NewFromConfig)
+}
+
 type EEBus struct {
 	mux sync.RWMutex
 	log *util.Logger
@@ -63,7 +68,10 @@ func NewFromConfig(ctx context.Context, other map[string]any, site site.API) (*E
 		Interval    time.Duration
 	}{
 		Limits: Limits{
-			ContractualConsumptionNominalMax:    24800,
+			// contractual max power at the grid connection point reported to the control box
+			// (EEBus LPC, EMS device type). Default: standard 3x35A x 230V house connection.
+			// This is the connection capacity, not the SteuVE Pmin (see failsafe limit below).
+			ContractualConsumptionNominalMax:    24150, // 3 * 35A * 230V
 			FailsafeConsumptionActivePowerLimit: 4200,
 
 			ProductionNominalMax:               0,

hems/fnn/fnn.go

@@ -9,11 +9,17 @@ import (
 
 	"github.com/evcc-io/evcc/api"
 	"github.com/evcc-io/evcc/core/site"
+	"github.com/evcc-io/evcc/hems/config"
 	"github.com/evcc-io/evcc/hems/smartgrid"
 	"github.com/evcc-io/evcc/plugin"
 	"github.com/evcc-io/evcc/util"
 )
 
+func init() {
+	config.AddCtx("fnn", NewFromConfig)
+	config.AddCtx("fnn-3", NewFromConfig)
+}
+
 // NewFromConfig creates an FNN HEMS from generic config.
 func NewFromConfig(ctx context.Context, other map[string]any, site site.API) (*Fnn, error) {
 	cc := struct {

hems/registry/registry.go

@@ -0,0 +1,52 @@
+package registry
+
+import (
+	"context"
+	"fmt"
+	"maps"
+	"slices"
+
+	"github.com/evcc-io/evcc/core/site"
+)
+
+type (
+	// TODO check is this can be abstracted into a generic type parameter
+	factoryFunc[T any] func(context.Context, map[string]any, site.API) (T, error)
+
+	registry[T any] struct {
+		typ  string
+		data map[string]factoryFunc[T]
+	}
+)
+
+func (r registry[T]) Add(name string, factory func(map[string]any, site.API) (T, error)) {
+	r.AddCtx(name, func(_ context.Context, cc map[string]any, site site.API) (T, error) {
+		return factory(cc, site)
+	})
+}
+
+func (r registry[T]) AddCtx(name string, factory factoryFunc[T]) {
+	if _, exists := r.data[name]; exists {
+		panic(fmt.Sprintf("cannot register duplicate %s type: %s", r.typ, name))
+	}
+	r.data[name] = factory
+}
+
+func (r registry[T]) Get(name string) (factoryFunc[T], error) {
+	factory, exists := r.data[name]
+	if !exists {
+		return nil, fmt.Errorf("invalid %s type: %s", r.typ, name)
+	}
+	return factory, nil
+}
+
+func (r registry[T]) Types() []string {
+	return slices.Sorted(maps.Keys(r.data))
+}
+
+func New[T any](typ string) registry[T] {
+	return registry[T]{
+		typ:  typ,
+		data: make(map[string]factoryFunc[T]),
+	}
+}

hems/relay/relay.go

@@ -9,11 +9,16 @@ import (
 
 	"github.com/evcc-io/evcc/api"
 	"github.com/evcc-io/evcc/core/site"
+	"github.com/evcc-io/evcc/hems/config"
 	"github.com/evcc-io/evcc/hems/smartgrid"
 	"github.com/evcc-io/evcc/plugin"
 	"github.com/evcc-io/evcc/util"
 )
 
+func init() {
+	config.AddCtx("relay", NewFromConfig)
+}
+
 type Relay struct {
 	mu  sync.Mutex
 	log *util.Logger

hems/template.go

@@ -0,0 +1,22 @@
+package hems
+
+import (
+	"context"
+
+	"github.com/evcc-io/evcc/core/site"
+	"github.com/evcc-io/evcc/hems/hems"
+	"github.com/evcc-io/evcc/util/templates"
+)
+
+func init() {
+	registry.AddCtx("template", NewHemsFromTemplateConfig)
+}
+
+func NewHemsFromTemplateConfig(ctx context.Context, other map[string]any, site site.API) (hems.API, error) {
+	instance, err := templates.RenderInstance(templates.Hems, other)
+	if err != nil {
+		return nil, err
+	}
+
+	return NewFromConfig(ctx, instance.Type, instance.Other, site)
+}