Add Tesla Powerwall (#92)

meter/config.go

@@ -18,6 +18,8 @@ func NewFromConfig(log *util.Logger, typ string, other map[string]interface{}) a
 		c = NewModbusFromConfig(log, other)
 	case "sma":
 		c = NewSMAFromConfig(log, other)
+	case "tesla", "powerwall":
+		c = NewTeslaFromConfig(log, other)
 	default:
 		log.FATAL.Fatalf("invalid meter type '%s'", typ)
 	}

meter/tesla.go

@@ -0,0 +1,118 @@
+package meter
+
+import (
+	"crypto/tls"
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"github.com/andig/evcc/api"
+	"github.com/andig/evcc/util"
+)
+
+// credits to https://github.com/vloschiavo/powerwall2
+
+type teslaResponse map[string]struct {
+	LastCommunicationTime string  `json:"last_communication_time"`
+	InstantPower          float64 `json:"instant_power"`
+	InstantReactivePower  float64 `json:"instant_reactive_power"`
+	InstantApparentPower  float64 `json:"instant_apparent_power"`
+	Frequency             float64 `json:"frequency"`
+	EnergyExported        float64 `json:"energy_exported"`
+	EnergyImported        float64 `json:"energy_imported"`
+	InstantAverageVoltage float64 `json:"instant_average_voltage"`
+	InstantTotalCurrent   float64 `json:"instant_total_current"`
+	IACurrent             float64 `json:"i_a_current"`
+	IBCurrent             float64 `json:"i_b_current"`
+	ICCurrent             float64 `json:"i_c_current"`
+}
+
+// Tesla is the tesla powerwall meter
+type Tesla struct {
+	*util.HTTPHelper
+	uri, usage string
+}
+
+// NewTeslaFromConfig creates a Tesla Powerwall Meter from generic config
+func NewTeslaFromConfig(log *util.Logger, other map[string]interface{}) api.Meter {
+	cc := struct {
+		URI, Usage string
+	}{}
+	util.DecodeOther(log, other, &cc)
+
+	if cc.Usage == "" {
+		log.FATAL.Fatalf("config: missing usage")
+	}
+
+	url, err := url.ParseRequestURI(cc.URI)
+	if err != nil {
+		log.FATAL.Fatalf("config: invalid uri %s", cc.URI)
+	}
+
+	if url.Path == "" {
+		url.Path = "api/meters/aggregates"
+		cc.URI = url.String()
+	}
+
+	return NewTesla(cc.URI, cc.Usage)
+}
+
+// NewTesla creates a Tesla Meter
+func NewTesla(uri, usage string) api.Meter {
+	m := &Tesla{
+		HTTPHelper: util.NewHTTPHelper(util.NewLogger("tsla")),
+		uri:        uri,
+		usage:      strings.ToLower(usage),
+	}
+
+	// ignore the self signed certificate
+	customTransport := http.DefaultTransport.(*http.Transport).Clone()
+	customTransport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
+	m.HTTPHelper.Client.Transport = customTransport
+
+	// decorate api.MeterEnergy
+	if m.usage == "load" || m.usage == "solar" {
+		return &TeslaEnergy{Tesla: m}
+	}
+
+	return m
+}
+
+// CurrentPower implements the Meter.CurrentPower interface
+func (m *Tesla) CurrentPower() (float64, error) {
+	var tr teslaResponse
+	_, err := m.GetJSON(m.uri, &tr)
+
+	if err == nil {
+		if o, ok := tr[m.usage]; ok {
+			return o.InstantPower, nil
+		}
+	}
+
+	return 0, fmt.Errorf("invalid usage: %s", m.usage)
+}
+
+// TeslaEnergy decorates Tesla with api.MeterEnergy interface
+type TeslaEnergy struct {
+	*Tesla
+}
+
+// TotalEnergy implements the api.MeterEnergy interface
+func (m *TeslaEnergy) TotalEnergy() (float64, error) {
+	var tr teslaResponse
+	_, err := m.GetJSON(m.uri, &tr)
+
+	if err == nil {
+		if o, ok := tr[m.usage]; ok {
+			if m.usage == "load" {
+				return o.EnergyImported, nil
+			}
+			if m.usage == "solar" {
+				return o.EnergyExported, nil
+			}
+		}
+	}
+
+	return 0, fmt.Errorf("invalid usage: %s", m.usage)
+}