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Add go-e wallbox charger integration

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- charger.go: polls go-e /api/status?filter=nrg,eto every 10 s
- db.go: WriteCharger() inserts into charger hypertable
- config.go: ChargerConf with host field
- main.go: polls charger in parallel with inverter and meters
- schema.sql: charger table + charger_10m/1h/daily aggregates + policies

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
Thomas Klaehn
2026-04-18 11:30:59 +02:00
parent 8295d1cf47
commit 62ffd06444
5 changed files with 135 additions and 16 deletions
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43
charger.go Normal file
View File

@@ -0,0 +1,43 @@
package main
import (
"encoding/json"
"fmt"
"net/http"
"time"
)
type ChargerReading struct {
Time time.Time
Power float32 // W total
EtoWh int64 // Wh cumulative
}
type chargerStatus struct {
Nrg []float64 `json:"nrg"` // [0..15] voltages/currents/powers; [11] = total W
Eto int64 `json:"eto"` // cumulative Wh
}
var chargerClient = &http.Client{Timeout: 5 * time.Second}
func PollCharger(host string) (ChargerReading, error) {
url := "http://" + host + "/api/status?filter=nrg,eto"
resp, err := chargerClient.Get(url)
if err != nil {
return ChargerReading{}, fmt.Errorf("get: %w", err)
}
defer resp.Body.Close()
var s chargerStatus
if err := json.NewDecoder(resp.Body).Decode(&s); err != nil {
return ChargerReading{}, fmt.Errorf("decode: %w", err)
}
if len(s.Nrg) < 12 {
return ChargerReading{}, fmt.Errorf("nrg array too short (%d)", len(s.Nrg))
}
return ChargerReading{
Time: time.Now(),
Power: float32(s.Nrg[11]),
EtoWh: s.Eto,
}, nil
}

5
config.go
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@@ -9,9 +9,14 @@ type Config struct {
SampleRate int `json:"sample_rate"` // seconds
AlphaEss AlphaConf `json:"alphaess"`
MQTT MQTTConf `json:"mqtt"`
Charger ChargerConf `json:"charger"`
DB DBConf `json:"db"`
}
type ChargerConf struct {
Host string `json:"host"` // hostname or IP of go-e charger
}
type AlphaConf struct {
Host string `json:"host"`
Port int `json:"port"`

8
db.go
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@@ -50,6 +50,14 @@ func (db *DB) WriteMeter(ctx context.Context, t time.Time, r MeterReading) error
return err
}
func (db *DB) WriteCharger(ctx context.Context, r ChargerReading) error {
_, err := db.pool.Exec(ctx,
`INSERT INTO charger (time, power, eto_wh) VALUES ($1, $2, $3)`,
r.Time, r.Power, r.EtoWh,
)
return err
}
func (db *DB) Close() {
db.pool.Close()
}

31
main.go
View File

@@ -44,7 +44,7 @@ func main() {
defer meters.Close()
interval := time.Duration(cfg.SampleRate) * time.Second
go runPollLoop(ctx, alpha, meters, db, interval)
go runPollLoop(ctx, alpha, meters, cfg.Charger.Host, db, interval)
sig := make(chan os.Signal, 1)
signal.Notify(sig, syscall.SIGINT, syscall.SIGTERM)
@@ -52,7 +52,7 @@ func main() {
logger.Println("shutting down")
}
func runPollLoop(ctx context.Context, alpha *AlphaEss, meters *MeterPoller, db *DB, interval time.Duration) {
func runPollLoop(ctx context.Context, alpha *AlphaEss, meters *MeterPoller, chargerHost string, db *DB, interval time.Duration) {
ticker := time.NewTicker(interval)
defer ticker.Stop()
for {
@@ -60,22 +60,22 @@ func runPollLoop(ctx context.Context, alpha *AlphaEss, meters *MeterPoller, db *
case <-ctx.Done():
return
case <-ticker.C:
poll(ctx, alpha, meters, db)
poll(ctx, alpha, meters, chargerHost, db)
}
}
}
func poll(ctx context.Context, alpha *AlphaEss, meters *MeterPoller, db *DB) {
func poll(ctx context.Context, alpha *AlphaEss, meters *MeterPoller, chargerHost string, db *DB) {
t := time.Now()
// Poll AlphaEss and all SDM630 meters in parallel.
var (
inverterData *InverterData
meterData []MeterReading
chargerData *ChargerReading
wg sync.WaitGroup
)
wg.Add(2)
wg.Add(3)
go func() {
defer wg.Done()
d, err := alpha.Poll()
@@ -89,9 +89,21 @@ func poll(ctx context.Context, alpha *AlphaEss, meters *MeterPoller, db *DB) {
defer wg.Done()
meterData = meters.PollAll()
}()
go func() {
defer wg.Done()
if chargerHost == "" {
return
}
r, err := PollCharger(chargerHost)
if err != nil {
logger.Printf("charger: %v", err)
return
}
r.Time = t
chargerData = &r
}()
wg.Wait()
// Write everything with the same timestamp t.
if inverterData != nil {
if err := db.WriteInverter(ctx, t, inverterData); err != nil {
logger.Printf("write inverter: %v", err)
@@ -102,4 +114,9 @@ func poll(ctx context.Context, alpha *AlphaEss, meters *MeterPoller, db *DB) {
logger.Printf("write meter %s: %v", r.Device, err)
}
}
if chargerData != nil {
if err := db.WriteCharger(ctx, *chargerData); err != nil {
logger.Printf("write charger: %v", err)
}
}
}

50
schema.sql
View File

@@ -98,10 +98,40 @@ SELECT time_bucket('1 day', time) AS bucket,
FROM power_meter
GROUP BY bucket, device;
-- Written by energy-collector every 10 s
CREATE TABLE charger (
time TIMESTAMPTZ NOT NULL,
power REAL, -- W total charging power
eto_wh BIGINT -- Wh cumulative total energy (from go-e eto field)
);
SELECT create_hypertable('charger', 'time', chunk_time_interval => INTERVAL '7 days');
CREATE MATERIALIZED VIEW charger_10m
WITH (timescaledb.continuous, timescaledb.materialized_only = false) AS
SELECT time_bucket('10 minutes', time) AS bucket,
AVG(power) AS power
FROM charger
GROUP BY bucket;
CREATE MATERIALIZED VIEW charger_1h
WITH (timescaledb.continuous, timescaledb.materialized_only = false) AS
SELECT time_bucket('1 hour', bucket) AS bucket,
AVG(power) AS power
FROM charger_10m
GROUP BY 1;
CREATE MATERIALIZED VIEW charger_daily
WITH (timescaledb.continuous, timescaledb.materialized_only = false) AS
SELECT time_bucket('1 day', time) AS bucket,
last(eto_wh, time) AS eto_wh
FROM charger
GROUP BY bucket;
-- ── Retention — keep 30 days of raw data; aggregates stay forever ─────────────
SELECT add_retention_policy('inverter', INTERVAL '30 days');
SELECT add_retention_policy('power_meter', INTERVAL '30 days');
SELECT add_retention_policy('charger', INTERVAL '30 days');
-- ── Refresh policies ──────────────────────────────────────────────────────────
@@ -135,6 +165,22 @@ SELECT add_continuous_aggregate_policy('power_meter_daily',
end_offset => INTERVAL '1 day',
schedule_interval => INTERVAL '1 day');
-- Grant SELECT on all tables and views (including continuous aggregates) to energy.
-- Run after all views are created so the grant covers them.
SELECT add_continuous_aggregate_policy('charger_10m',
start_offset => INTERVAL '1 hour',
end_offset => INTERVAL '10 minutes',
schedule_interval => INTERVAL '10 minutes');
SELECT add_continuous_aggregate_policy('charger_1h',
start_offset => INTERVAL '3 hours',
end_offset => INTERVAL '1 hour',
schedule_interval => INTERVAL '1 hour');
SELECT add_continuous_aggregate_policy('charger_daily',
start_offset => INTERVAL '3 days',
end_offset => INTERVAL '1 day',
schedule_interval => INTERVAL '1 day');
-- Grant privileges after all objects are created.
-- INSERT on raw hypertables (collector writes), SELECT on everything else (frontend reads).
GRANT INSERT ON inverter, power_meter, charger TO energy;
GRANT SELECT ON ALL TABLES IN SCHEMA public TO energy;