63 lines
1.4 KiB
Go
63 lines
1.4 KiB
Go
package metrics
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import (
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"errors"
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"time"
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"github.com/evcc-io/evcc/server/db"
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"github.com/evcc-io/evcc/tariff"
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)
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var ErrIncomplete = errors.New("meter profile incomplete")
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// energyProfile returns a 15min average meter profile in Wh. The profile
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// is sorted by timestamp starting at 00:00. It is guaranteed to contain 96 15min values.
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func energyProfile(entity entity, from time.Time) (*[96]float64, error) {
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db, err := db.Instance.DB()
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if err != nil {
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return nil, err
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}
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// COALESCE guards against legacy rows with NULL energy
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rows, err := db.Query(`SELECT min(ts) AS ts, COALESCE(avg(energy), 0) AS energy
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FROM meters
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WHERE meter = ? AND ts >= ?
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GROUP BY strftime("%H:%M", ts, 'unixepoch', 'localtime')
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ORDER BY strftime("%H:%M", ts, 'unixepoch', 'localtime') ASC`,
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entity.Id, from.Unix(),
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)
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if err != nil {
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return nil, err
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}
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defer rows.Close()
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var prev time.Time
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res := make([]float64, 0, 96)
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for rows.Next() {
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var ts SqlTime
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var val float64
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if err := rows.Scan(&ts, &val); err != nil {
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return nil, err
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}
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// interpolate single missing value, maybe due to regular restarts?
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if time.Time(ts).Sub(prev) == 2*tariff.SlotDuration {
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res = append(res, (val+res[len(res)-1])/2)
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}
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prev = time.Time(ts)
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res = append(res, val)
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}
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if err := rows.Err(); err != nil {
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return nil, err
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}
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if len(res) != 96 {
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return nil, ErrIncomplete
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}
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return (*[96]float64)(res), nil
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}
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