Write device aliases as startup metadata

internal/pipeline/service.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"log/slog"
 	"regexp"
+	"sort"
 	"strings"
 	"sync/atomic"
 	"time"
@@ -22,6 +23,7 @@ type writer interface {
 type Service struct {
 	config        config.Config
 	deviceAliases map[string]string
+	aliasRecords  []model.Record
 	influxClient  writer
 	input         chan model.RawMessage
 	received      atomic.Uint64
@@ -40,9 +42,11 @@ type Snapshot struct {
 }
 
 func NewService(cfg config.Config, influxClient writer) *Service {
+	normalizedAliases := normalizeDeviceAliases(cfg.DeviceAliases)
 	return &Service{
 		config:        cfg,
-		deviceAliases: normalizeDeviceAliases(cfg.DeviceAliases),
+		deviceAliases: normalizedAliases,
+		aliasRecords:  buildAliasRecords(normalizedAliases),
 		influxClient:  influxClient,
 		input:         make(chan model.RawMessage, cfg.App.BufferSize),
 	}
@@ -63,7 +67,18 @@ func (service *Service) Run(ctx context.Context) error {
 	ticker := time.NewTicker(service.config.App.FlushInterval.Duration)
 	defer ticker.Stop()
 
-	batch := make([]model.Record, 0, service.config.App.BatchSize)
+	batch := append(make([]model.Record, 0, service.config.App.BatchSize+len(service.aliasRecords)), service.aliasRecords...)
+	if len(batch) > 0 {
+		flushCtx, cancel := context.WithTimeout(ctx, service.config.App.FlushTimeout.Duration)
+		err := service.flush(flushCtx, batch)
+		cancel()
+		if err != nil {
+			slog.Error("failed to flush alias metadata to influx; will retry on next interval", "count", len(batch), "error", err)
+		} else {
+			batch = batch[:0]
+		}
+	}
+
 	var input <-chan model.RawMessage = service.input
 
 	for {
@@ -204,3 +219,33 @@ func normalizeDeviceKey(value string) string {
 	normalized = strings.Trim(normalized, "_")
 	return normalized
 }
+
+func buildAliasRecords(aliases map[string]string) []model.Record {
+	if len(aliases) == 0 {
+		return nil
+	}
+
+	devices := make([]string, 0, len(aliases))
+	for device := range aliases {
+		devices = append(devices, device)
+	}
+	sort.Strings(devices)
+
+	timestamp := time.Now().UTC()
+	records := make([]model.Record, 0, len(devices))
+	for _, device := range devices {
+		records = append(records, model.Record{
+			Measurement: "tasmota_device_meta",
+			Tags: map[string]string{
+				"device": device,
+				"source": "config",
+			},
+			Fields: map[string]any{
+				"device_alias": aliases[device],
+			},
+			Timestamp: timestamp,
+		})
+	}
+
+	return records
+}