Add configurable device aliases

internal/config/config.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"os"
+	"regexp"
 	"strconv"
 	"strings"
 	"time"
@@ -12,10 +13,13 @@ import (
 
 const envPrefix = "MQTT_SCRUBBER_"
 
+var invalidDeviceCharacters = regexp.MustCompile(`[^a-z0-9_]+`)
+
 type Config struct {
-	MQTT   MQTTConfig   `json:"mqtt"`
-	Influx InfluxConfig `json:"influx"`
-	App    AppConfig    `json:"app"`
+	MQTT          MQTTConfig        `json:"mqtt"`
+	Influx        InfluxConfig      `json:"influx"`
+	App           AppConfig         `json:"app"`
+	DeviceAliases map[string]string `json:"device_aliases"`
 }
 
 type MQTTConfig struct {
@@ -80,6 +84,8 @@ func Load(path string) (Config, error) {
 		return Config{}, err
 	}
 
+	cfg.DeviceAliases = normalizeDeviceAliases(cfg.DeviceAliases)
+
 	if err := cfg.Validate(); err != nil {
 		return Config{}, err
 	}
@@ -161,6 +167,18 @@ func applyEnvOverrides(cfg *Config) error {
 	setString(&cfg.App.LogLevel, envPrefix+"APP_LOG_LEVEL")
 	setString(&cfg.App.HealthAddress, envPrefix+"APP_HEALTH_ADDRESS")
 
+	if raw, ok := os.LookupEnv(envPrefix + "DEVICE_ALIASES"); ok {
+		if strings.TrimSpace(raw) == "" {
+			cfg.DeviceAliases = nil
+		} else {
+			aliases := make(map[string]string)
+			if err := json.Unmarshal([]byte(raw), &aliases); err != nil {
+				return fmt.Errorf("parse %sDEVICE_ALIASES: %w", envPrefix, err)
+			}
+			cfg.DeviceAliases = aliases
+		}
+	}
+
 	if raw, ok := os.LookupEnv(envPrefix + "MQTT_TOPICS"); ok {
 		cfg.MQTT.Topics = splitAndTrim(raw)
 	}
@@ -227,3 +245,34 @@ func splitAndTrim(value string) []string {
 
 	return result
 }
+
+func normalizeDeviceAliases(aliases map[string]string) map[string]string {
+	if len(aliases) == 0 {
+		return nil
+	}
+
+	normalized := make(map[string]string, len(aliases))
+	for device, alias := range aliases {
+		cleanDevice := normalizeDeviceKey(device)
+		cleanAlias := strings.TrimSpace(alias)
+		if cleanDevice == "" || cleanAlias == "" {
+			continue
+		}
+		normalized[cleanDevice] = cleanAlias
+	}
+
+	if len(normalized) == 0 {
+		return nil
+	}
+
+	return normalized
+}
+
+func normalizeDeviceKey(value string) string {
+	normalized := strings.ToLower(strings.TrimSpace(value))
+	normalized = strings.ReplaceAll(normalized, "-", "_")
+	normalized = strings.ReplaceAll(normalized, " ", "_")
+	normalized = invalidDeviceCharacters.ReplaceAllString(normalized, "_")
+	normalized = strings.Trim(normalized, "_")
+	return normalized
+}

internal/config/config_test.go

@@ -0,0 +1,107 @@
+package config
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+)
+
+func TestLoadNormalizesDeviceAliases(t *testing.T) {
+	t.Setenv("MQTT_SCRUBBER_DEVICE_ALIASES", "")
+
+	configPath := filepath.Join(t.TempDir(), "config.json")
+	contents := `{
+	  "mqtt": {
+	    "broker": "tcp://127.0.0.1:1883",
+	    "client_id": "mqqt-scrubber",
+	    "topics": ["tele/+/STATE"],
+	    "qos": 0
+	  },
+	  "influx": {
+	    "url": "http://127.0.0.1:8181",
+	    "database": "home",
+	    "precision": "ns"
+	  },
+	  "app": {
+	    "batch_size": 200,
+	    "buffer_size": 1000,
+	    "flush_interval": "10s",
+	    "flush_timeout": "10s",
+	    "log_level": "info",
+	    "health_address": ":8080"
+	  },
+	  "device_aliases": {
+	    "Kitchen-Plug": "Kitchen Plug",
+	    " Patio Sensor ": "Patio Sensor",
+	    "unused": "   "
+	  }
+	}`
+
+	if err := os.WriteFile(configPath, []byte(contents), 0o644); err != nil {
+		t.Fatalf("write config file: %v", err)
+	}
+
+	cfg, err := Load(configPath)
+	if err != nil {
+		t.Fatalf("Load returned error: %v", err)
+	}
+
+	if got := cfg.DeviceAliases["kitchen_plug"]; got != "Kitchen Plug" {
+		t.Fatalf("unexpected kitchen alias: got %q", got)
+	}
+
+	if got := cfg.DeviceAliases["patio_sensor"]; got != "Patio Sensor" {
+		t.Fatalf("unexpected patio alias: got %q", got)
+	}
+
+	if _, exists := cfg.DeviceAliases["unused"]; exists {
+		t.Fatal("expected blank aliases to be discarded")
+	}
+}
+
+func TestLoadOverridesDeviceAliasesFromEnv(t *testing.T) {
+	t.Setenv("MQTT_SCRUBBER_DEVICE_ALIASES", `{"Desk-Plug":"Desk Plug"}`)
+
+	configPath := filepath.Join(t.TempDir(), "config.json")
+	contents := `{
+	  "mqtt": {
+	    "broker": "tcp://127.0.0.1:1883",
+	    "client_id": "mqqt-scrubber",
+	    "topics": ["tele/+/STATE"],
+	    "qos": 0
+	  },
+	  "influx": {
+	    "url": "http://127.0.0.1:8181",
+	    "database": "home",
+	    "precision": "ns"
+	  },
+	  "app": {
+	    "batch_size": 200,
+	    "buffer_size": 1000,
+	    "flush_interval": "10s",
+	    "flush_timeout": "10s",
+	    "log_level": "info",
+	    "health_address": ":8080"
+	  },
+	  "device_aliases": {
+	    "Kitchen-Plug": "Kitchen Plug"
+	  }
+	}`
+
+	if err := os.WriteFile(configPath, []byte(contents), 0o644); err != nil {
+		t.Fatalf("write config file: %v", err)
+	}
+
+	cfg, err := Load(configPath)
+	if err != nil {
+		t.Fatalf("Load returned error: %v", err)
+	}
+
+	if len(cfg.DeviceAliases) != 1 {
+		t.Fatalf("expected env aliases to replace file aliases, got %d entries", len(cfg.DeviceAliases))
+	}
+
+	if got := cfg.DeviceAliases["desk_plug"]; got != "Desk Plug" {
+		t.Fatalf("unexpected desk alias: got %q", got)
+	}
+}