feat(sense): establish M1 offline intake skeleton

Sense/internal/config/config.go

@@ -0,0 +1,113 @@
+// Package config loads and validates the Sense process configuration.
+package config
+
+import (
+	"fmt"
+	"net"
+	"net/url"
+	"os"
+	"strconv"
+	"time"
+)
+
+const (
+	defaultHTTPAddress     = "127.0.0.1:8080"
+	defaultDatabaseDSN     = "file:data/sense.db"
+	defaultMediaMTXURL     = "http://127.0.0.1:9997"
+	defaultReconcilePeriod = 5 * time.Second
+	defaultProbePeriod     = 10 * time.Second
+)
+
+type Config struct {
+	HTTPAddress       string
+	AllowNonLoopback  bool
+	DatabaseDSN       string
+	MediaMTXURL       string
+	ReconcileInterval time.Duration
+	ProbeInterval     time.Duration
+}
+
+func Load() (Config, error) {
+	allow, err := boolEnv("SENSE_ALLOW_NON_LOOPBACK", false)
+	if err != nil {
+		return Config{}, err
+	}
+	reconcilePeriod, err := durationEnv("SENSE_RECONCILE_INTERVAL", defaultReconcilePeriod)
+	if err != nil {
+		return Config{}, err
+	}
+	probePeriod, err := durationEnv("SENSE_PROBE_INTERVAL", defaultProbePeriod)
+	if err != nil {
+		return Config{}, err
+	}
+
+	cfg := Config{
+		HTTPAddress:       stringEnv("SENSE_HTTP_ADDR", defaultHTTPAddress),
+		AllowNonLoopback:  allow,
+		DatabaseDSN:       stringEnv("SENSE_DB_DSN", defaultDatabaseDSN),
+		MediaMTXURL:       stringEnv("SENSE_MEDIAMTX_URL", defaultMediaMTXURL),
+		ReconcileInterval: reconcilePeriod,
+		ProbeInterval:     probePeriod,
+	}
+	if err := cfg.Validate(); err != nil {
+		return Config{}, err
+	}
+	return cfg, nil
+}
+
+func (c Config) Validate() error {
+	host, _, err := net.SplitHostPort(c.HTTPAddress)
+	if err != nil {
+		return fmt.Errorf("invalid SENSE_HTTP_ADDR: %w", err)
+	}
+	ip := net.ParseIP(host)
+	isLoopback := host == "localhost" || (ip != nil && ip.IsLoopback())
+	if !isLoopback && !c.AllowNonLoopback {
+		return fmt.Errorf("non-loopback HTTP bind requires SENSE_ALLOW_NON_LOOPBACK=true")
+	}
+	if c.DatabaseDSN == "" {
+		return fmt.Errorf("SENSE_DB_DSN must not be empty")
+	}
+	mediaURL, err := url.Parse(c.MediaMTXURL)
+	if err != nil || mediaURL.Scheme == "" || mediaURL.Host == "" {
+		return fmt.Errorf("invalid SENSE_MEDIAMTX_URL")
+	}
+	if mediaURL.User != nil {
+		return fmt.Errorf("SENSE_MEDIAMTX_URL must not contain credentials")
+	}
+	if c.ReconcileInterval <= 0 || c.ProbeInterval <= 0 {
+		return fmt.Errorf("loop intervals must be positive")
+	}
+	return nil
+}
+
+func stringEnv(name, fallback string) string {
+	if value, ok := os.LookupEnv(name); ok {
+		return value
+	}
+	return fallback
+}
+
+func boolEnv(name string, fallback bool) (bool, error) {
+	value, ok := os.LookupEnv(name)
+	if !ok {
+		return fallback, nil
+	}
+	parsed, err := strconv.ParseBool(value)
+	if err != nil {
+		return false, fmt.Errorf("invalid %s: %w", name, err)
+	}
+	return parsed, nil
+}
+
+func durationEnv(name string, fallback time.Duration) (time.Duration, error) {
+	value, ok := os.LookupEnv(name)
+	if !ok {
+		return fallback, nil
+	}
+	parsed, err := time.ParseDuration(value)
+	if err != nil {
+		return 0, fmt.Errorf("invalid %s: %w", name, err)
+	}
+	return parsed, nil
+}