DB 적재 초기구조

internal/geo/resolver.go

@@ -2,17 +2,33 @@ package geo
 
 import (
 	"errors"
-	"net"
+	"fmt"
 	"strings"
-
-	"github.com/oschwald/geoip2-golang"
 )
 
 // ErrInvalidIP is returned when an IP cannot be parsed.
 var ErrInvalidIP = errors.New("invalid ip address")
 
-type Resolver struct {
-	db *geoip2.Reader
+// ErrNotFound is returned when a backend cannot resolve the IP.
+var ErrNotFound = errors.New("location not found")
+
+type Backend string
+
+const (
+	BackendMMDB     Backend = "mmdb"
+	BackendPostgres Backend = "postgres"
+)
+
+type Config struct {
+	Backend     Backend
+	MMDBPath    string
+	DatabaseURL string
+	LookupQuery string
+}
+
+type Resolver interface {
+	Lookup(string) (Location, error)
+	Close() error
 }
 
 type Location struct {
@@ -25,56 +41,23 @@ type Location struct {
 	Longitude float64
 }
 
-func NewResolver(dbPath string) (*Resolver, error) {
-	if dbPath == "" {
-		return nil, errors.New("db path is required")
+func NewResolver(cfg Config) (Resolver, error) {
+	switch cfg.Backend {
+	case "", BackendMMDB:
+		return newMMDBResolver(cfg.MMDBPath)
+	case BackendPostgres:
+		return newPostgresResolver(cfg.DatabaseURL, cfg.LookupQuery)
+	default:
+		return nil, fmt.Errorf("unsupported backend %q", cfg.Backend)
 	}
-
-	db, err := geoip2.Open(dbPath)
-	if err != nil {
-		return nil, err
-	}
-
-	return &Resolver{db: db}, nil
 }
 
-func (r *Resolver) Close() error {
-	return r.db.Close()
-}
-
-func (r *Resolver) Lookup(ipStr string) (Location, error) {
-	ip := net.ParseIP(ipStr)
-	if ip == nil {
-		return Location{}, ErrInvalidIP
-	}
-
-	record, err := r.db.City(ip)
-	if err != nil {
-		return Location{}, err
-	}
-
-	country := record.Country.Names["en"]
-	region := ""
-	if len(record.Subdivisions) > 0 {
-		region = record.Subdivisions[0].Names["en"]
-	}
-
-	city := record.City.Names["en"]
-
-	addressParts := make([]string, 0, 3)
-	for _, part := range []string{city, region, country} {
+func buildAddress(parts ...string) string {
+	addressParts := make([]string, 0, len(parts))
+	for _, part := range parts {
 		if part != "" {
 			addressParts = append(addressParts, part)
 		}
 	}
-
-	return Location{
-		IP:        ip.String(),
-		Country:   country,
-		Region:    region,
-		City:      city,
-		Address:   strings.Join(addressParts, ", "),
-		Latitude:  record.Location.Latitude,
-		Longitude: record.Location.Longitude,
-	}, nil
+	return strings.Join(addressParts, ", ")
 }