improve file and redis loader

internal/loader/file.go

@@ -1,6 +1,7 @@
 package loader
 
 import (
+	"bufio"
 	"bytes"
 	"context"
 	"io"
@@ -26,6 +27,23 @@ func (l *fileLoader) Load(ctx context.Context) (io.Reader, error) {
 	return bytes.NewReader(data), nil
 }
 
+// List implements Lister interface{}
+func (l *fileLoader) List(ctx context.Context) (list []string, err error) {
+	f, err := os.Open(l.filename)
+	if err != nil {
+		return
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		list = append(list, scanner.Text())
+	}
+	err = scanner.Err()
+
+	return
+}
+
 func (l *fileLoader) Close() error {
 	return nil
 }

internal/loader/loader.go

@@ -9,3 +9,11 @@ type Loader interface {
 	Load(context.Context) (io.Reader, error)
 	Close() error
 }
+
+type Lister interface {
+	List(ctx context.Context) ([]string, error)
+}
+
+type Mapper interface {
+	Map(ctx context.Context) (map[string]string, error)
+}

internal/loader/redis.go

@@ -68,13 +68,18 @@ func RedisSetLoader(addr string, opts ...RedisLoaderOption) Loader {
 }
 
 func (p *redisSetLoader) Load(ctx context.Context) (io.Reader, error) {
-	v, err := p.client.SMembers(ctx, p.key).Result()
+	v, err := p.List(ctx)
 	if err != nil {
 		return nil, err
 	}
 	return bytes.NewReader([]byte(strings.Join(v, "\n"))), nil
 }
 
+// List implements Lister interface{}
+func (p *redisSetLoader) List(ctx context.Context) ([]string, error) {
+	return p.client.SMembers(ctx, p.key).Result()
+}
+
 func (p *redisSetLoader) Close() error {
 	return p.client.Close()
 }
@@ -107,13 +112,18 @@ func RedisListLoader(addr string, opts ...RedisLoaderOption) Loader {
 }
 
 func (p *redisListLoader) Load(ctx context.Context) (io.Reader, error) {
-	v, err := p.client.LRange(ctx, p.key, 0, -1).Result()
+	v, err := p.List(ctx)
 	if err != nil {
 		return nil, err
 	}
 	return bytes.NewReader([]byte(strings.Join(v, "\n"))), nil
 }
 
+// List implements Lister interface{}
+func (p *redisListLoader) List(ctx context.Context) ([]string, error) {
+	return p.client.LRange(ctx, p.key, 0, -1).Result()
+}
+
 func (p *redisListLoader) Close() error {
 	return p.client.Close()
 }
@@ -146,7 +156,7 @@ func RedisHashLoader(addr string, opts ...RedisLoaderOption) Loader {
 }
 
 func (p *redisHashLoader) Load(ctx context.Context) (io.Reader, error) {
-	m, err := p.client.HGetAll(ctx, p.key).Result()
+	m, err := p.Map(ctx)
 	if err != nil {
 		return nil, err
 	}
@@ -158,6 +168,25 @@ func (p *redisHashLoader) Load(ctx context.Context) (io.Reader, error) {
 	return bytes.NewBufferString(b.String()), nil
 }
 
+// List implements Lister interface{}
+func (p *redisHashLoader) List(ctx context.Context) (list []string, err error) {
+	m, err := p.Map(ctx)
+	if err != nil {
+		return
+	}
+
+	for k, v := range m {
+		list = append(list, fmt.Sprintf("%s %s", k, v))
+	}
+
+	return
+}
+
+// Map implements Mapper interface{}
+func (p *redisHashLoader) Map(ctx context.Context) (map[string]string, error) {
+	return p.client.HGetAll(ctx, p.key).Result()
+}
+
 func (p *redisHashLoader) Close() error {
 	return p.client.Close()
 }