refactor conf a lil

src/config.go

@@ -2,6 +2,7 @@ package src
 
 import (
 	"bufio"
+	"bytes"
 	"context"
 	"encoding/base64"
 	"encoding/json"
@@ -17,6 +18,7 @@ import (
 )
 
 type Config struct {
+	ctx      context.Context
 	Listen   string `json:"LISTEN"`
 	Forwards string `json:"FORWARDS"`
 	Hello    string `json:"HELLO_B64"`
@@ -25,14 +27,28 @@ type Config struct {
 
 func NewConfig(ctx context.Context) (Config, error) {
 	config := Config{
+		ctx:      ctx,
 		Listen:   ":10000",
 		Forwards: "",
 		Hello:    base64.StdEncoding.EncodeToString([]byte("*1\r\n$4\r\nping\r\n")),
 	}
-	b, _ := json.Marshal(config)
+
+	if err := config.loadEnv(); err != nil {
+		return config, err
+	}
+
+	if err := config.setForwards(); err != nil {
+		return config, err
+	}
+
+	return config, nil
+}
+
+func (c *Config) loadEnv() error {
+	b, _ := json.Marshal(*c)
 	var m map[string]any
 	if err := json.Unmarshal(b, &m); err != nil {
-		return config, err
+		return err
 	}
 	for k := range m {
 		if v := os.Getenv(k); v != "" {
@@ -40,52 +56,62 @@ func NewConfig(ctx context.Context) (Config, error) {
 		}
 	}
 	b2, _ := json.Marshal(m)
-	if err := json.Unmarshal(b2, &config); err != nil {
-		return config, err
-	}
+	return json.Unmarshal(b2, c)
+}
 
-	hello, err := base64.StdEncoding.DecodeString(config.Hello)
+func (c *Config) setForwards() error {
+	hello, err := base64.StdEncoding.DecodeString(c.Hello)
 	if err != nil {
-		return config, err
+		return err
 	}
 
-	forwards := strings.Split(config.Forwards, ",")
-	forwards = slices.DeleteFunc(forwards, func(s string) bool { return s == "" })
-	if len(forwards) == 0 {
-		return config, fmt.Errorf("at least one $FORWARD required")
+	addresses := strings.Split(c.Forwards, ",")
+	addresses = slices.DeleteFunc(addresses, func(s string) bool { return s == "" })
+	if len(addresses) == 0 {
+		return fmt.Errorf("at least one $FORWARD required")
 	}
-	config.forwards = make([]*sync.Pool, len(forwards))
-	for i := range forwards {
-		forward := forwards[i]
-		config.forwards[i] = &sync.Pool{
+
+	c.forwards = make([]*sync.Pool, len(addresses))
+	for i := range addresses {
+		address := addresses[i]
+		c.forwards[i] = &sync.Pool{
 			New: func() any {
-				if ctx.Err() != nil {
-					return nil
-				}
-				log.Printf("dialing %q with %q", forward, hello)
-				v, err := (&net.Dialer{}).DialContext(ctx, "tcp", forward)
+				conn, err := c.dial(address, hello)
 				if err != nil {
-					log.Printf("! failed dial %q: %v", forward, err)
-					return nil
+					log.Printf("! failed to dial %q: %v", address, err)
 				}
-				if _, err := v.Write([]byte(hello)); err != nil {
-					log.Printf("! failed write hello %q: %v", forward, err)
-					v.Close()
-					return nil
-				}
-				if raw, err := readMessage(bufio.NewReader(v)); err != nil {
-					log.Printf("! failed read hello %q: %v", forward, err)
-					v.Close()
-					return nil
-				} else {
-					log.Printf("dial reply: %q", raw)
-				}
-				return v
+				return conn
 			},
 		}
 	}
+	return nil
+}
 
-	return config, nil
+func (c *Config) dial(address string, hello []byte) (net.Conn, error) {
+	if err := c.ctx.Err(); err != nil {
+		return nil, err
+	}
+
+	log.Printf("dialing %q with %q", address, hello)
+	v, err := (&net.Dialer{}).DialContext(c.ctx, "tcp", address)
+	if err != nil {
+		return nil, err
+	}
+
+	if _, err := v.Write([]byte(hello)); err != nil {
+		v.Close()
+		return nil, err
+	}
+
+	if raw, err := readMessage(bufio.NewReader(v)); err != nil {
+		v.Close()
+		return nil, err
+	} else if bytes.HasPrefix(raw, []byte("-")) {
+		v.Close()
+		return nil, fmt.Errorf("failed hello: %s", raw)
+	}
+
+	return v, nil
 }
 
 func (c Config) Close() {