Initial CPONE middleware implementation

internal/config/config.go

@@ -0,0 +1,131 @@
+package config
+
+import (
+	"bufio"
+	"fmt"
+	"net/url"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+)
+
+type Config struct {
+	AppHost           string
+	AppPort           string
+	DBHost            string
+	DBPort            string
+	DBDatabase        string
+	DBUsername        string
+	DBPassword        string
+	BearerToken       string
+	DBMaxOpenConns    int
+	DBMaxIdleConns    int
+	DBConnMaxLifetime time.Duration
+}
+
+func Load(path string) (Config, error) {
+	if err := loadDotEnv(path); err != nil {
+		return Config{}, err
+	}
+
+	cfg := Config{
+		AppHost:           env("APP_HOST", "0.0.0.0"),
+		AppPort:           env("APP_PORT", "8080"),
+		DBHost:            env("DB_HOST", "127.0.0.1"),
+		DBPort:            env("DB_PORT", "3306"),
+		DBDatabase:        env("DB_DATABASE", ""),
+		DBUsername:        env("DB_USERNAME", "root"),
+		DBPassword:        env("DB_PASSWORD", ""),
+		BearerToken:       env("CPONE_BEARER_TOKEN", ""),
+		DBMaxOpenConns:    envInt("DB_MAX_OPEN_CONNS", 25),
+		DBMaxIdleConns:    envInt("DB_MAX_IDLE_CONNS", 25),
+		DBConnMaxLifetime: time.Duration(envInt("DB_CONN_MAX_LIFETIME_MINUTES", 5)) * time.Minute,
+	}
+
+	if cfg.DBDatabase == "" {
+		return Config{}, fmt.Errorf("DB_DATABASE wajib diisi")
+	}
+	if cfg.BearerToken == "" {
+		return Config{}, fmt.Errorf("CPONE_BEARER_TOKEN wajib diisi")
+	}
+
+	return cfg, nil
+}
+
+func (c Config) Addr() string {
+	return c.AppHost + ":" + c.AppPort
+}
+
+func (c Config) MySQLDSN() string {
+	values := url.Values{}
+	values.Set("charset", "utf8mb4")
+	values.Set("parseTime", "true")
+	values.Set("loc", "Local")
+
+	return fmt.Sprintf(
+		"%s:%s@tcp(%s:%s)/%s?%s",
+		c.DBUsername,
+		c.DBPassword,
+		c.DBHost,
+		c.DBPort,
+		c.DBDatabase,
+		values.Encode(),
+	)
+}
+
+func loadDotEnv(path string) error {
+	file, err := os.Open(path)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil
+		}
+		return err
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		line := strings.TrimSpace(scanner.Text())
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+
+		key, value, ok := strings.Cut(line, "=")
+		if !ok {
+			continue
+		}
+
+		key = strings.TrimSpace(key)
+		value = strings.TrimSpace(value)
+		value = strings.Trim(value, `"'`)
+
+		if key != "" {
+			_ = os.Setenv(key, value)
+		}
+	}
+
+	return scanner.Err()
+}
+
+func env(key string, fallback string) string {
+	value := os.Getenv(key)
+	if value == "" {
+		return fallback
+	}
+	return value
+}
+
+func envInt(key string, fallback int) int {
+	value := os.Getenv(key)
+	if value == "" {
+		return fallback
+	}
+
+	parsed, err := strconv.Atoi(value)
+	if err != nil {
+		return fallback
+	}
+
+	return parsed
+}