feat(backend): add configurable CORS and optimize Dockerfile

- Add CORS_ORIGINS env var for multiple domains support
- Update config.go with CORSOrigins field and getEnvStringSlice helper
- Rewrite CORS middleware with CORSWithConfig for dynamic origins
- Update server.go to use configurable CORS
- Update .env.example with all configuration variables
- Optimize Dockerfile: switch to distroless image, update port to 8214

backend/.env.example

@@ -1,7 +1,32 @@
-DATABASE_URL=postgres://user:password@host:port/dbname?sslmode=disable
+# ============================================
+# SaveInMed Backend - Environment Variables
+# ============================================
+
+# Application Settings
+APP_NAME=saveinmed-performance-core
 PORT=8214
+
+# Database Configuration
+DATABASE_URL=postgres://user:password@host:port/dbname?sslmode=disable
 DB_MAX_OPEN_CONNS=25
 DB_MAX_IDLE_CONNS=25
 DB_CONN_MAX_IDLE=15m
+
+# JWT Authentication
+JWT_SECRET=your-secret-key-here
+JWT_EXPIRES_IN=24h
+
+# MercadoPago Payment Gateway
 MERCADOPAGO_BASE_URL=https://api.mercadopago.com
 MARKETPLACE_COMMISSION=2.5
+
+# CORS Configuration
+# Comma-separated list of allowed origins, use * for all
+# Examples:
+#   CORS_ORIGINS=*
+#   CORS_ORIGINS=https://example.com
+#   CORS_ORIGINS=https://app.saveinmed.com,https://admin.saveinmed.com,http://localhost:3000
+CORS_ORIGINS=*
+
+# Testing (Optional)
+# SKIP_DB_TEST=1

backend/Dockerfile

@@ -3,9 +3,6 @@
 # ===== STAGE 1: Build =====
 FROM golang:1.24-alpine AS builder
 
-# Instala certificados SSL para HTTPS
-RUN apk add --no-cache ca-certificates tzdata
-
 WORKDIR /build
 
 # Cache de dependências - só rebuild se go.mod/go.sum mudar
@@ -20,22 +17,15 @@ COPY . .
 RUN --mount=type=cache,target=/go/pkg/mod \
     --mount=type=cache,target=/root/.cache/go-build \
     CGO_ENABLED=0 GOOS=linux GOARCH=amd64 \
-    go build -trimpath -ldflags="-s -w -extldflags '-static'" \
+    go build -trimpath -ldflags="-s -w" \
     -o /app/server ./cmd/api
 
-# ===== STAGE 2: Runtime (scratch - imagem mínima ~5MB) =====
-FROM scratch
-
-# Certificados SSL e timezone
-COPY --from=builder /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/
-COPY --from=builder /usr/share/zoneinfo /usr/share/zoneinfo
+# ===== STAGE 2: Runtime (distroless - segurança + mínimo ~2MB) =====
+FROM gcr.io/distroless/static-debian12:nonroot
 
 # Binary
 COPY --from=builder /app/server /server
 
-# Usuário não-root (UID 65534 = nobody)
-USER 65534:65534
-
-EXPOSE 8080
+EXPOSE 8214
 
 ENTRYPOINT ["/server"]

backend/internal/config/config.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"os"
 	"strconv"
+	"strings"
 	"time"
 )
 
@@ -19,6 +20,7 @@ type Config struct {
 	MarketplaceCommission float64
 	JWTSecret             string
 	JWTExpiresIn          time.Duration
+	CORSOrigins           []string
 }
 
 // Load reads configuration from environment variables and applies sane defaults
@@ -35,6 +37,7 @@ func Load() Config {
 		MarketplaceCommission: getEnvFloat("MARKETPLACE_COMMISSION", 2.5),
 		JWTSecret:             getEnv("JWT_SECRET", "dev-secret"),
 		JWTExpiresIn:          getEnvDuration("JWT_EXPIRES_IN", 24*time.Hour),
+		CORSOrigins:           getEnvStringSlice("CORS_ORIGINS", []string{"*"}),
 	}
 
 	return cfg
@@ -78,3 +81,19 @@ func getEnvFloat(key string, fallback float64) float64 {
 	}
 	return fallback
 }
+
+func getEnvStringSlice(key string, fallback []string) []string {
+	if value := os.Getenv(key); value != "" {
+		parts := strings.Split(value, ",")
+		result := make([]string, 0, len(parts))
+		for _, p := range parts {
+			if trimmed := strings.TrimSpace(p); trimmed != "" {
+				result = append(result, trimmed)
+			}
+		}
+		if len(result) > 0 {
+			return result
+		}
+	}
+	return fallback
+}

backend/internal/http/middleware/cors.go

@@ -1,22 +1,57 @@
 package middleware
 
-import "net/http"
+import (
+	"net/http"
+	"strings"
+)
+
+// CORSConfig holds the configuration for CORS middleware.
+type CORSConfig struct {
+	AllowedOrigins []string
+}
 
 // CORS adds Cross-Origin Resource Sharing headers to the response.
-// For now, it allows all origins (*).
-func CORS(next http.Handler) http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		w.Header().Set("Access-Control-Allow-Origin", "*")
-		w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS, PATCH")
-		w.Header().Set("Access-Control-Allow-Headers", "Content-Type, Authorization")
-		w.Header().Set("Access-Control-Max-Age", "86400")
-
-		// Handle preflight requests
-		if r.Method == http.MethodOptions {
-			w.WriteHeader(http.StatusOK)
-			return
+// If allowedOrigins contains "*", it allows all origins.
+// Otherwise, it checks if the request origin is in the allowed list.
+func CORSWithConfig(cfg CORSConfig) func(http.Handler) http.Handler {
+	allowAll := false
+	originsMap := make(map[string]bool)
+	for _, origin := range cfg.AllowedOrigins {
+		if origin == "*" {
+			allowAll = true
+			break
 		}
+		originsMap[strings.ToLower(origin)] = true
+	}
 
-		next.ServeHTTP(w, r)
-	})
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			origin := r.Header.Get("Origin")
+
+			if allowAll {
+				w.Header().Set("Access-Control-Allow-Origin", "*")
+			} else if origin != "" && originsMap[strings.ToLower(origin)] {
+				w.Header().Set("Access-Control-Allow-Origin", origin)
+				w.Header().Set("Vary", "Origin")
+			}
+
+			w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS, PATCH")
+			w.Header().Set("Access-Control-Allow-Headers", "Content-Type, Authorization")
+			w.Header().Set("Access-Control-Max-Age", "86400")
+
+			// Handle preflight requests
+			if r.Method == http.MethodOptions {
+				w.WriteHeader(http.StatusOK)
+				return
+			}
+
+			next.ServeHTTP(w, r)
+		})
+	}
+}
+
+// CORS is a compatibility wrapper that allows all origins.
+// Deprecated: Use CORSWithConfig for more control.
+func CORS(next http.Handler) http.Handler {
+	return CORSWithConfig(CORSConfig{AllowedOrigins: []string{"*"}})(next)
 }

backend/internal/server/server.go

@@ -117,9 +117,10 @@ func (s *Server) Start(ctx context.Context) error {
 		return err
 	}
 
+	corsConfig := middleware.CORSConfig{AllowedOrigins: s.cfg.CORSOrigins}
 	srv := &http.Server{
 		Addr:              s.cfg.Addr(),
-		Handler:           middleware.CORS(s.mux),
+		Handler:           middleware.CORSWithConfig(corsConfig)(s.mux),
 		ReadHeaderTimeout: 5 * time.Second,
 	}