Initial import of map-asset-gateway

services/api-go/internal/config/envfile.go

@@ -0,0 +1,73 @@
+package config
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+func LoadEnvDefaults() error {
+	if explicit := strings.TrimSpace(os.Getenv("APP_ENV_FILE")); explicit != "" {
+		if err := loadEnvFile(explicit); err != nil {
+			return fmt.Errorf("load APP_ENV_FILE %s: %w", explicit, err)
+		}
+		return nil
+	}
+
+	for _, candidate := range []string{
+		filepath.Join("config", "service.env"),
+		filepath.Join("..", "..", "config", "service.env"),
+	} {
+		if _, err := os.Stat(candidate); err == nil {
+			if err := loadEnvFile(candidate); err != nil {
+				return fmt.Errorf("load env file %s: %w", candidate, err)
+			}
+			return nil
+		}
+	}
+	return nil
+}
+
+func loadEnvFile(path string) error {
+	file, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	lineNo := 0
+	for scanner.Scan() {
+		lineNo++
+		line := strings.TrimSpace(scanner.Text())
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+		if strings.HasPrefix(line, "export ") {
+			line = strings.TrimSpace(strings.TrimPrefix(line, "export "))
+		}
+
+		key, value, found := strings.Cut(line, "=")
+		if !found {
+			return fmt.Errorf("line %d: missing '='", lineNo)
+		}
+		key = strings.TrimSpace(key)
+		value = strings.TrimSpace(value)
+		value = strings.Trim(value, `"'`)
+		if key == "" {
+			return fmt.Errorf("line %d: empty key", lineNo)
+		}
+		if _, exists := os.LookupEnv(key); exists {
+			continue
+		}
+		if err := os.Setenv(key, value); err != nil {
+			return fmt.Errorf("line %d: set %s: %w", lineNo, key, err)
+		}
+	}
+	if err := scanner.Err(); err != nil {
+		return err
+	}
+	return nil
+}