Initial commit

internal/platform/environment/environment.go

@@ -0,0 +1,95 @@
+// Package environment provides strict parsing for runtime configuration.
+package environment
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+)
+
+// String returns a trimmed environment value or fallback when it is empty.
+func String(name, fallback string) string {
+	if value := strings.TrimSpace(os.Getenv(name)); value != "" {
+		return value
+	}
+	return fallback
+}
+
+// Required returns a non-empty environment value.
+func Required(name string) (string, error) {
+	value := strings.TrimSpace(os.Getenv(name))
+	if value == "" {
+		return "", fmt.Errorf("%s must be set", name)
+	}
+	return value, nil
+}
+
+// Int parses an integer environment value.
+func Int(name string, fallback int) (int, error) {
+	value := strings.TrimSpace(os.Getenv(name))
+	if value == "" {
+		return fallback, nil
+	}
+	parsed, err := strconv.Atoi(value)
+	if err != nil {
+		return 0, fmt.Errorf("%s must be an integer: %w", name, err)
+	}
+	return parsed, nil
+}
+
+// Float parses a floating-point environment value.
+func Float(name string, fallback float64) (float64, error) {
+	value := strings.TrimSpace(os.Getenv(name))
+	if value == "" {
+		return fallback, nil
+	}
+	parsed, err := strconv.ParseFloat(value, 64)
+	if err != nil {
+		return 0, fmt.Errorf("%s must be a number: %w", name, err)
+	}
+	return parsed, nil
+}
+
+// Bool parses a boolean environment value.
+func Bool(name string, fallback bool) (bool, error) {
+	value := strings.TrimSpace(os.Getenv(name))
+	if value == "" {
+		return fallback, nil
+	}
+	parsed, err := strconv.ParseBool(value)
+	if err != nil {
+		return false, fmt.Errorf("%s must be a boolean: %w", name, err)
+	}
+	return parsed, nil
+}
+
+// Duration parses a Go duration environment value.
+func Duration(name string, fallback time.Duration) (time.Duration, error) {
+	value := strings.TrimSpace(os.Getenv(name))
+	if value == "" {
+		return fallback, nil
+	}
+	parsed, err := time.ParseDuration(value)
+	if err != nil {
+		return 0, fmt.Errorf("%s must be a duration: %w", name, err)
+	}
+	return parsed, nil
+}
+
+// CSV returns non-empty, trimmed comma-separated values.
+func CSV(name string) []string {
+	value := strings.TrimSpace(os.Getenv(name))
+	if value == "" {
+		return nil
+	}
+	parts := strings.Split(value, ",")
+	result := make([]string, 0, len(parts))
+	for _, part := range parts {
+		if part = strings.TrimSpace(part); part != "" {
+			result = append(result, part)
+		}
+	}
+	return result
+}