Ensure int env variables are not negative

internal/environment/Environment.go

@@ -4,6 +4,8 @@ import (
 	"fmt"
 	"os"
 	"path"
+	"reflect"
+	"strconv"
 
 	envParser "github.com/caarlos0/env/v6"
 	"github.com/forceu/gokapi/internal/environment/deprecation"
@@ -20,15 +22,15 @@ type Environment struct {
 	ConfigFile         string `env:"CONFIG_FILE" envDefault:"config.json"`
 	ConfigPath         string
 	DataDir            string `env:"DATA_DIR" envDefault:"data"`
-	ChunkSizeMB        int    `env:"CHUNK_SIZE_MB" envDefault:"45"`
-	LengthId           int    `env:"LENGTH_ID" envDefault:"15"`
-	LengthHotlinkId    int    `env:"LENGTH_HOTLINK_ID" envDefault:"40"`
-	MaxFileSize        int    `env:"MAX_FILESIZE" envDefault:"102400"` // 102400==100GB
-	MaxMemory          int    `env:"MAX_MEMORY_UPLOAD" envDefault:"50"`
-	MaxParallelUploads int    `env:"MAX_PARALLEL_UPLOADS" envDefault:"3"`
-	MinFreeSpaceMB     int    `env:"MIN_FREE_SPACE" envDefault:"400"`
-	MinLengthPassword  int    `env:"MIN_LENGTH_PASSWORD" envDefault:"8"`
-	WebserverPort      int    `env:"PORT" envDefault:"53842"`
+	ChunkSizeMB        int    `env:"CHUNK_SIZE_MB" envDefault:"45" onlyPositive:"true"`
+	LengthId           int    `env:"LENGTH_ID" envDefault:"15" onlyPositive:"true"`
+	LengthHotlinkId    int    `env:"LENGTH_HOTLINK_ID" envDefault:"40" onlyPositive:"true"`
+	MaxFileSize        int    `env:"MAX_FILESIZE" envDefault:"102400" onlyPositive:"true"` // 102400 = 100GB
+	MaxMemory          int    `env:"MAX_MEMORY_UPLOAD" envDefault:"50" onlyPositive:"true"`
+	MaxParallelUploads int    `env:"MAX_PARALLEL_UPLOADS" envDefault:"3" onlyPositive:"true"`
+	MinFreeSpaceMB     int    `env:"MIN_FREE_SPACE" envDefault:"400" onlyPositive:"true"`
+	MinLengthPassword  int    `env:"MIN_LENGTH_PASSWORD" envDefault:"8" onlyPositive:"true"`
+	WebserverPort      int    `env:"PORT" envDefault:"53842" onlyPositive:"true"`
 	DisableCorsCheck   bool   `env:"DISABLE_CORS_CHECK" envDefault:"false"`
 	LogToStdout        bool   `env:"LOG_STDOUT" envDefault:"false"`
 	HotlinkVideos      bool   `env:"ENABLE_HOTLINK_VIDEOS" envDefault:"false"`
@@ -38,13 +40,26 @@ type Environment struct {
 	AwsKeySecret       string `env:"AWS_KEY_SECRET"`
 	AwsEndpoint        string `env:"AWS_ENDPOINT"`
 	ActiveDeprecations []deprecation.Deprecation
+	isSet              bool
+}
+
+func (e *Environment) IsParsed() bool {
+	return e.isSet
 }
 
 // New parses the env variables
 func New() Environment {
-	result := Environment{WebserverPort: DefaultPort}
+	result := Environment{
+		WebserverPort: DefaultPort,
+		isSet:         true,
+	}
 
 	result = parseEnvVars(result)
+	err := enforceOnlyPositiveDefaults(&result)
+	if err != nil {
+		fmt.Println("Error parsing env variables:", err)
+		osExit(1)
+	}
 	result = parseFlags(result)
 	result.ActiveDeprecations = deprecation.GetActive()
 
@@ -78,6 +93,49 @@ func parseEnvVars(result Environment) Environment {
 	return result
 }
 
+func enforceOnlyPositiveDefaults(result *Environment) error {
+	v := reflect.ValueOf(result)
+	if v.Kind() != reflect.Ptr || v.Elem().Kind() != reflect.Struct {
+		return fmt.Errorf("env must be a pointer to a struct")
+	}
+
+	v = v.Elem()
+	t := v.Type()
+
+	for i := 0; i < v.NumField(); i++ {
+		fieldVal := v.Field(i)
+		fieldType := t.Field(i)
+
+		if fieldType.Tag.Get("onlyPositive") != "true" {
+			continue
+		}
+
+		// Only handle signed integers
+		switch fieldVal.Kind() {
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+			if fieldVal.Int() >= 0 {
+				continue
+			}
+
+			defaultStr := fieldType.Tag.Get("envDefault")
+			defaultVal, err := strconv.ParseInt(defaultStr, 10, fieldVal.Type().Bits())
+			if err != nil {
+				return fmt.Errorf("invalid envDefault for field %s: %w", fieldType.Name, err)
+			}
+
+			if fieldVal.CanSet() {
+				fieldVal.SetInt(defaultVal)
+			} else {
+				return fmt.Errorf("cannot set fieldval %s", fieldType.Name)
+			}
+		default:
+			continue
+		}
+	}
+
+	return nil
+}
+
 func parseFlags(result Environment) Environment {
 	flags := flagparser.ParseFlags()
 	if flags.IsPortSet {