defaults

README

Defaults

Provide some global default values, supporting Go 1.21+.

By default, the value is not atomic, however, which can be enabled by setting the tags atomic when compiling it, such as go build -tags atomic.

Documentation

Overview

Package defaults provides some global default values.

Index

• Variables
• func Exit(code int)
• func GetClientIP(ctx context.Context, req any) netip.Addr
• func GetRequestID(ctx context.Context, req any) string
• func GetStacks(skip int) []string
• func GetStructFieldName(sf reflect.StructField) (name, arg string)
• func HandlePanic(ctx context.Context, r any)
• func Now() time.Time
• func Recover(ctx context.Context)
• func TrimPkgFile(file string) string
• func ValidateStruct(value any) (err error)
• func ValidateWithRule(value any, rule string) (err error)
• type Value
  • func NewValue[T any](initial T) *Value[T]
  • func NewValueWithValidation[T any](initial T, validate func(T) error) *Value[T]
  • func (v *Value[T]) Get() T
  • func (v *Value[T]) Set(new T)
  • func (v *Value[T]) Swap(new T) (old T)
  • func (v *Value[T]) Validate(value T) error

Examples

• TrimPkgFile

Variables

var (
	// HeaderXRequestID is used by GetRequestIDFunc to try
	// to get the request id from the http request.
	HeaderXRequestID = "X-Request-Id"

	// GetRequestIDFunc is used to get the unique request session id.
	//
	// For the default implementation, it only supports the types and interfaces:
	//
	// 	*http.Request
	//	interface{ RequestID() string }
	//	interface{ GetRequestID() string }
	//
	// Or, return "".
	GetRequestIDFunc = NewValueWithValidation(getRequestID, fActxAifaceR1[string]("GetRequestID"))
)

var (
	// TrimPkgFileFunc is used to trim the prefix of the package file path.
	TrimPkgFileFunc = NewValueWithValidation(trimPkgFile, fA1R1Validation[string, string]("TrimPkgFile"))

	// GetStacksFunc is used to get the stacks of the function calling.
	GetStacksFunc = NewValueWithValidation(getStacks, fA1R1Validation[int, []string]("GetStacks"))
)

var (
	TimeFormat   = NewValueWithValidation(time.RFC3339Nano, validateTimeFormat)
	TimeFormats  = NewValueWithValidation([]string{time.RFC3339Nano, "2006-01-02 15:04:05"}, validateTimeFormats)
	TimeLocation = NewValueWithValidation(time.UTC, validateTimeLocation)
	TimeNowFunc  = NewValueWithValidation(time.Now, validateTimeNow)
)

Pre-define some global variables about time.

var (
	// RuleValidator is used to validate whether a value conforms with the rule.
	//
	// Note: in general, it is used to validate a struct field with the tag rule.
	RuleValidator = NewValue(assists.RuleValidator(nil))

	// StructValidator is used to validate whether a struct value is valid.
	StructValidator = NewValue(assists.StructValidator(nil))
)

var (
	// ExitFunc is used to exit the program.
	//
	// Default: os.Exit
	ExitFunc = NewValueWithValidation(os.Exit, fA1Validation[int]("Exit"))
)

var (
	// GetClientIPFunc is used to get the client ip of the request.
	//
	// For the default implementation, it only supports the types or interfaces:
	//
	// 	*http.Request
	// 	interface{ ClientIP() netip.Addr }
	// 	interface{ ClientIP() net.IP }
	// 	interface{ ClientIP() string }
	// 	interface{ RemoteAddr() netip.Addr }
	// 	interface{ RemoteAddr() net.Addr }
	// 	interface{ RemoteAddr() string }
	//
	// Or, return nil.
	GetClientIPFunc = NewValueWithValidation(getClientIP, fActxAifaceR1[netip.Addr]("GetClientIP"))
)

var (
	// HandlePanicFunc is used to handle the panic value returned by recover().
	HandlePanicFunc = NewValueWithValidation(handlePanic, fActxAiface("HandlePanic"))
)

var (
	// StructFieldNameFunc is used to get the obtain the name and arg
	// of the struct field, which needs to return a empty string for
	// the field name, that's "", if the field should be ignored.
	//
	// Example:
	//
	//	StructFieldNameFunc.Set(func(sf reflect.StructField) (name string, arg string) {
	//	    value := sf.Tag.Get("json")
	//	    if index := strings.IndexByte(value, ','); index > -1 {
	//	        arg = strings.TrimSpace(value[index+1:])
	//	        value = strings.TrimSpace(value[:index])
	//	    }
	//
	//	    switch value {
	//	    case "-":
	//	    case "":
	//	        name = sf.Name
	//	    default:
	//	        name = value
	//	    }
	//
	//	    return
	//	})
	//
	StructFieldNameFunc = NewValueWithValidation(assists.StructFieldNameFuncWithTags("json"),
		fA1R2Validation[reflect.StructField, string, string]("StructFieldName"))
)

Functions

func Exit

func Exit(code int)

Exit is the proxy of ExitFunc to call the function to exit the program.

func GetClientIP

func GetClientIP(ctx context.Context, req any) netip.Addr

GetClientIP is the proxy of GetClientIPFunc to call the function.

func GetRequestID

func GetRequestID(ctx context.Context, req any) string

GetRequestID is the proxy of GetRequestIDFunc to call the function.

func GetStacks

func GetStacks(skip int) []string

GetStacks is the proxy of GetStacksFunc to call the funciton.

func GetStructFieldName

func GetStructFieldName(sf reflect.StructField) (name, arg string)

GetStructFieldName is the proxy of StructFieldNameFunc to call the function, just like StructFieldNameFunc.Get()(sf).

func HandlePanic

func HandlePanic(ctx context.Context, r any)

HandlePanic is the proxy of HandlePanicFunc to call the funciton.

func Now

func Now() time.Time

Now returns the current time by using TimeNow and TimeLocation.

func Recover

func Recover(ctx context.Context)

Recover is a convenient function to wrap and recover the panic if occurring, then call HandlePanic to handle it.

NOTICE: It must be called after defer, like

defer Recover(context.Background())

func TrimPkgFile

func TrimPkgFile(file string) string

TrimPkgFile is the proxy of TrimPkgFileFunc to call the funciton.

Example

srcfile := TrimPkgFile("/path/to/src/github.com/xgfone/go-defaults/srcfile.go")
modfile := TrimPkgFile("/path/to/pkg/mod/github.com/xgfone/go-defaults/modfile.go")
origfile := TrimPkgFile("/path/to/github.com/xgfone/go-defaults/modfile.go")

fmt.Println(srcfile)
fmt.Println(modfile)
fmt.Println(origfile)

Output:

github.com/xgfone/go-defaults/srcfile.go
github.com/xgfone/go-defaults/modfile.go
/path/to/github.com/xgfone/go-defaults/modfile.go

func ValidateStruct

func ValidateStruct(value any) (err error)

ValidateStruct uses Validator to validate the struct value if StructValidator is not nil.

func ValidateWithRule

func ValidateWithRule(value any, rule string) (err error)

ValidateWithRule uses RuleValidator to validate a value conforms with the rule if RuleValidator is not nil.

Types

type Value

type Value[T any] struct {
	// contains filtered or unexported fields
}

Value represents a common value.

func NewValue

func NewValue[T any](initial T) *Value[T]

NewValue returns a new Value with the initial value.

func NewValueWithValidation

func NewValueWithValidation[T any](initial T, validate func(T) error) *Value[T]

NewValueWithValidation returns a new Value with the initial value and the validation.

validate may be nil, which is equal to always return nil.

func (*Value[T]) Get

func (v *Value[T]) Get() T

Get returns the inner value.

func (*Value[T]) Set

func (v *Value[T]) Set(new T)

Set sets the value to new.

It will panic if failing to validate the new value.

func (*Value[T]) Swap

func (v *Value[T]) Swap(new T) (old T)

Swap sets the value to new and returns the old value.

It will panic if failing to validate the new value.

func (*Value[T]) Validate

func (v *Value[T]) Validate(value T) error

Validate validate whether the input value is valid.