cron

README

cron

cron is a Go library that parses a cron expression and outputs a human readable description of the cron schedule.
For example, given the expression "*/5 * * * *" it will output "Every 5 minutes".

Translated to Go from cron-expression-descriptor (C#) via cRonstrue (Javascript).
Original Author & Credit: Brady Holt (http://www.geekytidbits.com).

Features

• Zero dependencies
• Supports all cron expression special characters including * / , - ? L W, #
• Supports 5, 6 (w/ seconds or year), or 7 (w/ seconds and year) part cron expressions
• Supports Quartz Job Scheduler cron expressions
• i18n support with 25 languages

Installation

cron module can be used with Go >= 1.13.

go get github.com/lnquy/cron

Usage

// Init with default EN locale
exprDesc, _ := cron.NewDescriptor()

desc, _ := exprDesc.ToDescription("* * * * *", cron.Locale_en)
// "Every minute" 

desc, _ := exprDesc.ToDescription("0 23 ? * MON-FRI", cron.Locale_en)
// "At 11:00 PM, Monday through Friday" 

desc, _ := exprDesc.ToDescription("23 14 * * SUN#2", cron.Locale_en)
// "At 02:23 PM, on the second Sunday of the month"

// Init with custom configs
exprDesc, _ := cron.NewDescriptor(
    cron.Use24HourTimeFormat(true),
    cron.DayOfWeekStartsAtOne(true),
    cron.Verbose(true),
    cron.SetLogger(log.New(os.Stdout, "cron: ", 0)),
    cron.SetLocales(cron.Locale_en, cron.Locale_fr),
)

For more usage examples, including a demonstration of how cRonstrue can handle some very complex cron expressions, you can reference the unit tests or the example codes.

Demo

[...]

i18n

To use the i18n support, you must configure the locales when create a new ExpressionDescriptor via SetLocales() option.

exprDesc, _ := cron.NewDescriptor(
    cron.SetLocales(cron.Locale_en, cron.Locale_es, cron.Locale_fr),
)
// or load all cron.LocaleAll
exprDesc, _ := cron.NewDescriptor(cron.SetLocales(cron.LocaleAll))

desc, _ := exprDesc.ToDescription("* * * * *", cron.Locale_fr)
// Toutes les minutes

By default, ExpressionDescriptor always load the Locale_en. If you passes an unregistered locale into ToDescription() function, the result will be returned in English.

Supported Locales

• en - English
• cs - Czech
• es - Spanish
• da - Danish
• de - German
• fi - Finnish
• fr - French
• fa - Farsi
• he - Hebrew
• it - Italian
• ja - Japanese
• ko - Korean
• nb - Norwegian
• nl - Dutch
• pl - Polish
• pt_BR - Portuguese (Brazil)
• ro - Romanian
• ru - Russian
• sk - Slovakian
• sl - Slovenian
• sw - Swahili
• sv - Swedish
• tr - Turkish
• uk - Ukrainian
• zh_CN - Chinese (Simplified)
• zh_TW - Chinese (Traditional)
  [TODO]

Project status

• Port 1-1 code from cRonstrue Javascript
• Port and pass all test cases from cRonstrue
• i18n for 25 languages
• Test cases i18n
• Fix i18n issues of FA, HE, RO, RU, UK, ZH_CN and ZH_TW
• hcron CLI tool
• Performance improvement
• Release v1.0

License

This project is under the MIT License. See the LICENSE file for the full license text.

Documentation

Index

• Variables
• type ExpressionDescriptor
  • func NewDescriptor(options ...Option) (exprDesc *ExpressionDescriptor, err error)
  • func (e *ExpressionDescriptor) ToDescription(expr string, loc LocaleType) (desc string, err error)
• type Locale
  • func NewLocaleLoaders(types ...LocaleType) (loaders []Locale, err error)
• type LocaleKey
• type LocaleLoader
  • func (l *LocaleLoader) GetBool(key LocaleKey) (value bool)
  • func (l *LocaleLoader) GetLocaleType() (typ LocaleType)
  • func (l *LocaleLoader) GetSlice(key LocaleKey) (values []string)
  • func (l *LocaleLoader) GetString(key LocaleKey) (value string)
• type LocaleType
  • func ParseLocale(s string) (l LocaleType, err error)
• type Logger
• type Option
  • func DayOfWeekStartsAtOne(v bool) Option
  • func SetLocales(locales ...LocaleType) Option
  • func SetLogger(logger Logger) Option
  • func Use24HourTimeFormat(v bool) Option
  • func Verbose(v bool) Option
• type Parser

Variables

var (
	InvalidExprError           = errors.New("invalid expression")
	InvalidExprSecondError     = errors.New("invalid expression, second part")
	InvalidExprMinuteError     = errors.New("invalid expression, minute part")
	InvalidExprHourError       = errors.New("invalid expression, hour part")
	InvalidExprDayOfMonthError = errors.New("invalid expression, day of month part")
	InvalidExprMonthError      = errors.New("invalid expression, month part")
	InvalidExprDayOfWeekError  = errors.New("invalid expression, day of week part")
	InvalidExprYearError       = errors.New("invalid expression, year part")
)

Types

type ExpressionDescriptor

type ExpressionDescriptor struct {
	// contains filtered or unexported fields
}

func NewDescriptor

func NewDescriptor(options ...Option) (exprDesc *ExpressionDescriptor, err error)

func (*ExpressionDescriptor) ToDescription

func (e *ExpressionDescriptor) ToDescription(expr string, loc LocaleType) (desc string, err error)

type Locale

type Locale interface {
	GetLocaleType() (typ LocaleType)
	GetBool(key LocaleKey) (value bool)
	GetString(key LocaleKey) (value string)
	GetSlice(key LocaleKey) (values []string)
}

func NewLocaleLoaders

func NewLocaleLoaders(types ...LocaleType) (loaders []Locale, err error)

type LocaleKey

type LocaleKey string

type LocaleLoader

type LocaleLoader struct {
	// contains filtered or unexported fields
}

func (*LocaleLoader) GetBool

func (l *LocaleLoader) GetBool(key LocaleKey) (value bool)

func (*LocaleLoader) GetLocaleType

func (l *LocaleLoader) GetLocaleType() (typ LocaleType)

func (*LocaleLoader) GetSlice

func (l *LocaleLoader) GetSlice(key LocaleKey) (values []string)

func (*LocaleLoader) GetString

func (l *LocaleLoader) GetString(key LocaleKey) (value string)

type LocaleType

type LocaleType string

const (
	LocaleAll LocaleType = "all"

	Locale_cs    LocaleType = "cs"
	Locale_da    LocaleType = "da"
	Locale_de    LocaleType = "de"
	Locale_en    LocaleType = "en"
	Locale_es    LocaleType = "es"
	Locale_fa    LocaleType = "fa"
	Locale_fi    LocaleType = "fi"
	Locale_fr    LocaleType = "fr"
	Locale_he    LocaleType = "he"
	Locale_it    LocaleType = "it"
	Locale_ja    LocaleType = "ja"
	Locale_ko    LocaleType = "ko"
	Locale_nb    LocaleType = "nb"
	Locale_nl    LocaleType = "nl"
	Locale_pl    LocaleType = "pl"
	Locale_pt_BR LocaleType = "pt_BR"
	Locale_ro    LocaleType = "ro"
	Locale_ru    LocaleType = "ru"
	Locale_sk    LocaleType = "sk"
	Locale_sl    LocaleType = "sl"
	Locale_sv    LocaleType = "sv"
	Locale_sw    LocaleType = "sw"
	Locale_tr    LocaleType = "tr"
	Locale_uk    LocaleType = "uk"
	Locale_zh_CN LocaleType = "zh_CN"
	Locale_zh_TW LocaleType = "zh_TW"
)

func ParseLocale

func ParseLocale(s string) (l LocaleType, err error)

type Logger

type Logger interface {
	Printf(format string, v ...interface{})
}

type Option

type Option func(exprDesc *ExpressionDescriptor)

func DayOfWeekStartsAtOne

func DayOfWeekStartsAtOne(v bool) Option

func SetLocales

func SetLocales(locales ...LocaleType) Option

func SetLogger

func SetLogger(logger Logger) Option

func Use24HourTimeFormat

func Use24HourTimeFormat(v bool) Option

func Verbose

func Verbose(v bool) Option

type Parser

type Parser interface {
	Parse(expr string) (exprParts []string, err error)
}