Documentation
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Index ¶
- type Chain
- type ConstantDelaySchedule
- type Cron
- func (c *Cron) AddFunc(id uint32, spec string, cmd func()) error
- func (c *Cron) AddJob(id uint32, spec string, cmd Job) error
- func (c *Cron) Entries() []Entry
- func (c *Cron) Entry(id uint32) Entry
- func (c *Cron) HasEntry(id uint32) bool
- func (c *Cron) Location() *time.Location
- func (c *Cron) Remove(id uint32)
- func (c *Cron) Run()
- func (c *Cron) Schedule(id uint32, spec string, cmd Job) error
- func (c *Cron) Spec(id uint32) string
- func (c *Cron) Specs() map[uint32]string
- func (c *Cron) Start()
- func (c *Cron) Stop() context.Context
- func (c *Cron) ValidateSpec(spec string) error
- type Entry
- type FuncJob
- type Job
- type JobWrapper
- type Option
- type ParseOption
- type Parser
- type Schedule
- type ScheduleParser
- type SpecSchedule
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Chain ¶
type Chain struct {
// contains filtered or unexported fields
}
Chain is a sequence of JobWrappers that decorates submitted jobs with cross-cutting behaviors like logging or synchronization.
func NewChain ¶
func NewChain(c ...JobWrapper) Chain
NewChain returns a Chain consisting of the given JobWrappers.
type ConstantDelaySchedule ¶
ConstantDelaySchedule represents a simple recurring duty cycle, e.g. "Every 5 minutes". It does not support jobs more frequent than once a second.
func Every ¶
func Every(duration time.Duration) ConstantDelaySchedule
Every returns a crontab Schedule that activates once every duration. Delays of less than a second are not supported (will round up to 1 second). Any fields less than a Second are truncated.
type Cron ¶
type Cron struct {
// contains filtered or unexported fields
}
Cron keeps track of any number of entries, invoking the associated func as specified by the schedule. It may be started, stopped, and the entries may be inspected while running.
func New ¶
New returns a new Cron job runner, modified by the given options.
Available Settings
Time Zone Description: The time zone in which schedules are interpreted Default: time.Local Parser Description: Parser converts cron spec strings into cron.Schedules. Default: Accepts this spec: https://en.wikipedia.org/wiki/Cron Chain Description: Wrap submitted jobs to customize behavior. Default: A chain that recovers panics and logs them to stderr.
See "cron.With*" to modify the default behavior.
func (*Cron) AddFunc ¶
AddFunc adds a func to the Cron to be run on the given schedule. The spec is parsed using the time zone of this Cron instance as the default. An opaque ID is returned that can be used to later remove it.
func (*Cron) AddJob ¶
AddJob adds a Job to the Cron to be run on the given schedule. The spec is parsed using the time zone of this Cron instance as the default. An opaque ID is returned that can be used to later remove it.
func (*Cron) HasEntry ¶
HasEntry returns a snapshot of the given entry, or nil if it couldn't be found.
func (*Cron) Schedule ¶
Schedule adds a Job to the Cron to be run on the given schedule. The job is wrapped with the configured Chain.
func (*Cron) Start ¶
func (c *Cron) Start()
Start the cron scheduler in its own goroutine, or no-op if already started.
func (*Cron) Stop ¶
Stop stops the cron scheduler if it is running; otherwise it does nothing. A context is returned so the caller can wait for running jobs to complete.
func (*Cron) ValidateSpec ¶
type Entry ¶
type Entry struct {
// ID is the cron-assigned ID of this entry, which may be used to look up a
// snapshot or remove it.
ID uint32
Spec string
// Schedule on which this job should be run.
Schedule Schedule
// Next time the job will run, or the zero time if Cron has not been
// started or this entry's schedule is unsatisfiable
Next time.Time
// Prev is the last time this job was run, or the zero time if never.
Prev time.Time
// WrappedJob is the thing to run when the Schedule is activated.
WrappedJob Job
// Job is the thing that was submitted to cron.
// It is kept around so that user code that needs to get at the job later,
// e.g. via Entries() can do so.
Job Job
}
Entry consists of a schedule and the func to execute on that schedule.
type JobWrapper ¶
JobWrapper decorates the given Job with some behavior.
func DelayIfStillRunning ¶
func DelayIfStillRunning(logger log.Helper) JobWrapper
DelayIfStillRunning serializes jobs, delaying subsequent runs until the previous one is complete. Jobs running after a delay of more than a minute have the delay logged at Info.
func Recover ¶
func Recover(logger log.Helper) JobWrapper
Recover panics in wrapped jobs and log them with the provided logger.
func SkipIfStillRunning ¶
func SkipIfStillRunning(logger log.Helper) JobWrapper
SkipIfStillRunning skips an invocation of the Job if a previous invocation is still running. It logs skips to the given logger at Info level.
type Option ¶
type Option func(*Cron)
Option represents a modification to the default behavior of a Cron.
func WithChain ¶
func WithChain(wrappers ...JobWrapper) Option
WithChain specifies Job wrappers to apply to all jobs added to this cron. Refer to the Chain* functions in this package for provided wrappers.
func WithLocation ¶
WithLocation overrides the timezone of the cron instance.
func WithParser ¶
func WithParser(p ScheduleParser) Option
WithParser overrides the parser used for interpreting job schedules.
func WithSeconds ¶
func WithSeconds() Option
WithSeconds overrides the parser used for interpreting job schedules to include a seconds field as the first one.
type ParseOption ¶
type ParseOption int
Configuration options for creating a parser. Most options specify which fields should be included, while others enable features. If a field is not included the parser will assume a default value. These options do not change the order fields are parse in.
const ( Second ParseOption = 1 << iota // Seconds field, default 0 SecondOptional // Optional seconds field, default 0 Minute // Minutes field, default 0 Hour // Hours field, default 0 Dom // Day of month field, default * Month // Month field, default * Dow // Day of week field, default * DowOptional // Optional day of week field, default * Descriptor // Allow descriptors such as @monthly, @weekly, etc. )
type Parser ¶
type Parser struct {
// contains filtered or unexported fields
}
A custom Parser that can be configured.
func NewParser ¶
func NewParser(options ParseOption) Parser
NewParser creates a Parser with custom options.
It panics if more than one Optional is given, since it would be impossible to correctly infer which optional is provided or missing in general.
Examples
// Standard parser without descriptors
specParser := NewParser(Minute | Hour | Dom | Month | Dow)
sched, err := specParser.Parse("0 0 15 */3 *")
// Same as above, just excludes time fields
specParser := NewParser(Dom | Month | Dow)
sched, err := specParser.Parse("15 */3 *")
// Same as above, just makes Dow optional
specParser := NewParser(Dom | Month | DowOptional)
sched, err := specParser.Parse("15 */3")
type Schedule ¶
type Schedule interface {
// Next returns the next activation time, later than the given time.
// Next is invoked initially, and then each time the job is run.
Next(time.Time) time.Time
}
Schedule describes a job's duty cycle.
func ParseStandard ¶
ParseStandard returns a new crontab schedule representing the given standardSpec (https://en.wikipedia.org/wiki/Cron). It requires 5 entries representing: minute, hour, day of month, month and day of week, in that order. It returns a descriptive error if the spec is not valid.
It accepts
- Standard crontab specs, e.g. "* * * * ?"
- Descriptors, e.g. "@midnight", "@every 1h30m"
type ScheduleParser ¶
ScheduleParser is an interface for schedule spec parsers that return a Schedule
type SpecSchedule ¶
type SpecSchedule struct {
Second, Minute, Hour, Dom, Month, Dow uint64
// Override location for this schedule.
Location *time.Location
}
SpecSchedule specifies a duty cycle (to the second granularity), based on a traditional crontab specification. It is computed initially and stored as bit sets.
Source Files