go.temporal.io/server@v1.23.0/common/backoff/cron.go (about)

     1  // The MIT License
     2  //
     3  // Copyright (c) 2020 Temporal Technologies Inc.  All rights reserved.
     4  //
     5  // Copyright (c) 2020 Uber Technologies, Inc.
     6  //
     7  // Permission is hereby granted, free of charge, to any person obtaining a copy
     8  // of this software and associated documentation files (the "Software"), to deal
     9  // in the Software without restriction, including without limitation the rights
    10  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    11  // copies of the Software, and to permit persons to whom the Software is
    12  // furnished to do so, subject to the following conditions:
    13  //
    14  // The above copyright notice and this permission notice shall be included in
    15  // all copies or substantial portions of the Software.
    16  //
    17  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    18  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    19  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    20  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    21  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    22  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    23  // THE SOFTWARE.
    24  
    25  package backoff
    26  
    27  import (
    28  	"time"
    29  
    30  	"github.com/robfig/cron/v3"
    31  	"go.temporal.io/api/serviceerror"
    32  
    33  	"go.temporal.io/server/common/convert"
    34  )
    35  
    36  // NoBackoff is used to represent backoff when no cron backoff is needed
    37  const NoBackoff = time.Duration(-1)
    38  
    39  // ValidateSchedule validates a cron schedule spec
    40  func ValidateSchedule(cronSchedule string) error {
    41  	if cronSchedule == "" {
    42  		return nil
    43  	}
    44  	schedule, err := cron.ParseStandard(cronSchedule)
    45  	if err != nil {
    46  		return serviceerror.NewInvalidArgument("invalid CronSchedule.")
    47  	}
    48  	nextTime := schedule.Next(time.Now().UTC())
    49  	if nextTime.IsZero() {
    50  		// no time can be found to satisfy the schedule
    51  		return serviceerror.NewInvalidArgument("invalid CronSchedule, no time can be found to satisfy the schedule")
    52  	}
    53  	return nil
    54  }
    55  
    56  // GetBackoffForNextSchedule calculates the backoff time for the next run given
    57  // a cronSchedule, current scheduled time, and now.
    58  func GetBackoffForNextSchedule(cronSchedule string, scheduledTime time.Time, now time.Time) time.Duration {
    59  	if len(cronSchedule) == 0 {
    60  		return NoBackoff
    61  	}
    62  
    63  	schedule, err := cron.ParseStandard(cronSchedule)
    64  	if err != nil {
    65  		return NoBackoff
    66  	}
    67  
    68  	scheduledUTCTime := scheduledTime.UTC()
    69  	nowUTC := now.UTC()
    70  
    71  	var nextScheduleTime time.Time
    72  	if nowUTC.Before(scheduledUTCTime) {
    73  		nextScheduleTime = scheduledUTCTime
    74  	} else {
    75  		nextScheduleTime = schedule.Next(scheduledUTCTime)
    76  		// Calculate the next schedule start time which is nearest to now (right after now).
    77  		for !nextScheduleTime.IsZero() && nextScheduleTime.Before(nowUTC) {
    78  			nextScheduleTime = schedule.Next(nextScheduleTime)
    79  		}
    80  	}
    81  	if nextScheduleTime.IsZero() {
    82  		// no time can be found to satisfy the schedule
    83  		return NoBackoff
    84  	}
    85  
    86  	backoffInterval := nextScheduleTime.Sub(nowUTC)
    87  	roundedInterval := time.Second * time.Duration(convert.Int64Ceil(backoffInterval.Seconds()))
    88  	return roundedInterval
    89  }
    90  
    91  // GetBackoffForNextScheduleNonNegative calculates the backoff time and ensures a non-negative duration.
    92  func GetBackoffForNextScheduleNonNegative(cronSchedule string, scheduledTime time.Time, now time.Time) time.Duration {
    93  	backoffDuration := GetBackoffForNextSchedule(cronSchedule, scheduledTime, now)
    94  	if backoffDuration == NoBackoff || backoffDuration < 0 {
    95  		backoffDuration = 0
    96  	}
    97  	return backoffDuration
    98  }