wait_info/wait_info.go

   1 package wait_info
   2
   3 import (
   4         "github.com/sjmudd/pstop/lib"
   5         "time"
   6 )
   7
   8 const extra_delay = 200 * time.Millisecond
   9
  10 // used to record when we need to wa
  11 type WaitInfo struct {
  12         last_collected   time.Time
  13         collect_interval time.Duration
  14 }
  15
  16 // return the configured wait interval
  17 func (wi *WaitInfo) WaitInterval() time.Duration {
  18         return wi.collect_interval
  19 }
  20
  21 // recognise we've done a collection
  22 func (wi *WaitInfo) CollectedNow() {
  23         wi.SetCollected(time.Now())
  24 }
  25
  26 // change the configured wait interval
  27 func (wi *WaitInfo) SetWaitInterval(required_interval time.Duration) {
  28         wi.collect_interval = required_interval
  29 }
  30
  31 // set the time the last collection happened
  32 func (wi *WaitInfo) SetCollected(collect_time time.Time) {
  33         wi.last_collected = collect_time
  34         lib.Logger.Println("WaitInfo.SetCollected() last_collected=", wi.last_collected)
  35 }
  36
  37 // return the time the last collection happened
  38 func (wi WaitInfo) LastCollected() time.Time {
  39         return wi.last_collected
  40 }
  41
  42 // return the amount of time to wait before doing the next collection
  43 func (wi WaitInfo) TimeToWait() time.Duration {
  44         now := time.Now()
  45         lib.Logger.Println("WaitInfo.TimeToWait() now: ", now)
  46
  47         next_time := wi.last_collected.Add(wi.collect_interval)
  48         lib.Logger.Println("WaitInfo.TimeToWait() next_time: ", next_time)
  49         if next_time.Before(now) {
  50                 lib.Logger.Println("WaitInfo.TimeToWait() next_time scheduled time in the past, so schedule", extra_delay, "after", now)
  51                 next_time = now
  52                 next_time.Add(extra_delay) // add a deliberate tiny delay
  53                 lib.Logger.Println("WaitInfo.TimeToWait() next_time: ", next_time, "(corrected)")
  54         }
  55         wait_time := next_time.Sub(now)
  56         lib.Logger.Println("WaitInfo.TimeToWait() returning wait_time:", wait_time)
  57
  58         return wait_time
  59 }
  60
  61 // behave like time.After()
  62 func (wi WaitInfo) WaitNextPeriod() <-chan time.Time {
  63         return time.After(wi.TimeToWait())
  64 }