github.com/koko1123/flow-go-1@v0.29.6/utils/liveness/check.go (about)

     1  package liveness
     2  
     3  import (
     4  	"sync"
     5  	"time"
     6  )
     7  
     8  // Check is a heartbeat style liveness reporter.
     9  //
    10  // It is not guaranteed to be safe to CheckIn across multiple goroutines.
    11  // IsLive must be safe to be called concurrently with CheckIn.
    12  type Check interface {
    13  	CheckIn()
    14  	IsLive(time.Duration) bool
    15  }
    16  
    17  // internalCheck implements a Check.
    18  type internalCheck struct {
    19  	lock             sync.RWMutex
    20  	lastCheckIn      time.Time
    21  	defaultTolerance time.Duration
    22  }
    23  
    24  // CheckIn adds a heartbeat at the current time.
    25  func (c *internalCheck) CheckIn() {
    26  	c.lock.Lock()
    27  	c.lastCheckIn = time.Now()
    28  	c.lock.Unlock()
    29  }
    30  
    31  // IsLive checks if we are still live against the given the tolerace between hearbeats.
    32  //
    33  // If tolerance is 0, the default tolerance is used.
    34  func (c *internalCheck) IsLive(tolerance time.Duration) bool {
    35  	c.lock.RLock()
    36  	defer c.lock.RUnlock()
    37  	if tolerance == 0 {
    38  		tolerance = c.defaultTolerance
    39  	}
    40  
    41  	return c.lastCheckIn.Add(tolerance).After(time.Now())
    42  }