Probe simplification
* Probe simplification
- the main reason of rework is that previous implementation hung
when calling Do() after Stop()
* replace atomics with mutex
* access Probe.interval under lock
@@ -10,49 +10,27 @@ import (
// Probe is used to run a single Func until it returns true (indicating a target is healthy). If an Func
// is already in progress no new one will be added, i.e. there is always a maximum of 1 checks in flight.
type Probe struct {
- do chan Func
- stop chan bool
-
- target string
-
sync.Mutex
inprogress int
+ interval time.Duration
}
// Func is used to determine if a target is alive. If so this function must return nil.
type Func func() error
// New returns a pointer to an intialized Probe.
-func New() *Probe {
- return &Probe{stop: make(chan bool), do: make(chan Func)}
-}
+func New() *Probe { return &Probe{} }
// Do will probe target, if a probe is already in progress this is a noop.
-func (p *Probe) Do(f Func) { p.do <- f }
-
-// Stop stops the probing.
-func (p *Probe) Stop() { p.stop <- true }
-
-// Start will start the probe manager, after which probes can be initialized with Do.
-func (p *Probe) Start(interval time.Duration) { go p.start(interval) }
-
-func (p *Probe) start(interval time.Duration) {
- for {
- select {
- case <-p.stop:
+func (p *Probe) Do(f Func) {
p.Lock()
- p.inprogress = stop
+ if p.inprogress != idle {
p.Unlock()
return
- case f := <-p.do:
- p.Lock()
- if p.inprogress == active || p.inprogress == stop {
- p.Unlock()
- continue
}
p.inprogress = active
+ interval := p.interval
p.Unlock()
-
// Passed the lock. Now run f for as long it returns false. If a true is returned
// we return from the goroutine and we can accept another Func to run.
go func() {
@@ -74,7 +52,22 @@ func (p *Probe) start(interval time.Duration) {
p.Unlock()
}()
}
+
+// Stop stops the probing.
+func (p *Probe) Stop() {
+ p.Lock()
+ p.inprogress = stop
+ p.Unlock()
}
+
+// Start will initialize the probe manager, after which probes can be initiated with Do.
+func (p *Probe) Start(interval time.Duration) { p.SetInterval(interval) }
+
+// SetInterval sets the probing interval to be used by upcoming probes initiated with Do.
+func (p *Probe) SetInterval(interval time.Duration) {
+ p.Lock()
+ p.interval = interval
+ p.Unlock()
}
const (
