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authorGravatar Ruslan Drozhdzh <30860269+rdrozhdzh@users.noreply.github.com> 2018-05-16 22:38:14 +0300
committerGravatar Miek Gieben <miek@miek.nl> 2018-05-16 20:38:13 +0100
commitcffa1948ab21e36b3eb4397e23acc9cea6830201 (patch)
treede18a664e076f0220f9bfaf74f5c16552ea248ed /plugin
parentbffb955f6952c197d17f028f30b6bee069b15f2b (diff)
downloadcoredns-cffa1948ab21e36b3eb4397e23acc9cea6830201.tar.gz
coredns-cffa1948ab21e36b3eb4397e23acc9cea6830201.tar.zst
coredns-cffa1948ab21e36b3eb4397e23acc9cea6830201.zip
Probe simplification (#1784)
* 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
Diffstat (limited to 'plugin')
-rw-r--r--plugin/pkg/up/up.go91
1 files changed, 42 insertions, 49 deletions
diff --git a/plugin/pkg/up/up.go b/plugin/pkg/up/up.go
index 4d0ec21bc..e4752ce4d 100644
--- a/plugin/pkg/up/up.go
+++ b/plugin/pkg/up/up.go
@@ -10,71 +10,64 @@ 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:
- p.Lock()
- p.inprogress = stop
- p.Unlock()
- return
- case f := <-p.do:
+func (p *Probe) Do(f Func) {
+ p.Lock()
+ if p.inprogress != idle {
+ p.Unlock()
+ return
+ }
+ 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() {
+ for {
+ if err := f(); err == nil {
+ break
+ }
+ time.Sleep(interval)
p.Lock()
- if p.inprogress == active || p.inprogress == stop {
+ if p.inprogress == stop {
p.Unlock()
- continue
+ return
}
- p.inprogress = active
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() {
- for {
- if err := f(); err == nil {
- break
- }
- time.Sleep(interval)
- p.Lock()
- if p.inprogress == stop {
- p.Unlock()
- return
- }
- p.Unlock()
- }
+ p.Lock()
+ p.inprogress = idle
+ p.Unlock()
+ }()
+}
- p.Lock()
- p.inprogress = idle
- 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 (