diff options
Diffstat (limited to 'vendor/github.com/hashicorp/memberlist/awareness.go')
-rw-r--r-- | vendor/github.com/hashicorp/memberlist/awareness.go | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/vendor/github.com/hashicorp/memberlist/awareness.go b/vendor/github.com/hashicorp/memberlist/awareness.go new file mode 100644 index 000000000..ea95c7538 --- /dev/null +++ b/vendor/github.com/hashicorp/memberlist/awareness.go @@ -0,0 +1,69 @@ +package memberlist + +import ( + "sync" + "time" + + "github.com/armon/go-metrics" +) + +// awareness manages a simple metric for tracking the estimated health of the +// local node. Health is primary the node's ability to respond in the soft +// real-time manner required for correct health checking of other nodes in the +// cluster. +type awareness struct { + sync.RWMutex + + // max is the upper threshold for the timeout scale (the score will be + // constrained to be from 0 <= score < max). + max int + + // score is the current awareness score. Lower values are healthier and + // zero is the minimum value. + score int +} + +// newAwareness returns a new awareness object. +func newAwareness(max int) *awareness { + return &awareness{ + max: max, + score: 0, + } +} + +// ApplyDelta takes the given delta and applies it to the score in a thread-safe +// manner. It also enforces a floor of zero and a max of max, so deltas may not +// change the overall score if it's railed at one of the extremes. +func (a *awareness) ApplyDelta(delta int) { + a.Lock() + initial := a.score + a.score += delta + if a.score < 0 { + a.score = 0 + } else if a.score > (a.max - 1) { + a.score = (a.max - 1) + } + final := a.score + a.Unlock() + + if initial != final { + metrics.SetGauge([]string{"memberlist", "health", "score"}, float32(final)) + } +} + +// GetHealthScore returns the raw health score. +func (a *awareness) GetHealthScore() int { + a.RLock() + score := a.score + a.RUnlock() + return score +} + +// ScaleTimeout takes the given duration and scales it based on the current +// score. Less healthyness will lead to longer timeouts. +func (a *awareness) ScaleTimeout(timeout time.Duration) time.Duration { + a.RLock() + score := a.score + a.RUnlock() + return timeout * (time.Duration(score) + 1) +} |