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)
+}