3 files changed, 161 insertions, 0 deletions
diff --git a/vendor/github.com/hpcloud/tail/ratelimiter/leakybucket.go b/vendor/github.com/hpcloud/tail/ratelimiter/leakybucket.go
new file mode 100644
index 000000000..358b69e7f
--- /dev/null
+++ b/vendor/github.com/hpcloud/tail/ratelimiter/leakybucket.go
@@ -0,0 +1,97 @@
+// Package ratelimiter implements the Leaky Bucket ratelimiting algorithm with memcached and in-memory backends.
+package ratelimiter
+
+import (
+	"time"
+)
+
+type LeakyBucket struct {
+	Size         uint16
+	Fill         float64
+	LeakInterval time.Duration // time.Duration for 1 unit of size to leak
+	Lastupdate   time.Time
+	Now          func() time.Time
+}
+
+func NewLeakyBucket(size uint16, leakInterval time.Duration) *LeakyBucket {
+	bucket := LeakyBucket{
+		Size:         size,
+		Fill:         0,
+		LeakInterval: leakInterval,
+		Now:          time.Now,
+		Lastupdate:   time.Now(),
+	}
+
+	return &bucket
+}
+
+func (b *LeakyBucket) updateFill() {
+	now := b.Now()
+	if b.Fill > 0 {
+		elapsed := now.Sub(b.Lastupdate)
+
+		b.Fill -= float64(elapsed) / float64(b.LeakInterval)
+		if b.Fill < 0 {
+			b.Fill = 0
+		}
+	}
+	b.Lastupdate = now
+}
+
+func (b *LeakyBucket) Pour(amount uint16) bool {
+	b.updateFill()
+
+	var newfill float64 = b.Fill + float64(amount)
+
+	if newfill > float64(b.Size) {
+		return false
+	}
+
+	b.Fill = newfill
+
+	return true
+}
+
+// The time at which this bucket will be completely drained
+func (b *LeakyBucket) DrainedAt() time.Time {
+	return b.Lastupdate.Add(time.Duration(b.Fill * float64(b.LeakInterval)))
+}
+
+// The duration until this bucket is completely drained
+func (b *LeakyBucket) TimeToDrain() time.Duration {
+	return b.DrainedAt().Sub(b.Now())
+}
+
+func (b *LeakyBucket) TimeSinceLastUpdate() time.Duration {
+	return b.Now().Sub(b.Lastupdate)
+}
+
+type LeakyBucketSer struct {
+	Size         uint16
+	Fill         float64
+	LeakInterval time.Duration // time.Duration for 1 unit of size to leak
+	Lastupdate   time.Time
+}
+
+func (b *LeakyBucket) Serialise() *LeakyBucketSer {
+	bucket := LeakyBucketSer{
+		Size:         b.Size,
+		Fill:         b.Fill,
+		LeakInterval: b.LeakInterval,
+		Lastupdate:   b.Lastupdate,
+	}
+
+	return &bucket
+}
+
+func (b *LeakyBucketSer) DeSerialise() *LeakyBucket {
+	bucket := LeakyBucket{
+		Size:         b.Size,
+		Fill:         b.Fill,
+		LeakInterval: b.LeakInterval,
+		Lastupdate:   b.Lastupdate,
+		Now:          time.Now,
+	}
+
+	return &bucket
+}
diff --git a/vendor/github.com/hpcloud/tail/ratelimiter/memory.go b/vendor/github.com/hpcloud/tail/ratelimiter/memory.go
new file mode 100644
index 000000000..8f6a5784a
--- /dev/null
+++ b/vendor/github.com/hpcloud/tail/ratelimiter/memory.go
@@ -0,0 +1,58 @@
+package ratelimiter
+
+import (
+	"errors"
+	"time"
+)
+
+const GC_SIZE int = 100
+
+type Memory struct {
+	store           map[string]LeakyBucket
+	lastGCCollected time.Time
+}
+
+func NewMemory() *Memory {
+	m := new(Memory)
+	m.store = make(map[string]LeakyBucket)
+	m.lastGCCollected = time.Now()
+	return m
+}
+
+func (m *Memory) GetBucketFor(key string) (*LeakyBucket, error) {
+
+	bucket, ok := m.store[key]
+	if !ok {
+		return nil, errors.New("miss")
+	}
+
+	return &bucket, nil
+}
+
+func (m *Memory) SetBucketFor(key string, bucket LeakyBucket) error {
+
+	if len(m.store) > GC_SIZE {
+		m.GarbageCollect()
+	}
+
+	m.store[key] = bucket
+
+	return nil
+}
+
+func (m *Memory) GarbageCollect() {
+	now := time.Now()
+
+	// rate limit GC to once per minute
+	if now.Add(60*time.Second).Unix() > m.lastGCCollected.Unix() {
+
+		for key, bucket := range m.store {
+			// if the bucket is drained, then GC
+			if bucket.DrainedAt().Unix() > now.Unix() {
+				delete(m.store, key)
+			}
+		}
+
+		m.lastGCCollected = now
+	}
+}
diff --git a/vendor/github.com/hpcloud/tail/ratelimiter/storage.go b/vendor/github.com/hpcloud/tail/ratelimiter/storage.go
new file mode 100644
index 000000000..89b2fe882
--- /dev/null
+++ b/vendor/github.com/hpcloud/tail/ratelimiter/storage.go
@@ -0,0 +1,6 @@
+package ratelimiter
+
+type Storage interface {
+	GetBucketFor(string) (*LeakyBucket, error)
+	SetBucketFor(string, LeakyBucket) error
+}