Support http service graceful restart (#416)

* support http service graceful restart

* fix dependencies

vendor/github.com/facebookgo/stats/aggregation.go

@@ -0,0 +1,35 @@
+package stats
+
+import "sort"
+
+// Average returns the average value
+func Average(values []float64) float64 {
+	if len(values) == 0 {
+		return 0
+	}
+
+	var val float64
+	for _, point := range values {
+		val += point
+	}
+	return val / float64(len(values))
+}
+
+// Sum returns the sum of all the given values
+func Sum(values []float64) float64 {
+	var val float64
+	for _, point := range values {
+		val += point
+	}
+	return val
+}
+
+// Percentiles returns a map containing the asked for percentiles
+func Percentiles(values []float64, percentiles map[string]float64) map[string]float64 {
+	sort.Float64s(values)
+	results := map[string]float64{}
+	for label, p := range percentiles {
+		results[label] = values[int(float64(len(values))*p)]
+	}
+	return results
+}

vendor/github.com/facebookgo/stats/counter.go

@@ -0,0 +1,112 @@
+package stats
+
+import "fmt"
+
+// Type is the type of aggregation of apply
+type Type int
+
+const (
+	AggregateAvg Type = iota
+	AggregateSum
+	AggregateHistogram
+)
+
+var (
+	// HistogramPercentiles is used to determine which percentiles to return for
+	// SimpleCounter.Aggregate
+	HistogramPercentiles = map[string]float64{
+		"p50": 0.5,
+		"p95": 0.95,
+		"p99": 0.99,
+	}
+
+	// MinSamplesForPercentiles is used by SimpleCounter.Aggregate to determine
+	// what the minimum number of samples is required for percentile analysis
+	MinSamplesForPercentiles = 10
+)
+
+// Aggregates can be used to merge counters together. This is not goroutine safe
+type Aggregates map[string]Counter
+
+// Add adds the counter for aggregation. This is not goroutine safe
+func (a Aggregates) Add(c Counter) error {
+	key := c.FullKey()
+	if counter, ok := a[key]; ok {
+		if counter.GetType() != c.GetType() {
+			return fmt.Errorf("stats: mismatched aggregation type for: %s", key)
+		}
+		counter.AddValues(c.GetValues()...)
+	} else {
+		a[key] = c
+	}
+	return nil
+}
+
+// Counter is the interface used by Aggregates to merge counters together
+type Counter interface {
+	// FullKey is used to uniquely identify the counter
+	FullKey() string
+
+	// AddValues adds values for aggregation
+	AddValues(...float64)
+
+	// GetValues returns the values for aggregation
+	GetValues() []float64
+
+	// GetType returns the type of aggregation to apply
+	GetType() Type
+}
+
+// SimpleCounter is a basic implementation of the Counter interface
+type SimpleCounter struct {
+	Key    string
+	Values []float64
+	Type   Type
+}
+
+// FullKey is part of the Counter interace
+func (s *SimpleCounter) FullKey() string {
+	return s.Key
+}
+
+// GetValues is part of the Counter interface
+func (s *SimpleCounter) GetValues() []float64 {
+	return s.Values
+}
+
+// AddValues is part of the Counter interface
+func (s *SimpleCounter) AddValues(vs ...float64) {
+	s.Values = append(s.Values, vs...)
+}
+
+// GetType is part of the Counter interface
+func (s *SimpleCounter) GetType() Type {
+	return s.Type
+}
+
+// Aggregate aggregates the provided values appropriately, returning a map
+// from key to value. If AggregateHistogram is specified, the map will contain
+// the relevant percentiles as specified by HistogramPercentiles
+func (s *SimpleCounter) Aggregate() map[string]float64 {
+	switch s.Type {
+	case AggregateAvg:
+		return map[string]float64{
+			s.Key: Average(s.Values),
+		}
+	case AggregateSum:
+		return map[string]float64{
+			s.Key: Sum(s.Values),
+		}
+	case AggregateHistogram:
+		histogram := map[string]float64{
+			s.Key: Average(s.Values),
+		}
+		if len(s.Values) > MinSamplesForPercentiles {
+			for k, v := range Percentiles(s.Values, HistogramPercentiles) {
+				histogram[fmt.Sprintf("%s.%s", s.Key, k)] = v
+			}
+		}
+		return histogram
+	}
+	panic("stats: unsupported aggregation type")
+}

vendor/github.com/facebookgo/stats/license

@@ -0,0 +1,30 @@
+BSD License
+
+For stats software
+
+Copyright (c) 2015, Facebook, Inc. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+ * Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+ * Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+ * Neither the name Facebook nor the names of its contributors may be used to
+   endorse or promote products derived from this software without specific
+   prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

vendor/github.com/facebookgo/stats/patents

@@ -0,0 +1,33 @@
+Additional Grant of Patent Rights Version 2
+
+"Software" means the stats software distributed by Facebook, Inc.
+
+Facebook, Inc. ("Facebook") hereby grants to each recipient of the Software
+("you") a perpetual, worldwide, royalty-free, non-exclusive, irrevocable
+(subject to the termination provision below) license under any Necessary
+Claims, to make, have made, use, sell, offer to sell, import, and otherwise
+transfer the Software. For avoidance of doubt, no license is granted under
+Facebook’s rights in any patent claims that are infringed by (i) modifications
+to the Software made by you or any third party or (ii) the Software in
+combination with any software or other technology.
+
+The license granted hereunder will terminate, automatically and without notice,
+if you (or any of your subsidiaries, corporate affiliates or agents) initiate
+directly or indirectly, or take a direct financial interest in, any Patent
+Assertion: (i) against Facebook or any of its subsidiaries or corporate
+affiliates, (ii) against any party if such Patent Assertion arises in whole or
+in part from any software, technology, product or service of Facebook or any of
+its subsidiaries or corporate affiliates, or (iii) against any party relating
+to the Software. Notwithstanding the foregoing, if Facebook or any of its
+subsidiaries or corporate affiliates files a lawsuit alleging patent
+infringement against you in the first instance, and you respond by filing a
+patent infringement counterclaim in that lawsuit against that party that is
+unrelated to the Software, the license granted hereunder will not terminate
+under section (i) of this paragraph due to such counterclaim.
+
+A "Necessary Claim" is a claim of a patent owned by Facebook that is
+necessarily infringed by the Software standing alone.
+
+A "Patent Assertion" is any lawsuit or other action alleging direct, indirect,
+or contributory infringement or inducement to infringe any patent, including a
+cross-claim or counterclaim.

vendor/github.com/facebookgo/stats/readme.md

@@ -0,0 +1,4 @@
+stats [![Build Status](https://secure.travis-ci.org/facebookgo/stats.png)](https://travis-ci.org/facebookgo/stats)
+=====
+
+Documentation: https://godoc.org/github.com/facebookgo/stats

vendor/github.com/facebookgo/stats/stats.go

@@ -0,0 +1,166 @@
+// Package stats defines a lightweight interface for collecting statistics. It
+// doesn't provide an implementation, just the shared interface.
+package stats
+
+// Client provides methods to collection statistics.
+type Client interface {
+	// BumpAvg bumps the average for the given key.
+	BumpAvg(key string, val float64)
+
+	// BumpSum bumps the sum for the given key.
+	BumpSum(key string, val float64)
+
+	// BumpHistogram bumps the histogram for the given key.
+	BumpHistogram(key string, val float64)
+
+	// BumpTime is a special version of BumpHistogram which is specialized for
+	// timers. Calling it starts the timer, and it returns a value on which End()
+	// can be called to indicate finishing the timer. A convenient way of
+	// recording the duration of a function is calling it like such at the top of
+	// the function:
+	//
+	//     defer s.BumpTime("my.function").End()
+	BumpTime(key string) interface {
+		End()
+	}
+}
+
+// PrefixClient adds multiple keys for the same value, with each prefix
+// added to the key and calls the underlying client.
+func PrefixClient(prefixes []string, client Client) Client {
+	return &prefixClient{
+		Prefixes: prefixes,
+		Client:   client,
+	}
+}
+
+type prefixClient struct {
+	Prefixes []string
+	Client   Client
+}
+
+func (p *prefixClient) BumpAvg(key string, val float64) {
+	for _, prefix := range p.Prefixes {
+		p.Client.BumpAvg(prefix+key, val)
+	}
+}
+
+func (p *prefixClient) BumpSum(key string, val float64) {
+	for _, prefix := range p.Prefixes {
+		p.Client.BumpSum(prefix+key, val)
+	}
+}
+
+func (p *prefixClient) BumpHistogram(key string, val float64) {
+	for _, prefix := range p.Prefixes {
+		p.Client.BumpHistogram(prefix+key, val)
+	}
+}
+
+func (p *prefixClient) BumpTime(key string) interface {
+	End()
+} {
+	var m multiEnder
+	for _, prefix := range p.Prefixes {
+		m = append(m, p.Client.BumpTime(prefix+key))
+	}
+	return m
+}
+
+// multiEnder combines many enders together.
+type multiEnder []interface {
+	End()
+}
+
+func (m multiEnder) End() {
+	for _, e := range m {
+		e.End()
+	}
+}
+
+// HookClient is useful for testing. It provides optional hooks for each
+// expected method in the interface, which if provided will be called. If a
+// hook is not provided, it will be ignored.
+type HookClient struct {
+	BumpAvgHook       func(key string, val float64)
+	BumpSumHook       func(key string, val float64)
+	BumpHistogramHook func(key string, val float64)
+	BumpTimeHook      func(key string) interface {
+		End()
+	}
+}
+
+// BumpAvg will call BumpAvgHook if defined.
+func (c *HookClient) BumpAvg(key string, val float64) {
+	if c.BumpAvgHook != nil {
+		c.BumpAvgHook(key, val)
+	}
+}
+
+// BumpSum will call BumpSumHook if defined.
+func (c *HookClient) BumpSum(key string, val float64) {
+	if c.BumpSumHook != nil {
+		c.BumpSumHook(key, val)
+	}
+}
+
+// BumpHistogram will call BumpHistogramHook if defined.
+func (c *HookClient) BumpHistogram(key string, val float64) {
+	if c.BumpHistogramHook != nil {
+		c.BumpHistogramHook(key, val)
+	}
+}
+
+// BumpTime will call BumpTimeHook if defined.
+func (c *HookClient) BumpTime(key string) interface {
+	End()
+} {
+	if c.BumpTimeHook != nil {
+		return c.BumpTimeHook(key)
+	}
+	return NoOpEnd
+}
+
+type noOpEnd struct{}
+
+func (n noOpEnd) End() {}
+
+// NoOpEnd provides a dummy value for use in tests as valid return value for
+// BumpTime().
+var NoOpEnd = noOpEnd{}
+
+// BumpAvg calls BumpAvg on the Client if it isn't nil. This is useful when a
+// component has an optional stats.Client.
+func BumpAvg(c Client, key string, val float64) {
+	if c != nil {
+		c.BumpAvg(key, val)
+	}
+}
+
+// BumpSum calls BumpSum on the Client if it isn't nil. This is useful when a
+// component has an optional stats.Client.
+func BumpSum(c Client, key string, val float64) {
+	if c != nil {
+		c.BumpSum(key, val)
+	}
+}
+
+// BumpHistogram calls BumpHistogram on the Client if it isn't nil. This is
+// useful when a component has an optional stats.Client.
+func BumpHistogram(c Client, key string, val float64) {
+	if c != nil {
+		c.BumpHistogram(key, val)
+	}
+}
+
+// BumpTime calls BumpTime on the Client if it isn't nil. If the Client is nil
+// it still returns a valid return value which will be a no-op. This is useful
+// when a component has an optional stats.Client.
+func BumpTime(c Client, key string) interface {
+	End()
+} {
+	if c != nil {
+		return c.BumpTime(key)
+	}
+	return NoOpEnd
+}

vendor/github.com/facebookgo/stats/stopper.go

@@ -0,0 +1,17 @@
+package stats
+
+import "time"
+
+// Stopper calls Client.BumpSum and Client.BumpHistogram when End'ed
+type Stopper struct {
+	Key    string
+	Start  time.Time
+	Client Client
+}
+
+// End the Stopper
+func (s *Stopper) End() {
+	since := time.Since(s.Start).Seconds() * 1000.0
+	s.Client.BumpSum(s.Key+".total", since)
+	s.Client.BumpHistogram(s.Key, since)
+}