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Basic rate limiting implementation. 

Added `--limit-upload` and `--limit-download` flags to rate limit
backups and restores.
This commit is contained in:
rmdashrf 2017-10-08 11:28:03 -07:00
parent 8ceb22fe8a
commit 32637a0328
12 changed files with 1179 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
CHANGELOG.md
View File

@ -28,6 +28,9 @@ Important Changes in 0.X.Y
init` if the bucket already exists.
https://github.com/restic/restic/pull/1281
* Added support for rate limiting through `--limit-upload` and
`--limit-download` flags.
Small changes
-------------

12
Gopkg.lock generated
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@ -67,6 +67,12 @@
revision = "76626ae9c91c4f2a10f34cad8ce83ea42c93bb75"
version = "v1.0"
[[projects]]
branch = "master"
name = "github.com/juju/ratelimit"
packages = ["."]
revision = "5b9ff866471762aa2ab2dced63c9fb6f53921342"
[[projects]]
branch = "master"
name = "github.com/kr/fs"
@ -110,10 +116,10 @@
version = "v1.2.1"
[[projects]]
branch = "master"
name = "github.com/pkg/sftp"
packages = ["."]
revision = "98203f5a8333288eb3163b7c667d4260fe1333e9"
version = "1.0.0"
revision = "7c1f7a370726a2457b33b29baefc2402b4965c65"
[[projects]]
name = "github.com/pkg/xattr"
@ -202,6 +208,6 @@
[solve-meta]
analyzer-name = "dep"
analyzer-version = 1
inputs-digest = "2dcd9dd39ea4ddc31d36a6ed04dec261ab34484e350fba08a44f8cc5366d4d3f"
inputs-digest = "1cd40a4f4ee9009890482c6076d6725360d8b4475a8106cc5150d825989ba163"
solver-name = "gps-cdcl"
solver-version = 1

11
cmd/restic/global.go
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@ -22,6 +22,7 @@ import (
"github.com/restic/restic/internal/backend/swift"
"github.com/restic/restic/internal/cache"
"github.com/restic/restic/internal/debug"
"github.com/restic/restic/internal/limiter"
"github.com/restic/restic/internal/options"
"github.com/restic/restic/internal/repository"
"github.com/restic/restic/internal/restic"
@ -44,6 +45,9 @@ type GlobalOptions struct {
NoCache bool
CACerts []string
LimitUploadKb int
LimitDownloadKb int
ctx context.Context
password string
stdout io.Writer
@ -76,6 +80,8 @@ func init() {
f.StringVar(&globalOptions.CacheDir, "cache-dir", "", "set the cache directory")
f.BoolVar(&globalOptions.NoCache, "no-cache", false, "do not use a local cache")
f.StringSliceVar(&globalOptions.CACerts, "cacert", nil, "path to load root certificates from (default: use system certificates)")
f.IntVar(&globalOptions.LimitUploadKb, "limit-upload", 0, "limits uploads to a maximum rate in KiB/s. (default: unlimited)")
f.IntVar(&globalOptions.LimitDownloadKb, "limit-download", 0, "limits downloads to a maximum rate in KiB/s. (default: unlimited)")
f.StringSliceVarP(&globalOptions.Options, "option", "o", []string{}, "set extended option (`key=value`, can be specified multiple times)")
restoreTerminal()
@ -317,6 +323,11 @@ func OpenRepository(opts GlobalOptions) (*repository.Repository, error) {
return nil, err
}
if opts.LimitUploadKb > 0 || opts.LimitDownloadKb > 0 {
debug.Log("rate limiting backend to %d KiB/s upload and %d KiB/s download", opts.LimitUploadKb, opts.LimitDownloadKb)
be = limiter.LimitBackend(be, limiter.NewStaticLimiter(opts.LimitUploadKb, opts.LimitDownloadKb))
}
s := repository.New(be)
opts.password, err = ReadPassword(opts, "enter password for repository: ")

17
internal/limiter/limiter.go Normal file
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@ -0,0 +1,17 @@
package limiter
import (
"io"
)
// Limiter defines an interface that implementors can use to rate limit I/O
// according to some policy defined and configured by the implementor.
type Limiter interface {
// Upstream returns a rate limited reader that is intended to be used in
// uploads.
Upstream(r io.Reader) io.Reader
// Downstream returns a rate limited reader that is intended to be used
// for downloads.
Downstream(r io.Reader) io.Reader
}

53
internal/limiter/limiter_backend.go Normal file
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@ -0,0 +1,53 @@
package limiter
import (
"context"
"io"
"github.com/restic/restic/internal/restic"
)
// LimitBackend wraps a Backend and applies rate limiting to Load() and Save()
// calls on the backend.
func LimitBackend(be restic.Backend, l Limiter) restic.Backend {
return rateLimitedBackend{
Backend: be,
limiter: l,
}
}
type rateLimitedBackend struct {
restic.Backend
limiter Limiter
}
func (r rateLimitedBackend) Save(ctx context.Context, h restic.Handle, rd io.Reader) error {
return r.Backend.Save(ctx, h, r.limiter.Upstream(rd))
}
func (r rateLimitedBackend) Load(ctx context.Context, h restic.Handle, length int, offset int64) (io.ReadCloser, error) {
rc, err := r.Backend.Load(ctx, h, length, offset)
if err != nil {
return nil, err
}
return limitedReadCloser{
original: rc,
limited: r.limiter.Downstream(rc),
}, nil
}
type limitedReadCloser struct {
original io.ReadCloser
limited io.Reader
}
func (l limitedReadCloser) Read(b []byte) (n int, err error) {
return l.limited.Read(b)
}
func (l limitedReadCloser) Close() error {
return l.original.Close()
}
var _ restic.Backend = (*rateLimitedBackend)(nil)

53
internal/limiter/static_limiter.go Normal file
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@ -0,0 +1,53 @@
package limiter
import (
"io"
"github.com/juju/ratelimit"
)
type staticLimiter struct {
upstream *ratelimit.Bucket
downstream *ratelimit.Bucket
}
// NewStaticLimiter constructs a Limiter with a fixed (static) upload and
// download rate cap
func NewStaticLimiter(uploadKb, downloadKb int) Limiter {
var (
upstreamBucket *ratelimit.Bucket
downstreamBucket *ratelimit.Bucket
)
if uploadKb > 0 {
upstreamBucket = ratelimit.NewBucketWithRate(toByteRate(uploadKb), int64(toByteRate(uploadKb)))
}
if downloadKb > 0 {
downstreamBucket = ratelimit.NewBucketWithRate(toByteRate(downloadKb), int64(toByteRate(downloadKb)))
}
return staticLimiter{
upstream: upstreamBucket,
downstream: downstreamBucket,
}
}
func (l staticLimiter) Upstream(r io.Reader) io.Reader {
return l.limit(r, l.upstream)
}
func (l staticLimiter) Downstream(r io.Reader) io.Reader {
return l.limit(r, l.downstream)
}
func (l staticLimiter) limit(r io.Reader, b *ratelimit.Bucket) io.Reader {
if b == nil {
return r
}
return ratelimit.Reader(r, b)
}
func toByteRate(val int) float64 {
return float64(val) * 1024.
}

191
vendor/github.com/juju/ratelimit/LICENSE generated vendored Normal file
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@ -0,0 +1,191 @@
All files in this repository are licensed as follows. If you contribute
to this repository, it is assumed that you license your contribution
under the same license unless you state otherwise.
All files Copyright (C) 2015 Canonical Ltd. unless otherwise specified in the file.
This software is licensed under the LGPLv3, included below.
As a special exception to the GNU Lesser General Public License version 3
("LGPL3"), the copyright holders of this Library give you permission to
convey to a third party a Combined Work that links statically or dynamically
to this Library without providing any Minimal Corresponding Source or
Minimal Application Code as set out in 4d or providing the installation
information set out in section 4e, provided that you comply with the other
provisions of LGPL3 and provided that you meet, for the Application the
terms and conditions of the license(s) which apply to the Application.
Except as stated in this special exception, the provisions of LGPL3 will
continue to comply in full to this Library. If you modify this Library, you
may apply this exception to your version of this Library, but you are not
obliged to do so. If you do not wish to do so, delete this exception
statement from your version. This exception does not (and cannot) modify any
license terms which apply to the Application, with which you must still
comply.
GNU LESSER GENERAL PUBLIC LICENSE
Version 3, 29 June 2007
Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
This version of the GNU Lesser General Public License incorporates
the terms and conditions of version 3 of the GNU General Public
License, supplemented by the additional permissions listed below.
0. Additional Definitions.
As used herein, "this License" refers to version 3 of the GNU Lesser
General Public License, and the "GNU GPL" refers to version 3 of the GNU
General Public License.
"The Library" refers to a covered work governed by this License,
other than an Application or a Combined Work as defined below.
An "Application" is any work that makes use of an interface provided
by the Library, but which is not otherwise based on the Library.
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A "Combined Work" is a work produced by combining or linking an
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The "Minimal Corresponding Source" for a Combined Work means the
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The "Corresponding Application Code" for a Combined Work means the
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and utility programs needed for reproducing the Combined Work from the
Application, but excluding the System Libraries of the Combined Work.
1. Exception to Section 3 of the GNU GPL.
You may convey a covered work under sections 3 and 4 of this License
without being bound by section 3 of the GNU GPL.
2. Conveying Modified Versions.
If you modify a copy of the Library, and, in your modifications, a
facility refers to a function or data to be supplied by an Application
that uses the facility (other than as an argument passed when the
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a) under this License, provided that you make a good faith effort to
ensure that, in the event an Application does not supply the
function or data, the facility still operates, and performs
whatever part of its purpose remains meaningful, or
b) under the GNU GPL, with none of the additional permissions of
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3. Object Code Incorporating Material from Library Header Files.
The object code form of an Application may incorporate material from
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4. Combined Works.
You may convey a Combined Work under terms of your choice that,
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b) Give prominent notice with the combined library that part of it
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6. Revised Versions of the GNU Lesser General Public License.
The Free Software Foundation may publish revised and/or new versions
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Each version is given a distinguishing version number. If the
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117
vendor/github.com/juju/ratelimit/README.md generated vendored Normal file
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@ -0,0 +1,117 @@
# ratelimit
--
import "github.com/juju/ratelimit"
The ratelimit package provides an efficient token bucket implementation. See
http://en.wikipedia.org/wiki/Token_bucket.
## Usage
#### func Reader
```go
func Reader(r io.Reader, bucket *Bucket) io.Reader
```
Reader returns a reader that is rate limited by the given token bucket. Each
token in the bucket represents one byte.
#### func Writer
```go
func Writer(w io.Writer, bucket *Bucket) io.Writer
```
Writer returns a writer that is rate limited by the given token bucket. Each
token in the bucket represents one byte.
#### type Bucket
```go
type Bucket struct {
}
```
Bucket represents a token bucket that fills at a predetermined rate. Methods on
Bucket may be called concurrently.
#### func NewBucket
```go
func NewBucket(fillInterval time.Duration, capacity int64) *Bucket
```
NewBucket returns a new token bucket that fills at the rate of one token every
fillInterval, up to the given maximum capacity. Both arguments must be positive.
The bucket is initially full.
#### func NewBucketWithQuantum
```go
func NewBucketWithQuantum(fillInterval time.Duration, capacity, quantum int64) *Bucket
```
NewBucketWithQuantum is similar to NewBucket, but allows the specification of
the quantum size - quantum tokens are added every fillInterval.
#### func NewBucketWithRate
```go
func NewBucketWithRate(rate float64, capacity int64) *Bucket
```
NewBucketWithRate returns a token bucket that fills the bucket at the rate of
rate tokens per second up to the given maximum capacity. Because of limited
clock resolution, at high rates, the actual rate may be up to 1% different from
the specified rate.
#### func (*Bucket) Rate
```go
func (tb *Bucket) Rate() float64
```
Rate returns the fill rate of the bucket, in tokens per second.
#### func (*Bucket) Take
```go
func (tb *Bucket) Take(count int64) time.Duration
```
Take takes count tokens from the bucket without blocking. It returns the time
that the caller should wait until the tokens are actually available.
Note that if the request is irrevocable - there is no way to return tokens to
the bucket once this method commits us to taking them.
#### func (*Bucket) TakeAvailable
```go
func (tb *Bucket) TakeAvailable(count int64) int64
```
TakeAvailable takes up to count immediately available tokens from the bucket. It
returns the number of tokens removed, or zero if there are no available tokens.
It does not block.
#### func (*Bucket) TakeMaxDuration
```go
func (tb *Bucket) TakeMaxDuration(count int64, maxWait time.Duration) (time.Duration, bool)
```
TakeMaxDuration is like Take, except that it will only take tokens from the
bucket if the wait time for the tokens is no greater than maxWait.
If it would take longer than maxWait for the tokens to become available, it does
nothing and reports false, otherwise it returns the time that the caller should
wait until the tokens are actually available, and reports true.
#### func (*Bucket) Wait
```go
func (tb *Bucket) Wait(count int64)
```
Wait takes count tokens from the bucket, waiting until they are available.
#### func (*Bucket) WaitMaxDuration
```go
func (tb *Bucket) WaitMaxDuration(count int64, maxWait time.Duration) bool
```
WaitMaxDuration is like Wait except that it will only take tokens from the
bucket if it needs to wait for no greater than maxWait. It reports whether any
tokens have been removed from the bucket If no tokens have been removed, it
returns immediately.

284
vendor/github.com/juju/ratelimit/ratelimit.go generated vendored Normal file
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@ -0,0 +1,284 @@
// Copyright 2014 Canonical Ltd.
// Licensed under the LGPLv3 with static-linking exception.
// See LICENCE file for details.
// Package ratelimit provides an efficient token bucket implementation
// that can be used to limit the rate of arbitrary things.
// See http://en.wikipedia.org/wiki/Token_bucket.
package ratelimit
import (
"math"
"strconv"
"sync"
"time"
)
// Bucket represents a token bucket that fills at a predetermined rate.
// Methods on Bucket may be called concurrently.
type Bucket struct {
startTime time.Time
capacity int64
quantum int64
fillInterval time.Duration
clock Clock
// The mutex guards the fields following it.
mu sync.Mutex
// avail holds the number of available tokens
// in the bucket, as of availTick ticks from startTime.
// It will be negative when there are consumers
// waiting for tokens.
avail int64
availTick int64
}
// Clock is used to inject testable fakes.
type Clock interface {
Now() time.Time
Sleep(d time.Duration)
}
// realClock implements Clock in terms of standard time functions.
type realClock struct{}
// Now is identical to time.Now.
func (realClock) Now() time.Time {
return time.Now()
}
// Sleep is identical to time.Sleep.
func (realClock) Sleep(d time.Duration) {
time.Sleep(d)
}
// NewBucket returns a new token bucket that fills at the
// rate of one token every fillInterval, up to the given
// maximum capacity. Both arguments must be
// positive. The bucket is initially full.
func NewBucket(fillInterval time.Duration, capacity int64) *Bucket {
return NewBucketWithClock(fillInterval, capacity, realClock{})
}
// NewBucketWithClock is identical to NewBucket but injects a testable clock
// interface.
func NewBucketWithClock(fillInterval time.Duration, capacity int64, clock Clock) *Bucket {
return NewBucketWithQuantumAndClock(fillInterval, capacity, 1, clock)
}
// rateMargin specifes the allowed variance of actual
// rate from specified rate. 1% seems reasonable.
const rateMargin = 0.01
// NewBucketWithRate returns a token bucket that fills the bucket
// at the rate of rate tokens per second up to the given
// maximum capacity. Because of limited clock resolution,
// at high rates, the actual rate may be up to 1% different from the
// specified rate.
func NewBucketWithRate(rate float64, capacity int64) *Bucket {
return NewBucketWithRateAndClock(rate, capacity, realClock{})
}
// NewBucketWithRateAndClock is identical to NewBucketWithRate but injects a
// testable clock interface.
func NewBucketWithRateAndClock(rate float64, capacity int64, clock Clock) *Bucket {
for quantum := int64(1); quantum < 1<<50; quantum = nextQuantum(quantum) {
fillInterval := time.Duration(1e9 * float64(quantum) / rate)
if fillInterval <= 0 {
continue
}
tb := NewBucketWithQuantumAndClock(fillInterval, capacity, quantum, clock)
if diff := math.Abs(tb.Rate() - rate); diff/rate <= rateMargin {
return tb
}
}
panic("cannot find suitable quantum for " + strconv.FormatFloat(rate, 'g', -1, 64))
}
// nextQuantum returns the next quantum to try after q.
// We grow the quantum exponentially, but slowly, so we
// get a good fit in the lower numbers.
func nextQuantum(q int64) int64 {
q1 := q * 11 / 10
if q1 == q {
q1++
}
return q1
}
// NewBucketWithQuantum is similar to NewBucket, but allows
// the specification of the quantum size - quantum tokens
// are added every fillInterval.
func NewBucketWithQuantum(fillInterval time.Duration, capacity, quantum int64) *Bucket {
return NewBucketWithQuantumAndClock(fillInterval, capacity, quantum, realClock{})
}
// NewBucketWithQuantumAndClock is identical to NewBucketWithQuantum but injects
// a testable clock interface.
func NewBucketWithQuantumAndClock(fillInterval time.Duration, capacity, quantum int64, clock Clock) *Bucket {
if fillInterval <= 0 {
panic("token bucket fill interval is not > 0")
}
if capacity <= 0 {
panic("token bucket capacity is not > 0")
}
if quantum <= 0 {
panic("token bucket quantum is not > 0")
}
return &Bucket{
clock: clock,
startTime: clock.Now(),
capacity: capacity,
quantum: quantum,
avail: capacity,
fillInterval: fillInterval,
}
}
// Wait takes count tokens from the bucket, waiting until they are
// available.
func (tb *Bucket) Wait(count int64) {
if d := tb.Take(count); d > 0 {
tb.clock.Sleep(d)
}
}
// WaitMaxDuration is like Wait except that it will
// only take tokens from the bucket if it needs to wait
// for no greater than maxWait. It reports whether
// any tokens have been removed from the bucket
// If no tokens have been removed, it returns immediately.
func (tb *Bucket) WaitMaxDuration(count int64, maxWait time.Duration) bool {
d, ok := tb.TakeMaxDuration(count, maxWait)
if d > 0 {
tb.clock.Sleep(d)
}
return ok
}
const infinityDuration time.Duration = 0x7fffffffffffffff
// Take takes count tokens from the bucket without blocking. It returns
// the time that the caller should wait until the tokens are actually
// available.
//
// Note that if the request is irrevocable - there is no way to return
// tokens to the bucket once this method commits us to taking them.
func (tb *Bucket) Take(count int64) time.Duration {
d, _ := tb.take(tb.clock.Now(), count, infinityDuration)
return d
}
// TakeMaxDuration is like Take, except that
// it will only take tokens from the bucket if the wait
// time for the tokens is no greater than maxWait.
//
// If it would take longer than maxWait for the tokens
// to become available, it does nothing and reports false,
// otherwise it returns the time that the caller should
// wait until the tokens are actually available, and reports
// true.
func (tb *Bucket) TakeMaxDuration(count int64, maxWait time.Duration) (time.Duration, bool) {
return tb.take(tb.clock.Now(), count, maxWait)
}
// TakeAvailable takes up to count immediately available tokens from the
// bucket. It returns the number of tokens removed, or zero if there are
// no available tokens. It does not block.
func (tb *Bucket) TakeAvailable(count int64) int64 {
return tb.takeAvailable(tb.clock.Now(), count)
}
// takeAvailable is the internal version of TakeAvailable - it takes the
// current time as an argument to enable easy testing.
func (tb *Bucket) takeAvailable(now time.Time, count int64) int64 {
if count <= 0 {
return 0
}
tb.mu.Lock()
defer tb.mu.Unlock()
tb.adjust(now)
if tb.avail <= 0 {
return 0
}
if count > tb.avail {
count = tb.avail
}
tb.avail -= count
return count
}
// Available returns the number of available tokens. It will be negative
// when there are consumers waiting for tokens. Note that if this
// returns greater than zero, it does not guarantee that calls that take
// tokens from the buffer will succeed, as the number of available
// tokens could have changed in the meantime. This method is intended
// primarily for metrics reporting and debugging.
func (tb *Bucket) Available() int64 {
return tb.available(tb.clock.Now())
}
// available is the internal version of available - it takes the current time as
// an argument to enable easy testing.
func (tb *Bucket) available(now time.Time) int64 {
tb.mu.Lock()
defer tb.mu.Unlock()
tb.adjust(now)
return tb.avail
}
// Capacity returns the capacity that the bucket was created with.
func (tb *Bucket) Capacity() int64 {
return tb.capacity
}
// Rate returns the fill rate of the bucket, in tokens per second.
func (tb *Bucket) Rate() float64 {
return 1e9 * float64(tb.quantum) / float64(tb.fillInterval)
}
// take is the internal version of Take - it takes the current time as
// an argument to enable easy testing.
func (tb *Bucket) take(now time.Time, count int64, maxWait time.Duration) (time.Duration, bool) {
if count <= 0 {
return 0, true
}
tb.mu.Lock()
defer tb.mu.Unlock()
currentTick := tb.adjust(now)
avail := tb.avail - count
if avail >= 0 {
tb.avail = avail
return 0, true
}
// Round up the missing tokens to the nearest multiple
// of quantum - the tokens won't be available until
// that tick.
endTick := currentTick + (-avail+tb.quantum-1)/tb.quantum
endTime := tb.startTime.Add(time.Duration(endTick) * tb.fillInterval)
waitTime := endTime.Sub(now)
if waitTime > maxWait {
return 0, false
}
tb.avail = avail
return waitTime, true
}
// adjust adjusts the current bucket capacity based on the current time.
// It returns the current tick.
func (tb *Bucket) adjust(now time.Time) (currentTick int64) {
currentTick = int64(now.Sub(tb.startTime) / tb.fillInterval)
if tb.avail >= tb.capacity {
return
}
tb.avail += (currentTick - tb.availTick) * tb.quantum
if tb.avail > tb.capacity {
tb.avail = tb.capacity
}
tb.availTick = currentTick
return
}

389
vendor/github.com/juju/ratelimit/ratelimit_test.go generated vendored Normal file
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// Copyright 2014 Canonical Ltd.
// Licensed under the LGPLv3 with static-linking exception.
// See LICENCE file for details.
package ratelimit
import (
"math"
"testing"
"time"
gc "gopkg.in/check.v1"
)
func TestPackage(t *testing.T) {
gc.TestingT(t)
}
type rateLimitSuite struct{}
var _ = gc.Suite(rateLimitSuite{})
type takeReq struct {
time time.Duration
count int64
expectWait time.Duration
}
var takeTests = []struct {
about string
fillInterval time.Duration
capacity int64
reqs []takeReq
}{{
about: "serial requests",
fillInterval: 250 * time.Millisecond,
capacity: 10,
reqs: []takeReq{{
time: 0,
count: 0,
expectWait: 0,
}, {
time: 0,
count: 10,
expectWait: 0,
}, {
time: 0,
count: 1,
expectWait: 250 * time.Millisecond,
}, {
time: 250 * time.Millisecond,
count: 1,
expectWait: 250 * time.Millisecond,
}},
}, {
about: "concurrent requests",
fillInterval: 250 * time.Millisecond,
capacity: 10,
reqs: []takeReq{{
time: 0,
count: 10,
expectWait: 0,
}, {
time: 0,
count: 2,
expectWait: 500 * time.Millisecond,
}, {
time: 0,
count: 2,
expectWait: 1000 * time.Millisecond,
}, {
time: 0,
count: 1,
expectWait: 1250 * time.Millisecond,
}},
}, {
about: "more than capacity",
fillInterval: 1 * time.Millisecond,
capacity: 10,
reqs: []takeReq{{
time: 0,
count: 10,
expectWait: 0,
}, {
time: 20 * time.Millisecond,
count: 15,
expectWait: 5 * time.Millisecond,
}},
}, {
about: "sub-quantum time",
fillInterval: 10 * time.Millisecond,
capacity: 10,
reqs: []takeReq{{
time: 0,
count: 10,
expectWait: 0,
}, {
time: 7 * time.Millisecond,
count: 1,
expectWait: 3 * time.Millisecond,
}, {
time: 8 * time.Millisecond,
count: 1,
expectWait: 12 * time.Millisecond,
}},
}, {
about: "within capacity",
fillInterval: 10 * time.Millisecond,
capacity: 5,
reqs: []takeReq{{
time: 0,
count: 5,
expectWait: 0,
}, {
time: 60 * time.Millisecond,
count: 5,
expectWait: 0,
}, {
time: 60 * time.Millisecond,
count: 1,
expectWait: 10 * time.Millisecond,
}, {
time: 80 * time.Millisecond,
count: 2,
expectWait: 10 * time.Millisecond,
}},
}}
var availTests = []struct {
about string
capacity int64
fillInterval time.Duration
take int64
sleep time.Duration
expectCountAfterTake int64
expectCountAfterSleep int64
}{{
about: "should fill tokens after interval",
capacity: 5,
fillInterval: time.Second,
take: 5,
sleep: time.Second,
expectCountAfterTake: 0,
expectCountAfterSleep: 1,
}, {
about: "should fill tokens plus existing count",
capacity: 2,
fillInterval: time.Second,
take: 1,
sleep: time.Second,
expectCountAfterTake: 1,
expectCountAfterSleep: 2,
}, {
about: "shouldn't fill before interval",
capacity: 2,
fillInterval: 2 * time.Second,
take: 1,
sleep: time.Second,
expectCountAfterTake: 1,
expectCountAfterSleep: 1,
}, {
about: "should fill only once after 1*interval before 2*interval",
capacity: 2,
fillInterval: 2 * time.Second,
take: 1,
sleep: 3 * time.Second,
expectCountAfterTake: 1,
expectCountAfterSleep: 2,
}}
func (rateLimitSuite) TestTake(c *gc.C) {
for i, test := range takeTests {
tb := NewBucket(test.fillInterval, test.capacity)
for j, req := range test.reqs {
d, ok := tb.take(tb.startTime.Add(req.time), req.count, infinityDuration)
c.Assert(ok, gc.Equals, true)
if d != req.expectWait {
c.Fatalf("test %d.%d, %s, got %v want %v", i, j, test.about, d, req.expectWait)
}
}
}
}
func (rateLimitSuite) TestTakeMaxDuration(c *gc.C) {
for i, test := range takeTests {
tb := NewBucket(test.fillInterval, test.capacity)
for j, req := range test.reqs {
if req.expectWait > 0 {
d, ok := tb.take(tb.startTime.Add(req.time), req.count, req.expectWait-1)
c.Assert(ok, gc.Equals, false)
c.Assert(d, gc.Equals, time.Duration(0))
}
d, ok := tb.take(tb.startTime.Add(req.time), req.count, req.expectWait)
c.Assert(ok, gc.Equals, true)
if d != req.expectWait {
c.Fatalf("test %d.%d, %s, got %v want %v", i, j, test.about, d, req.expectWait)
}
}
}
}
type takeAvailableReq struct {
time time.Duration
count int64
expect int64
}
var takeAvailableTests = []struct {
about string
fillInterval time.Duration
capacity int64
reqs []takeAvailableReq
}{{
about: "serial requests",
fillInterval: 250 * time.Millisecond,
capacity: 10,
reqs: []takeAvailableReq{{
time: 0,
count: 0,
expect: 0,
}, {
time: 0,
count: 10,
expect: 10,
}, {
time: 0,
count: 1,
expect: 0,
}, {
time: 250 * time.Millisecond,
count: 1,
expect: 1,
}},
}, {
about: "concurrent requests",
fillInterval: 250 * time.Millisecond,
capacity: 10,
reqs: []takeAvailableReq{{
time: 0,
count: 5,
expect: 5,
}, {
time: 0,
count: 2,
expect: 2,
}, {
time: 0,
count: 5,
expect: 3,
}, {
time: 0,
count: 1,
expect: 0,
}},
}, {
about: "more than capacity",
fillInterval: 1 * time.Millisecond,
capacity: 10,
reqs: []takeAvailableReq{{
time: 0,
count: 10,
expect: 10,
}, {
time: 20 * time.Millisecond,
count: 15,
expect: 10,
}},
}, {
about: "within capacity",
fillInterval: 10 * time.Millisecond,
capacity: 5,
reqs: []takeAvailableReq{{
time: 0,
count: 5,
expect: 5,
}, {
time: 60 * time.Millisecond,
count: 5,
expect: 5,
}, {
time: 70 * time.Millisecond,
count: 1,
expect: 1,
}},
}}
func (rateLimitSuite) TestTakeAvailable(c *gc.C) {
for i, test := range takeAvailableTests {
tb := NewBucket(test.fillInterval, test.capacity)
for j, req := range test.reqs {
d := tb.takeAvailable(tb.startTime.Add(req.time), req.count)
if d != req.expect {
c.Fatalf("test %d.%d, %s, got %v want %v", i, j, test.about, d, req.expect)
}
}
}
}
func (rateLimitSuite) TestPanics(c *gc.C) {
c.Assert(func() { NewBucket(0, 1) }, gc.PanicMatches, "token bucket fill interval is not > 0")
c.Assert(func() { NewBucket(-2, 1) }, gc.PanicMatches, "token bucket fill interval is not > 0")
c.Assert(func() { NewBucket(1, 0) }, gc.PanicMatches, "token bucket capacity is not > 0")
c.Assert(func() { NewBucket(1, -2) }, gc.PanicMatches, "token bucket capacity is not > 0")
}
func isCloseTo(x, y, tolerance float64) bool {
return math.Abs(x-y)/y < tolerance
}
func (rateLimitSuite) TestRate(c *gc.C) {
tb := NewBucket(1, 1)
if !isCloseTo(tb.Rate(), 1e9, 0.00001) {
c.Fatalf("got %v want 1e9", tb.Rate())
}
tb = NewBucket(2*time.Second, 1)
if !isCloseTo(tb.Rate(), 0.5, 0.00001) {
c.Fatalf("got %v want 0.5", tb.Rate())
}
tb = NewBucketWithQuantum(100*time.Millisecond, 1, 5)
if !isCloseTo(tb.Rate(), 50, 0.00001) {
c.Fatalf("got %v want 50", tb.Rate())
}
}
func checkRate(c *gc.C, rate float64) {
tb := NewBucketWithRate(rate, 1<<62)
if !isCloseTo(tb.Rate(), rate, rateMargin) {
c.Fatalf("got %g want %v", tb.Rate(), rate)
}
d, ok := tb.take(tb.startTime, 1<<62, infinityDuration)
c.Assert(ok, gc.Equals, true)
c.Assert(d, gc.Equals, time.Duration(0))
// Check that the actual rate is as expected by
// asking for a not-quite multiple of the bucket's
// quantum and checking that the wait time
// correct.
d, ok = tb.take(tb.startTime, tb.quantum*2-tb.quantum/2, infinityDuration)
c.Assert(ok, gc.Equals, true)
expectTime := 1e9 * float64(tb.quantum) * 2 / rate
if !isCloseTo(float64(d), expectTime, rateMargin) {
c.Fatalf("rate %g: got %g want %v", rate, float64(d), expectTime)
}
}
func (rateLimitSuite) TestNewWithRate(c *gc.C) {
for rate := float64(1); rate < 1e6; rate += 7 {
checkRate(c, rate)
}
for _, rate := range []float64{
1024 * 1024 * 1024,
1e-5,
0.9e-5,
0.5,
0.9,
0.9e8,
3e12,
4e18,
} {
checkRate(c, rate)
checkRate(c, rate/3)
checkRate(c, rate*1.3)
}
}
func TestAvailable(t *testing.T) {
for i, tt := range availTests {
tb := NewBucket(tt.fillInterval, tt.capacity)
if c := tb.takeAvailable(tb.startTime, tt.take); c != tt.take {
t.Fatalf("#%d: %s, take = %d, want = %d", i, tt.about, c, tt.take)
}
if c := tb.available(tb.startTime); c != tt.expectCountAfterTake {
t.Fatalf("#%d: %s, after take, available = %d, want = %d", i, tt.about, c, tt.expectCountAfterTake)
}
if c := tb.available(tb.startTime.Add(tt.sleep)); c != tt.expectCountAfterSleep {
t.Fatalf("#%d: %s, after some time it should fill in new tokens, available = %d, want = %d",
i, tt.about, c, tt.expectCountAfterSleep)
}
}
}
func BenchmarkWait(b *testing.B) {
tb := NewBucket(1, 16*1024)
for i := b.N - 1; i >= 0; i-- {
tb.Wait(1)
}
}

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vendor/github.com/juju/ratelimit/reader.go generated vendored Normal file
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// Copyright 2014 Canonical Ltd.
// Licensed under the LGPLv3 with static-linking exception.
// See LICENCE file for details.
package ratelimit
import "io"
type reader struct {
r io.Reader
bucket *Bucket
}
// Reader returns a reader that is rate limited by
// the given token bucket. Each token in the bucket
// represents one byte.
func Reader(r io.Reader, bucket *Bucket) io.Reader {
return &reader{
r: r,
bucket: bucket,
}
}
func (r *reader) Read(buf []byte) (int, error) {
n, err := r.r.Read(buf)
if n <= 0 {
return n, err
}
r.bucket.Wait(int64(n))
return n, err
}
type writer struct {
w io.Writer
bucket *Bucket
}
// Writer returns a reader that is rate limited by
// the given token bucket. Each token in the bucket
// represents one byte.
func Writer(w io.Writer, bucket *Bucket) io.Writer {
return &writer{
w: w,
bucket: bucket,
}
}
func (w *writer) Write(buf []byte) (int, error) {
w.bucket.Wait(int64(len(buf)))
return w.w.Write(buf)
}

2
vendor/github.com/pkg/sftp/sftp.go generated vendored
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// Package sftp implements the SSH File Transfer Protocol as described in
// https://filezilla-project.org/specs/draft-ietf-secsh-filexfer-02.txt
// https://tools.ietf.org/html/draft-ietf-secsh-filexfer-02
package sftp
import (