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Improve IRC connection handling

This commit is contained in:
Ken-Håvard Lieng 2016-01-13 00:12:51 +01:00
parent 6f9f3cff95
commit c22b7d2a1d
6 changed files with 311 additions and 14 deletions
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4
Godeps/Godeps.json generated
View File

@ -53,6 +53,10 @@
"ImportPath": "github.com/inconshreveable/mousetrap",
"Rev": "76626ae9c91c4f2a10f34cad8ce83ea42c93bb75"
},
{
"ImportPath": "github.com/jpillora/backoff",
"Rev": "2ff7c4694083b5dbd71b21fd7cb7577477a74b31"
},
{
"ImportPath": "github.com/kr/pretty",
"Comment": "go.weekly.2011-12-22-27-ge6ac2fc",

138
Godeps/_workspace/src/github.com/jpillora/backoff/README.md generated vendored Normal file
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@ -0,0 +1,138 @@
# Backoff
A simple backoff algorithm in Go (Golang)
[![GoDoc](https://godoc.org/github.com/jpillora/backoff?status.svg)](https://godoc.org/github.com/jpillora/backoff)
### Install
```
$ go get -v github.com/jpillora/backoff
```
### Usage
Backoff is a `time.Duration` counter. It starts at `Min`. After every call to `Duration()` it is multiplied by `Factor`. It is capped at `Max`. It returns to `Min` on every call to `Reset()`. `Jitter` adds randomness ([see below](#example-using-jitter)). Used in conjunction with the `time` package.
---
#### Simple example
``` go
b := &backoff.Backoff{
//These are the defaults
Min: 100 * time.Millisecond,
Max: 10 * time.Second,
Factor: 2,
Jitter: false,
}
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
fmt.Printf("Reset!\n")
b.Reset()
fmt.Printf("%s\n", b.Duration())
```
```
100ms
200ms
400ms
Reset!
100ms
```
---
#### Example using `net` package
``` go
b := &backoff.Backoff{
Max: 5 * time.Minute,
}
for {
conn, err := net.Dial("tcp", "example.com:5309")
if err != nil {
d := b.Duration()
fmt.Printf("%s, reconnecting in %s", err, d)
time.Sleep(d)
continue
}
//connected
b.Reset()
conn.Write([]byte("hello world!"))
// ... Read ... Write ... etc
conn.Close()
//disconnected
}
```
---
#### Example using `Jitter`
Enabling `Jitter` adds some randomization to the backoff durations. [See Amazon's writeup of performance gains using jitter](http://www.awsarchitectureblog.com/2015/03/backoff.html). Seeding is not necessary but doing so gives repeatable results.
```go
import "math/rand"
b := &backoff.Backoff{
Jitter: true,
}
rand.Seed(42)
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
fmt.Printf("Reset!\n")
b.Reset()
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
fmt.Printf("%s\n", b.Duration())
```
```
100ms
106.600049ms
281.228155ms
Reset!
100ms
104.381845ms
214.957989ms
```
#### Credits
Ported from some JavaScript written by [@tj](https://github.com/tj)
#### MIT License
Copyright © 2015 Jaime Pillora <dev@jpillora.com>
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
'Software'), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

54
Godeps/_workspace/src/github.com/jpillora/backoff/backoff.go generated vendored Normal file
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@ -0,0 +1,54 @@
package backoff
import (
"math"
"math/rand"
"time"
)
//Backoff is a time.Duration counter. It starts at Min.
//After every call to Duration() it is multiplied by Factor.
//It is capped at Max. It returns to Min on every call to Reset().
//Used in conjunction with the time package.
type Backoff struct {
//Factor is the multiplying factor for each increment step
attempts, Factor float64
//Jitter eases contention by randomizing backoff steps
Jitter bool
//Min and Max are the minimum and maximum values of the counter
Min, Max time.Duration
}
//Returns the current value of the counter and then
//multiplies it Factor
func (b *Backoff) Duration() time.Duration {
//Zero-values are nonsensical, so we use
//them to apply defaults
if b.Min == 0 {
b.Min = 100 * time.Millisecond
}
if b.Max == 0 {
b.Max = 10 * time.Second
}
if b.Factor == 0 {
b.Factor = 2
}
//calculate this duration
dur := float64(b.Min) * math.Pow(b.Factor, b.attempts)
if b.Jitter == true {
dur = rand.Float64()*(dur-float64(b.Min)) + float64(b.Min)
}
//cap!
if dur > float64(b.Max) {
return b.Max
}
//bump attempts count
b.attempts++
//return as a time.Duration
return time.Duration(dur)
}
//Resets the current value of the counter back to Min
func (b *Backoff) Reset() {
b.attempts = 0
}

81
Godeps/_workspace/src/github.com/jpillora/backoff/backoff_test.go generated vendored Normal file
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@ -0,0 +1,81 @@
package backoff
import (
"testing"
"time"
)
func Test1(t *testing.T) {
b := &Backoff{
Min: 100 * time.Millisecond,
Max: 10 * time.Second,
Factor: 2,
}
equals(t, b.Duration(), 100*time.Millisecond)
equals(t, b.Duration(), 200*time.Millisecond)
equals(t, b.Duration(), 400*time.Millisecond)
b.Reset()
equals(t, b.Duration(), 100*time.Millisecond)
}
func Test2(t *testing.T) {
b := &Backoff{
Min: 100 * time.Millisecond,
Max: 10 * time.Second,
Factor: 1.5,
}
equals(t, b.Duration(), 100*time.Millisecond)
equals(t, b.Duration(), 150*time.Millisecond)
equals(t, b.Duration(), 225*time.Millisecond)
b.Reset()
equals(t, b.Duration(), 100*time.Millisecond)
}
func Test3(t *testing.T) {
b := &Backoff{
Min: 100 * time.Nanosecond,
Max: 10 * time.Second,
Factor: 1.75,
}
equals(t, b.Duration(), 100*time.Nanosecond)
equals(t, b.Duration(), 175*time.Nanosecond)
equals(t, b.Duration(), 306*time.Nanosecond)
b.Reset()
equals(t, b.Duration(), 100*time.Nanosecond)
}
func TestJitter(t *testing.T) {
b := &Backoff{
Min: 100 * time.Millisecond,
Max: 10 * time.Second,
Factor: 2,
Jitter: true,
}
equals(t, b.Duration(), 100*time.Millisecond)
between(t, b.Duration(), 100*time.Millisecond, 200*time.Millisecond)
between(t, b.Duration(), 100*time.Millisecond, 400*time.Millisecond)
b.Reset()
equals(t, b.Duration(), 100*time.Millisecond)
}
func between(t *testing.T, actual, low, high time.Duration) {
if actual < low {
t.Fatalf("Got %s, Expecting >= %s", actual, low)
}
if actual > high {
t.Fatalf("Got %s, Expecting <= %s", actual, high)
}
}
func equals(t *testing.T, d1, d2 time.Duration) {
if d1 != d2 {
t.Fatalf("Got %s, Expecting %s", d1, d2)
}
}

6
irc/client.go
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@ -31,6 +31,7 @@ type Client struct {
quit chan struct{}
reconnect chan struct{}
ready sync.WaitGroup
sendRecv sync.WaitGroup
once resync.Once
lock sync.Mutex
}
@ -83,11 +84,6 @@ func (c *Client) Quit() {
c.write("QUIT")
}
close(c.quit)
c.lock.Lock()
if c.conn != nil {
c.conn.Close()
}
c.lock.Unlock()
}()
}

42
irc/conn.go
View File

@ -7,6 +7,8 @@ import (
"net"
"strings"
"time"
"github.com/khlieng/dispatch/Godeps/_workspace/src/github.com/jpillora/backoff"
)
func (c *Client) Connect(address string) {
@ -82,11 +84,15 @@ func (c *Client) connect() error {
}
func (c *Client) tryConnect() {
// TODO: backoff
b := &backoff.Backoff{
Jitter: true,
}
for {
select {
case <-c.quit:
return
default:
}
@ -94,30 +100,36 @@ func (c *Client) tryConnect() {
if err == nil {
return
}
time.Sleep(b.Duration())
}
}
func (c *Client) run() {
c.tryConnect()
for {
select {
case <-c.quit:
c.close()
c.lock.Lock()
c.connected = false
c.lock.Unlock()
return
case <-c.reconnect:
c.sendRecv.Wait()
c.reconnect = make(chan struct{})
c.once.Reset()
c.tryConnect()
}
}
}
func (c *Client) send() {
c.sendRecv.Add(1)
defer c.sendRecv.Done()
c.ready.Wait()
for {
select {
case <-c.quit:
@ -136,18 +148,24 @@ func (c *Client) send() {
}
func (c *Client) recv() {
defer c.conn.Close()
c.sendRecv.Add(1)
defer c.sendRecv.Done()
for {
line, err := c.reader.ReadString('\n')
if err != nil {
c.lock.Lock()
c.connected = false
c.lock.Unlock()
c.once.Do(c.ready.Done)
select {
case <-c.quit:
return
default:
c.lock.Lock()
c.connected = false
c.lock.Unlock()
c.once.Do(c.ready.Done)
c.conn.Close()
close(c.reconnect)
return
}
@ -168,8 +186,14 @@ func (c *Client) recv() {
func (c *Client) close() {
if c.Connected() {
c.lock.Lock()
c.connected = false
c.lock.Unlock()
c.once.Do(c.ready.Done)
c.conn.Close()
}
close(c.out)
close(c.Messages)
}