偷偷努力，悄无声息地变强，然后惊艳所有人！哈哈，小伙伴们又来学习啦~今天我将给大家介绍《sync.Waitgroup 不被尊重》，这篇文章主要会讲到等等知识点，不知道大家对其都有多少了解，下面我们就一起来看一吧！当然，非常希望大家能多多评论，给出合理的建议，我们一起学习，一起进步！
问题内容我注意到许多 goroutine 仍在运行，尽管程序应该等待它们全部完成。我的理解是添加等待组可以解决此问题，但事实并非如此。
func runintradayscanner() {
// waitgroup for channels
var wg sync.waitgroup
logrus.info("clearing out pattern slices...")
var tf5 []request.stratnotification
var tf15 []request.stratnotification
var tf30 []request.stratnotification
var tf60 []request.stratnotification
// make the channel for comms to functions
var intradaychannel = make(chan request.stratnotification)
// range through db table
symbols := sources.getsymbols()
wg.add(len(symbols))
go func() {
logrus.info("------waiting for workers to finish")
wg.wait()
logrus.info("------closing intraday channel")
close(intradaychannel)
}()
for _, s := range symbols {
// wg.add(1)
go intradaystratify(strings.trimspace(s.symbol), intradaychannel, &wg)
match := <-intradaychannel
switch match.timeframe {
case 5:
tf5 = append(tf5, match)
case 15:
tf15 = append(tf15, match)
case 30:
tf30 = append(tf30, match)
case 60:
tf60 = append(tf60, match)
default:
}
}
if len(tf5) > 0 {
splitupandsendembedtodiscord(5, tf5)
}
if len(tf15) > 0 {
splitupandsendembedtodiscord(15, tf15)
}
if len(tf30) > 0 {
splitupandsendembedtodiscord(30, tf30)
}
if len(tf60) > 0 {
splitupandsendembedtodiscord(60, tf60)
}
}
// intradaystratify - go routine to run during market hours
func intradaystratify(ticker string, c chan request.stratnotification, wg *sync.waitgroup) {
defer wg.done()
candles := request.getintraday(ticker)
for _, tf := range timeframes {
chunkedcandles := request.determinetimeframes(tf, ticker, candles)
if len(chunkedcandles) > 1 {
highlows := request.calculateintradayhighlow(chunkedcandles)
// logrus.infof("%s highlows calculated: %d", ticker, len(highlows))
// should have more than 2 candles to start detecting patterns now
if len(highlows) > 2 {
bl, stratpattern := request.determinestratpattern(ticker, tf, highlows)
if bl {
c <- stratpattern
}
}
}
// otherwise return an empty channel
c <- request.stratnotification{}
}
}
func main() {
runintradayscanner()
}我期望程序在 for 循环遍历符号之后再次成为单线程。相反，stdout 如下所示，看起来 goroutine 仍在返回。结果应该是每行“在时间范围内找到模式 x-x”也会有相应的“发送到不和谐”输出行。
...
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="Getting intraday data for CRM"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="SNAP Pattern 3-1 found for timeframe: 5!"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="Getting intraday data for EBAY"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="Getting intraday data for MRVL"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="Sending to discord: \n**SPY** :green_circle: $467.16 :red_circle: $466.92"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="Getting intraday data for CVS"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="Getting intraday data for QCOM"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="Getting intraday data for ZM"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="X Pattern 3-2D found for timeframe: 5!"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="SQ Pattern 2D-1 found for timeframe: 5!"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="MSFT Pattern 1-2U found for timeframe: 5!"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="NVDA Pattern 2D-1 found for timeframe: 5!"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="PTON Pattern 1-2U found for timeframe: 5!"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="MARA Pattern 2U-1 found for timeframe: 5!"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="COIN Pattern 1-2U found for timeframe: 5!"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="ROKU Pattern 1-2D found for timeframe: 5!"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="SHOP Pattern 1-2U found for timeframe: 5!"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="PFE Pattern 3-1 found for timeframe: 5!"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="RBLX Pattern 1-2U found for timeframe: 5!"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="AFRM Pattern 2D-1 found for timeframe: 5!"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="Sending to discord: \n**SNAP** :green_circle: $54.71 :red_circle: $54.59"
strat_1 | time="2021-11-09T20:54:57Z" level=info msg="Done with Intraday scanner"正确答案
原始代码在每次 go 例程启动后都会阻塞，等待通过非缓冲通道发送一个值，此外，当 waitgroup 倒计时时，通道会关闭，这也关闭了接收端的通道.
恕我直言，一般规则是：
不要从接收方关闭通道，如果通道有多个并发发送方，也不要关闭通道。
package main
import (
"fmt"
"strings"
)
type StratNotification struct {
Symbol string
}
func GetSymbols() []StratNotification {
return []StratNotification{
{Symbol: "a"},
{Symbol: "b"},
{Symbol: "c"},
{Symbol: "d"},
}
}
func RunIntradayScanner() {
symbols := GetSymbols()
var intradayChannel = make(chan StratNotification)
for _, s := range symbols {
go IntradayStratify(strings.TrimSpace(s.Symbol), intradayChannel)
}
for _ = range symbols {
s := <-intradayChannel
fmt.Println(s)
}
}
func IntradayStratify(ticker string, c chan StratNotification) {
// do some heavy lifting
fmt.Println(ticker)
c <- StratNotification{}
}
func main() {
RunIntradayScanner()
}文中关于的知识介绍，希望对你的学习有所帮助！若是受益匪浅，那就动动鼠标收藏这篇《sync.Waitgroup 不被尊重》文章吧，也可关注编程网公众号了解相关技术文章。
