Why GOGC=off?

[ebarped]

Just wondering why the Dockerfile compiles the code disabling go garbage collector? There is no explanation of this decision...

Besides, executing a build that prints the escape analysis returns a lot of heap allocations:

Command: go build -gcflags="-m" main.go 2>&1 | grep "escapes to heap" Result:

./main.go:205:21: str_fl escapes to heap
./main.go:205:21: str_Size escapes to heap
./main.go:251:21: str_fl escapes to heap
./main.go:251:21: str_Size escapes to heap
./main.go:134:16: "Could not convert value to int" escapes to heap
./main.go:270:15: "template_time_zone is not set, if you use template and `str_FormatDa... escapes to heap
./main.go:275:15: "template_time_outdata param is not set, if you use template and `str... escapes to heap
./main.go:287:13: (interface {})(string("time: missing Location in call to Time.In")) escapes to heap
./main.go:330:104: update.Message.Chat.ID escapes to heap
./main.go:334:11: msg escapes to heap
./main.go:340:16: update escapes to heap
./main.go:364:14: tmplPath escapes to heap
./main.go:372:18: []string{} escapes to heap
./main.go:377:13: sub + string(r) escapes to heap
./main.go:462:48: string(~R0) escapes to heap
./main.go:463:46: gin.H{...} escapes to heap
./main.go:464:4: fmt.Sprint(... argument...) escapes to heap
./main.go:463:9: render.Render(render.JSON{...}) escapes to heap
./main.go:469:13: chatid escapes to heap
./main.go:470:25: chatid escapes to heap
./main.go:475:26: msg escapes to heap
./main.go:477:11: render.Render(render.String{...}) escapes to heap
./main.go:479:38: gin.H{...} escapes to heap
./main.go:480:4: fmt.Sprint(... argument...) escapes to heap
./main.go:481:4: sendmsg escapes to heap
./main.go:479:9: render.Render(render.JSON{...}) escapes to heap
./main.go:487:14: make([]string, 0, len(alerts.GroupLabels)) escapes to heap
./main.go:491:14: sort.Interface(sort.StringSlice(sort.x)) escapes to heap
./main.go:492:21: make([]string, 0, len(alerts.GroupLabels)) escapes to heap
./main.go:494:49: k escapes to heap
./main.go:497:13: make([]string, 0, len(alerts.CommonLabels)) escapes to heap
./main.go:501:14: sort.Interface(sort.StringSlice(sort.x)) escapes to heap
./main.go:502:22: make([]string, 0, len(alerts.CommonLabels)) escapes to heap
./main.go:505:52: k escapes to heap
./main.go:509:13: make([]string, 0, len(alerts.CommonAnnotations)) escapes to heap
./main.go:513:14: sort.Interface(sort.StringSlice(sort.x)) escapes to heap
./main.go:514:27: make([]string, 0, len(alerts.CommonAnnotations)) escapes to heap
./main.go:516:61: k escapes to heap
./main.go:519:22: make([]string, len(alerts.Alerts)) escapes to heap
./main.go:529:58: a.GeneratorURL escapes to heap
./main.go:529:85: alertDetails[i] escapes to heap
./main.go:534:9: alerts.ExternalURL escapes to heap
./main.go:535:9: alerts.Receiver escapes to heap
./main.go:536:18: strings.ToUpper(alerts.Status) escapes to heap
./main.go:537:6: len(alerts.Alerts) escapes to heap
./main.go:538:15: strings.Join(groupLabels, ", ") escapes to heap
./main.go:539:15: strings.Join(commonLabels, ", ") escapes to heap
./main.go:540:15: strings.Join(commonAnnotations, "") escapes to heap
./main.go:541:15: strings.Join(alertDetails, ", ") escapes to heap
./main.go:558:20: alerts escapes to heap
./main.go:565:25: string(bytes.b.buf[bytes.b.off:]) escapes to heap
./main.go:571:24: &strings.Reader{...} escapes to heap
./main.go:582:16: "HTML is valid, sending it..." escapes to heap
./main.go:587:16: "HTML is not valid, strip all tags to prevent error" escapes to heap
./main.go:607:13: chatid escapes to heap
./main.go:610:48: string(~R0) escapes to heap
./main.go:611:46: gin.H{...} escapes to heap
./main.go:612:4: fmt.Sprint(... argument...) escapes to heap
./main.go:611:9: render.Render(render.JSON{...}) escapes to heap
./main.go:619:24: alerts escapes to heap
./main.go:625:14: "+------------------  A L E R T  J S O N  -------------------+" escapes to heap
./main.go:626:13: s escapes to heap
./main.go:627:14: "+-----------------------------------------------------------+\n\n" escapes to heap
./main.go:643:15: "+---------------  F I N A L   M E S S A G E  ---------------+" escapes to heap
./main.go:644:14: subString escapes to heap
./main.go:645:15: "+-----------------------------------------------------------+" escapes to heap
./main.go:652:27: msg escapes to heap
./main.go:654:12: render.Render(render.String{...}) escapes to heap
./main.go:657:47: gin.H{...} escapes to heap
./main.go:658:5: fmt.Sprint(... argument...) escapes to heap
./main.go:659:5: sendmsg escapes to heap
./main.go:660:5: fmt.Sprint(... argument...) escapes to heap
./main.go:660:26: msgtext escapes to heap
./main.go:657:10: render.Render(render.JSON{...}) escapes to heap
./main.go:666:12: msg escapes to heap
./main.go:410:47: string(content) escapes to heap
./main.go:417:36: &http.Client{} escapes to heap
./main.go:432:9: -1 escapes to heap
./main.go:440:14: (interface {})(string("gin mode unknown: ") + gin.value) escapes to heap
./main.go:440:14: string("gin mode unknown: ") + gin.value escapes to heap
./main.go:443:49: bot.Self.UserName escapes to heap
./main.go:453:12: []gin.HandlerFunc{...} escapes to heap
./main.go:454:13: []gin.HandlerFunc{...} escapes to heap
./main.go:309:31: "html/template".FuncMap{...} escapes to heap

[aminvakil]

This has been changed lately in https://github.com/inCaller/prometheus_bot/pull/81 by @skillcoder.

Maybe they have some insight about this?

[skillcoder]

GOGC=off in go build just to speed up building process. It's not affected runtime, just disable GC for compiler during compilation. It's not related to heap allocations in prometheus_bot.