delve:Golang的最佳调试工具

推荐使用Golang原生调试器delve,gdb不能切换goroutine。

推荐文章Golang程序调试工具介绍(gdb vs dlv)
,分析得很棒! gdb只能切换thread,而不能切换goroutine,将dlv切换goroutine、查看变量的过程摘抄如下:

(dlv) goroutine 6
Switched from 1 to 6 (thread 9022)

在此基础上,执行bt,则可以看到当前goroutine的调用栈情况

(dlv) bt
 0 0x0000000000454730 in runtime.systemstack_switch
 at /home/lday/Tools/Dev_Tools/Go_Tools/go_1_6_2/src/runtime/asm_amd64.s:245
 1 0x000000000040f700 in runtime.mallocgc
 at /home/lday/Tools/Dev_Tools/Go_Tools/go_1_6_2/src/runtime/malloc.go:643
 2 0x000000000040fc43 in runtime.rawmem
 at /home/lday/Tools/Dev_Tools/Go_Tools/go_1_6_2/src/runtime/malloc.go:809
 3 0x000000000043c2a5 in runtime.growslice
 at /home/lday/Tools/Dev_Tools/Go_Tools/go_1_6_2/src/runtime/slice.go:95
 4 0x000000000043c015 in runtime.growslice_n
 at /home/lday/Tools/Dev_Tools/Go_Tools/go_1_6_2/src/runtime/slice.go:44
 5 0x0000000000459545 in fmt.(*fmt).padString
 at /home/lday/Tools/Dev_Tools/Go_Tools/go_1_6_2/src/fmt/format.go:130
 6 0x000000000045a13f in fmt.(*fmt).fmt_s
 at /home/lday/Tools/Dev_Tools/Go_Tools/go_1_6_2/src/fmt/format.go:322
 7 0x000000000045e905 in fmt.(*pp).fmtString
 at /home/lday/Tools/Dev_Tools/Go_Tools/go_1_6_2/src/fmt/print.go:518
 8 0x000000000046200f in fmt.(*pp).printArg
 at /home/lday/Tools/Dev_Tools/Go_Tools/go_1_6_2/src/fmt/print.go:797
 9 0x0000000000468a8d in fmt.(*pp).doPrintf
 at /home/lday/Tools/Dev_Tools/Go_Tools/go_1_6_2/src/fmt/print.go:1238
10 0x000000000045c654 in fmt.Fprintf
 at /home/lday/Tools/Dev_Tools/Go_Tools/go_1_6_2/src/fmt/print.go:188

此时输出了10层调用栈,但似乎最原始的我自身程序dbgTest.go的调用栈没有输出, 可以通过bt加depth参数,设定bt的输出深度,进而找到我们自己的调用栈,例如bt 13

(dlv) bt 13
...
10 0x000000000045c654 in fmt.Fprintf
 at /home/lday/Tools/Dev_Tools/Go_Tools/go_1_6_2/src/fmt/print.go:188
11 0x000000000045c74b in fmt.Printf
 at /home/lday/Tools/Dev_Tools/Go_Tools/go_1_6_2/src/fmt/print.go:197
12 0x000000000045846f in GoWorks/GoDbg/mylib.RunFunc2
 at ./mylib/dbgTest.go:50
13 0x0000000000456df0 in runtime.goexit
 at /home/lday/Tools/Dev_Tools/Go_Tools/go_1_6_2/src/runtime/asm_amd64.s:1998

我们看到,我们自己dbgTest.go的调用栈在第12层。当前goroutine已经不再我们自己的调用栈上,而是进入到系统函数的调用中,在这种情况下,使用gdb进行调试时,我们发现,此时我们没有很好的方法能够输出我们需要的调用栈变量信息。dlv可以!此时只需简单的通过frame x cmd就可以输出我们想要的调用栈信息了

(dlv) frame 12 ls
 45: time.Sleep(10 * time.Second)
 46: waiter.Done()
 47: }
 48: 
 49: func RunFunc2(variable string, waiter *sync.WaitGroup) {
=> 50: fmt.Printf("var2:%v\n", variable)
 51: time.Sleep(10 * time.Second)
 52: waiter.Done()
 53: }
 54: 
 55: func RunFunc3(pVariable *[]int, waiter *sync.WaitGroup) {
(dlv) frame 12 print variable 
"golang dbg test"
(dlv) frame 12 print waiter
*sync.WaitGroup {
 state1: [12]uint8 [0,0,0,0,2,0,0,0,0,0,0,0],
 sema: 0,}

dlv还可以attach到一个程序进行调试。

参考:
Getting started with Delve
Debugging Go Code with GDB 官方
Using the gdb debugger with Go

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