你是使用什么工具调试 golang 程序的？

写过 C/C++ 的都是到，调试程序的时候通常使用 gdb 工具来进行调试，用起来可爽了，那么 gdb 是否也适合 golang 程序的调试的

我个人到是通常使用 dlv 来进行 golang 程序的调试，分享一波

dlv 是什么，全称 Delve

Delve 可以让你通过控制程序的执行来与程序进行交互，他可以计算变量，并提供线程 / goroutine 状态、CPU 寄存器状态等信息

Delve 的目标是为调试 Go 程序提供一个简单强大的调试功能

尝试看一下 dlv 的 help 信息

Usage:
  dlv [command]

Available Commands:
  attach      Attach to running process and begin debugging.
  connect     Connect to a headless debug server.
  core        Examine a core dump.
  dap         [EXPERIMENTAL] Starts a headless TCP server communicating via Debug Adaptor Protocol (DAP).
  debug       Compile and begin debugging main package in current directory, or the package specified.
  exec        Execute a precompiled binary, and begin a debug session.
  help        Help about any command
  run         Deprecated command. Use 'debug' instead.
  test        Compile test binary and begin debugging program.
  trace       Compile and begin tracing program.
  version     Prints version.

通过 help 我们可以看到可以使用这些命令来调试我们的程序，根据不同的应用场景

例如，

我们直接编译并调试的时候就可以使用 dlv debug

调试一个正在运行的程序，就可以使用 dlv attach

调试一个编译好的二进制文件，可以使用 dlv exec

其他的使用方式也类似，看上述的英文大概就知道啥意思了

开始调试小程序

简单写一个小程序来应用一下这个调试工具

const NUM = 10

func main() {
    arr := make([]int, NUM)

    for i := 1; i < NUM; i++ {
        arr[i] = i + i
        fmt.Printf("arr[%d] == %d\n", i, arr[i])
    }
    fmt.Println("program over")
}

1、使用 dlv debug main.go 开始调试

>dlv debug main.go
Type 'help' for list of commands.
(dlv)

2、dlv 里面使用 help 查看一下可以使用哪些命令

这些命令对应的解释相对还是比较清楚的，我们可以来用一下

3、使用 break 打给 main 函数一个端点，或者是用 b

(dlv) b main.main
Breakpoint 1 set at 0xef84ea for main.main() d:/mycode/my_new_first/dlvtest/main.go:7

给 main 函数打 1 断点，断点号是 1

4、continue 继续执行代码，直到运行到 main 的中断

(dlv) c
> main.main() d:/mycode/my_new_first/dlvtest/main.go:7 (hits goroutine(1):1 total:1) (PC: 0xef84ea)
     2: 
     3: import "fmt"
     4: 
     5: const NUM = 10
     6: 
=>   7: func main() {
     8:         arr := make([]int, NUM)
     9: 
    10:         for i := 1; i < NUM; i++ {
    11:                 arr[i] = i + i
    12:                 fmt.Printf("arr[%d] == %d\n", i, arr[i])

5、再 打一个断点，加上具体的条件

• b 文件:行数
• condition 中断号 具体的条件

(dlv) b main.go:12
Breakpoint 2 set at 0xef85a4 for main.main() d:/mycode/my_new_first/dlvtest/main.go:12
(dlv) condition 2 i==7

6、continue 继续执行代码

(dlv) c
arr[1] == 2
arr[2] == 4
arr[3] == 6
arr[4] == 8
arr[5] == 10
arr[6] == 12
> main.main() d:/mycode/my_new_first/dlvtest/main.go:12 (hits goroutine(1):1 total:1) (PC: 0xef85a4)
     7: func main() {
     8:         arr := make([]int, NUM)
     9: 
    10:         for i := 1; i < NUM; i++ {
    11:                 arr[i] = i + i
=>  12:                 fmt.Printf("arr[%d] == %d\n", i, arr[i])
    13:         }
    14:         fmt.Println("program over")
    15: }

7、locals 查看本地变量信息 ， p/print 打印变量信息

(dlv) locals
arr = []int len: 10, cap: 10, [...]
i = 7
(dlv) args
(no args)
(dlv) p i
7
(dlv) p arr
[]int len: 10, cap: 10, [0,2,4,6,8,10,12,14,0,0]

• 使用 p 查看多个变量的信息，打印出具体的值

8、bp/breakpoints 查看中断列表 ， clear 清空中断

• 查看中断列表
• 清空其中一个中断
• 再查看中断列表看看效果

(dlv) bp
Breakpoint runtime-fatal-throw (enabled) at 0xe6ca00 for runtime.throw() c:/program files/go/src/runtime/panic.go:1107 (0)
Breakpoint unrecovered-panic (enabled) at 0xe6cc80 for runtime.fatalpanic() c:/program files/go/src/runtime/panic.go:1190 (0)
        print runtime.curg._panic.arg
Breakpoint 1 (enabled) at 0xef84ea for main.main() d:/mycode/my_new_first/dlvtest/main.go:7 (1)
Breakpoint 2 (enabled) at 0xef85a4 for main.main() d:/mycode/my_new_first/dlvtest/main.go:12 (1)
        cond i == 7
(dlv) clear 2
Breakpoint 2 cleared at 0xef85a4 for main.main() d:/mycode/my_new_first/dlvtest/main.go:12
(dlv) bp
Breakpoint runtime-fatal-throw (enabled) at 0xe6ca00 for runtime.throw() c:/program files/go/src/runtime/panic.go:1107 (0)
Breakpoint unrecovered-panic (enabled) at 0xe6cc80 for runtime.fatalpanic() c:/program files/go/src/runtime/panic.go:1190 (0)
        print runtime.curg._panic.arg
Breakpoint 1 (enabled) at 0xef84ea for main.main() d:/mycode/my_new_first/dlvtest/main.go:7 (1)

9、ls 查看当前代码运行的位置 ，next 执行源码的下一行

(dlv) ls
> main.main() d:/mycode/my_new_first/dlvtest/main.go:12 (hits total:0) (PC: 0xef85a4)
     7: func main() {
     8:         arr := make([]int, NUM)
     9: 
    10:         for i := 1; i < NUM; i++ {
    11:                 arr[i] = i + i
=>  12:                 fmt.Printf("arr[%d] == %d\n", i, arr[i])
    13:         }
    14:         fmt.Println("program over")
    15: }

(dlv) next
> main.main() d:/mycode/my_new_first/dlvtest/main.go:12 (hits total:0) (PC: 0xef85a4)
     7: func main() {
     8:         arr := make([]int, NUM)
     9: 
    10:         for i := 1; i < NUM; i++ {
    11:                 arr[i] = i + i
    12:                 fmt.Printf("arr[%d] == %d\n", i, arr[i])
=>  13:         }
    14:         fmt.Println("program over")
    15: }

通过箭头我们就可以看出来 ，没有毛病

10、bt/stack 打印堆栈信息

(dlv) bt
0  0x0000000000ef85a4 in main.main
   at d:/mycode/my_new_first/dlvtest/main.go:12
1  0x0000000000e6f2f6 in runtime.main
   at c:/program files/go/src/runtime/proc.go:225
2  0x0000000000e9f3a1 in runtime.goexit
   at c:/program files/go/src/runtime/asm_amd64.s:1371

查看堆栈信息，可以直接看到汇编里面的具体信息

11、goroutines 查看程序中的协程列表，以及其对应的代码行数

(dlv) goroutines
* Goroutine 1 - User: d:/mycode/my_new_first/dlvtest/main.go:12 main.main (0xef85a4) (thread 26592)
  Goroutine 2 - User: c:/program files/go/src/runtime/proc.go:337 runtime.gopark (0xe6f6f6) [force gc (idle)]
  Goroutine 3 - User: c:/program files/go/src/runtime/proc.go:337 runtime.gopark (0xe6f6f6) [GC sweep wait]
  Goroutine 4 - User: c:/program files/go/src/runtime/proc.go:337 runtime.gopark (0xe6f6f6) [GC scavenge wait]
  Goroutine 5 - User: c:/program files/go/src/runtime/proc.go:337 runtime.gopark (0xe6f6f6) [finalizer wait]
[5 goroutines]
(dlv) goroutine
Thread 26592 at d:/mycode/my_new_first/dlvtest/main.go:12
Goroutine 1:
        Runtime: d:/mycode/my_new_first/dlvtest/main.go:12 main.main (0xef85a4)
        User: d:/mycode/my_new_first/dlvtest/main.go:12 main.main (0xef85a4)
        Go: c:/program files/go/src/runtime/asm_amd64.s:226 runtime.rt0_go (0xe9d3cc)
        Start: c:/program files/go/src/runtime/proc.go:115 runtime.main (0xe6f0e0)

goroutine 执行的时候默认是查看当前协程的信息，上面打印可以知道，总共有 5 个协程，当前打印的协程信息是第 1 个

12、goroutine 显示当前当前协程的具体信息和切换协程

主动切换到 第 2 个协程，并查看当前协程的信息

(dlv) goroutine 2
Switched from 1 to 2 (thread 26592)
(dlv) goroutine
Thread 26592 at d:/mycode/my_new_first/dlvtest/main.go:12
Goroutine 2:
        Runtime: c:/program files/go/src/runtime/proc.go:337 runtime.gopark (0xe6f6f6)
        User: c:/program files/go/src/runtime/proc.go:337 runtime.gopark (0xe6f6f6)
        Go: c:/program files/go/src/runtime/proc.go:264 runtime.init.6 (0xe6f47c)
        Start: c:/program files/go/src/runtime/proc.go:267 runtime.forcegchelper (0xe6f4a0)
(dlv) goroutines
  Goroutine 1 - User: d:/mycode/my_new_first/dlvtest/main.go:12 main.main (0xef85a4) (thread 26592)
* Goroutine 2 - User: c:/program files/go/src/runtime/proc.go:337 runtime.gopark (0xe6f6f6) [force gc (idle)]
  Goroutine 3 - User: c:/program files/go/src/runtime/proc.go:337 runtime.gopark (0xe6f6f6) [GC sweep wait]
  Goroutine 4 - User: c:/program files/go/src/runtime/proc.go:337 runtime.gopark (0xe6f6f6) [GC scavenge wait]
  Goroutine 5 - User: c:/program files/go/src/runtime/proc.go:337 runtime.gopark (0xe6f6f6) [finalizer wait]
[5 goroutines]

工具需要用起来才有意义

好了，本次就到这里

技术是开放的，我们的心态，更应是开放的。拥抱变化，向阳而生，努力向前行。

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