Go调试工具—— Delve

参考https://github.com/go-delve/delve

安装

首先你必须有等于或高于1.8版本的Go,我的版本是：

userdeMBP:go-learning user$ go version
go version go1.11.4 darwin/amd64

我是用的是Mac,所以使用的是OSX安装方法：

然后使用go get 进行安装：

go get -u github.com/go-delve/delve/cmd/dlv

使用这种方法，你将无法使用delve的本机后端，但无论如何您都不需要它:macOS上的本机后端已经知道该操作系统最近出现的问题，并且目前没有进行维护。详情可见https://github.com/go-delve/delve/issues/1112

安装完后查看版本：

userdeMBP:go-learning user$ dlv version
Delve Debugger
Version: 1.2.0
Build: $Id: 068e...57e34f0f08ce01466 $

使用：

1）首先先使用dlv或dlv --help来查看delve支持的命令：

userdeMBP:go-learning user$ dlv
Delve是Go程序的源代码级调试器.

Delve通过控制进程的执行、评估变量以及提供线程/ goroutine状态、CPU寄存器状态等信息，使你能够与程序进行交互。

这个工具的目标是为调试Go程序提供一个简单而强大的接口.

使用“--”将标志传递给正在调试的程序，例如:

`dlv exec ./hello -- server --config conf/config.toml`

Usage:
  dlv [command]

Available Commands:
  attach      连接到正在运行的流程并开始调试.
  connect     连接到无头调试服务器.
  core        检查核心转储.
  debug       编译并开始调试当前目录下的主包或指定的包.
  exec        执行预编译的二进制文件，并开始调试会话.
  help        帮助信息
  run         弃用的命令。使用“debug”替代它.
  test        编译测试二进制文件并开始调试程序.
  trace       编译并开始跟踪程序.
  version     打印版本.

Flags:
      --accept-multiclient   允许无头服务器接受多个客户机连接。注意，服务器API不是可重入的，客户端必须协调.
      --api-version int      无头时选择API版本. (default 1)
      --backend string       后端选择:
            default        在macOS上使用lldb，其他地方都是本地的.
            native        本地后端.
            lldb        使用lldb-server或debugserver.
            rr            使用mozilla rr (https://github.com/mozilla/rr).
         (default "default") 默认使用的是default
      --build-flags string   生成标志，以传递给编译器.
      --headless             仅在headless模式下运行调试服务器.
      --init string          初始化文件，由终端客户端执行.
  -l, --listen string        调试服务器监听地址. (default "localhost:0")
      --log                  启用调试服务器日志记录.
      --log-output string    应该产生调试输出的组件的逗号分隔列表，可能的值为:
            debugger    记录调试器命令
            gdbwire        日志连接到gdbserial后端
            lldbout        将输出从debugserver/lldb复制到标准输出
            debuglineerr    读取.debug_line时日志可恢复错误
            rpc            记录所有RPC消息
            fncall        日志函数调用协议
            minidump    日志minidump加载
            使用--log启用日志时，默认为“debugger”.
      --wd string            用于运行程序的工作目录. (default ".")

使用"dlv [command] --help"获取有关命令的详细信息.

支持的命令太多了，在这里我们主要介绍它的调试命令——debug

2.dlv debug

首先使用dlv debug --help 查看其的帮助信息：

userdeMBP:go-learning user$ dlv debug --help
编译禁用优化的程序，启动并附加到该程序。

默认情况下，没有参数，Delve将编译当前目录中的“main”包，并开始调试它。或者，您可以指定一个包名，Delve将编译该包，并开始一个新的调试会话。

Usage:
  dlv debug [package] [flags]

Flags:
      --output string   二进制文件的输出路径. (default "debug")

Global Flags:和上面的一样，这里省略

举例说明：

首先要进行调试的代码为：

package main

import (
    "fmt"
    "time"
)

func counting(c chan<- int){
    for i := 0; i < 10; i++{
        time.Sleep(2 * time.Second)
        c <- i
    }
    close(c)
}

func main() {
    msg := "Starting main"
    fmt.Println(msg)
    bus := make(chan int)
    msg = "starting a gofunc"
    go counting(bus)
    for count := range bus{
        fmt.Println("count : ", count)
    }
}

然后开启调试：

userdeMBP:go-learning user$ dlv debug test.go
Type 'help' for list of commands.
(dlv) 

然后我们可以输入help来查看能够使用的debug命令有哪些：

The following commands are available:
    args ------------------------ 打印函数参数.
    break (alias: b) ------------ 设置断点.
    breakpoints (alias: bp) ----- 输出活动断点的信息.
    call ------------------------ 恢复进程，注入一个函数调用(还在实验阶段!!)
    clear ----------------------- 删除断点.
    clearall -------------------- 删除多个断点.
    condition (alias: cond) ----- 设置断点条件.
    config ---------------------- 修改配置参数.
    continue (alias: c) --------- 运行到断点或程序终止.
    deferred -------------------- 在延迟调用的上下文中执行命令.
    disassemble (alias: disass) - 反汇编程序.
    down ------------------------ 将当前帧向下移动.
    edit (alias: ed) ------------ 在$DELVE_EDITOR或$EDITOR中打开你所在的位置
    exit (alias: quit | q) ------ 退出调试器.
    frame ----------------------- 设置当前帧，或在不同的帧上执行命令.
    funcs ----------------------- 打印函数列表.
    goroutine ------------------- 显示或更改当前goroutine
    goroutines ------------------ 列举程序goroutines.
    help (alias: h) ------------- 打印帮助信息.
    list (alias: ls | l) -------- 显示源代码.
    locals ---------------------- 打印局部变量.
    next (alias: n) ------------- 转到下一个源行.
    on -------------------------- 在命中断点时执行命令.
    print (alias: p) ------------ 计算一个表达式.
    regs ------------------------ 打印CPU寄存器的内容.
    restart (alias: r) ---------- 重启进程.
    set ------------------------- 更改变量的值.
    source ---------------------- 执行包含delve命令列表的文件
    sources --------------------- 打印源文件列表.
    stack (alias: bt) ----------- 打印堆栈跟踪信息.
    step (alias: s) ------------- 单步执行程序.
    step-instruction (alias: si)  单步执行一条cpu指令.
    stepout --------------------- 跳出当前函数.
    thread (alias: tr) ---------- 切换到指定的线程.
    threads --------------------- 打印每个跟踪线程的信息.
    trace (alias: t) ------------ 设置跟踪点.
    types ----------------------- 打印类型列表
    up -------------------------- 向上移动当前帧.
    vars ------------------------ 打印包变量.
    whatis ---------------------- 打印表达式的类型.
在命令前键入help来获得命令的完整文档，如help goroutine

2)首先开始进行调试，这里先什么都不做直接输入continue，即c,运行到断点或程序终止

(dlv) c
Starting main
count :  0
count :  1
count :  2
count :  3
count :  4
count :  5
count :  6
count :  7
count :  8
count :  9
Process 1324 has exited with status 0

可见这个代码跑了起来

3)restart（缩写r）重启进程

(dlv) b main.main
Process 1324 has exited with status 0

上面进行添加断点的操作，但是并没有返回想要的信息

这是因为我们之前已经将程序运行结束了，这时候不能直接添加断点信息

所以要先调用restart来将进程重启

4）break（即b）添加断点

现在我们可以为其添加断点了

(dlv) b main.main //在main函数处添加断点
Breakpoint 1 set at 0x10b123b for main.main() ./test.go:16
(dlv) b main.counting //在counting函数处添加断点
Breakpoint 2 set at 0x10b118f for main.counting() ./test.go:8

我们也可以使用"文件：行号"的格式来添加断点，如：

b /Users/user/go-learning/test.go:8 //等价于在函数counting处添加断点

然后继续程序运行，可见会先停在main函数处：

(dlv) c
> main.main() ./test.go:16 (hits goroutine(1):1 total:1) (PC: 0x10b123b)
    11:            c <- i
    12:        }
    13:        close(c)
    14:    }
    15:    
=>  16:    func main() {
    17:        msg := "Starting main"
    18:        fmt.Println(msg)
    19:        bus := make(chan int)
    20:        msg = "starting a gofunc"
    21:        go counting(bus)

5）breakpoints（缩写bp）输出活动断点信息

(dlv) bp
Breakpoint runtime-fatal-throw at 0x102b3e0 for runtime.fatalthrow() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:654 (0)
Breakpoint unrecovered-panic at 0x102b450 for runtime.fatalpanic() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:681 (0)
    print runtime.curg._panic.arg
Breakpoint 1 at 0x10b123b for main.main() ./test.go:16 (1)
Breakpoint 2 at 0x10b118f for main.counting() ./test.go:8 (0)

可见上面的两个设置的断点

6）list 显示从停止行起前后5行的源代码

(dlv) list
> main.main() ./test.go:16 (hits goroutine(1):1 total:1) (PC: 0x10b123b)
    11:            c <- i
    12:        }
    13:        close(c)
    14:    }
    15:    
=>  16:    func main() {
    17:        msg := "Starting main"
    18:        fmt.Println(msg)
    19:        bus := make(chan int)
    20:        msg = "starting a gofunc"
    21:        go counting(bus)

7)next (缩写n)转到下一个源行

可见现在的指针从16行转到了17行

如果想继续向下，可以直接回车，Delve会默认重复上一条命令

(dlv) n
> main.main() ./test.go:17 (PC: 0x10b1252)
    12:        }
    13:        close(c)
    14:    }
    15:    
    16:    func main() {
=>  17:        msg := "Starting main"
    18:        fmt.Println(msg)
    19:        bus := make(chan int)
    20:        msg = "starting a gofunc"
    21:        go counting(bus)
    22:        for count := range bus{

8）print（缩写p）计算一个表达式

在这里用来打印一个变量的值，举例看下面

9）locals 打印局部变量

10)step（缩写s）单步执行程序

(dlv) p msg
"H�ax00�x00x00x00��x05x01x00x00x00x00x00x03x00x00�x00x00x00��ax00�x00x00x00�Qx00x01x00x00x00x00X�x06x00�x00x00x00x00x00x00x00x00x00x00x00�x0fvx01x00x00x00x00...+16825344 more"
(dlv) locals
msg = "H�ax00�x00x00x00��x05x01x00x00x00x00x00x03x00x00�x00x00x00��ax00�x00x00x00�Qx00x01x00x00x00x00X�x06x00�x00x00x00x00x00x00x00x00x00x00x00�x0fvx01x00x00x00x00...+16825344 more"
(dlv) p count
Command failed: could not find symbol value for count
(dlv) s
> main.main() ./test.go:18 (PC: 0x10b1267)
    13:        close(c)
    14:    }
    15:    
    16:    func main() {
    17:        msg := "Starting main"
=>  18:        fmt.Println(msg)
    19:        bus := make(chan int)
    20:        msg = "starting a gofunc"
    21:        go counting(bus)
    22:        for count := range bus{
    23:            fmt.Println("count : ", count)
(dlv) p msg
"Starting main"
(dlv) locals
msg = "Starting main"

在执行s前，使用p打印了msg局部变量的值，locals打印了局部变量的值，因为还没有运行到给msg复制的代码，所以返回的结果不是期望的值

然后当我们运行s后，可见指针也从17变成了18，然后这时候再运行p和locals,可见返回了期望的值

print还可以用来判断一个表达式：

(dlv) p msg == "Starting main"
true

11）whatis打印表达式类型

(dlv) whatis msg
string

能够得到msg变量为string类型

然后我们接着运行到下一个断点，这时候开启了一个groutine

(dlv) c
Starting main
> main.counting() ./test.go:8 (hits goroutine(18):1 total:1) (PC: 0x10b118f)
     3:    import (
     4:        "fmt"
     5:        "time"
     6:    )
     7:    
=>   8:    func counting(c chan<- int){
     9:        for i := 0; i < 10; i++{
    10:            time.Sleep(2 * time.Second)
    11:            c <- i
    12:        }
    13:        close(c)

12）goroutine 显示或更改当前goroutine

(dlv) help goroutine

    goroutine
    goroutine <id>
    goroutine <id> <command>

调用时不带参数，它将显示关于当前goroutine的信息。
使用单个参数调用时，它将切换到指定的goroutine。
使用更多参数调用时，它将在指定的goroutine上执行命令。

可见现在正在运行的goroutine

(dlv) goroutine
Thread 77795 at ./test.go:8
Goroutine 18:
    Runtime: ./test.go:8 main.counting (0x10b118f)
    User: ./test.go:8 main.counting (0x10b118f)
    Go: ./test.go:21 main.main (0x10b138a)
    Start: ./test.go:8 main.counting (0x10b1180)

 指定查看的是goroutine 1 :

(dlv) goroutine 1
Switched from 18 to 1 (thread 77795)
(dlv) goroutine
Thread 77795 at ./test.go:8
Goroutine 1:
    Runtime: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/proc.go:303 runtime.gopark (0x102d0f4)
    User: ./test.go:22 main.main (0x10b13ae)
    Go: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/asm_amd64.s:201 runtime.rt0_go (0x10557fb)
    Start: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/proc.go:110 runtime.main (0x102cb60)

这时候如果运行locals,得到的是goroutine 1所在处的局部变量：

(dlv) locals
gp = (*runtime.g)(0xc000000300)
mp = (*runtime.m)(0x11904c0)
status = (unreadable read out of bounds)

要回去原来的goroutine就调用:

(dlv) goroutine 18
Switched from 1 to 18 (thread 77795)

13)goroutines 列举程序goroutines

(dlv) help goroutines
列举程序goroutines.

    goroutines [-u (default: user location)|-r (runtime location)|-g (go statement location)|-s (start location)] [ -t (stack trace)]

Print out info for every goroutine. The flag controls what information is shown along with each goroutine:

    -u  显示用户代码中最顶层堆栈帧的位置
    -r  显示最顶层stackframe的位置(包括私有运行时函数中的帧)
    -g  显示创建goroutine的go指令的位置
    -s  显示起始函数的位置
    -t  显示goroutine的堆栈跟踪

如果没有指定具体的标志，则默认使用-u.

(dlv) goroutines
  Goroutine 1 - User: ./test.go:22 main.main (0x10b13ae)
  Goroutine 2 - User: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/proc.go:303 runtime.gopark (0x102d0f4)
  Goroutine 3 - User: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/proc.go:303 runtime.gopark (0x102d0f4)
  Goroutine 17 - User: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/proc.go:303 runtime.gopark (0x102d0f4)
* Goroutine 18 - User: ./test.go:8 main.counting (0x10b118f) (thread 77795)
[5 goroutines]
(dlv) goroutines -s
  Goroutine 1 - Start: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/proc.go:110 runtime.main (0x102cb60)
  Goroutine 2 - Start: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/proc.go:243 runtime.forcegchelper (0x102ced0)
  Goroutine 3 - Start: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/mgcsweep.go:46 runtime.bgsweep (0x1020170)
  Goroutine 17 - Start: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/mfinal.go:161 runtime.runfinq (0x1017ae0)
* Goroutine 18 - Start: ./test.go:8 main.counting (0x10b1180) (thread 77795)
[5 goroutines]

14)args 打印函数参数

得到counting函数的参数值：

(dlv) args
c = chan<- int 0/0

因为之前只设置了两个断点，因此再次调用c则又将运行程序完毕：

(dlv) c
count :  0
count :  1
...

15）stepout 跳出当前函数

(dlv) restart
Process restarted with PID 1352
(dlv) b main.main //之前的断点一直存在，即使程序结束，因此此时的counting函数中也有断点
Command failed: Breakpoint exists at /Users/user/go-learning/test.go:16 at 10b123b
(dlv) c
> main.main() ./test.go:16 (hits goroutine(1):1 total:1) (PC: 0x10b123b)
    11:         c <- i
    12:     }
    13:     close(c)
    14: }
    15: 
=>  16: func main() {
    17:     msg := "Starting main"
    18:     fmt.Println(msg)
    19:     bus := make(chan int)
    20:     msg = "starting a gofunc"
    21:     go counting(bus)
(dlv) stepout
Starting main
> main.counting() ./test.go:8 (hits goroutine(5):1 total:1) (PC: 0x10b118f)
    breakpoint hit during stepout, continuing...
count :  0
count :  1
count :  2
...

因为stepout跳过的是main()函数，可见直接也跳过了counting的断点，然后执行程序到结束

16）clear删除断点clearall删除多个断点

因为如果不手动清除断点，即使程序结束并restart程序，断点信息也仍然在

(dlv) breakpoints //查看当前的断点信息
Breakpoint runtime-fatal-throw at 0x102b3e0 for runtime.fatalthrow() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:654 (0)
Breakpoint unrecovered-panic at 0x102b450 for runtime.fatalpanic() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:681 (0)
    print runtime.curg._panic.arg
Breakpoint 1 at 0x10b123b for main.main() ./test.go:16 (1)
Breakpoint 2 at 0x10b118f for main.counting() ./test.go:8 (0)
(dlv) clear 1 //先删除第一个断点，即main函数上的断点
Breakpoint 1 cleared at 0x10b123b for main.main() ./test.go:16
(dlv) breakpoints //查看可见果然成功删除
Breakpoint runtime-fatal-throw at 0x102b3e0 for runtime.fatalthrow() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:654 (0)
Breakpoint unrecovered-panic at 0x102b450 for runtime.fatalpanic() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:681 (0)
    print runtime.curg._panic.arg
Breakpoint 2 at 0x10b118f for main.counting() ./test.go:8 (0)
(dlv) clearall //然后将所有断点都删除
Breakpoint 2 cleared at 0x10b118f for main.counting() ./test.go:8
(dlv) breakpoints //查看可见断点信息为空
Breakpoint runtime-fatal-throw at 0x102b3e0 for runtime.fatalthrow() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:654 (0)
Breakpoint unrecovered-panic at 0x102b450 for runtime.fatalpanic() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:681 (0)
    print runtime.curg._panic.arg
(dlv) 

17)on 在命中断点时执行命令

(dlv) help on
Executes a command when a breakpoint is hit.

    on <breakpoint name or id> <command>.

Supported commands: print, stack and goroutine)

(dlv) b /Users/user/go-learning/test.go:21 //添加断点
Breakpoint 2 set at 0x10b1368 for main.main() ./test.go:21
(dlv) on 2 print msg == "starting a gofunc" //设置当到达该断点后运行的命令，即判断msg的值是否为"starting a gofunc"
(dlv) breakpoints //查看此时的断点信息
Breakpoint runtime-fatal-throw at 0x102b3e0 for runtime.fatalthrow() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:654 (0)
Breakpoint unrecovered-panic at 0x102b450 for runtime.fatalpanic() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:681 (0)
    print runtime.curg._panic.arg
Breakpoint 2 at 0x10b1368 for main.main() ./test.go:21 (0)
    print msg == "starting a gofunc"
(dlv) c
Starting main
> main.main() ./test.go:21 (hits goroutine(1):1 total:1) (PC: 0x10b1368)
    msg == "starting a gofunc": true //可见打印出来了，并返回值为true
    16: func main() {
    17:     msg := "Starting main"
    18:     fmt.Println(msg)
    19:     bus := make(chan int)
    20:     msg = "starting a gofunc"
=>  21:     go counting(bus)
    22:     for count := range bus{
    23:         fmt.Println("count : ", count)
    24:     }
    25: }

18)set 更改变量的值

(dlv) help set
Changes the value of a variable.

    [goroutine <n>] [frame <m>] set <variable> = <value>

⚠️Only numerical variables and pointers can be changed.

因此更改string类型变量将报错：

(dlv) set msg = "change msg"
Command failed: can not set variables of type string (not implemented)

19)up向上移动当前帧/dowm向下移动当前帧

(dlv) up
> main.main() ./test.go:21 (hits goroutine(1):1 total:1) (PC: 0x10b1368)
Frame 1: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/proc.go:201 (PC: 102cd25)
   196:            // A program compiled with -buildmode=c-archive or c-shared
   197:            // has a main, but it is not executed.
   198:            return
   199:        }
   200:        fn = main_main // make an indirect call, as the linker doesn't know the address of the main package when laying down the runtime
=> 201:        fn()
   202:        if raceenabled {
   203:            racefini()
   204:        }
   205:    
   206:        // Make racy client program work: if panicking on
(dlv) down
> main.main() ./test.go:21 (hits goroutine(1):1 total:1) (PC: 0x10b1368)
Frame 0: ./test.go:21 (PC: 10b1368)
    16:    func main() {
    17:        msg := "Starting main"
    18:        fmt.Println(msg)
    19:        bus := make(chan int)
    20:        msg = "starting a gofunc"
=>  21:        go counting(bus)
    22:        for count := range bus{
    23:            fmt.Println("count : ", count)
    24:        }
    25:    }

20)exit (alias: quit | q)退出调试器

(dlv) exit
userdeMBP:go-learning user$ 

3.dlv attach

如果项目正在运行中，想要对正在运行的项目进行调试

1)首先使用"ps aux | grep 编译文件名"来查看运行程序的进程号pid

2)然后就能够使用"dlv attach pid"来连接该运行程序，然后就能使用之前debug中的命令来进行调试了

其他的命令之后如果用到了再添加