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GO语言调试利器dlv快速上手

发布时间 2023-07-17 15:18:39作者: 我家有只江小白

GO语言调试利器dlv快速上手

 

golang 安装

 tar -xvf go1.15.2.linux-arm64.tar.gz  -C  /usr/local/go

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[root@centos7 ~]# ls  /usr/local/go
go
[root@centos7 ~]# ls  /usr/local/go/go/
api  AUTHORS  bin  CONTRIBUTING.md  CONTRIBUTORS  doc  favicon.ico  lib  LICENSE  misc  PATENTS  pkg  README.md  robots.txt  SECURITY.md  src  test  VERSION
[root@centos7 ~]#
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[root@centos7 ~]# go  version
go version go1.15.2 linux/arm64
[root@centos7 ~]# cat go.source 
export GOPATH=/opt/gopath
export GOROOT=/usr/local/go/go
export GOARCH=arm64
export GOOS=linux
export GOTOOLS=/pkg/tool
#export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin:/root/bin:/bin:/bin
export PATH=$PATH:$GOROOT/bin
[root@centos7 ~]#
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 增加 
export PATH=$PATH:$GOPATH/bin
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[root@centos7 ~]# cat go.source 
export GOPATH=/opt/gopath
export GOROOT=/usr/local/go15.2/go
export GOARCH=arm64
export GOOS=linux
export GOTOOLS=/pkg/tool
#export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin:/root/bin:/bin:/bin
export PATH=$PATH:$GOPATH/bin
export PATH=$PATH:$GOROOT/bin
[root@centos7 ~]# ls /opt/gopath/bin/dlv 
/opt/gopath/bin/dlv
[root@centos7 ~]#
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一、dlv的安装

1）下载dlv

git clone https://github.com/go-delve/delve.git $GOPATH/src/github.com/go-delve/delve

或者 go get github.com/derekparker/delve/cmd/dlv

root@cloud:~# go version
go version go1.14.10 linux/arm64

 

2）安装

cd $GOPATH/src/github.com/go-delve/delve

make install

 

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root@cloud:~/delve# make install -j $(nproc)
go install "-ldflags=-X main.Build=1b2357092c8fee7406988d8191f71059700c5399" github.com/go-delve/delve/cmd/dlv
root@cloud:~/delve# dlv -h
Delve is a source level debugger for Go programs.

Delve enables you to interact with your program by controlling the execution of the process,
evaluating variables, and providing information of thread / goroutine state, CPU register state and more.

The goal of this tool is to provide a simple yet powerful interface for debugging Go programs.

Pass flags to the program you are debugging using `--`, for example:

`dlv exec ./hello -- server --config conf/config.toml`
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(dlv) bp
Breakpoint runtime-fatal-throw at 0x429a0 for runtime.fatalthrow() GOROOT/src/runtime/panic.go:1162 (0)
Breakpoint unrecovered-panic at 0x42a00 for runtime.fatalpanic() GOROOT/src/runtime/panic.go:1189 (0)
        print runtime.curg._panic.arg
Breakpoint 1 at 0x3edc70 for gvisor.dev/gvisor/pkg/sentry/mm.(*MemoryManager).MMap() pkg/sentry/mm/syscalls.go:75 (1)
(dlv) clear 1
Breakpoint 1 cleared at 0x3edc70 for gvisor.dev/gvisor/pkg/sentry/mm.(*MemoryManager).MMap() pkg/sentry/mm/syscalls.go:75
(dlv) bp
Breakpoint runtime-fatal-throw at 0x429a0 for runtime.fatalthrow() GOROOT/src/runtime/panic.go:1162 (0)
Breakpoint unrecovered-panic at 0x42a00 for runtime.fatalpanic() GOROOT/src/runtime/panic.go:1189 (0)
        print runtime.curg._panic.arg
(dlv) quit
Would you like to kill the process? [Y/n] n
root@cloud:~/delve#
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dlv和golang

 

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root@cloud:~/delve# dlv -h

Command 'dlv' not found, did you mean:

  command 'ddv' from deb ncbi-tools-x11
  command 'delv' from deb dnsutils
  command 'dav' from deb dav-text
  command 'lv' from deb lv
  command 'dlg' from deb pccts
  command 'dll' from deb brickos

Try: apt install <deb name>

root@cloud:~/delve# source ~/hyper/go_source 
root@cloud:~/delve# dlv -h
Delve is a source level debugger for Go programs.

Delve enables you to interact with your program by controlling the execution of the process,
evaluating variables, and providing information of thread / goroutine state, CPU register state and more.

The goal of this tool is to provide a simple yet powerful interface for debugging Go programs.

Pass flags to the program you are debugging using `--`, for example:

`dlv exec ./hello -- server --config conf/config.toml`
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查看协程

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(dlv) goroutines
Goroutine 1 - User: GOROOT/src/runtime/sema.go:56 sync.runtime_Semacquire (0x73ac8) [semacquire]
Goroutine 2 - User: GOROOT/src/runtime/proc.go:307 runtime.gopark (0x450c0) [force gc (idle)]
Goroutine 3 - User: GOROOT/src/runtime/proc.go:307 runtime.gopark (0x450c0) [GC sweep wait]
Goroutine 4 - User: GOROOT/src/runtime/proc.go:307 runtime.gopark (0x450c0) [GC scavenge wait]
Goroutine 5 - User: GOROOT/src/runtime/proc.go:307 runtime.gopark (0x450c0) [GC worker (idle)]
Goroutine 6 - User: GOROOT/src/runtime/proc.go:307 runtime.gopark (0x450c0) [GC worker (idle)]
Goroutine 7 - User: GOROOT/src/runtime/proc.go:307 runtime.gopark (0x450c0) [GC worker (idle)]
Goroutine 8 - User: GOROOT/src/runtime/proc.go:307 runtime.gopark (0x450c0) [GC worker (idle)]
Goroutine 9 - User: GOROOT/src/runtime/proc.go:307 runtime.gopark (0x450c0) [GC worker (idle)]
Goroutine 10 - User: GOROOT/src/runtime/proc.go:307 runtime.gopark (0x450c0) [GC worker (idle)]
Goroutine 11 - User: GOROOT/src/runtime/proc.go:307 runtime.gopark (0x450c0) [GC worker (idle)]
Goroutine 12 - User: GOROOT/src/runtime/proc.go:307 runtime.gopark (0x450c0) [GC worker (idle)]
Goroutine 13 - User: GOROOT/src/runtime/proc.go:307 runtime.gopark (0x450c0) [GC worker (idle)]
Goroutine 14 - User: GOROOT/src/runtime/proc.go:307 runtime.gopark (0x450c0) [GC worker (idle)]
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could not open debug info

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[root@centos7 ~]# cat go.source 
export GOPATH=/opt/gopath
export GOROOT=/usr/local/go15.2/go
export GOARCH=arm64
export GOOS=linux
export GOTOOLS=/pkg/tool
#export PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin:/root/bin:/bin:/bin
export PATH=$PATH:$GOPATH/bin
export PATH=$PATH:$GOROOT/bin
[root@centos7 ~]# ls /opt/gopath/bin/dlv 
/opt/gopath/bin/dlv
[root@centos7 ~]# ps -elf | grep nginx | grep ingress
4 S 101       64638  64619  0  80   0 -     7 SyS_rt 03:05 ?        00:00:00 /usr/bin/dumb-init -- /nginx-ingress-controller --publish-service=ingress-nginx/ingress-nginx-controller --election-id=ingress-controller-leader --ingress-class=nginx --configmap=ingress-nginx/ingress-nginx-controller --validating-webhook=:8443 --validating-webhook-certificate=/usr/local/certificates/cert --validating-webhook-key=/usr/local/certificates/key
4 S 101       64679  64638  0  80   0 - 11673 SyS_ep 03:05 ?        00:00:13 /nginx-ingress-controller --publish-service=ingress-nginx/ingress-nginx-controller --election-id=ingress-controller-leader --ingress-class=nginx --configmap=ingress-nginx/ingress-nginx-controller --validating-webhook=:8443 --validating-webhook-certificate=/usr/local/certificates/cert --validating-webhook-key=/usr/local/certificates/key
[root@centos7 ~]# dlv attach 64679
could not attach to pid 64679: could not open debug info
[root@centos7 ~]#
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一、dlv的安装

1）下载dlv

git clone https://github.com/go-delve/delve.git $GOPATH/src/github.com/go-delve/delve

或者 go get github.com/derekparker/delve/cmd/dlv

2）安装

cd $GOPATH/src/github.com/go-delve/delve

make install

二、dlv简要使用说明

2.1、获取帮助信息

安装后执行dlv -h将会看到帮助信息：

image

上面的信息只是列出了命令列表，具体使用方法没有给出，我们可以执行dlv help + 具体命令来查看详细说明，

比如我们执行dlv help attach：

image

2.2、进入调试模式

1）dlv attach pid：类似与gdb attach pid，可以对正在运行的进程直接进行调试(pid为进程号)。

2）dlv debug：运行dlv debug test.go会先编译go源文件，同时执行attach命令进入调试模式，该命令会在当前目录下生成一个名为debug的可执行二进制文件，退出调试模式会自动被删除。

3）dlv exec executable_file ：直接从二进制文件启动调试模式。如果要带参数执行需要添加--，如dlv exec executable_file -- -f xxx.conf

4）dlv core executable_file core_file：以core文件启动调试，通常进行dlv的目的就是为了找出可执行文件core的原因，通过core文件可直接找出具体进程异常的信息。

3、常用调试方法

3.1 dlv trace追踪调用轨迹

该命令最直接的用途是可以追踪代码里函数的调用轨迹，

如下源代码，现用trace命令跟踪其调轨迹。

package main import ( "fmt" "time" ) func Test() { fmt.Println("hello") time.Sleep(1000 * 1000 * 100) } func Test2() { fmt.Println("world") time.Sleep(1000 * 1000 * 100) } func main() { for i := 0; i < 2; i++ { go Test() go Test2() } time.Sleep(1000 * 1000 * 2000) fmt.Println("end") }

运行结果，这里看除了Test，test2也被追踪：

$ dlv trace hello.go Test

> goroutine(19): main.Test2()

> goroutine(21): main.Test2()

> goroutine(18): main.Test()

world

hello

world

> goroutine(20): main.Test()

hello

=> ()

=> ()

=> ()

=> ()

end

3.2 调试模式基本命令

这里用上节的源码作为示例进行调试。开始调试：dlv debug hello.go

1）b(break)：打断点

设置断点，当需要设置多个断点时，为了断点可识别可进行自定义命名。进入调试模式后先打断点。

例：b Test

b test.go:13

image

2）r(restart)：重启当前进程

类似gdb里的run，如果刚执行dlv debug hello.go，进程已经起来，不用执行。如果进程已结算或需要重新开始则需要执行r

3）c(continue)：继续执行到断点处

image

4）bp：查看所有断点

image

5）on  ：当运行到某断点时执行相应命令

断点可以是名称（在设置断点时可命名断点）或者编号，例如on 3 p i表示运行到断点3时打印变量i。

image

6）cond(condition)   ：有条件的断点

针对某个断点，只有表达式成立才会被中断。例：

condition 3 i==1

image

image

7）n(next)：逐行执行代码，不进入函数内

8）s(step)：逐行执行代码，遇到函数会跳进内部

9）stepout：当使用s命令进入某个函数后，执行它可跳出函数

10）si(step-instruction)：单步单核执行代码

如果不希望多协程并发执行可以使用该命令，这在多协程调试时极为方便。

11）args：查看被调用函数所传入的参数值

12）locals：查看所有局部变量

locals var_name：查看具体某个变量，var_name可以是正则表达式。

13）clear：清除单个断点

14）clearall：清除所有断点

15）list：打印当前断点位置的源代码

list后面加行号可以展示该行附近的源代码，要注意该行必须是代码行而不能是空行。

16）bt：打印当前栈信息。

3.3 多协程调试

1）goroutines：显示所有协程

image

2）goroutine：协程切换

先执行goroutine 7表示切换到7号协程上

3.4 其他命令

1）frame：切换栈。

2）regs：打印寄存器内容。

3）sources：打印所有源代码文件路径

4）source：执行一个含有dlv命令的文件

source命令允许将dlv命令放在一个文件中，然后逐行执行文件内的命令。

5）trace：类似于打断点，但不会中断，同时会输出一行提示信息