【Go调试】Delve调试学习

参考：

• https://github.com/go-delve/delve/blob/master/Documentation/cli/README.md
• https://juejin.im/entry/5aa1f98d6fb9a028c522c84b

1.Linux下安装

注意：go需要更新到1.10以上了，否则报错。

方法1，采用go安装：

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

方法2，git普通安装，需设置好$GOPATH环境变量：

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

2.简单用法

（1）调试main packages

只要和main packages在同一目录，不需要参数就能运行。

例如以下目录结构：

    .
    ├── github.com/me/foo
    ├── cmd
    │   └── foo
    │       └── main.go
    ├── pkg
    │   └── baz
    │       ├── bar.go
    │       └── bar_test.go

若就在github.com/me/foo/cmd/foo目录，则直接运行dlv debug；否则运行dlv debug github.com/me/foo/cmd/foo；若提供其他参数，则加"—"隔开，dlv debug github.com/me/foo/cmd/foo – -arg1 value。

    $ dlv debug github.com/me/foo/cmd/foo
    Type 'help' for list of commands.
    (dlv) break main.main
    Breakpoint 1 set at 0x49ecf3 for main.main() ./test.go:5
    (dlv) continue
    > main.main() ./test.go:5 (hits goroutine(1):1 total:1) (PC: 0x49ecf3)
         1:	package main
         2:	
         3:	import "fmt"
         4:	
    =>   5:	func main() {
         6:		fmt.Println("delve test")
         7:	}
    (dlv) 

（2）调试tests

也可以测试自己的test suite，命令是dlv test。若没有给定参数则构建当前package。

    $ dlv test github.com/me/foo/pkg/baz
    Type 'help' for list of commands.
    (dlv) funcs test.Test*
    /home/me/go/src/github.com/me/foo/pkg/baz/test.TestHi
    (dlv) break TestHi
    Breakpoint 1 set at 0x536513 for /home/me/go/src/github.com/me/foo/pkg/baz/test.TestHi() ./test_test.go:5
    (dlv) continue
    > /home/me/go/src/github.com/me/foo/pkg/baz/test.TestHi() ./bar_test.go:5 (hits goroutine(5):1 total:1) (PC: 0x536513)
         1:	package baz
         2:	
         3:	import "testing"
         4:	
    =>   5:	func TestHi(t *testing.T) {
         6:		t.Fatal("implement me!")
         7:	}
    (dlv) 

通过funcs命令加正则参数来筛查函数，调试test二进制文件。其他命令见delve help。

3.详细用法

（1）调试选项和模式

调试选项，例如dlv exec ./hello – server --config conf/config.toml。

          --accept-multiclient   Allows a headless server to accept multiple client connections. Note that the server API is not reentrant and clients will have to coordinate.
          --api-version int      Selects API version when headless. (default 1)
          --backend string       Backend selection:
    	default		Uses lldb on macOS, native everywhere else.
    	native		Native backend.
    	lldb		Uses lldb-server or debugserver.
    	rr		Uses mozilla rr (https://github.com/mozilla/rr).
     (default "default")
          --build-flags string   Build flags, to be passed to the compiler.
          --check-go-version     Checks that the version of Go in use is compatible with Delve. (default true)
          --headless             Run debug server only, in headless mode.
          --init string          Init file, executed by the terminal client.
      -l, --listen string        Debugging server listen address. (default "localhost:0")
          --log                  Enable debugging server logging.
          --log-dest string      Writes logs to the specified file or file descriptor. If the argument is a number it will be interpreted as a file descriptor, otherwise as a file path. This option will also redirect the "API listening" message in headless mode.
          --log-output string    Comma separated list of components that should produce debug output, possible values:
    	debugger	Log debugger commands
    	gdbwire		Log connection to gdbserial backend
    	lldbout		Copy output from debugserver/lldb to standard output
    	debuglineerr	Log recoverable errors reading .debug_line
    	rpc		Log all RPC messages
    	fncall		Log function call protocol
    	minidump	Log minidump loading
    Defaults to "debugger" when logging is enabled with --log.
          --wd string            Working directory for running the program. (default ".")

调试模式：

• dlv attach - 附加到运行的进程进行调试— dlv attach pid [executable]
• dlv connect - 连接到调试服务器— dlv connect 127.0.0.1:8181
• dlv core - 检查一个core dump— dlv core
• dlv debug - 编译并开始调试当前目录下的main package或指定的package—dlv debug [package]
• dlv exec - 执行并调试一个已编译的binary—dlv exec
• dlv replay - 重放mozilla rr记录的trace—dlv replay [trace directory]
• dlv run - 弃用的命令，用’debug’代替
• dlv test - 编译test并调试—dlv test [package]
• dlv version - 打印版本
• dlv trace - 编译并开始追踪程序—dlv trace [package] regexp。当执行到匹配正则表达式的函数时输出提示信息，如果不想调试整个程序，只想知道你的进程执行了哪些函数，就很有用。选项如下

      -e, --exec string     需执行和追踪的二进制文件
          --output string   二进制文件的输出路径(default "debug")
      -p, --pid int         待附加的进程号
      -s, --stack int       显示给定深度的stack trace
      -t, --test            追踪一个test binary.

（2）详细命令

• Command Description
• args 打印函数参数
• break—b 设置一个断点
• breakpoints—bp 打印活动断点信息
• call Resumes process, injecting a function call (EXPERIMENTAL!!!)
• check Creates a checkpoint at the current position.
• checkpoints Print out info for existing checkpoints.
• clear 删除断点
• clear-checkpoint Deletes checkpoint.
• clearall 删除所有的断点
• condition—cond 设置断点条件
• config 改变配置参数
• continue—c 运行到断点或程序终止
• deferred Executes command in the context of a deferred call.
• disassemble Disassembler.
• down Move the current frame down.
• edit Open where you are in DELVE_EDITOR or EDITOR
• exit—quit 退出调试
• frame Set the current frame, or execute command on a different -frame.
• funcs 打印函数列表
• goroutine 显示或更改当前goroutine
• goroutines 列出程序的全部goroutines
• help—h 打印出帮助信息
• libraries List loaded dynamic libraries
• list—ls Show source code.
• locals 打印局部变量
• next—n 跳到下一行
• on 在遇到断点时执行一个命令
• print—p Evaluate an 表达式.
• regs 打印CPU寄存器的内容
• restart—r 从a checkpoint or event重启进程
• rev Reverses the execution of the target program for the command specified.
• rewind Run backwards until breakpoint or program termination.
• 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—bt 打印堆栈跟踪信息
• step—s 单步执行程序
• step-instruction—si 单步单个执行cpu指令
• stepout 退出当前函数
• thread—tr 切换到指定的线程
• threads 打印每一个跟踪线程的信息
• trace—t 设置跟踪点
• types 打印类型列表
• up Move the current frame up.
• vars 打印某个包内的(全局)变量
• whatis 打印表达式的类型

常用命令：

    #直接调试
    $ dlv debug ./main.go
    $ b main.main
    $ c
    $ b main.hi      #在func li  里打一个断点
    $ b /home/goworkspace/src/github.com/mytest/main.go:20  #使用   "文件:行号"来打断点
    $ n  #回车，单步执行
    $ print #（别名p）输出变量信息　     p  hostName
    $ args #打印出所有的方法参数信息
    $ locals  #打印所有的本地变量
    
    #附加调试
    $ go build main.go
    $ ./main
    $ ps aux|grep main   #查pid
    $ dlv attach 29260