【Go調試】Delve調試學習

參考：

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

1.Linux下安裝

注意：go需要更新到1.10以上了，否則報錯。

方法1，采用go安裝：

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

方法2，git普通安裝，需設定好$GOPATH環境變量：

$ 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.簡單用法

（1）調試main packages

隻要和main packages在同一目錄，不需要參數就能運作。

例如以下目錄結構：

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

若就在github.com/me/foo/cmd/foo目錄，則直接運作dlv debug；否則運作dlv debug github.com/me/foo/cmd/foo；若提供其他參數，則加"—"隔開，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）調試tests

也可以測試自己的test suite，指令是dlv test。若沒有給定參數則建構目前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) 
           

通過funcs指令加正則參數來篩查函數，調試test二進制檔案。其他指令見delve help。

3.詳細用法

（1）調試選項和模式

調試選項，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 ".")
           

調試模式：

• dlv attach - 附加到運作的程序進行調試— dlv attach pid [executable]
• dlv connect - 連接配接到調試伺服器— dlv connect 127.0.0.1:8181
• dlv core - 檢查一個core dump— dlv core
• dlv debug - 編譯并開始調試目前目錄下的main package或指定的package—dlv debug [package]
• dlv exec - 執行并調試一個已編譯的binary—dlv exec <path/to/binary>
• dlv replay - 重放mozilla rr記錄的trace—dlv replay [trace directory]
• dlv run - 棄用的指令，用’debug’代替
• dlv test - 編譯test并調試—dlv test [package]
• dlv version - 列印版本
• dlv trace - 編譯并開始追蹤程式—dlv trace [package] regexp。當執行到比對正規表達式的函數時輸出提示資訊，如果不想調試整個程式，隻想知道你的程序執行了哪些函數，就很有用。選項如下

-e, --exec string     需執行和追蹤的二進制檔案
          --output string   二進制檔案的輸出路徑(default "debug")
      -p, --pid int         待附加的程序号
      -s, --stack int       顯示給定深度的stack trace
      -t, --test            追蹤一個test binary.
           

（2）詳細指令

• Command Description
• args 列印函數參數
• break—b 設定一個斷點
• breakpoints—bp 列印活動斷點資訊
• call Resumes process, injecting a function call (EXPERIMENTAL!!!)
• check Creates a checkpoint at the current position.
• checkpoints Print out info for existing checkpoints.
• clear 删除斷點
• clear-checkpoint Deletes checkpoint.
• clearall 删除所有的斷點
• condition—cond 設定斷點條件
• config 改變配置參數
• continue—c 運作到斷點或程式終止
• 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 退出調試
• frame Set the current frame, or execute command on a different -frame.
• funcs 列印函數清單
• goroutine 顯示或更改目前goroutine
• goroutines 列出程式的全部goroutines
• help—h 列印出幫助資訊
• libraries List loaded dynamic libraries
• list—ls Show source code.
• locals 列印局部變量
• next—n 跳到下一行
• on 在遇到斷點時執行一個指令
• print—p Evaluate an 表達式.
• regs 列印CPU寄存器的内容
• restart—r 從a checkpoint or event重新開機程序
• rev Reverses the execution of the target program for the command specified.
• rewind Run backwards until breakpoint or program termination.
• set 更改變量的值
• source 執行包含delve指令清單的檔案
• sources 列印源檔案清單
• stack—bt 列印堆棧跟蹤資訊
• step—s 單步執行程式
• step-instruction—si 單步單個執行cpu指令
• stepout 退出目前函數
• thread—tr 切換到指定的線程
• threads 列印每一個跟蹤線程的資訊
• trace—t 設定跟蹤點
• types 列印類型清單
• up Move the current frame up.
• vars 列印某個包内的(全局)變量
• whatis 列印表達式的類型

常用指令：

#直接調試
    $ dlv debug ./main.go
    $ b main.main
    $ c
    $ b main.hi      #在func li  裡打一個斷點
    $ b /home/goworkspace/src/github.com/mytest/main.go:20  #使用   "檔案:行号"來打斷點
    $ n  #回車，單步執行
    $ print #（别名p）輸出變量資訊　     p  hostName
    $ args #列印出所有的方法參數資訊
    $ locals  #列印所有的本地變量
    
    #附加調試
    $ go build main.go
    $ ./main
    $ ps aux|grep main   #查pid
    $ dlv attach 29260