如何使用 dlv 进行 golang 代码调试

dlv 是什么

dlv(Delve) 是一个非常流行的 Go 调试工具，包括设置断点、单步执行代码、检查变量、分析跟踪堆栈信息等功能。

安装

1. 首先确保安装了 Cli 开发者工具（Command line developer tools）：

xcode-select --install

2. 如果你没有开启开发者模式，每次调试的时候都会询问你授权；开启后每次会话仅授权一次：

sudo /usr/sbin/DevToolsSecurity -enable

3. 可能同时需要添加用户组：

sudo dscl . append /Groups/_developer GroupMembership $(whoami)

Mac

brew install delve

通过源码安装

go install github.com/go-delve/delve/cmd/dlv@latest

快速开始：使用 dlv 进行调试

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

调试普通函数

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) 

调试测试函数

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) 

调试 Web API Server

1. 以无头（守护进程）启动 debug server：

dlv debug --headless --listen=:8081 main.go

看到下面的信息表明启动成功：

API server listening at: [::]:8081
2024-06-09T13:10:28+08:00 warning layer=rpc Listening for remote connections (connections are not authenticated nor encrypted)
debugserver-@(#)PROGRAM:LLDB  PROJECT:lldb-1400.0.38.17
 for x86_64.
Got a connection, launched process /xxx/__debug_bin1863605193 (pid = 77532).

2. 连接 debug server 进行调试

dlv connect :8081

如何使用

$ dlv -h
Usage:
  dlv [command]
 
Available Commands:
  attach      Attach to running process and begin debugging.
  connect     Connect to a headless debug server with a terminal client.
  core        Examine a core dump.
  dap         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.

基本用法

1. 启动调试会话

dlv debug main.go

2. 设置断点

# 1）第一种方式
(dlv) break main.main
# 2）或者指定行数（b 等价于 break）
(dlv) b main.go:10

3. 运行程序

(dlv) continue
# 等价于
(dlv) c

4. 单步执行

(dlv) next
# 等价于
(dlv) n

5. 查看变量

(dlv) print myVar
# 等价于
(dlv) p myVar

6. 查看堆栈信息

(dlv) stack

7. 设置条件断点

(dlv) break main.go:10 if x == 5

8. 显示当前代码位置

(dlv) list
# 等价于
(dlv) l