Golang-语言源码级调试器 Delve

前言

Go 目前的调试器有如下几种：

• GDB 最早期的调试工具，现在用的很少。
• LLDB macOS 系统推荐的标准调试工具，单 Go 的一些专有特性支持的比较少。
• Delve 专门为 Go 语言打造的调试工具，使用最为广泛。

本篇简单说明如何使用 Delve 工具来调试 Go 程序，使用的 delve 版本为 1.20.1。

delve 的汉语意思是：钻研、探索；用这个来命名一个debug工具还是非常的形象。

安装

已知以下说明适用于 Linux、macOS、Windows 和 FreeBSD。

克隆 git 存储库并构建：

$ git clone https://github.com/go-delve/delve
$ cd delve
$ go install github.com/go-delve/delve/cmd/dlv

或者，在 Go 版本 1.16 或更高版本上：

Install the latest release:
$ go install github.com/go-delve/delve/cmd/dlv@latest

Install at tree head:
$ go install github.com/go-delve/delve/cmd/dlv@master

安装在一个特定的版本或:

$ go install github.com/go-delve/delve/cmd/dlv@v1.7.3
$ go install github.com/go-delve/delve/cmd/dlv@v1.7.4-0.20211208103735-2f13672765fe

命令

Usage:dlv [command]Available Commands:attach      附加到正在运行的进程并开始调试.connect     使用终端客户端连接到无头调试服务器.core        检查核心转储.dap         启动一个通过调试适配器协议(DAP)通信的无头TCP服务器.debug       编译并开始调试当前目录中的主包或指定的包.exec        执行预编译的二进制文件，并开始调试会话.help        Help about any commandrun         弃用的命令。使用'debug'代替.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     Prints version.

[操作] 示例代码

下面是检查操作的代码

.test/
├── go.mod
├── main.go
└── main_test.go

module debug_samplego 1.18

main.go 执行以下处理：

package mainimport ("fmt"
)var abc stringfunc init() {abc = "wakuwaku bank"
}func add(a, b int) int {fmt.Printf("func add %v\n", abc)return a + b
}func sub(a, b int) int {fmt.Printf("func sub %v\n", abc)return a - b
}func calculate(a, b int) (addValue, subValue int) {addValue = add(a, b)subValue = sub(a, b)return addValue, subValue
}func sampleFunc1() {for i := 0; i < 10; i++ {a := i + 10b := iaddValue, subValue := calculate(a, b)fmt.Printf("addValue: %v subValue: %v\n", addValue, subValue)}
}func main() {sampleFunc1()
}

main_test.go 执行以下处理：

package mainimport "testing"func Test_add(t *testing.T) {type args struct {a intb int}tests := []struct {name stringargs argswant int}{{name: "Both positive values", args: args{10, 3}, want: 13}}for _, tt := range tests {t.Run(tt.name, func(t *testing.T) {if got := add(tt.args.a, tt.args.b); got != tt.want {t.Errorf("add() = %v, want %v", got, tt.want)}})}
}func Test_sub(t *testing.T) {type args struct {a intb int}tests := []struct {name stringargs argswant int}{{name: "Both positive values", args: args{10, 3}, want: 7}}for _, tt := range tests {t.Run(tt.name, func(t *testing.T) {if got := sub(tt.args.a, tt.args.b); got != tt.want {t.Errorf("sub() = %v, want %v", got, tt.want)}})}
}

[调试] dlv 调试

开始调试

$ dlv debug main.go
Type 'help' for list of commands.
(dlv) 

检查功能/代码( funcs list )

funcs main\..* 查看 main 文件 所有定义的方法

(dlv) funcs main\..*
main.add
main.calculate
main.init.0
main.main
main.sampleFunc1
main.sub
runtime.main.func1
runtime.main.func2

list 您可以在以下位置查看某个方法源代码

(dlv) list main.main
Showing /debug_sample/main.go:38 (PC: 0x1029dda10)33:                 addValue, subValue := calculate(a, b)34:                 fmt.Printf("addValue: %v subValue: %v\n", addValue, subValue)35:         }36: }37: 38: func main() {39:         sampleFunc1()40: }

(dlv) list main.sampleFunc1:3
Showing /debug_sample/main.go:32 (PC: 0x1029dd8c0)27: }28: 29: func sampleFunc1() {30:         for i := 0; i < 10; i++ {31:                 a := i + 1032:                 b := i33:                 addValue, subValue := calculate(a, b)34:                 fmt.Printf("addValue: %v subValue: %v\n", addValue, subValue)35:         }36: }37: 

设置/删除断点 ( break clear )

break 您可以使用以下命令设置断点

(dlv) break main.main
Breakpoint 1 set at 0x1029dda10 for main.main() ./main.go:38

(dlv) break main.sampleFunc1:3
Breakpoint 2 set at 0x1029dd8c0 for main.sampleFunc1() ./main.go:32

breakpoints 您可以检查中设置的断点。

(dlv) breakpoints
Breakpoint runtime-fatal-throw (enabled) at 0x10296c880 for runtime.throw() /Users/w/.gvm/gos/go1.18/src/runtime/panic.go:982 (0)
Breakpoint unrecovered-panic (enabled) at 0x10296cb90 for runtime.fatalpanic() /Users/w/.gvm/gos/go1.18/src/runtime/panic.go:1065 (0)print runtime.curg._panic.arg
Breakpoint 1 (enabled) at 0x1029dda10 for main.main() ./main.go:38 (0)
Breakpoint 2 (enabled) at 0x1029dd8c0 for main.sampleFunc1() ./main.go:32 (0)

clear 您可以使用 删除指定的断点。

(dlv) clear 1
Breakpoint 1 cleared at 0x1029dda10 for main.main() ./main.go:38
(dlv) breakpoints
Breakpoint runtime-fatal-throw (enabled) at 0x10296c880 for runtime.throw() /Users/w/.gvm/gos/go1.18/src/runtime/panic.go:982 (0)
Breakpoint unrecovered-panic (enabled) at 0x10296cb90 for runtime.fatalpanic() /Users/w/.gvm/gos/go1.18/src/runtime/panic.go:1065 (0)print runtime.curg._panic.arg
Breakpoint 2 (enabled) at 0x1029dd8c0 for main.sampleFunc1() ./main.go:32 (0)

clearall 删除所有断点。

(dlv) clearall
Breakpoint 1 cleared at 0x4986e6 for main.main() ./main.go:38
Breakpoint 5 cleared at 0x49858c for main.sampleFunc1() ./main.go:32

提前处理到断点( continue )

continue 让我们继续执行中设置的断点。

(dlv) continue
> main.sampleFunc1() ./main.go:32 (hits goroutine(1):1 total:1) (PC: 0x1029dd8c0)27: }28: 29: func sampleFunc1() {30:         for i := 0; i < 10; i++ {31:                 a := i + 10
=>  32:                 b := i33:                 addValue, subValue := calculate(a, b)34:                 fmt.Printf("addValue: %v subValue: %v\n", addValue, subValue)35:         }36: }37: 

continue 或者，您可以继续执行以下命令。

next
向前迈出一行（跨过）。
step
前进一行。
stepout
退出当前功能。

检查并覆盖变量 ( locals set )

[root@cdh2 test]# dlv debug main.go  // 调试
Type 'help' for list of commands.(dlv) break main.sampleFunc1:3  // 设置断点
Breakpoint 1 set at 0x49858c for main.sampleFunc1() ./main.go:32(dlv) c  // 跳到断点
> main.sampleFunc1() ./main.go:32 (hits goroutine(1):1 total:1) (PC: 0x49858c)27:	}28:29:	func sampleFunc1() {30:		for i := 0; i < 10; i++ {31:			a := i + 10
=>  32:			b := i33:			addValue, subValue := calculate(a, b)34:			fmt.Printf("addValue: %v subValue: %v\n", addValue, subValue)35:		}36:	}37:(dlv) locals  // 打印局部变量
i = 0
a = 10(dlv) vars main.abc
main.abc = "wakuwaku bank"(dlv) print i
0
(dlv) print a
10(dlv) set i = 2  // 重新给变量赋值
(dlv) print i
2

堆栈跟踪显示( stack frame )

首先，要检查操作，请继续添加功能。

(dlv) break main.add
Breakpoint 3 set at 0x1029dd610 for main.add() ./main.go:13
(dlv) c
> main.add() ./main.go:13 (hits goroutine(1):1 total:1) (PC: 0x1029dd610)8: 9: func init() {10:         abc = "wakuwaku bank"11: }12: 
=>  13: func add(a, b int) int {14:         fmt.Printf("func add %v\n", abc)15:         return a + b16: }17: 18: func sub(a, b int) int {

显示堆栈跟踪

(dlv) stack
0  0x00000000004982aa in main.addat ./main.go:13
1  0x00000000004984df in main.calculateat ./main.go:24
2  0x00000000004985a5 in main.sampleFunc1at ./main.go:33
3  0x00000000004986f7 in main.mainat ./main.go:39
4  0x00000000004372d8 in runtime.mainat /root/.go/src/runtime/proc.go:250
5  0x0000000000461661 in runtime.goexitat /root/.go/src/runtime/asm_amd64.s:1571

frame 您可以通过指定堆栈跟踪编号来检查代码和变量

(dlv) frame 2 ls
Goroutine 1 frame 2 at /debug_sample/main.go:33 (PC: 0x1029dd8d0)28: 29: func sampleFunc1() {30:         for i := 0; i < 10; i++ {31:                 a := i + 1032:                 b := i
=>  33:                 addValue, subValue := calculate(a, b)34:                 fmt.Printf("addValue: %v subValue: %v\n", addValue, subValue)35:         }36: }37: 38: func main() {

(dlv) frame 2 locals
i = 2
a = 10
b = 2

指定条件 ( condition )

首先，进行for语句的处理

$ dlv debug main.go
Type 'help' for list of commands.
(dlv) b main.sampleFunc1:3
Breakpoint 1 set at 0x1050958c0 for main.sampleFunc1() ./main.go:32
(dlv) c
> main.sampleFunc1() ./main.go:32 (hits goroutine(1):1 total:1) (PC: 0x1050958c0)27: }28: 29: func sampleFunc1() {30:         for i := 0; i < 10; i++ {31:                 a := i + 10
=>  32:                 b := i33:                 addValue, subValue := calculate(a, b)34:                 fmt.Printf("addValue: %v subValue: %v\n", addValue, subValue)35:         }36: }37: 
(dlv) locals
i = 0
a = 10

condition 您可以使用 设置断点条件。
i==5 让我们将其设置为停止时

(dlv) condition 1 i==5(dlv) c
func add wakuwaku bank
func sub wakuwaku bank
addValue: 10 subValue: 10
func add wakuwaku bank
func sub wakuwaku bank
addValue: 12 subValue: 10
func add wakuwaku bank
func sub wakuwaku bank
addValue: 14 subValue: 10
func add wakuwaku bank
func sub wakuwaku bank
addValue: 16 subValue: 10
func add wakuwaku bank
func sub wakuwaku bank
addValue: 18 subValue: 10
> main.sampleFunc1() ./main.go:32 (hits goroutine(1):2 total:2) (PC: 0x1050958c0)27: }28: 29: func sampleFunc1() {30:         for i := 0; i < 10; i++ {31:                 a := i + 10
=>  32:                 b := i33:                 addValue, subValue := calculate(a, b)34:                 fmt.Printf("addValue: %v subValue: %v\n", addValue, subValue)35:         }36: }37: (dlv) locals
i = 5
a = 15

调试结束( exit )

exit 您可以使用 完成调试。

(dlv) exit

[debug] dlv测试（调试测试）

dlv test 您可以使用以下命令调试您的测试代码

$ dlv test
Type 'help' for list of commands.
(dlv) funcs test.Test*  // test.Test*  test 包含 Xxx_test.go 文件夹
debug_sample.Test_add
debug_sample.Test_add.func1
debug_sample.Test_sub
debug_sample.Test_sub.func1(dlv) b test.Test_add
Breakpoint 1 set at 0x104891e90 for debug_sample.Test_add() ./main_test.go:5(dlv) c
> debug_sample.Test_add() ./main_test.go:5 (hits goroutine(4):1 total:1) (PC: 0x104891e90)1: package main2: 3: import "testing"4: 
=>   5: func Test_add(t *testing.T) {6:         type args struct {7:                 a int8:                 b int9:         }10:         tests := []struct { 

[debug] dlv Attach（调试运行进程）

更正操作检查代码

对其进行修改以保持作为 Web 服务器运行，如下所示。

package mainimport ("fmt""net/http"
)var abc stringfunc init() {abc = "wakuwaku bank"
}func add(a, b int) int {fmt.Printf("func add %v\n", abc)return a + b
}func sub(a, b int) int {fmt.Printf("func sub %v\n", abc)return a - b
}func calculate(a, b int) (addValue, subValue int) {addValue = add(a, b)subValue = sub(a, b)return addValue, subValue
}func sampleFunc1(w http.ResponseWriter, r *http.Request) {for i := 0; i < 10; i++ {a := i * 2b := iaddValue, subValue := calculate(a, b)fmt.Fprintf(w, "addValue: %v subValue: %v\n", addValue, subValue)}
}func main() {http.HandleFunc("/sample_func_1", sampleFunc1)http.ListenAndServe(":80", nil)
}

启动。

$ go build     
$ ./test

调试运行进程

检查进程 ID。

$ ps -ef | grep "test"
root     254882  56889  0 15:24 pts/2    00:00:00 ./test
root     257090  18100  0 15:25 pts/0    00:00:00 grep --color=auto test

调试

# dlv attach 254882
Type 'help' for list of commands.
(dlv)

设置断点并等待进程被调用。

(dlv) b main.sampleFunc1
Breakpoint 1 set at 0x1010e8470 for main.sampleFunc1() ./main.go:30(dlv) c

尝试在另一个控制台中向端点发出请求。

$ curl http://localhost/sample_func_1

处理在设置的断点处停止，如下所示。

(dlv) c
> main.sampleFunc1() ./main.go:30 (hits goroutine(21):1 total:1) (PC: 0x1010e8470)
Warning: debugging optimized function25:         addValue = add(a, b)26:         subValue = sub(a, b)27:         return addValue, subValue28: }29: 
=>  30: func sampleFunc1(w http.ResponseWriter, r *http.Request) {31:         for i := 0; i < 10; i++ {32:                 a := i * 233:                 b := i34:                 addValue, subValue := calculate(a, b)35:                 fmt.Fprintf(w, "addValue: %v subValue: %v\n", addValue, subValue)

命令说明

以下是一些最常用的命令。

断点相关

命令	别名	解释
break	b	设置断点
breakpoints	bp	显示活动断点
clear		删除断点
clearall		删除所有断点
condition	cond	设置断点条件

继续

命令	别名	解释
continue	c	继续到“下一个断点”或“程序结束”或“指定点”。（例如 c main.add:1 ）
next	n	向前迈出一行（跨过）。
step	s	前进一行。
stepout	so	退出当前功能。
restart		恢复该过程。
exit	q	退出调试器。

其他的

命令	别名	解释
funcs		检查功能列表。（例如 funcs main…* ）
list	l	显示代码。（例如 l 10 l main.main:3 ）
locals		检查局部变量。
vars		检查包变量。
print	p	评估一个表达式。
set		覆盖变量。
stack	bt	显示堆栈跟踪。

您还可以通过在调试过程中执行来查看如何使用其他命令 help

(dlv) help
The following commands are available:Running the program:call ------------------------ Resumes process, injecting a function call (EXPERIMENTAL!!!)continue (alias: c) --------- Run until breakpoint or program termination.next (alias: n) ------------- Step over to next source line.rebuild --------------------- Rebuild the target executable and restarts it. It does not work if the executable was not built by delve.restart (alias: r) ---------- Restart process.step (alias: s) ------------- Single step through program.step-instruction (alias: si)  Single step a single cpu instruction.stepout (alias: so) --------- Step out of the current function.Manipulating breakpoints:break (alias: b) ------- Sets a breakpoint.breakpoints (alias: bp)  Print out info for active breakpoints.clear ------------------ Deletes breakpoint.clearall --------------- Deletes multiple breakpoints.condition (alias: cond)  Set breakpoint condition.on --------------------- Executes a command when a breakpoint is hit.toggle ----------------- Toggles on or off a breakpoint.trace (alias: t) ------- Set tracepoint.watch ------------------ Set watchpoint.Viewing program variables and memory:args ----------------- Print function arguments.display -------------- Print value of an expression every time the program stops.examinemem (alias: x)  Examine raw memory at the given address.locals --------------- Print local variables.print (alias: p) ----- Evaluate an expression.regs ----------------- Print contents of CPU registers.set ------------------ Changes the value of a variable.vars ----------------- Print package variables.whatis --------------- Prints type of an expression.Listing and switching between threads and goroutines:goroutine (alias: gr) -- Shows or changes current goroutinegoroutines (alias: grs)  List program goroutines.thread (alias: tr) ----- Switch to the specified thread.threads ---------------- Print out info for every traced thread.Viewing the call stack and selecting frames:deferred --------- Executes command in the context of a deferred call.down ------------- Move the current frame down.frame ------------ Set the current frame, or execute command on a different frame.stack (alias: bt)  Print stack trace.up --------------- Move the current frame up.Other commands:config --------------------- Changes configuration parameters.disassemble (alias: disass)  Disassembler.dump ----------------------- Creates a core dump from the current process stateedit (alias: ed) ----------- Open where you are in $DELVE_EDITOR or $EDITORexit (alias: quit | q) ----- Exit the debugger.funcs ---------------------- Print list of functions.help (alias: h) ------------ Prints the help message.libraries ------------------ List loaded dynamic librarieslist (alias: ls | l) ------- Show source code.source --------------------- Executes a file containing a list of delve commandssources -------------------- Print list of source files.transcript ----------------- Appends command output to a file.types ---------------------- Print list of typesType help followed by a command for full documentation.

参考

go-delve/delve：Delve 是 Go 编程语言的调试器