Go调试工具Delve
安装
首先你必须有等于或高于1.8版本的Go,我的版本是：
userdeMBP:go-learning user$ go version
go version go1.11.4 darwin/amd64
我是用的是Mac,所以使用的是OSX安装方法：
然后使用go get 进行安装：
go get -u github.com/go-delve/delve/cmd/dlv
使用这种方法，你将无法使用delve的本机后端，但无论如何您都不需要它:macOS上的本机后端已经知道该操作系统最近出现的问题，并且目前没有进行维护。详情可见https://github.com/go-delve/delve/issues/1112
安装完后查看版本：
userdeMBP:go-learning user$ dlv version
Delve Debugger
Version: 1.2.0
Build: $Id: 068e...57e34f0f08ce01466 $
使用
首先先使用dlv或dlv --help来查看delve支持的命令：
userdeMBP:go-learning user$ dlv
Delve是Go程序的源代码级调试器.
Delve通过控制进程的执行、评估变量以及提供线程/ goroutine状态、CPU寄存器状态等信息，使你能够与程序进行交互。
这个工具的目标是为调试Go程序提供一个简单而强大的接口.
使用“--”将标志传递给正在调试的程序，例如:
`dlv exec ./hello -- server --config conf/config.toml`
Usage:
dlv [command]
Available Commands:
attach 连接到正在运行的流程并开始调试.
connect 连接到无头调试服务器.
core 检查核心转储.
debug 编译并开始调试当前目录下的主包或指定的包.
exec 执行预编译的二进制文件，并开始调试会话.
help 帮助信息
run 弃用的命令。使用“debug”替代它.
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 打印版本.
Flags:
--accept-multiclient 允许无头服务器接受多个客户机连接。注意，服务器API不是可重入的，客户端必须协调.
--api-version int 无头时选择API版本. (default 1)
--backend string 后端选择:
default 在macOS上使用lldb，其他地方都是本地的.
native 本地后端.
lldb 使用lldb-server或debugserver.
rr 使用mozilla rr (https://github.com/mozilla/rr).
(default "default") 默认使用的是default
--build-flags string 生成标志，以传递给编译器.
--headless 仅在headless模式下运行调试服务器.
--init string 初始化文件，由终端客户端执行.
-l, --listen string 调试服务器监听地址. (default "localhost:0")
--log 启用调试服务器日志记录.
--log-output string 应该产生调试输出的组件的逗号分隔列表，可能的值为:
debugger 记录调试器命令
gdbwire 日志连接到gdbserial后端
lldbout 将输出从debugserver/lldb复制到标准输出
debuglineerr 读取.debug_line时日志可恢复错误
rpc 记录所有RPC消息
fncall 日志函数调用协议
minidump 日志minidump加载
使用--log启用日志时，默认为“debugger”.
--wd string 用于运行程序的工作目录. (default ".")
使用"dlv [command] --help"获取有关命令的详细信息.
支持的命令太多了，在这里我们主要介绍它的调试命令——debug
dlv debug
首先使用dlv debug --help 查看其的帮助信息：
userdeMBP:go-learning user$ dlv debug --help
编译禁用优化的程序，启动并附加到该程序。
默认情况下，没有参数，Delve将编译当前目录中的“main”包，并开始调试它。或者，您可以指定一个包名，Delve将编译该包，并开始一个新的调试会话。
Usage:
dlv debug [package] [flags]
Flags:
--output string 二进制文件的输出路径. (default "debug")
Global Flags:和上面的一样，这里省略
举例说明：
首先要进行调试的代码为：
package main
import (
"fmt"
"time"
)
func counting(c chan<- int){
for i := 0; i < 10; i++{
time.Sleep(2 * time.Second)
c <- i
}
close(c)
}
func main() {
msg := "Starting main"
fmt.Println(msg)
bus := make(chan int)
msg = "starting a gofunc"
go counting(bus)
for count := range bus{
fmt.Println("count : ", count)
}
}
然后开启调试：
$ dlv debug test.go
Type 'help' for list of commands.
(dlv)
然后我们可以输入help来查看能够使用的debug命令有哪些：
The following commands are available:
args ------------------------ 打印函数参数.
break (alias: b) ------------ 设置断点.
breakpoints (alias: bp) ----- 输出活动断点的信息.
call ------------------------ 恢复进程，注入一个函数调用(还在实验阶段!!)
clear ----------------------- 删除断点.
clearall -------------------- 删除多个断点.
condition (alias: cond) ----- 设置断点条件.
config ---------------------- 修改配置参数.
continue (alias: c) --------- 运行到断点或程序终止.
deferred -------------------- 在延迟调用的上下文中执行命令.
disassemble (alias: disass) - 反汇编程序.
down ------------------------ 将当前帧向下移动.
edit (alias: ed) ------------ 在$DELVE_EDITOR或$EDITOR中打开你所在的位置
exit (alias: quit | q) ------ 退出调试器.
frame ----------------------- 设置当前帧，或在不同的帧上执行命令.
funcs ----------------------- 打印函数列表.
goroutine ------------------- 显示或更改当前goroutine
goroutines ------------------ 列举程序goroutines.
help (alias: h) ------------- 打印帮助信息.
list (alias: ls | l) -------- 显示源代码.
locals ---------------------- 打印局部变量.
next (alias: n) ------------- 转到下一个源行.
on -------------------------- 在命中断点时执行命令.
print (alias: p) ------------ 计算一个表达式.
regs ------------------------ 打印CPU寄存器的内容.
restart (alias: r) ---------- 重启进程.
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 (alias: bt) ----------- 打印堆栈跟踪信息.
step (alias: s) ------------- 单步执行程序.
step-instruction (alias: si) 单步执行一条cpu指令.
stepout --------------------- 跳出当前函数.
thread (alias: tr) ---------- 切换到指定的线程.
threads --------------------- 打印每个跟踪线程的信息.
trace (alias: t) ------------ 设置跟踪点.
types ----------------------- 打印类型列表
up -------------------------- 向上移动当前帧.
vars ------------------------ 打印包变量.
whatis ---------------------- 打印表达式的类型.
在命令前键入help来获得命令的完整文档，如help goroutine
首先开始进行调试，这里先什么都不做直接输入continue，即c,运行到断点或程序终止
(dlv) c
Starting main
count : 0
count : 1
count : 2
count : 3
count : 4
count : 5
count : 6
count : 7
count : 8
count : 9
Process 1324 has exited with status 0
可见这个代码跑了起来
restart（缩写r）重启进程
(dlv) b main.main
Process 1324 has exited with status 0
上面进行添加断点的操作，但是并没有返回想要的信息
这是因为我们之前已经将程序运行结束了，这时候不能直接添加断点信息
所以要先调用restart来将进程重启
(dlv) restart
Process restarted with PID 3018
(dlv) b main.main
Breakpoint 1 set at 0x10b123b for main.main() ./test.go:16
break（即b）添加断点
现在我们可以为其添加断点了
(dlv) b main.main //在main函数处添加断点
Breakpoint 1 set at 0x10b123b for main.main() ./test.go:16
(dlv) b main.counting //在counting函数处添加断点
Breakpoint 2 set at 0x10b118f for main.counting() ./test.go:8
我们也可以使用"文件：行号"的格式来添加断点，如：
b test.go:8 //等价于在函数counting处添加断点
然后继续程序运行，可见会先停在main函数处：
(dlv) c
> main.main() ./test.go:16 (hits goroutine(1):1 total:1) (PC: 0x10b123b)
11: c <- i
12: }
13: close(c)
14: }
15:
=> 16: func main() {
17: msg := "Starting main"
18: fmt.Println(msg)
19: bus := make(chan int)
20: msg = "starting a gofunc"
21: go counting(bus)
breakpoints（缩写bp）输出活动断点信息
(dlv) bp
Breakpoint runtime-fatal-throw at 0x102b3e0 for runtime.fatalthrow() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:654 (0)
Breakpoint unrecovered-panic at 0x102b450 for runtime.fatalpanic() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:681 (0)
print runtime.curg._panic.arg
Breakpoint 1 at 0x10b123b for main.main() ./test.go:16 (1)
Breakpoint 2 at 0x10b118f for main.counting() ./test.go:8 (0)
可见上面的两个设置的断点
list 显示从停止行起前后5行的源代码
(dlv) list
> main.main() ./test.go:16 (hits goroutine(1):1 total:1) (PC: 0x10b123b)
11: c <- i
12: }
13: close(c)
14: }
15:
=> 16: func main() {
17: msg := "Starting main"
18: fmt.Println(msg)
19: bus := make(chan int)
20: msg = "starting a gofunc"
21: go counting(bus)
next (缩写n)转到下一个源行
可见现在的指针从16行转到了17行
如果想继续向下，可以直接回车，Delve会默认重复上一条命令
next不会进入当前函数
(dlv) n
> main.main() ./test.go:17 (PC: 0x10b1252)
12: }
13: close(c)
14: }
15:
16: func main() {
=> 17: msg := "Starting main"
18: fmt.Println(msg)
19: bus := make(chan int)
20: msg = "starting a gofunc"
21: go counting(bus)
22: for count := range bus{
print（缩写p）计算一个表达式
(dlv)
> main.main() ./test_del.go:18 (PC: 0x4adf57)
13: close(c)
14: }
15:
16: func main() {
17: msg := "Starting main"
=> 18: fmt.Println(msg)
19: bus := make(chan int)
20: msg = "starting a gofunc"
21: go counting(bus)
22: for count := range bus{
23: fmt.Println("count : ", count)
(dlv) print msg
"Starting main"
locals 打印局部变量
(dlv) locals
msg = "Starting main"
step（缩写s）单步执行程序
(dlv) p count
Command failed: could not find symbol value for count
(dlv) s
> main.main() ./test.go:18 (PC: 0x10b1267)
13: close(c)
14: }
15:
16: func main() {
17: msg := "Starting main"
=> 18: fmt.Println(msg)
19: bus := make(chan int)
20: msg = "starting a gofunc"
21: go counting(bus)
22: for count := range bus{
23: fmt.Println("count : ", count)
(dlv) p msg
"Starting main"
(dlv) locals
msg = "Starting main"
在执行s前，使用p打印了msg局部变量的值，locals打印了局部变量的值，因为还没有运行到给msg复制的代码，所以返回的结果不是期望的值
然后当我们运行s后，可见指针也从17变成了18，然后这时候再运行p和locals,可见返回了期望的值
print还可以用来判断一个表达式：
(dlv) p msg == "Starting main"
true
whatis打印表达式类型
(dlv) whatis msg
string
能够得到msg变量为string类型
然后我们接着运行到下一个断点，这时候开启了一个groutine
(dlv) c
Starting main
> main.counting() ./test.go:8 (hits goroutine(18):1 total:1) (PC: 0x10b118f)
3: import (
4: "fmt"
5: "time"
6: )
7:
=> 8: func counting(c chan<- int){
9: for i := 0; i < 10; i++{
10: time.Sleep(2 * time.Second)
11: c <- i
12: }
13: close(c)
goroutine 显示或更改当前goroutine
(dlv) help goroutine
goroutine
goroutine
goroutine
调用时不带参数，它将显示关于当前goroutine的信息。
使用单个参数调用时，它将切换到指定的goroutine。
使用更多参数调用时，它将在指定的goroutine上执行命令。
可见现在正在运行的goroutine
(dlv) goroutine
Thread 77795 at ./test.go:8
Goroutine 18:
Runtime: ./test.go:8 main.counting (0x10b118f)
User: ./test.go:8 main.counting (0x10b118f)
Go: ./test.go:21 main.main (0x10b138a)
Start: ./test.go:8 main.counting (0x10b1180)
指定查看的是goroutine 1 :
(dlv) goroutine 1
Switched from 18 to 1 (thread 77795)
(dlv) goroutine
Thread 77795 at ./test.go:8
Goroutine 1:
Runtime: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/proc.go:303 runtime.gopark (0x102d0f4)
User: ./test.go:22 main.main (0x10b13ae)
Go: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/asm_amd64.s:201 runtime.rt0_go (0x10557fb)
Start: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/proc.go:110 runtime.main (0x102cb60)
这时候如果运行locals,得到的是goroutine 1所在处的局部变量：
(dlv) locals
gp = (*runtime.g)(0xc000000300)
mp = (*runtime.m)(0x11904c0)
status = (unreadable read out of bounds)
要回去原来的goroutine就调用:
(dlv) goroutine 18
Switched from 1 to 18 (thread 77795)
goroutines 列举程序goroutines
(dlv) help goroutines
列举程序goroutines.
goroutines [-u (default: user location)|-r (runtime location)|-g (go statement location)|-s (start location)] [ -t (stack trace)]
Print out info for every goroutine. The flag controls what information is shown along with each goroutine:
-u 显示用户代码中最顶层堆栈帧的位置
-r 显示最顶层stackframe的位置(包括私有运行时函数中的帧)
-g 显示创建goroutine的go指令的位置
-s 显示起始函数的位置
-t 显示goroutine的堆栈跟踪
如果没有指定具体的标志，则默认使用-u.
(dlv) goroutines
Goroutine 1 - User: ./test.go:22 main.main (0x10b13ae)
Goroutine 2 - User: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/proc.go:303 runtime.gopark (0x102d0f4)
Goroutine 3 - User: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/proc.go:303 runtime.gopark (0x102d0f4)
Goroutine 17 - User: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/proc.go:303 runtime.gopark (0x102d0f4)
* Goroutine 18 - User: ./test.go:8 main.counting (0x10b118f) (thread 77795)
[5 goroutines]
(dlv) goroutines -s
Goroutine 1 - Start: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/proc.go:110 runtime.main (0x102cb60)
Goroutine 2 - Start: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/proc.go:243 runtime.forcegchelper (0x102ced0)
Goroutine 3 - Start: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/mgcsweep.go:46 runtime.bgsweep (0x1020170)
Goroutine 17 - Start: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/mfinal.go:161 runtime.runfinq (0x1017ae0)
* Goroutine 18 - Start: ./test.go:8 main.counting (0x10b1180) (thread 77795)
[5 goroutines]
args 打印函数参数
得到counting函数的参数值：
(dlv) args
c = chan<- int 0/0
因为之前只设置了两个断点，因此再次调用c则又将运行程序完毕：
(dlv) c
count : 0
count : 1
...
stepout 跳出当前函数
(dlv) restart
Process restarted with PID 1352
(dlv) b main.main //之前的断点一直存在，即使程序结束，因此此时的counting函数中也有断点
Command failed: Breakpoint exists at /Users/user/go-learning/test.go:16 at 10b123b
(dlv) c
> main.main() ./test.go:16 (hits goroutine(1):1 total:1) (PC: 0x10b123b)
11: c <- i
12: }
13: close(c)
14: }
15:
=> 16: func main() {
17: msg := "Starting main"
18: fmt.Println(msg)
19: bus := make(chan int)
20: msg = "starting a gofunc"
21: go counting(bus)
(dlv) stepout
Starting main
> main.counting() ./test.go:8 (hits goroutine(5):1 total:1) (PC: 0x10b118f)
breakpoint hit during stepout, continuing...
count : 0
count : 1
count : 2
...
因为stepout跳过的是main()函数，可见直接也跳过了counting的断点，然后执行程序到结束
clear删除断点\clearall删除多个断点
因为如果不手动清除断点，即使程序结束并restart程序，断点信息也仍然在
(dlv) breakpoints //查看当前的断点信息
Breakpoint runtime-fatal-throw at 0x102b3e0 for runtime.fatalthrow() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:654 (0)
Breakpoint unrecovered-panic at 0x102b450 for runtime.fatalpanic() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:681 (0)
print runtime.curg._panic.arg
Breakpoint 1 at 0x10b123b for main.main() ./test.go:16 (1)
Breakpoint 2 at 0x10b118f for main.counting() ./test.go:8 (0)
(dlv) clear 1 //先删除第一个断点，即main函数上的断点
Breakpoint 1 cleared at 0x10b123b for main.main() ./test.go:16
(dlv) breakpoints //查看可见果然成功删除
Breakpoint runtime-fatal-throw at 0x102b3e0 for runtime.fatalthrow() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:654 (0)
Breakpoint unrecovered-panic at 0x102b450 for runtime.fatalpanic() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:681 (0)
print runtime.curg._panic.arg
Breakpoint 2 at 0x10b118f for main.counting() ./test.go:8 (0)
(dlv) clearall //然后将所有断点都删除
Breakpoint 2 cleared at 0x10b118f for main.counting() ./test.go:8
(dlv) breakpoints //查看可见断点信息为空
Breakpoint runtime-fatal-throw at 0x102b3e0 for runtime.fatalthrow() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:654 (0)
Breakpoint unrecovered-panic at 0x102b450 for runtime.fatalpanic() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:681 (0)
print runtime.curg._panic.arg
(dlv)
on 在命中断点时执行命令
(dlv) help on
Executes a command when a breakpoint is hit.
on .
Supported commands: print, stack and goroutine)
(dlv) b /Users/user/go-learning/test.go:21 //添加断点
Breakpoint 2 set at 0x10b1368 for main.main() ./test.go:21
(dlv) on 2 print msg == "starting a gofunc" //设置当到达该断点后运行的命令，即判断msg的值是否为"starting a gofunc"
(dlv) breakpoints //查看此时的断点信息
Breakpoint runtime-fatal-throw at 0x102b3e0 for runtime.fatalthrow() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:654 (0)
Breakpoint unrecovered-panic at 0x102b450 for runtime.fatalpanic() /usr/local/Cellar/go/1.11.4/libexec/src/runtime/panic.go:681 (0)
print runtime.curg._panic.arg
Breakpoint 2 at 0x10b1368 for main.main() ./test.go:21 (0)
print msg == "starting a gofunc"
(dlv) c
Starting main
> main.main() ./test.go:21 (hits goroutine(1):1 total:1) (PC: 0x10b1368)
msg == "starting a gofunc": true //可见打印出来了，并返回值为true
16: func main() {
17: msg := "Starting main"
18: fmt.Println(msg)
19: bus := make(chan int)
20: msg = "starting a gofunc"
=> 21: go counting(bus)
22: for count := range bus{
23: fmt.Println("count : ", count)
24: }
25: }
set 更改变量的值
(dlv) help set
Changes the value of a variable.
[goroutine ] [frame ] set =
Only numerical variables and pointers can be changed.
因此更改string类型变量将报错：
(dlv) set msg = "change msg"
Command failed: can not set variables of type string (not implemented)
up向上移动当前帧/dowm向下移动当前帧
(dlv) up
> main.main() ./test.go:21 (hits goroutine(1):1 total:1) (PC: 0x10b1368)
Frame 1: /usr/local/Cellar/go/1.11.4/libexec/src/runtime/proc.go:201 (PC: 102cd25)
196: // A program compiled with -buildmode=c-archive or c-shared
197: // has a main, but it is not executed.
198: return
199: }
200: fn = main_main // make an indirect call, as the linker doesn't know the address of the main package when laying down the runtime
=> 201: fn()
202: if raceenabled {
203: racefini()
204: }
205:
206: // Make racy client program work: if panicking on
(dlv) down
> main.main() ./test.go:21 (hits goroutine(1):1 total:1) (PC: 0x10b1368)
Frame 0: ./test.go:21 (PC: 10b1368)
16: func main() {
17: msg := "Starting main"
18: fmt.Println(msg)
19: bus := make(chan int)
20: msg = "starting a gofunc"
=> 21: go counting(bus)
22: for count := range bus{
23: fmt.Println("count : ", count)
24: }
25: }
exit (alias: quit | q)退出调试器
(dlv) exit
userdeMBP:go-learning user$
dlv attach
如果项目正在运行中，想要对正在运行的项目进行调试
- 首先使用"ps aux | grep 编译文件名"来查看运行程序的进程号pid
- 然后就能够使用"dlv attach pid"来连接该运行程序，然后就能使用之前debug中的命令来进行调试了