Golang 深入学习 5 - 使用 dlv 调试程序

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$ dlv
Delve is a source level debugger for Go programs.

Delve enables you to interact with your program by controlling the execution of the process,
evaluating variables, and providing information of thread / goroutine state, CPU register state and more.

The goal of this tool is to provide a simple yet powerful interface for debugging Go programs.

Pass flags to the program you are debugging using `--`, for example:

`dlv exec ./hello -- server --config conf/config.toml`

Usage:
  dlv [command]

Available Commands:
  attach      Attach to running process and begin debugging.
  connect     Connect to a headless debug server.
  core        Examine a core dump.
  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.

Flags:
      --accept-multiclient   Allows a headless server to accept multiple client connections.
      --api-version int      Selects API version when headless. (default 1)
      --backend string       Backend selection (see 'dlv help backend'). (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 "127.0.0.1:0")
      --log                  Enable debugging server logging.
      --log-dest string      Writes logs to the specified file or file descriptor (see 'dlv help log').
      --log-output string    Comma separated list of components that should produce debug output (see 'dlv help log')
      --only-same-user       Only connections from the same user that started this instance of Delve are allowed to connect. (default true)
      --wd string            Working directory for running the program. (default ".")

Additional help topics:
  dlv backend Help about the --backend flag.
  dlv log     Help about logging flags.

Use "dlv [command] --help" for more information about a command.

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$ dlv debug main.go
Type 'help' for list of commands.
(dlv) help
The following commands are available:
    args ------------------------ Print function arguments.
    break (alias: b) ------------ Sets a breakpoint.
    breakpoints (alias: bp) ----- Print out info for active breakpoints.
    call ------------------------ Resumes process, injecting a function call (EXPERIMENTAL!!!)
    clear ----------------------- Deletes breakpoint.
    clearall -------------------- Deletes multiple breakpoints.
    condition (alias: cond) ----- Set breakpoint condition.
    config ---------------------- Changes configuration parameters.
    continue (alias: c) --------- Run until breakpoint or program termination.
    deferred -------------------- Executes command in the context of a deferred call.
    disassemble (alias: disass) - Disassembler.
    down ------------------------ Move the current frame down.
    edit (alias: ed) ------------ Open where you are in $DELVE_EDITOR or $EDITOR
    exit (alias: quit | q) ------ Exit the debugger.
    frame ----------------------- Set the current frame, or execute command on a different frame.
    funcs ----------------------- Print list of functions.
    goroutine (alias: gr) ------- Shows or changes current goroutine
    goroutines (alias: grs) ----- List program goroutines.
    help (alias: h) ------------- Prints the help message.
    libraries ------------------- List loaded dynamic libraries
    list (alias: ls | l) -------- Show source code.
    locals ---------------------- Print local variables.
    next (alias: n) ------------- Step over to next source line.
    on -------------------------- Executes a command when a breakpoint is hit.
    print (alias: p) ------------ Evaluate an expression.
    regs ------------------------ Print contents of CPU registers.
    restart (alias: r) ---------- Restart process.
    set ------------------------- Changes the value of a variable.
    source ---------------------- Executes a file containing a list of delve commands
    sources --------------------- Print list of source files.
    stack (alias: bt) ----------- Print stack trace.
    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.
    thread (alias: tr) ---------- Switch to the specified thread.
    threads --------------------- Print out info for every traced thread.
    trace (alias: t) ------------ Set tracepoint.
    types ----------------------- Print list of types
    up -------------------------- Move the current frame up.
    vars ------------------------ Print package variables.
    whatis ---------------------- Prints type of an expression.
Type help followed by a command for full documentation.

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package main

import (
	"fmt"
	"time"
)

func main() {
	a := 10
	go printA(a)

	time.Sleep(1e9)
}

func printA(a int) {
	fmt.Println(a)
}

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> b main.go:12
Breakpoint 1 set at 0x4bd5be for main.main() F:/Gotest/main.go:12
(dlv) c
> main.main() F:/Gotest/main.go:12 (hits goroutine(1):1 total:1) (PC: 0x4bd5be)
     7: 
     8: func main() {
     9:         a := 10
    10:         go printA(a)
    11: 
=>  12:         time.Sleep(1e9)
    13: }
    14: 
    15: func printA(a int) {
    16:         fmt.Println(a)
    17: }