How to read input when debugging GO in Visual Studio Code?

Question

I want to debug a Go program in Visual Studio Code 1.24.0 which goes like this:

package main

import (
   "fmt"
)

func main() {
 fmt.Println("Hello World")
 var input int
 fmt.Scanf("%d", &input)
 fmt.Printf("Hello %v", input)
}

When start debugging, the program waits for input. I tried giving input via Debug Console, but it didn't work. Properties like externalConsole don't seem to work in launch.json for Go. Any inputs?

Winand · Accepted Answer · 2022-01-27 18:42:10Z

56

There's a simple solution now. You can append the following line to your launch configuration:

"console": "integratedTerminal"

See vscode-go issue #2015

edited Jan 27, 2022 at 18:42

answered Jan 27, 2022 at 17:50

Winand

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1 Comment

Pham Duc Toan Over a year ago

Voted for this answer.

Dan Ortega · Accepted Answer · 2021-03-30 02:57:02Z

7

I'm happy to share that a more usable solution (It automatically runs the task before launching) is found.

...

launch.json:

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Connect to server",
            "type": "go",
            "request": "attach",
            "preLaunchTask": "delve",
            "mode": "remote",
            "remotePath": "${workspaceFolder}",
            "port": 23456,
            "host": "127.0.0.1",
            "cwd": "${workspaceFolder}"
        }
    ]
}

And
tasks.json:

{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "2.0.0",
    "tasks": [
        {
            "label": "delve",
            "type": "shell",
            "command": "dlv debug --headless --listen=:23456 --api-version=2 \"${workspaceFolder}\"",
            "isBackground": true,
            "presentation": {
                "focus": true,
                "panel": "dedicated",
                "clear": false
            },
            "group": {
                "kind": "build",
                "isDefault": true
            },
            "problemMatcher": {
                "pattern": {
                    "regexp": ""
                },
                "background": {
                    "activeOnStart": true,
                    "beginsPattern": {
                        "regexp": ".*"
                    },
                    "endsPattern": {
                        "regexp": ".*server listening.*"
                    }
                }
            }
        }
    ]
}

It expects you are working with a go.mod since delve also looks for it to debug the directory.

edited Mar 30, 2021 at 2:57

answered Mar 18, 2021 at 4:35

Dan Ortega

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5 Comments

Poutrathor Over a year ago

It failed saying open *\__debugèbin: The process can't access this file because another process already uses it :(

Dan Ortega Over a year ago

that happened to me when another session was debugging, just make sure nothing else is debugging, or in the worst scenario you could go and kill all processes running "dlv".

trofchik Over a year ago

"command": "dlv debug --headless --listen=:23456 --api-version=2 " worked for me while the original solution gave cannot import absolute path error. I'm on Linux.

Dan Ortega Over a year ago

Interesting. I actually develop on Linux with it. But it is great it worked with your adjustment. Thanks for posting it.

A.G. Over a year ago

works like a charm. tested under Linux.

Cpt.Ohlund · Accepted Answer · 2020-04-03 07:49:01Z

4

In the same Issue HowieLiuX shared a sinmpler solution that works for me:

In tasks.json:

{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "2.0.0",
    "tasks": [
        {
            "label": "echo",
            "type": "shell",
            "command": "cd ${fileDirname} && dlv debug --headless --listen=:2345 --log --api-version=2",
            "problemMatcher": [],
            "group": {
                "kind": "build",
                "isDefault": true
            }
        }
    ]
}

I, however, had to change command to:

"command": "dlv debug --headless --listen=:2345 --log --api-version=2",

since I'm running through powershell.

Then in launch.json

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Connect to server",
            "type": "go",
            "request": "launch",
            "mode": "remote",
            "remotePath": "${fileDirname}",
            "port": 2345,
            "host": "127.0.0.1",
            "program": "${fileDirname}",
            "env": {},
            "args": []
        }
    ]
}

First run the task then debug.

answered Apr 3, 2020 at 7:49

Cpt.Ohlund

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4 Comments

VonC Over a year ago

Thank you. I missed that update on the issue I reported in my own answer. I have updated it accordingly.

Dan Ortega Over a year ago

This works, we just need to make sure we manually run the task before launching code ... run the task with Ctrl + Shift + B, (it might fail to launch it since that same shortcut sometimes works for setting debug breakpoints, if that is the case adjust your shortcuts or run it from vscode menus: Terminal > Run task > "echo" > Continue without scanning ...)

Poutrathor Over a year ago

It failed saying open *\__debugèbin: The process can't access this file because another process already uses it :(

trofchik Over a year ago

Change of command you did makes it work on my Linux machine.

Water · Accepted Answer · 2023-04-05 03:36:57Z

4

Setting console

"console": "integratedTerminal"

did not work when I have

"program": "${fileDirname}",

defined by vscode as default.

It changes directory to /.vscode directory.

Setting "console", and changing "program" to "${workspaceFolder}" worked for me.
launch.json looks like this:

"version": "0.2.0",
"configurations": [
  {
    "name": "Launch Package",
    "type": "go",
    "request": "launch",
    "mode": "auto",
    "program": "${workspaceFolder}",
    "console": "integratedTerminal"
  }
]

edited Apr 5, 2023 at 3:36

answered Apr 4, 2023 at 9:43

Water

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Comments

VonC · Accepted Answer · 2020-04-03 08:12:43Z

This is similar to vscode-go issue 219

The workaround (proposed by KingRikkie) is:

There is a workaround however. I wrote a script that does the following:

Compile your app without optimizations and inlining
Start app in a new window
Attach delve headlessly onto its process id.

I then created a new task in VScode that starts the script and specified said task under preLaunchTask in a remote debug configuration in launch.json.

In my case a powershell script resting inside {workspaceRoot} compiling a package called 'main' in 'main' dir:

$EXECUTABLE_NAME="main"
$EXECUTABLE_PATH=".\main"
$GoPath=((go env | Select-String -Pattern "GOPATH=" | Out-String) -split "=")[1].TrimEnd()
$GoPath+="\bin"
Set-Location $EXECUTABLE_PATH
Start-Process go -ArgumentList 'build -gcflags "-N -l"' -Wait -NoNewWindow # compile without optimizations and inlining
Start-Process ".\$EXECUTABLE_NAME.exe"
$timeOut = 20
$started = $false
# wait for process to start
Do {
    Start-Sleep -Milliseconds 250
    $timeOut--
    $Proc = Get-Process main -ErrorAction SilentlyContinue
    If ($Proc) { 
        $started = $true 
    }
}
Until ($started -or $timeOut -eq 0)
If (!($started)) {
    Write-Error 'Process did not start' 
    Exit
}
$ProcId=($Proc | Select-Object -expand Id)
Start-Process -FilePath "$GoPath\dlv.exe" -ArgumentList "attach $ProcId --headless --listen=:2345 --log" -WindowStyle Hidden

The task:

"label": "debug-attach",
"type": "shell",
"command": "powershell -ExecutionPolicy UnRestricted -File ${workspaceRoot}\\debug-attach.ps1",
"presentation": {
    "reveal": "silent",
    "panel": "shared",
    "echo": false
}

The launch configuration:

"name": "Attach",
"type": "go",
"request": "launch",
"mode": "remote",
"remotePath": "${workspaceRoot}\\main",
"port": 2345,
"host": "127.0.0.1",
"program": "${workspaceRoot}\\main",
"preLaunchTask": "debug-attach",
"env": {},
"args": [],
"showLog": true

When I hit F5 now my app will pop up and debugging will automatically start, delve is hidden.

Since July 2018, HowieLiuX reported the following workaround in Dec. 2018

using remote debug + vscode task:

task.json

{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "2.0.0",
    "tasks": [
        {
            "label": "echo",
            "type": "shell",
            "command": "cd ${fileDirname} && dlv debug --headless --listen=:2345 --log --api-version=2",
            "problemMatcher": [],
            "group": {
                "kind": "build",
                "isDefault": true
            }
        }
    ]
}

And:

launch.json:

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Connect to server",
            "type": "go",
            "request": "launch",
            "mode": "remote",
            "remotePath": "${fileDirname}",
            "port": 2345,
            "host": "127.0.0.1",
            "program": "${fileDirname}",
            "env": {},
            "args": []
        }
    ]
}

Run the task using shortcut key (shift + cmd + B in Mac OS): VSCode will start a new shell and run the delve server.
Pressing F5 to debug the .go file.

Jason Goemaat · Accepted Answer · 2024-12-16 00:05:46Z

1

Ading "console": "externalTerminal" to launch.json worked for me. Maybe it's because this is an older question or is just works with my configuration:

I'm on windows 10
This opened a new 'windows terminal' window, so I have that installed
The tab title looks like it's running C:\WINDOWS\System32\cmd.exe
vscode was started from a PowerShell prompt, if I start from git bash it messes with gopls

Full launch.json:

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Launch Package",
            "type": "go",
            "request": "launch",
            "mode": "auto",
            "program": "${fileDirname}",
            "console": "externalTerminal"
        }
    ]
}

answered Dec 16, 2024 at 0:05

Jason Goemaat

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