I could not find an in-depth guide on setting up debugging with VS Code.
Decided to go into detail to go through each step understanding the fundamentals of the process like:
- Meanings of the options in various commands
- How the the tools work
VS Code Extension
Search for Go
in VS Code Extensions and install it.
Debugger
You will need to install Delve to get debugging (breakpoints, step through, etc) in VS Code.
go install github.com/go-delve/delve/cmd/dlv@latest
If you used asdf
to install Go, delve
will be located in:
~/.asdf/shims/dlv
You might want to run asdf reshim
after installing a go package.
Live Reloading
Since GoLang is a compiled language, code will be compiled into a single executable. During development, making changes will require us to constantly recompile, which can be a manual process, especially in VS Code.
We will use https://github.com/air-verse/air to do live reloading for us.
It is a command line tool that only needs to be run once within your project folder to watch for changes.
Installation
Install the package. Assuming you have go v1.22 or higher.
go install github.com/air-verse/air@latest
If you used asdf
to install Go, air
will be located in:
~/.asdf/shims/air
Initialise an air.toml
config file in your project root
cd ~/myproject
air init
Edit air.toml
's go build
command like so:
- cmd = "go build -o ./tmp/main ."
+ cmd = 'CGO_ENABLED=0 go build -gcflags=all="-N -l"-o ./tmp/main .'"'
-
all
: flags should be applied to all packages in build packages -
-N
: disabled optimisations to ensure generated code closer to source code for easier debugging -
-l
: disables inlining optimisation where small functions are expanded in place to reduce overhead of function calls, making it easier for debugging - Reasoning from Delve Reference
INFO
air
will run with default configurations if:
air.toml
file is invalid- You ran the command
air
withoutair -c air.toml
It will not use your
air.toml
file.
Edit air.toml
full_bin
to run the built binary with [[Delve]].
- full_bin = ""
+ full_bin = "dlv exec ./tmp/main --listen=127.0.0.1:2345 --headless=true --api-version=2 --accept-multiclient --continue --log --"
This will run Delve on port 2345.
Run air
in your project folder. You should see the following output.
> cd ~/my-project
> air
__ _ ___
/ /\ | | | |_)
/_/--\ |_| |_| \_ v1.52.3, built with Go go1.22.5
mkdir ~/my-project/tmp
watching .
!exclude tmp
building...
running...
API server listening at: 127.0.0.1:2345
2024-07-28T18:47:07+07:00 info layer=debugger launching process with args: [./tmp/main]
2024-07-28T18:47:09+07:00 debug layer=debugger entryPoint 0x1006e8000 machoOff 0x100000000
2024-07-28T18:47:09+07:00 warning layer=debugger debug_frame workaround not applied: function internal/abi.(*RegArgs).IntRegArgAddr (at 0x1006e9070) covered by 0x1006e9070-0x1006e9110
2024-07-28T18:47:09+07:00 debug layer=debugger Adding target 11503 "/Users/alaay/projects/scheduleasy/tmp/main"
2024-07-28T18:47:09+07:00 debug layer=debugger continuing
2024-07-28T18:47:09+07:00 debug layer=debugger ContinueOnce
2024/07/28 18:47:09 Starting server on :5602
Attaching VS Code to Delve
In your .vscode/launch.config
file, add the following:
{
// 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": "Attach to Air",
"type": "go",
"request": "attach",
"mode": "remote",
"port": 2345,
"host": "127.0.0.1"
}
]
}
In VS Code Run and Debug (CMD + SHIFT + D), start debugging with Attach to Air
[!info] VS Code unable to connect
If VS Code is unable to connect, it is most likely that Delve is not running on port 2345. Try usinglsof -i :2345
to check ifdlv
is running using that port. If it is running, you should see:$ lsof -i :2345 COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME dlv 15464 username 3u IPv4 0x201bff14586139e3 0t0 TCP localhost:dbm (LISTEN)
Gotchas
Go is a compiled language. That means that code is compiled into a binary and then executed. Whenever we make changes to the code in vscode:
-
air
will watch for the changes - rebuild the binary
- start Delve at 2345
This means that the vscode will be disconnected and you will need to reattach vscode to delve.
Reach out
If anyone has a solution to the gotchas above, please leave a comment! I would really love to find a solution to this.
- I come from a Rails background, so I'm super used to being able to just leave the debugger running while I make changes to the code.
References
These great guides helped me out when I first started setting up:
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