How to debug your application with Delve

Encore makes it easy to debug your application using Delve.

First, make sure you have dlv installed by running (Go 1.16 and later):

$ go install github.com/go-delve/delve/cmd/dlv@latest

You have two debugger options, you can either debug by attaching to a running process or by starting the process in debug mode.

Debug by starting the process in debug mode

Run your Encore application with encore run --debug=break. This will launch your encore application with a headless Delve server, which will pause your application until a debugger is attached.

$ encore run --debug=break
API Base URL:      http://localhost:4000
Dev Dashboard URL: http://localhost:9400/hello-world-cgu2
API server listening at: 127.0.0.1:2345

Now it's time to attach the debugger. The instructions differ depending on how you would like to debug (in your terminal or in your editor). If instructions for your editor aren’t listed below, consult your editor for information on how to attach to a Delve server.

Terminal debugging

To debug in your terminal, run dlv attach :2345. You should see:

$ dlv connect :2345
Type 'help' for list of commands.
(dlv)

How to use Delve’s terminal interface for debugging is out of scope for this guide, but there are great resources available. For a good introduction, see .

Visual Studio Code

To debug with VS Code you must first add a debug configuration. Press Run -> Add Configuration, choose Go -> Connect to server. Input 127.0.0.1 as host and 2345 as port. The resulting configuration should look something like this:

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Connect to server",
            "type": "go",
            "request": "attach",
            "mode": "remote",
            "remotePath": "${workspaceFolder}",
            "port": 2345,
            "host": "127.0.0.1"
        }
    ]
}

Next, open the Run and Debug menu in the toolbar on the left, select Connect to server (the configuration you just created), and then press the green arrow.

That’s it! You should be able to set breakpoints and have the Encore application pause when they’re hit like you would expect.

Goland

To debug with Goland, you must create a new Go Remote configuration. Press Run | Edit Configurations, click the + button, and choose Go Remote. Give it a name and hit OK.

Now select the configuration you just created and press the green bug.

That's it. You should be able to set breakpoints and have the Encore application pause when they’re hit like you would expect.

Debug by attaching to a running process

Run your Encore application with encore run --debug. This will cause Encore to print the Process ID to the terminal, which you will use to attach your debugger:

$ encore run --debug
API Base URL:      http://localhost:4000
Dev Dashboard URL: http://localhost:9400/hello-world-cgu2
Process ID:        51894
1:48PM INF registered endpoint path=/hello/:name service=hello endpoint=Hello

(Your process id will differ).

When your Encore application is running, it’s time to attach the debugger. The instructions differ depending on how you would like to debug (in your terminal or in your editor). If instructions for your editor aren’t listed below, consult your editor for information on how to attach a debugger to a running process.

Terminal debugging

To debug in your terminal, run dlv attach $PID (replace $PID with your Process ID from the previous step). You should see:

$ dlv attach 51894
Type 'help' for list of commands.
(dlv)

How to use Delve’s terminal interface for debugging is out of scope for this guide, but there are great resources available. For a good introduction, see .

Visual Studio Code

To debug with VS Code you must first add a debug configuration. Press Run -> Add Configuration, choose Go -> Attach to local process. In the generated configuration, you should see "processId": 0 as a field. Replace 0 with the process id from above.

Next, open the Run and Debug menu in the toolbar on the left, select Attach to Process (the configuration you just created), and then press the green arrow.

That’s it! You should be able to set breakpoints and have the Encore application pause when they’re hit like you would expect.

Goland

To debug with Goland, you must first install the gops package. Open a terminal and run the following command

go get -t github.com/google/gops/

Then click Run | Attach to Process. If a notification window appears, click the Invoke 'go get gops' link. Once it has completed, click Run | Attach to Process again. In the dialog that appears, select the process with the process ID from above.

That's it. You should be able to set breakpoints and have the Encore application pause when they’re hit like you would expect.