Basic setup for VSCode debugging of a Dockerized Go application with Delve

docker-compose.yaml

version: '2'
services:
  tutorial:
    build: .
    security_opt:
      - seccomp:unconfined
    entrypoint: dlv debug tutorial -l :40000 --headless=true --api-version=2 --log=true
    ports:
      - "8080:8080"
      - "40000:40000"
    expose:
      - "8080"
      - "40000"

Dockerfile

FROM golang:1.11.10-alpine3.8
ENV CGO_ENABLED 0
ENV GOPATH /opt/go:$GOPATH
ENV PATH /opt/go/bin:$PATH
ADD . /opt/go/src/tutorial
WORKDIR /opt/go/src/tutorial
 
RUN apk add --no-cache git
RUN go get github.com/derekparker/delve/cmd/dlv
RUN go build -o tutorial tutorial.go
CMD ["./tutorial"]

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": "Remote Docker",
            "type": "go",
            "request": "launch",
            "mode": "remote",
            "remotePath": "/opt/go/src/tutorial",
            "port": 40000,
            "host": "172.19.0.2",
            "program": "${workspaceRoot}",
            "env": {},
            "args": []
        }
    ]
}

tutorial.go

package main

import (
	"fmt"
	"log"
	"net/http"
)

func main() {
	log.Println("Starting server")
	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
		log.Printf("Handling request\n")
		nr := 1
		msg := `Hello World`
		w.Write([]byte(fmt.Sprintf("Message: \"%s\" Number: %d", msg, nr)))
	})
	log.Fatal(http.ListenAndServe(":8080", nil))
}

This assumes that the project lives in a directory also named tutorial.