add Dockerfile to build the go app

Dockerfile

@@ -0,0 +1,42 @@
+# Stage 1: Build the Go application
+FROM golang:1.23 AS builder
+
+ENV CGO_ENABLED=0
+ENV GOOS=linux
+ENV GOARCH=amd64
+
+WORKDIR /app
+
+# Copy the Go modules and dependencies
+COPY ./golang/go.mod ./golang/go.sum ./
+RUN go mod download
+
+# Copy the source code
+COPY ./golang/cmd ./cmd
+COPY ./golang/assets ./assets
+COPY ./golang/internal ./internal
+
+# Build the application
+RUN  go build -o main cmd/frontend/*
+
+# Stage 2: Run the application
+FROM alpine:latest
+
+ENV DB_HOST="10.99.0.3"
+ENV DB_PORT="5432"
+ENV DB_NAME="crowsnest"
+ENV DB_USER="crow"
+ENV DB_PASS=""
+
+# Set the working directory
+WORKDIR /app
+
+# Copy the built binary from the builder stage
+COPY --from=builder /app/main .
+COPY ./golang/assets ./assets
+
+# Expose the desired port (e.g., 8080)
+EXPOSE 8080
+
+# Command to run the application
+CMD ["/app/main"]

golang/Makefile

@@ -1,6 +1,6 @@
 serv:
-	DB_DRIVER="postgres" DB_URL="user=crow password=4LlKpnQ2RZPzL13BSpkW4k dbname=crowsnest host=192.168.0.2 port=5432 sslmode=disable" go run cmd/frontend/*
+	DB_USER=crow DB_PASS=4LlKpnQ2RZPzL13BSpkW4k DB_NAME=crowsnest DB_HOST=10.99.0.3 go run cmd/frontend/*
 crawl:
-	DB_DRIVER="postgres" DB_URL="user=crow password=4LlKpnQ2RZPzL13BSpkW4k dbname=crowsnest host=192.168.0.2 port=5432 sslmode=disable" go run cmd/crawler/main.go
+	DB_USER=crow DB_PASS=4LlKpnQ2RZPzL13BSpkW4k DB_NAME=crowsnest DB_HOST=192.168.0.2 go run cmd/crawler/main.go
 summ:
-	DB_DRIVER="postgres" DB_URL="user=crow password=4LlKpnQ2RZPzL13BSpkW4k dbname=crowsnest host=192.168.0.2 port=5432 sslmode=disable" go run cmd/summarizer/main.go
+	DB_USER=crow DB_PASS=4LlKpnQ2RZPzL13BSpkW4k DB_NAME=crowsnest DB_HOST=192.168.0.2 go run cmd/summarizer/main.go

golang/cmd/frontend/main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"crowsnest/internal/model/database"
 	"database/sql"
+	"fmt"
 	"log"
 	"net/http"
 	"os"
@@ -16,14 +17,35 @@ type App struct {
 
 func main() {
 	// collect environement variables
-	databaseURL := os.Getenv("DB_URL")
+	dbPass := os.Getenv("DB_PASS")
+	if dbPass == "" {
+		log.Fatal("empty DB_PASS")
+	}
+	dbHost := os.Getenv("DB_HOST")
+	if dbHost == "" {
+		log.Fatal("empty DB_HOST")
+	}
+	dbPort := os.Getenv("DB_PORT")
+	if dbPort == "" {
+		dbPort = "5432"
+	}
+	dbUser := os.Getenv("DB_USER")
+	if dbUser == "" {
+		dbUser = "postgres"
+	}
+	dbName := os.Getenv("DB_NAME")
 
 	// connect to database
+	databaseURL := fmt.Sprintf("user=%s password=%s dbname=%s host=%s port=%s sslmode=disable",
+		dbUser, dbPass, dbName, dbHost, dbPort)
 	db, err := sql.Open("postgres", databaseURL)
 	if err != nil {
 		log.Fatal(err)
 	}
 	defer db.Close()
+	if err = db.Ping(); err != nil {
+		log.Fatal(err)
+	}
 
 	// define app
 	app := &App{