swrm/server/main.go

package main

import (
	"fmt"
	"io"
	"net/http"
	"os"
	"time"

	"github.com/jmoiron/sqlx"
	_ "github.com/mattn/go-sqlite3"
)

// This is a function that takes a long time to run
// Useful for demonstrating concurrency (goroutines)
func delayPrint() {
	time.Sleep(5 * time.Second)
	fmt.Printf("delay print\n")
}

// Reads files from the migrations directory and runs them
func runMigrations(db *sqlx.DB) error {
	// Read the migrations directory
	files, err := os.ReadDir("migrations")
	if err != nil {
		return err
	}

	// Run each migration file
	for _, file := range files {
		// Skip directories
		if file.IsDir() {
			continue
		}

		// Read the migration file
		content, err := os.ReadFile("migrations/" + file.Name())
		if err != nil {
			return err
		}

		// Execute the migration SQL
		_, err = db.Exec(string(content))
		if err != nil {
			fmt.Printf("Error executing migration %s: %s\n", file.Name(), err)
			return err
		}

		fmt.Printf("Migration %s executed\n", file.Name())
	}

	fmt.Println("Migrations complete")
	return nil
}

// This is what a handler looks like
func handler(w http.ResponseWriter, r *http.Request) {
	fmt.Println("Request received")
	go delayPrint() // This will run in the background
	io.WriteString(w, "This is my website!\n")
}

func dbConnect() *sqlx.DB {
	// Check for the environment variable
	dbpath := os.Getenv("SQLITE_DB_PATH")

	// Default to something reasonable
	if dbpath == "" {
		dbpath = "./db.sqlite3"
	}

	// Open the database
	// db, err := sqlx.Connect("sqlite3", ":memory:")
	db, err := sqlx.Connect("sqlite3", dbpath)
	if err != nil {
		panic(err)
	}

	err = db.Ping()
	if err != nil {
		panic(err)
	}

	// Run the migrations
	err = runMigrations(db)
	if err != nil {
		panic(err)
	}

	return db
}

func main() {
	println("Starting server...")

	// Connect to the database
	db := dbConnect()
	defer db.Close()

	// Tx is a transaction
	tx := db.MustBegin()
	tx.MustExec("INSERT INTO users (username, password) VALUES (?, ?)", "John Doe", "a")
	err := tx.Commit()
	if err != nil {
		panic(err)
	}

	// This is how you query the database
	rows, err := db.Queryx("SELECT * FROM users")
	if err != nil {
		panic(err)
	}

	for rows.Next() {
		var user struct {
			ID       int
			Username string
			Password string
		}
		err = rows.StructScan(&user)
		if err != nil {
			panic(err)
		}
		fmt.Printf("User: %d %s %s\n", user.ID, user.Username, user.Password)
	}

	// Mounting the handler

	fs := http.FileServer(http.Dir("static"))
	http.Handle("/", fs)
	http.HandleFunc("/hello", handler)

	// Start the server on port 8080
	err = http.ListenAndServe(":8080", nil)
	if err != nil {
		panic(err)
	}
}