Golang Controller / Service / Repository with Postgres

handler.go

package main

import (
    "net/http"
    "github.com/labstack/echo/v4"
)

type Handler struct {
    service *Service
}

func NewHandler(service *Service) *Handler {
    return &Handler{service: service}
}

func (h *Handler) GetUser(c echo.Context) error {
    id := c.Param("id")
    user, err := h.service.GetUser(id)
    if err != nil {
        return echo.NewHTTPError(http.StatusInternalServerError, err.Error())
    }
    return c.JSON(http.StatusOK, user)
}

main.go

package main

import (
    "net/http"
    "github.com/labstack/echo/v4"
    "github.com/labstack/echo/v4/middleware"
)

func main() {
    e := echo.New()

    e.Use(middleware.Logger())
    e.Use(middleware.Recover())

    db := NewPostgresDB() // replace with your actual DB initialization
    repo := NewRepository(db)
    service := NewService(repo)
    handler := NewHandler(service)

    e.GET("/users/:id", handler.GetUser)

    e.Start(":8080")
}

model.go

package main

type User struct {
    ID   string `json:"id"`
    Name string `json:"name"`
}

repository.go

package main

import (
    "database/sql"
)

type Repository struct {
    db *sql.DB
}

func NewRepository(db *sql.DB) *Repository {
    return &Repository{db: db}
}

func (r *Repository) GetUser(id string) (*User, error) {
    // implement your SQL query to fetch user by id from Postgres
}

service.go

package main

type Service struct {
    repo *Repository
}

func NewService(repo *Repository) *Service {
    return &Service{repo: repo}
}

func (s *Service) GetUser(id string) (*User, error) {
    return s.repo.GetUser(id)
}