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Create the Go project

Table of contents

Initialize the project

Start by creating a Go project.

$ mkdir testcontainers-go-demo
$ cd testcontainers-go-demo
$ go mod init github.com/testcontainers/testcontainers-go-demo

This guide uses the jackc/pgx PostgreSQL driver to interact with the Postgres database and the testcontainers-go Postgres module to spin up a Postgres Docker instance for testing. It also uses testify for running multiple tests as a suite and for writing assertions.

Install these dependencies:

$ go get github.com/jackc/pgx/v5
$ go get github.com/testcontainers/testcontainers-go
$ go get github.com/testcontainers/testcontainers-go/modules/postgres
$ go get github.com/stretchr/testify

Create Customer struct

Create a types.go file in the customer package and define the Customer struct to model the customer details:

package customer

type Customer struct {
	Id    int
	Name  string
	Email string
}

Create Repository

Next, create customer/repo.go, define the Repository struct, and add methods to create a customer and get a customer by email:

package customer

import (
	"context"
	"fmt"
	"os"

	"github.com/jackc/pgx/v5"
)

type Repository struct {
	conn *pgx.Conn
}

func NewRepository(ctx context.Context, connStr string) (*Repository, error) {
	conn, err := pgx.Connect(ctx, connStr)
	if err != nil {
		_, _ = fmt.Fprintf(os.Stderr, "Unable to connect to database: %v\n", err)
		return nil, err
	}
	return &Repository{
		conn: conn,
	}, nil
}

func (r Repository) CreateCustomer(ctx context.Context, customer Customer) (Customer, error) {
	err := r.conn.QueryRow(ctx,
		"INSERT INTO customers (name, email) VALUES ($1, $2) RETURNING id",
		customer.Name, customer.Email).Scan(&customer.Id)
	return customer, err
}

func (r Repository) GetCustomerByEmail(ctx context.Context, email string) (Customer, error) {
	var customer Customer
	query := "SELECT id, name, email FROM customers WHERE email = $1"
	err := r.conn.QueryRow(ctx, query, email).
		Scan(&customer.Id, &customer.Name, &customer.Email)
	if err != nil {
		return Customer{}, err
	}
	return customer, nil
}

Here's what the code does:

  • Repository holds a *pgx.Conn for performing database operations.
  • NewRepository(connStr) takes a database connection string and initializes a Repository.
  • CreateCustomer() and GetCustomerByEmail() are methods on the Repository receiver that insert and query customer records.
Write tests with Testcontainers »