/repository-pattern-postgres

Go Repository Pattern with Postgres Example

Primary LanguageGoMIT LicenseMIT

Repository Pattern Postgres Example

This is an example project that demonstrates the use of the Repository Pattern with PostgreSQL in Go.

Prerequisites

  • Go programming language
  • Docker (optional, for running PostgreSQL in a container)

Getting Started

  1. Clone the repository to your local machine.

  2. Set up a PostgreSQL database. You can either install PostgreSQL locally or use a Docker container.

  • If you have PostgreSQL installed locally, make sure it's running and create a new database.

  • If you want to use a Docker container, run the following command to start a PostgreSQL container:

$ docker run --name my-postgres-container -e POSTGRES_PASSWORD=mysecretpassword -p 5432:5432 -d postgres
  1. Set up the database schema by applying the migration scripts located in the migrations folder.

  • Ensure that you have the migrate tool installed. You can install it following the tutorial here.

  • Apply the migrations using the following command:

$ migrate -database "postgres://postgres:mysecretpassword@localhost:5432/postgres?sslmode=disable" -path ./migrations up
Output: 1/u create_users_table (14.613453ms)

Optional: you can validate the migration really created the tables inside the docker container postgres instance.

$ migrate -path migrations/ -database "postgres://postgres:mysecretpassword@localhost:5432/postgres?sslmode=disable" up
1/u create_users_table (14.613453ms)

$ docker exec -it my-postgres-container bash
$ psql -U postgres -d postgres # run inside the container
$ postgres=# \dt
               List of relations
 Schema |       Name        | Type  |  Owner
--------+-------------------+-------+----------
 public | schema_migrations | table | postgres
 public | users             | table | postgres
(2 rows)

$ postgres=# \d+ users
                                                                Table "public.users"
  Column  |          Type          | Collation | Nullable |              Default              | Storage  | Compression | Stats target | Description
----------+------------------------+-----------+----------+-----------------------------------+----------+-------------+--------------+-------------
 id       | integer                |           | not null | nextval('users_id_seq'::regclass) | plain    |             |              |
 username | character varying(50)  |           | not null |                                   | extended |             |              |
 email    | character varying(100) |           | not null |                                   | extended |             |              |
Indexes:
    "users_pkey" PRIMARY KEY, btree (id)
  1. Update the connString variable in the main.go file with your PostgreSQL connection details.
connString := "host=localhost port=5432 user=postgres password=mysecretpassword dbname=postgres sslmode=disable"
  1. Run the project:
$ go run main.go

Project Structure

.
├── go.mod
├── go.sum
├── LICENSE
├── main.go # Contains the main entry point of the application
├── migrations # Directory containing the database migration scripts
│   ├── 1_create_users_table.down.sql
│   └── 1_create_users_table.up.sql
├── README.md
└── user # Directory for the user domain
    ├── user.go # Definition of the User struct
    └── user_repository # Directory for the user repository
        ├── postgres_user_repository.go # Implementation of the UserRepository interface using PostgreSQL
        └── user_repository.go # Definition of the UserRepository interface

Contributing

Contributions are welcome! If you find any issues with the project or want to extend it further, feel free to open an issue or submit a pull request.