go-api: Postgres & sqlc (#80)

* go-api: Postgres & sqlc

* linting

* linting

* refactor: first refactor of the project including ai suggestions

* refactor: add layers to separate logic

* fix: format issues in .gitignore and dockerfile

* fix: add password hashing

* fix: error response header

* fix: NewText return

* fix: add .sqlfluff file

* fix: error handling in db conn

---------

Co-authored-by: Chelo Doz <[email protected]>

examples/golang-api-with-postgres-and-sqlc/.gitignore

@@ -0,0 +1,22 @@
+# If you prefer the allow list template instead of the deny list, see community template:
+# https://github.com/github/gitignore/blob/main/community/Golang/Go.AllowList.gitignore
+#
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+
+# Go workspace file
+go.work
+go.work.sum

examples/golang-api-with-postgres-and-sqlc/.sqlfluff

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+[sqlfluff]
+dialect = postgres

examples/golang-api-with-postgres-and-sqlc/Dockerfile

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+# Build stage
+FROM golang:1.22 AS builder
+
+WORKDIR /go/src/app
+
+# Pre-copy/cache go.mod and go.sum for pre-downloading dependencies
+COPY go.mod go.sum ./
+RUN go mod download
+
+# Copy the source code
+COPY . .
+
+# Build the Go application
+RUN go build -v -o /go/bin/app .
+
+# Final stage
+FROM gcr.io/distroless/base-debian12:latest
+
+# Copy the compiled binary from the build stage
+COPY --from=builder /go/bin/app /
+
+# Expose the application port
+EXPOSE 8080
+
+# Set the command to run the application
+CMD ["/app"]

examples/golang-api-with-postgres-and-sqlc/README.md

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+# Go API with Docker Compose
+
+This project containerizes a Go API and a PostgreSQL database using Docker Compose.
+
+## Motivation for Using `sqlc`
+
+Incorporating `sqlc` into a Go project provides numerous advantages:
+
+- **Strong Type Safety**: Compile-time checks ensure that type errors are caught early in the development process, reducing runtime errors and increasing code reliability.
+- **Enhanced Developer Productivity**: By automating the generation of SQL queries and their corresponding Go code, `sqlc` allows developers to concentrate on building application features instead of writing boilerplate database interaction code.
+- **Improved Readability and Maintainability**: Using native SQL queries directly in the codebase makes the queries more transparent and easier to understand, debug, and optimize. This approach aligns well with the principles of clean code and maintainability.
+- **Optimized Performance**: `sqlc` enables developers to write and fine-tune raw SQL queries, providing greater control over database interactions compared to ORM-based solutions. This can lead to more efficient query execution and better overall performance.
+
+## Prerequisites
+
+- Docker
+- Docker Compose
+- `sqlc`
+
+## Setup
+
+1. **Clone the Repository**:
+
+    ```bash
+    git clone https://github.com/nanlabs/backend-reference
+    ```
+
+2. **Navigate to the Project Directory**:
+
+    ```bash
+    cd backend-reference/examples/golang-api-with-postgres-and-sqlc
+    ```
+
+3. **Generate SQL Queries and Models with `sqlc`**:
+
+    ```bash
+    sqlc generate
+    ```
+
+4. **Build and Run the Docker Containers**:
+
+    ```bash
+    docker-compose build
+    docker-compose up
+    ```
+
+The Go API will be accessible at `localhost:8080`.
+
+## Stopping the Application
+
+To stop the application and remove the containers, networks, and volumes defined in `docker-compose.yml`, run:
+
+```bash
+docker-compose down
+docker volume rm db_data
+```

examples/golang-api-with-postgres-and-sqlc/compose.yml

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+version: "3"
+services:
+  db:
+    container_name: db
+    image: postgres:16
+    environment:
+      POSTGRES_PASSWORD: postgres
+      POSTGRES_USER: postgres
+      POSTGRES_DB: poc
+    volumes:
+      - db_data:/var/lib/postgresql/data
+    ports:
+      - "5432:5432"
+  go_api:
+    container_name: go_api
+    build: .
+    depends_on:
+      - db
+    ports:
+      - "8080:8080"
+volumes:
+  db_data:
+    name: db_data

examples/golang-api-with-postgres-and-sqlc/db/database.go

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+package db
+
+import (
+	"context"
+	"fmt"
+	"go-postgres-sqlc/db/sqlc"
+	"log"
+
+	"github.com/jackc/pgx/v5"
+)
+
+// DB holds the database connection configuration
+type DB struct {
+	DSN     string
+	Context context.Context
+	Conn    *pgx.Conn
+	Queries *sqlc.Queries
+}
+
+// New initializes a new DBConfig instance
+func New(dsn string) (*DB, error) {
+	ctx := context.Background()
+	conn, err := pgx.Connect(ctx, dsn)
+	if err != nil {
+		return nil, fmt.Errorf("unable to connect to database: %v", err)
+	}
+	log.Println("Connected to database")
+
+	queries := sqlc.New(conn)
+
+	return &DB{
+		DSN:     dsn,
+		Context: ctx,
+		Conn:    conn,
+		Queries: queries,
+	}, nil
+}

examples/golang-api-with-postgres-and-sqlc/db/migrations/schema.sql

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+CREATE TABLE users (
+  id BIGINT GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+  username VARCHAR(30) NOT NULL,
+  password VARCHAR(100) NOT NULL,
+  email VARCHAR(50),
+  created_at TIMESTAMPTZ NOT NULL DEFAULT CURRENT_TIMESTAMP
+);

examples/golang-api-with-postgres-and-sqlc/db/query/user.sql

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+-- name: GetUser :one
+SELECT 
+  id,
+  username,
+  email,
+  created_at
+FROM users
+WHERE id = @user_id
+LIMIT 1;
+
+-- name: ListUsers :many
+SELECT 
+  id,
+  username,
+  email,
+  created_at
+FROM users
+ORDER BY username;
+
+-- name: CreateUser :one
+INSERT INTO users (
+  username,
+  password,
+  email
+) VALUES (
+  @username,
+  @password,
+  @email
+) RETURNING *;