Initialize directory structure (#437)

* init directory

* add readme

* Replace empty file to .gitkeep

* Add server config

* Add basic server

* Add routes

* Edit document

- project-root -> backend-go

* Edit document

- yorkie directory explain

* Add graceful shutdown

* Clear server configuration

- This implement is out of this PR's goal

* Apply code rabbit's comment

* Replace net/http to echo

* Remove read timeout in server config

* Refactor server Start and Shutdown

- run gorutine in main.go
- logging in main.go
- server only return error

* Fix directory_structure.md

- domain directory -> core
- remove API documentation in api directory

* Remove graceful shutdown

- this is not needed for now
- this implementation makes more complexity for contribution

* Rename directory name `domain` -> `core`

* Rename `dto` directory to `codepair/v1`

* Remove `auth` directory

* Fix redundant error

* Remove .gitkeep in `api/codepair/v1`

* Change logger

---------

Co-authored-by: devleejb <[email protected]>

backend-go/cmd/codepair/main.go

@@ -1,17 +1,17 @@
 package main
 
 import (
-	"fmt"
-	"net/http"
-
 	"github.com/labstack/echo/v4"
+	"github.com/yorkie-team/codepair/backend/internal/config"
+	"github.com/yorkie-team/codepair/backend/internal/server"
 )
 
 func main() {
 	e := echo.New()
-	e.GET("/", func(c echo.Context) error {
-		err := c.String(http.StatusOK, "Hello, World!")
-		return fmt.Errorf("error: %w", err)
-	})
-	e.Logger.Fatal(e.Start(":3001"))
+	conf := config.LoadConfig()
+	cp := server.New(e, conf)
+
+	if err := cp.Start(); err != nil {
+		e.Logger.Fatal(err)
+	}
 }

backend-go/design/directory_structure.md

@@ -0,0 +1,74 @@
+# Directory Structure
+
+This document explains the purpose and structure of the project's directories.
+
+## Project Structure
+
+```
+backend-go/
+├── api        # DTO definitions
+├── bin        # Compiled binaries
+├── cmd        # Application entry points
+│   └── codepair  # Main application entry point (main.go)
+├── design     # Design documents and architecture references
+└── internal   # Core application logic (business logic, infrastructure, middleware)
+```
+### Structure of `internal`
+
+``` 
+internal
+├── config        # Configuration loading & validation
+├── core          # Business logic and domain entities
+│   ├── workspace # Workspace management module
+│   ├── user      # User management module
+│   └── ...       # Other domain-specific modules
+├── infra         # Infrastructure dependencies (DB, storage, external services)
+│   ├── database  # Database integrations
+│   │   └── mongo # MongoDB implementation
+│   ├── storage   # Object storage (MinIO, S3, etc.)
+│   │   ├── minio # MinIO storage implementation
+│   │   └── s3    # AWS S3 storage implementation
+│   └── yorkie    # Yorkie admin client implementation
+├── middleware    # Shared middleware (logging, auth, etc.)
+└── server        # Server setup, routing, and bootstrapping
+```
+
+### Explanation of Each Component
+
+#### 1. `internal/config`
+
+- Responsible for **loading and validating configurations** (e.g., using `viper` or `os.Getenv`).
+- Contains separate configuration files for authentication, database, and other settings.
+
+#### 2. `internal/core`
+
+- Contains the **business logic and domain models**.
+- Each domain (e.g., `workspace`, `user`) includes:
+    - `model.go` → Defines entity structures (e.g., `User`, `Workspace`).
+    - `repository.go` → Interface for database operations.
+    - `service.go` → Implementation of business logic.
+    - `handler.go` → Presentation layer handlers for processing HTTP requests.
+
+#### 3. `internal/infra`
+
+- Represents the **infrastructure layer** responsible for handling external dependencies such as databases, storage, and external services.
+- Organized into:
+    - `database/mongo/` → MongoDB implementation for repositories.
+    - `storage/` → Object storage implementations (MinIO, S3).
+    - `yorkie/` → Contains the Yorkie admin client, which handles administrative functions.
+
+#### 4. `internal/middleware`
+
+- Contains **shared middleware** applied across the application.
+- Common middleware includes:
+    - Logging
+    - Authentication & authorization
+    - Error handling & panic recovery
+    - Request validation
+
+#### 5. `internal/server`
+
+- Handles **server setup and routing**.
+- Includes:
+    - `routes.go` → Defines API endpoints and middleware.
+    - `server.go` → Initializes the server, sets up dependencies, and starts the application.

backend-go/internal/config/config.go

@@ -0,0 +1,13 @@
+package config
+
+type Config struct {
+	Server *Server
+}
+
+func LoadConfig() *Config {
+	return &Config{
+		Server: &Server{
+			Port: DefaultServerPort,
+		},
+	}
+}

backend-go/internal/config/server.go

@@ -0,0 +1,9 @@
+package config
+
+const (
+	DefaultServerPort = 3001
+)
+
+type Server struct {
+	Port int
+}

backend-go/internal/core/user/model.go

@@ -0,0 +1 @@
+package user

backend-go/internal/core/user/repository.go

@@ -0,0 +1 @@
+package user

backend-go/internal/core/user/service.go

@@ -0,0 +1 @@
+package user

backend-go/internal/infra/database/mongo/.gitkeep

@@ -0,0 +1 @@
+

backend-go/internal/server/routes.go

@@ -0,0 +1,15 @@
+package server
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/labstack/echo/v4"
+)
+
+func RegisterRoutes(e *echo.Echo) {
+	e.GET("/", func(c echo.Context) error {
+		err := c.String(http.StatusOK, "Hello, World!")
+		return fmt.Errorf("error: %w", err)
+	})
+}

backend-go/internal/server/server.go

@@ -0,0 +1,34 @@
+package server
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+
+	"github.com/labstack/echo/v4"
+
+	"github.com/yorkie-team/codepair/backend/internal/config"
+)
+
+type CodePair struct {
+	config *config.Config
+	echo   *echo.Echo
+}
+
+func New(e *echo.Echo, conf *config.Config) *CodePair {
+	RegisterRoutes(e)
+
+	cp := &CodePair{
+		config: conf,
+		echo:   e,
+	}
+	return cp
+}
+
+func (c *CodePair) Start() error {
+	addr := fmt.Sprintf(":%d", c.config.Server.Port)
+	if err := c.echo.Start(addr); !errors.Is(err, http.ErrServerClosed) {
+		return fmt.Errorf("failed to start server: %w", err)
+	}
+	return nil
+}