歡迎來到我們關於使用 Temporal 進行微服務編排實現複雜訂單處理系統的綜合部落格系列的第一部分。在本系列中，我們將探索建立一個強大、可擴展且可維護的系統的複雜性，該系統可以處理複雜、長時間運行的工作流程。
我們的旅程從為我們的專案奠定基礎開始。在本文結束時，您將擁有一個在 Golang 中實現的功能齊全的 CRUD REST API，與 Temporal 整合以進行工作流程編排，並由 Postgres 資料庫提供支援。我們將使用現代工具和最佳實踐來確保我們的程式碼庫乾淨、高效且易於維護。
讓我們深入了解並開始建立我們的訂單處理系統！
在開始實施之前，讓我們先簡單回顧一下我們將使用的關鍵技術和概念：
Go 是一種靜態類型的編譯語言，以其簡單、高效和對並發程式設計的出色支援而聞名。其標準庫和強大的生態系統使其成為建立微服務的絕佳選擇。
Temporal 是一個微服務編排平台，可簡化分散式應用程式的開發。它允許我們將複雜、長時間運行的工作流程編寫為簡單的程式碼，自動處理失敗和重試。
Gin 是一個用 Go 寫的高效能 HTTP Web 框架。它提供了類似 martini 的 API，具有更好的效能和更低的記憶體使用量。
OpenAPI（以前稱為 Swagger）是一種機器可讀介面檔案規範，用於描述、產生、使用和視覺化 RESTful Web 服務。 oapi-codegen 是一個根據 OpenAPI 3.0 規格產生 Go 程式碼的工具，允許我們先定義 API 合約並產生伺服器存根和用戶端程式碼。
sqlc 從 SQL 產生型別安全的 Go 程式碼。它允許我們編寫簡單的 SQL 查詢並產生完全類型安全的 Go 程式碼來與我們的資料庫交互，從而減少運行時錯誤的可能性並提高可維護性。
PostgreSQL 是一個強大的開源物件關聯式資料庫系統，以其可靠性、功能穩健性和效能而聞名。
Docker 允許我們將應用程式及其相依性打包到容器中，確保不同環境之間的一致性。 docker-compose 是一個用於定義和運行多容器 Docker 應用程式的工具，我們將使用它來設定本機開發環境。
現在我們已經了解了基礎知識，讓我們開始實現我們的系統。
首先，讓我們建立專案目錄並設定基本結構：
mkdir order-processing-system
cd order-processing-system
# Create directory structure
mkdir -p cmd/api \
internal/api \
internal/db \
internal/models \
internal/service \
internal/workflow \
migrations \
pkg/logger \
scripts
# Initialize Go module
go mod init github.com/yourusername/order-processing-system
# Create main.go file
touch cmd/api/main.go
此結構遵循標準 Go 專案佈局：
讓我們建立一個 Makefile 來簡化常見任務：
touch Makefile
將以下內容加入Makefile：
.PHONY: generate build run test clean
generate:
@echo "Generating code..."
go generate ./...
build:
@echo "Building..."
go build -o bin/api cmd/api/main.go
run:
@echo "Running..."
go run cmd/api/main.go
test:
@echo "Running tests..."
go test -v ./...
clean:
@echo "Cleaning..."
rm -rf bin
.DEFAULT_GOAL := build
此 Makefile 提供產生程式碼、建置應用程式、執行應用程式、執行測試和清理建置工件的目標。
建立一個名為 api/openapi.yaml 的檔案並定義我們的 API 規格：
openapi: 3.0.0
info:
title: Order Processing API
version: 1.0.0
description: API for managing orders in our processing system
paths:
/orders:
get:
summary: List all orders
responses:
'200':
description: Successful response
content:
application/json:
schema:
type: array
items:
$ref: '#/components/schemas/Order'
post:
summary: Create a new order
requestBody:
required: true
content:
application/json:
schema:
$ref: '#/components/schemas/CreateOrderRequest'
responses:
'201':
description: Created
content:
application/json:
schema:
$ref: '#/components/schemas/Order'
/orders/{id}:
get:
summary: Get an order by ID
parameters:
- name: id
in: path
required: true
schema:
type: integer
responses:
'200':
description: Successful response
content:
application/json:
schema:
$ref: '#/components/schemas/Order'
'404':
description: Order not found
put:
summary: Update an order
parameters:
- name: id
in: path
required: true
schema:
type: integer
requestBody:
required: true
content:
application/json:
schema:
$ref: '#/components/schemas/UpdateOrderRequest'
responses:
'200':
description: Successful response
content:
application/json:
schema:
$ref: '#/components/schemas/Order'
'404':
description: Order not found
delete:
summary: Delete an order
parameters:
- name: id
in: path
required: true
schema:
type: integer
responses:
'204':
description: Successful response
'404':
description: Order not found
components:
schemas:
Order:
type: object
properties:
id:
type: integer
customer_id:
type: integer
status:
type: string
enum: [pending, processing, completed, cancelled]
total_amount:
type: number
created_at:
type: string
format: date-time
updated_at:
type: string
format: date-time
CreateOrderRequest:
type: object
required:
- customer_id
- total_amount
properties:
customer_id:
type: integer
total_amount:
type: number
UpdateOrderRequest:
type: object
properties:
status:
type: string
enum: [pending, processing, completed, cancelled]
total_amount:
type: number
該規範定義了我們對訂單的基本 CRUD 操作。
安裝oapi-codegen：
go install github.com/deepmap/oapi-codegen/cmd/oapi-codegen@latest
Generate the server code:
oapi-codegen -package api -generate types,server,spec api/openapi.yaml > internal/api/api.gen.go
This command generates the Go code for our API, including types, server interfaces, and the OpenAPI specification.
Create a new file internal/api/handler.go:
package api
import (
"net/http"
"github.com/gin-gonic/gin"
)
type Handler struct {
// We'll add dependencies here later
}
func NewHandler() *Handler {
return &Handler{}
}
func (h *Handler) RegisterRoutes(r *gin.Engine) {
RegisterHandlers(r, h)
}
// Implement the ServerInterface methods
func (h *Handler) GetOrders(c *gin.Context) {
// TODO: Implement
c.JSON(http.StatusOK, []Order{})
}
func (h *Handler) CreateOrder(c *gin.Context) {
var req CreateOrderRequest
if err := c.ShouldBindJSON(&req); err != nil {
c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
return
}
// TODO: Implement order creation logic
order := Order{
Id: 1,
CustomerId: req.CustomerId,
Status: "pending",
TotalAmount: req.TotalAmount,
}
c.JSON(http.StatusCreated, order)
}
func (h *Handler) GetOrder(c *gin.Context, id int) {
// TODO: Implement
c.JSON(http.StatusOK, Order{Id: id})
}
func (h *Handler) UpdateOrder(c *gin.Context, id int) {
var req UpdateOrderRequest
if err := c.ShouldBindJSON(&req); err != nil {
c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
return
}
// TODO: Implement order update logic
order := Order{
Id: id,
Status: *req.Status,
}
c.JSON(http.StatusOK, order)
}
func (h *Handler) DeleteOrder(c *gin.Context, id int) {
// TODO: Implement
c.Status(http.StatusNoContent)
}
This implementation provides a basic structure for our API handlers. We’ll flesh out the actual logic when we integrate with the database and Temporal workflows.
Create a docker-compose.yml file in the project root:
version: '3.8'
services:
postgres:
image: postgres:13
environment:
POSTGRES_USER: orderuser
POSTGRES_PASSWORD: orderpass
POSTGRES_DB: orderdb
ports:
- "5432:5432"
volumes:
- postgres_data:/var/lib/postgresql/data
volumes:
postgres_data:
This sets up a Postgres container for our local development environment.
Install golang-migrate:
go install -tags 'postgres' github.com/golang-migrate/migrate/v4/cmd/migrate@latest
Create our first migration:
migrate create -ext sql -dir migrations -seq create_orders_table
Edit the migrations/000001_create_orders_table.up.sql file:
CREATE TABLE orders (
id SERIAL PRIMARY KEY,
customer_id INTEGER NOT NULL,
status VARCHAR(20) NOT NULL,
total_amount DECIMAL(10, 2) NOT NULL,
created_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP,
updated_at TIMESTAMP WITH TIME ZONE DEFAULT CURRENT_TIMESTAMP
);
CREATE INDEX idx_orders_customer_id ON orders(customer_id);
CREATE INDEX idx_orders_status ON orders(status);
Edit the migrations/000001_create_orders_table.down.sql file:
DROP TABLE IF EXISTS orders;
Add a new target to our Makefile:
migrate-up:
@echo "Running migrations..."
migrate -path migrations -database "postgresql://orderuser:orderpass@localhost:5432/orderdb?sslmode=disable" up
migrate-down:
@echo "Reverting migrations..."
migrate -path migrations -database "postgresql://orderuser:orderpass@localhost:5432/orderdb?sslmode=disable" down
Now we can run migrations with:
make migrate-up
go install github.com/kyleconroy/sqlc/cmd/sqlc@latest
Create a sqlc.yaml file in the project root:
version: "2"
sql:
- engine: "postgresql"
queries: "internal/db/queries.sql"
schema: "migrations"
gen:
go:
package: "db"
out: "internal/db"
emit_json_tags: true
emit_prepared_queries: false
emit_interface: true
emit_exact_table_names: false
Create a file internal/db/queries.sql:
-- name: GetOrder :one SELECT * FROM orders WHERE id = $1 LIMIT 1; -- name: ListOrders :many SELECT * FROM orders ORDER BY id; -- name: CreateOrder :one INSERT INTO orders ( customer_id, status, total_amount ) VALUES ( $1, $2, $3 ) RETURNING *; -- name: UpdateOrder :one UPDATE orders SET status = $2, total_amount = $3, updated_at = CURRENT_TIMESTAMP WHERE id = $1 RETURNING *; -- name: DeleteOrder :exec DELETE FROM orders WHERE id = $1;
Add a new target to our Makefile:
generate-sqlc:
@echo "Generating sqlc code..."
sqlc generate
Run the code generation:
make generate-sqlc
This will generate Go code for interacting with our database in the internal/db directory.
Add Temporal to our docker-compose.yml:
temporal:
image: temporalio/auto-setup:1.13.0
ports:
- "7233:7233"
environment:
- DB=postgresql
- DB_PORT=5432
- POSTGRES_USER=orderuser
- POSTGRES_PWD=orderpass
- POSTGRES_SEEDS=postgres
depends_on:
- postgres
temporal-admin-tools:
image: temporalio/admin-tools:1.13.0
depends_on:
- temporal
Create a file internal/workflow/order_workflow.go:
package workflow
import (
"time"
"go.temporal.io/sdk/workflow"
"github.com/yourusername/order-processing-system/internal/db"
)
func OrderWorkflow(ctx workflow.Context, order db.Order) error {
logger := workflow.GetLogger(ctx)
logger.Info("OrderWorkflow started", "OrderID", order.ID)
// Simulate order processing
err := workflow.Sleep(ctx, 5*time.Second)
if err != nil {
return err
}
// Update order status
err = workflow.ExecuteActivity(ctx, UpdateOrderStatus, workflow.ActivityOptions{
StartToCloseTimeout: time.Minute,
}, order.ID, "completed").Get(ctx, nil)
if err != nil {
return err
}
logger.Info("OrderWorkflow completed", "OrderID", order.ID)
return nil
}
func UpdateOrderStatus(ctx workflow.Context, orderID int64, status string) error {
// TODO: Implement database update
return nil
}
This basic workflow simulates order processing by waiting for 5 seconds and then updating the order status to “completed”.
Update the internal/api/handler.go file to include Temporal client and start the workflow:
package api
import (
"context"
"net/http"
"github.com/gin-gonic/gin"
"go.temporal.io/sdk/client"
"github.com/yourusername/order-processing-system/internal/db"
"github.com/yourusername/order-processing-system/internal/workflow"
)
type Handler struct {
queries *db.Queries
temporalClient client.Client
}
func NewHandler(queries *db.Queries, temporalClient client.Client) *Handler {
return &Handler{
queries: queries,
temporalClient: temporalClient,
}
}
// ... (previous handler methods)
func (h *Handler) CreateOrder(c *gin.Context) {
var req CreateOrderRequest
if err := c.ShouldBindJSON(&req); err != nil {
c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
return
}
order, err := h.queries.CreateOrder(c, db.CreateOrderParams{
CustomerID: req.CustomerId,
Status: "pending",
TotalAmount: req.TotalAmount,
})
if err != nil {
c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
return
}
// Start Temporal workflow
workflowOptions := client.StartWorkflowOptions{
ID: "order-" + order.ID,
TaskQueue: "order-processing",
}
_, err = h.temporalClient.ExecuteWorkflow(context.Background(), workflowOptions, workflow.OrderWorkflow, order)
if err != nil {
c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to start workflow"})
return
}
c.JSON(http.StatusCreated, order)
}
// ... (implement other handler methods)
Create a new file internal/service/service.go:
package service
import (
"database/sql"
"github.com/yourusername/order-processing-system/internal/api"
"github.com/yourusername/order-processing-system/internal/db"
"go.temporal.io/sdk/client"
)
type Service struct {
DB *sql.DB
Queries *db.Queries
TemporalClient client.Client
Handler *api.Handler
}
func NewService() (*Service, error) {
// Initialize database connection
db, err := sql.Open("postgres", "postgresql://orderuser:orderpass@localhost:5432/orderdb?sslmode=disable")
if err != nil {
return nil, err
}
// Initialize Temporal client
temporalClient, err := client.NewClient(client.Options{
HostPort: "localhost:7233",
})
if err != nil {
return nil, err
}
// Initialize queries
queries := db.New(db)
// Initialize handler
handler := api.NewHandler(queries, temporalClient)
return &Service{
DB: db,
Queries: queries,
TemporalClient: temporalClient,
Handler: handler,
}, nil
}
func (s *Service) Close() {
s.DB.Close()
s.TemporalClient.Close()
}
Update the cmd/api/main.go file:
package main
import (
"log"
"github.com/gin-gonic/gin"
_ "github.com/lib/pq"
"github.com/yourusername/order-processing-system/internal/service"
)
func main() {
svc, err := service.NewService()
if err != nil {
log.Fatalf("Failed to initialize service: %v", err)
}
defer svc.Close()
r := gin.Default()
svc.Handler.RegisterRoutes(r)
if err := r.Run(":8080"); err != nil {
log.Fatalf("Failed to run server: %v", err)
}
}
Create a Dockerfile in the project root:
# Build stage FROM golang:1.17-alpine AS build WORKDIR /app COPY go.mod go.sum ./ RUN go mod download COPY . . RUN CGO_ENABLED=0 GOOS=linux go build -o /order-processing-system ./cmd/api # Run stage FROM alpine:latest WORKDIR / COPY --from=build /order-processing-system /order-processing-system EXPOSE 8080 ENTRYPOINT ["/order-processing-system"]
Update the docker-compose.yml file to include our application:
version: '3.8'
services:
postgres:
# ... (previous postgres configuration)
temporal:
# ... (previous temporal configuration)
temporal-admin-tools:
# ... (previous temporal-admin-tools configuration)
app:
build: .
ports:
- "8080:8080"
depends_on:
- postgres
- temporal
environment:
- DB_HOST=postgres
- DB_USER=orderuser
- DB_PASSWORD=orderpass
- DB_NAME=orderdb
- TEMPORAL_HOST=temporal:7233
Throughout the implementation guide, we’ve provided code snippets with explanations. Here’s a more detailed look at a key part of our system: the Order Workflow.
package workflow
import (
"time"
"go.temporal.io/sdk/workflow"
"github.com/yourusername/order-processing-system/internal/db"
)
// OrderWorkflow defines the workflow for processing an order
func OrderWorkflow(ctx workflow.Context, order db.Order) error {
logger := workflow.GetLogger(ctx)
logger.Info("OrderWorkflow started", "OrderID", order.ID)
// Simulate order processing
// In a real-world scenario, this could involve multiple activities such as
// inventory check, payment processing, shipping arrangement, etc.
err := workflow.Sleep(ctx, 5*time.Second)
if err != nil {
return err
}
// Update order status
// We use ExecuteActivity to run the status update as an activity
// This allows for automatic retries and error handling
err = workflow.ExecuteActivity(ctx, UpdateOrderStatus, workflow.ActivityOptions{
StartToCloseTimeout: time.Minute,
}, order.ID, "completed").Get(ctx, nil)
if err != nil {
return err
}
logger.Info("OrderWorkflow completed", "OrderID", order.ID)
return nil
}
// UpdateOrderStatus is an activity that updates the status of an order
func UpdateOrderStatus(ctx workflow.Context, orderID int64, status string) error {
// TODO: Implement database update
// In a real implementation, this would use the db.Queries to update the order status
return nil
}
This workflow demonstrates several key concepts:
For this initial setup, we’ll focus on manual testing to ensure our system is working as expected. In future posts, we’ll dive into unit testing, integration testing, and end-to-end testing strategies.
To manually test our system:
docker-compose up
Use a tool like cURL or Postman to send requests to our API:
Check the logs to ensure the Temporal workflow is being triggered and completed successfully.
While setting up this initial version of our order processing system, we encountered several challenges and considerations:
Database Schema Design : Designing a flexible yet efficient schema for orders is crucial. We kept it simple for now, but in a real-world scenario, we might need to consider additional tables for order items, customer information, etc.
Error Handling : Our current implementation has basic error handling. In a production system, we’d need more robust error handling and logging, especially for the Temporal workflows.
Configuration Management : We hardcoded configuration values for simplicity. In a real-world scenario, we’d use environment variables or a configuration management system.
セキュリティ : 現在の設定には認証や認可が含まれていません。実稼働システムでは、適切なセキュリティ対策を実装する必要があります。
スケーラビリティ : Temporal はワークフローのスケーラビリティに役立ちますが、高トラフィック システムではデータベースのスケーラビリティと API のパフォーマンスを考慮する必要があります。
監視と可観測性 : 監視または可観測性ツールはまだ実装されていません。運用システムでは、これらはアプリケーションの保守とトラブルシューティングに非常に重要です。
シリーズの最初の部分では、注文処理システムの基礎を構築しました。基本的な CRUD API、データベース統合、およびシンプルなテンポラル ワークフローがあります。
次のパートでは、時間的なワークフローとアクティビティについて詳しく説明します。以下について調査していきます:
また、より現実的な注文処理ロジックを使用して API の肉付けを開始し、システムが複雑になるにつれてクリーンで保守可能なコードを維持するためのパターンを探索していきます。
注文処理システムを次のレベルに引き上げるパート 2 をお楽しみに!
困難な問題に直面していますか、それとも新しいアイデアやプロジェクトに関して外部の視点が必要ですか?お手伝いできます！大規模な投資を行う前にテクノロジーの概念実証を構築したい場合でも、難しい問題についてのガイダンスが必要な場合でも、私がお手伝いいたします。
私との仕事にご興味がございましたら、hungaikevin@gmail.com まで電子メールでご連絡ください。
課題をチャンスに変えましょう!
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