欢迎来到我们关于使用 Temporal 进行微服务编排实现复杂订单处理系统的综合博客系列的第一部分。在本系列中，我们将探索构建一个强大、可扩展且可维护的系统的复杂性，该系统可以处理复杂、长时间运行的工作流程。
我们的旅程从为我们的项目奠定基础开始。在本文结束时，您将拥有一个在 Golang 中实现的功能齐全的 CRUD REST API，与 Temporal 集成以进行工作流程编排，并由 Postgres 数据库提供支持。我们将使用现代工具和最佳实践来确保我们的代码库干净、高效且易于维护。
让我们深入了解并开始构建我们的订单处理系统！
在开始实施之前，让我们简要回顾一下我们将使用的关键技术和概念：
Go 是一种静态类型的编译语言，以其简单、高效和对并发编程的出色支持而闻名。其标准库和强大的生态系统使其成为构建微服务的绝佳选择。
Temporal 是一个微服务编排平台，可简化分布式应用程序的开发。它允许我们将复杂、长时间运行的工作流程编写为简单的程序代码，自动处理失败和重试。
Gin 是一个用 Go 编写的高性能 HTTP Web 框架。它提供了类似 martini 的 API，具有更好的性能和更低的内存使用量。
OpenAPI（以前称为 Swagger）是一种机器可读接口文件规范，用于描述、生成、使用和可视化 RESTful Web 服务。 oapi-codegen 是一个根据 OpenAPI 3.0 规范生成 Go 代码的工具，允许我们首先定义 API 合约并生成服务器存根和客户端代码。
sqlc 从 SQL 生成类型安全的 Go 代码。它允许我们编写简单的 SQL 查询并生成完全类型安全的 Go 代码来与数据库交互，从而减少运行时错误的可能性并提高可维护性。
PostgreSQL 是一个功能强大的开源对象关系数据库系统，以其可靠性、功能稳健性和性能而闻名。
Docker 允许我们将应用程序及其依赖项打包到容器中，确保不同环境之间的一致性。 docker-compose 是一个用于定义和运行多容器 Docker 应用程序的工具，我们将使用它来设置本地开发环境。
现在我们已经了解了基础知识，让我们开始实现我们的系统。
首先，让我们创建项目目录并设置基本结构：
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
此结构遵循标准 Go 项目布局：
让我们创建一个 Makefile 来简化常见任务：
touch Makefile
将以下内容添加到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 提供用于生成代码、构建应用程序、运行应用程序、运行测试和清理构建工件的目标。
创建一个名为 api/openapi.yaml 的文件并定义我们的 API 规范：
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
该规范定义了我们对订单的基本 CRUD 操作。
安装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.
安全性：我们当前的设置不包括任何身份验证或授权。在生产系统中，我们需要实施适当的安全措施。
可扩展性：虽然 Temporal 有助于提高工作流可扩展性，但我们需要考虑高流量系统的数据库可扩展性和 API 性能。
监控和可观察性：我们还没有实现任何监控或可观察性工具。在生产系统中，这些对于应用程序的维护和故障排除至关重要。
在我们系列的第一部分中，我们已经为订单处理系统奠定了基础。我们有基本的 CRUD API、数据库集成和简单的时态工作流程。
在下一部分中，我们将深入研究临时工作流程和活动。我们将探索：
我们还将开始用更现实的订单处理逻辑来充实我们的 API，并探索随着我们的系统复杂性的增长而保持干净、可维护的代码的模式。
请继续关注第 2 部分，我们将把我们的订单处理系统提升到一个新的水平！
您是否面临着具有挑战性的问题，或者需要外部视角来看待新想法或项目？我可以帮忙！无论您是想在进行更大投资之前建立技术概念验证，还是需要解决困难问题的指导，我都会为您提供帮助。
如果您有兴趣与我合作，请通过电子邮件与我联系：hungaikevin@gmail.com。
让我们将您的挑战转化为机遇！
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