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快速入门：向 Go Gin Web 应用添加功能标志

2025-07-24

在本快速入门中，你将在 Azure 应用配置中创建一个功能标志，并使用它在 Go Gin Web 应用中动态控制新网页的可用性，而无需重启或重新部署它。

功能管理支持扩展了应用程序配置中的动态配置功能。此示例演示如何使用实时更新和条件页面呈现将功能标志集成到 Go Gin Web 应用程序中。

先决条件

拥有有效订阅的 Azure 帐户。免费创建一个。
应用配置库。创建商店。
转到 1.21 或更高版本。有关安装 Go 的信息，请参阅 Go 下载页。
Azure 应用配置 Go 提供程序 v1.1.0-beta.1 或更高版本。

创建功能标志

将名为Beta的功能标志添加到应用配置存储中，并将Label和Description保留为默认值。有关如何使用 Azure 门户或 CLI 将功能标志添加到商店的信息，请转到创建功能标志。

创建 Go Web 应用程序

为 Go 项目创建新目录并导航到它：

mkdir gin-feature-flag-quickstart
cd gin-feature-flag-quickstart

初始化新的 Go 模块：

go mod init gin-feature-flag-quickstart

为 Azure 应用配置、Gin Web 框架和功能管理安装所需的 Go 包：

go get github.com/gin-gonic/gin
go get github.com/microsoft/Featuremanagement-Go/featuremanagement
go get github.com/microsoft/Featuremanagement-Go/featuremanagement/providers/azappconfig

为 HTML 模板创建模板目录。
```
mkdir templates
```

为主页创建 HTML 模板。将以下内容添加到 templates/index.html：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>{{.title}}</title>
    <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>
    <nav class="navbar navbar-expand-sm navbar-toggleable-sm navbar-light bg-white border-bottom box-shadow mb-3">
        <div class="container">
            <a class="navbar-brand" href="/">TestAppConfig</a>
            <button class="navbar-toggler" type="button" data-bs-toggle="collapse" data-bs-target=".navbar-collapse" aria-controls="navbarSupportedContent"
                    aria-expanded="false" aria-label="Toggle navigation">
                <span class="navbar-toggler-icon"></span>
            </button>
            <div class="navbar-collapse collapse d-sm-inline-flex justify-content-between">
                <ul class="navbar-nav flex-grow-1">
                    <li class="nav-item">
                        <a class="nav-link text-dark" href="/">Home</a>
                    </li>
                    {{if .betaEnabled}}
                    <li class="nav-item">
                        <a class="nav-link text-dark" href="/beta">Beta</a>
                    </li>
                    {{end}}
                </ul>
            </div>
        </div>
    </nav>    <div class="container">
        <div class="row justify-content-center">
            <div class="col-md-8 text-center">
                <h1>Hello from Azure App Configuration</h1>
        </div>
    </div>

    <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/js/bootstrap.bundle.min.js"></script>
</body>
</html>

为 beta 页面创建 HTML 模板。将以下内容添加到 templates/beta.html：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>{{.title}}</title>
    <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/css/bootstrap.min.css" rel="stylesheet">
</head>
<body>
    <!-- Navigation -->    <nav class="navbar navbar-expand-sm navbar-toggleable-sm navbar-light bg-white border-bottom box-shadow mb-3">
        <div class="container">
            <a class="navbar-brand" href="/">TestAppConfig</a>
            <div class="navbar-collapse collapse d-sm-inline-flex justify-content-between">
                <ul class="navbar-nav flex-grow-1">
                    <li class="nav-item">
                        <a class="nav-link text-dark" href="/">Home</a>
                    </li>
                    <li class="nav-item">
                        <a class="nav-link text-dark" href="/beta">Beta</a>
                    </li>
                </ul>
            </div>
        </div>
    </nav>    <div class="container">
        <div class="row justify-content-center">
            <div class="col-md-8 text-center">
                <h1>This is the beta website.</h1>
            </div>
        </div>
    </div>

    <script src="https://cdn.jsdelivr.net/npm/bootstrap@5.1.3/dist/js/bootstrap.bundle.min.js"></script>
</body>
</html>

使用功能标志

将options更新以在上一步中启用功能标志。

    options := &azureappconfiguration.Options{
        FeatureFlagOptions: azureappconfiguration.FeatureFlagOptions{
            Enabled: true,
            RefreshOptions: azureappconfiguration.RefreshOptions{
                Enabled: true,
            },
        },
    }

小窍门

当在 FeatureFlagOptions 中未指定选择器时，它会加载应用配置存储库中所有无标签的功能开关。功能标志的默认刷新间隔为 30 秒。可以通过 RefreshOptions 参数自定义此行为。例如，以下代码片段仅加载键名以“TestApp:”开头的，并具有标签“dev”的功能标志。该代码还将刷新间隔时间更改为 5 分钟。请注意，此刷新间隔时间与常规键值的刷新间隔时间不同。

FeatureFlagOptions{
    Enabled: true,
    Selectors: []azureappconfiguration.Selector{
        {
            KeyFilter:   "TestApp:*",
            LabelFilter: "dev",
        },
    },
    RefreshOptions: azureappconfiguration.RefreshOptions{
        Enabled: true,
        Interval: 5 * time.Minute,
    },
}

创建包含以下内容的文件 main.go ：

package main

import (
    "context"
    "fmt"
    "log"
    "net/http"
    "os"

    "github.com/Azure/AppConfiguration-GoProvider/azureappconfiguration"
    "github.com/gin-gonic/gin"
    "github.com/microsoft/Featuremanagement-Go/featuremanagement"
    "github.com/microsoft/Featuremanagement-Go/featuremanagement/providers/azappconfig"
)

type WebApp struct {
    featureManager *featuremanagement.FeatureManager
    appConfig      *azureappconfiguration.AzureAppConfiguration
}

func (app *WebApp) refreshMiddleware() gin.HandlerFunc {
    return func(c *gin.Context) {
        go func() {
            ctx := context.Background()
            if err := app.appConfig.Refresh(ctx); err != nil {
                log.Printf("Error refreshing configuration: %v", err)
            }
        }()
        c.Next()
    }
}

func (app *WebApp) featureMiddleware() gin.HandlerFunc {
    return func(c *gin.Context) {
        // Check if Beta feature is enabled
        betaEnabled, err := app.featureManager.IsEnabled("Beta")
        if err != nil {
            log.Printf("Error checking Beta feature: %v", err)
            betaEnabled = false
        }

        // Store feature flag status for use in templates
        c.Set("betaEnabled", betaEnabled)
        c.Next()
    }
}

func (app *WebApp) setupRoutes(r *gin.Engine) {
    r.Use(app.refreshMiddleware())
    r.Use(app.featureMiddleware())

    // Load HTML templates
    r.LoadHTMLGlob("templates/*.html")

    // Routes
    r.GET("/", app.homeHandler)
    r.GET("/beta", app.betaHandler)
}

// Home page handler
func (app *WebApp) homeHandler(c *gin.Context) {
    betaEnabled := c.GetBool("betaEnabled")

    c.HTML(http.StatusOK, "index.html", gin.H{
        "title":       "Feature Management Example App",
        "betaEnabled": betaEnabled,
    })
}

// Beta page handler
func (app *WebApp) betaHandler(c *gin.Context) {
    betaEnabled := c.GetBool("betaEnabled")

    if !betaEnabled {
        return
    }

    c.HTML(http.StatusOK, "beta.html", gin.H{
        "title": "Beta Page",
    })
}

func main() {
    ctx := context.Background()

    // Load Azure App Configuration
    appConfig, err := loadAzureAppConfiguration(ctx)
    if err != nil {
        log.Fatalf("Error loading Azure App Configuration: %v", err)
    }

    // Create feature flag provider
    featureFlagProvider, err := azappconfig.NewFeatureFlagProvider(appConfig)
    if err != nil {
        log.Fatalf("Error creating feature flag provider: %v", err)
    }

    // Create feature manager
    featureManager, err := featuremanagement.NewFeatureManager(featureFlagProvider, nil)
    if err != nil {
        log.Fatalf("Error creating feature manager: %v", err)
    }

    // Create web app
    app := &WebApp{
        featureManager: featureManager,
        appConfig:      appConfig,
    }

    // Set up Gin with default middleware (Logger and Recovery)
    r := gin.Default()

    // Set up routes
    app.setupRoutes(r)

    // Start server
    fmt.Println("Starting server on http://localhost:8080")
    fmt.Println("Open http://localhost:8080 in your browser")
    fmt.Println("Toggle the 'Beta' feature flag in Azure portal to see changes")
    fmt.Println()

    if err := r.Run(":8080"); err != nil {
        log.Fatalf("Failed to start server: %v", err)
    }
}