在 .NET Core 使用 Feature Flag (Feature Toggle) - 時間控制

承接上一篇，如果有一些情境是限時開放的功能，時間過了以後就要關閉，那就可以用到 TimeWindow

1. appsettings.json

"FeatureManagement": {
    "FeatureB": {
        "EnabledFor": [
            {
                "Name": "Microsoft.TimeWindow",
                "Parameters": {
                    "Start": "2020-11-09 04:58:00Z",
                    "End": "2099-11-09 05:00:00Z"
                }
            }
        ]
    }
}

2. 基本的 Feature Toggle 使用

var isFeatureAEnabled = await _featureManager.IsEnabledAsync("FeatureA");
if(isFeatureAEnabled) {
    // 有打開，走新邏輯
}
else {
    // 未打開，走舊邏輯
}

3. API Route 多個使用方式，驗證不過會回傳404

[FeatureGate("FeatureA")]
public async Task<ActionResult> Foo()
{
    return Ok(result); 
}

4. 也可指定任一或多個 Feature 是否有打開

[FeatureGate(requirementType: RequirementType.Any, "FeatureA", "FeatureB")]
public async Task<ActionResult> Foo()
{
    return Ok(result); 
}

5. 也可以用 Enum 避免弱型別的typo

[FeatureGate(MyFeatureFlags.FeatureA)]
public enum MyFeatureFlags
{
	FeatureA
}

6. startup 注入

services.AddFeatureManagement()
        .AddFeatureFilter<TargetingFilter>();