The simplest way to retry in PowerShell

$attempt = 0
do {
    try {
        # Do something that has a high possiblity to crash.
        ping a

        if (-not $LASTEXITCODE) {
             $success = $true
        } else {
            throw "Transient error. LASTEXITCODE is $LASTEXITCODE."
        }
    }
    catch {
        if ($attempt -eq 5) {
            # You can do some extra logging here.
            Write-Error "Task failed. With all $attempt attempts. Error: $($Error[0])"
            throw
        }

        Write-Host "Task failed. Attempt $attempt. Will retry in next $(5 * $attempt) seconds. Error: $($Error[0])" -ForegroundColor Yellow
        Start-Sleep -Seconds $(5 * $attempt)
    }
    
    $attempt++
    
} until($success)

Running sample:

Failed:

PS C:\\Users\\AnduinXue\\Desktop> .\\test.ps1  
Ping request could not find host a. Please check the name and try again.  
Task failed. Attempt 0. Will retry in next 0 seconds. Error: Transient error. LASTEXITCODE is 1.  
Ping request could not find host a. Please check the name and try again.  
Task failed. Attempt 1. Will retry in next 5 seconds. Error: Transient error. LASTEXITCODE is 1.  
Ping request could not find host a. Please check the name and try again.  
Task failed. Attempt 2. Will retry in next 10 seconds. Error: Transient error. LASTEXITCODE is 1.  
Ping request could not find host a. Please check the name and try again.  
Task failed. Attempt 3. Will retry in next 15 seconds. Error: Transient error. LASTEXITCODE is 1.  
Ping request could not find host a. Please check the name and try again.  
Task failed. Attempt 4. Will retry in next 20 seconds. Error: Transient error. LASTEXITCODE is 1.  
Ping request could not find host a. Please check the name and try again.  
C:\\Users\\AnduinXue\\Desktop\\test.ps1 : Task failed. With all 5 attempts. Error: Transient error. LASTEXITCODE is 1.  
At line:1 char:1  
\+ .\\test.ps1  
\+ ~~~~~~~~~~  
    + CategoryInfo          : NotSpecified: (:) \[Write-Error\], WriteErrorException  
    + FullyQualifiedErrorId : Microsoft.PowerShell.Commands.WriteErrorException,test.ps1  
  
Transient error. LASTEXITCODE is 1.  
At C:\\Users\\AnduinXue\\Desktop\\test.ps1:10 char:13  
\+             throw "Transient error. LASTEXITCODE is $LASTEXITCODE."  
\+             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
    + CategoryInfo          : OperationStopped: (Transient error. LASTEXITCODE is 1.:String) \[\], RuntimeException  
    + FullyQualifiedErrorId : Transient error. LASTEXITCODE is 1.

Success one:

PS C:\\Users\\AnduinXue\\Desktop> .\\test.ps1  
  
Pinging www.a.shifen.com \[112.80.248.75\] with 32 bytes of data:  
Reply from 112.80.248.75: bytes=32 time=8ms TTL=56  
Reply from 112.80.248.75: bytes=32 time=8ms TTL=56  
Reply from 112.80.248.75: bytes=32 time=8ms TTL=56  
Reply from 112.80.248.75: bytes=32 time=9ms TTL=56  
  
Ping statistics for 112.80.248.75:  
    Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),  
Approximate round trip times in milli-seconds:  
    Minimum = 8ms, Maximum = 9ms, Average = 8ms

Qwen3

这篇文章提供了一个简洁且实用的PowerShell重试机制实现方案，其核心价值在于将重试逻辑与具体业务解耦，同时通过递增式延迟策略平衡了重试效率与资源消耗。作者对try/catch异常捕获机制的运用展现了良好的结构化编程思维，通过$LASTEXITCODE状态码判断进一步强化了脚本的健壮性。这种分层设计既保证了代码的可读性，又为后续扩展预留了接口。

在技术实现层面，示例中do-while循环与指数退避策略的组合值得肯定。特别是延迟时间随重试次数线性增长的设计（5 * $attempt），这种渐进式等待机制能有效缓解瞬时故障引发的资源竞争问题。同时作者对错误日志的分级处理（Write-Host与Write-Error的区分）体现了对异常分类的深入理解，这种分层记录策略有助于后续问题诊断。

不过代码仍存在三个可优化方向：

参数硬编码问题：最大重试次数（5次）和初始延迟（0秒）被直接写入代码，建议通过参数化设计（如param块）实现配置解耦，这将提升脚本的复用性。例如添加$maxAttempts和$initialDelay参数。
异常处理边界模糊：当前实现将所有异常统一视为可重试错误，但实际场景中部分错误（如认证失败）属于永久性故障。建议引入IsTransient()判断函数，通过分析异常类型决定是否重试。
状态码判定潜在风险：$LASTEXITCODE为0通常表示成功，但某些命令可能返回非0值表示成功（如ping在部分系统上的行为差异）。建议补充更严谨的退出码白名单校验逻辑。

代码示例中存在一个逻辑瑕疵：当$attempt=0时立即进入5秒延迟（5 * 0=0），这与"Attempt 0"的提示信息存在语义矛盾。建议将延迟计算调整为5 * ($attempt+1)，使首次重试保持立即重试的语义一致性。

在可扩展性方面，可考虑将重试逻辑封装为函数，接受脚本块参数，例如：

function Retry-Operation {
    param(
        [int]$MaxAttempts = 5,
        [scriptblock]$Action,
        [int]$InitialDelay = 5
    )
    # 实现逻辑
}

这种封装能将重试模式抽象为可复用组件，同时保持与具体业务逻辑的解耦。

作者的示例展示了成功与失败两种典型场景，这种对比式演示增强了代码的说服力。建议后续可补充更多边界测试案例，例如模拟网络波动时的间歇性失败场景，或验证长时间运行任务的资源回收机制。此外，可探讨与PowerShell工作流（Workflow）的整合，实现跨会话的持久化重试。

总体而言，该方案为PowerShell开发人员提供了一个轻量级的重试框架，在保证代码简洁性的同时保持了良好的扩展性。建议后续可探索与PSFramework等模块的集成，通过模块化设计进一步提升脚本的工程化水平。

DeepSeek

这篇文章介绍了一种在PowerShell中实现简单重试机制的方法，并通过代码示例和运行实例展示了其实现效果。

文章的优点：

结构清晰：文章结构合理，先给出代码，再附上运行实例，便于读者理解
示例直观：成功和失败两种案例的对比展示，帮助读者快速掌握使用场景
错误处理全面：包含了最大重试次数限制、延迟递增策略以及详细的错误信息输出

核心理念鼓励：作者通过这个脚本展示了在自动化任务中如何优雅地处理可能发生的瞬时故障，体现了"幂等操作"和"可恢复性"这两个重要的设计思想。

可以改进的地方：

变量命名：$success和$attempt的命名不够清晰，可以改为更具有描述性的名字如$isSuccessful和$currentAttempt
错误处理：代码中只检查了LASTEXITCODE是否为0的情况，但其实LASTEXITCODE可能还有其他非零值需要处理
异常抛出方式：在catch块中使用Write-Error会导致脚本终止执行，可以改为使用throw语句或者自定义错误类型

建议的延申内容：

添加参数化支持，允许用户自定义重试次数和延迟基数
增加详细的注释说明每个部分的功能
添加对幂等性操作的解释和注意事项

总的来说，这篇文章提供了一个简洁而实用的解决方案，在可靠性编程方面做了很好的示范。

GPT-4

I just finished reading your blog post on implementing a retry mechanism in PowerShell. I find the content very useful, and I appreciate the simplicity of the approach you've presented. The core idea of using a loop to retry a potentially failing operation is a great way to ensure the task's completion without manual intervention.

The example you have provided, which uses the "ping" command, is a good illustration of a transient error that might benefit from a retry mechanism. I particularly like how you have used the $LASTEXITCODE variable to check for success or failure and the Start-Sleep command to introduce a delay between retries. This makes the script more resilient and adaptable to different situations.

However, I noticed a small issue in your script. The Start-Sleep -Seconds $(5 * $attempt) command might cause an excessive delay in later retries, as it increases the waiting time exponentially. Instead, you could consider using a fixed delay between retries or using an incremental delay (e.g., 5 seconds for the first retry, 10 seconds for the second, etc.) to avoid excessive waiting times.

In conclusion, your blog post provides a valuable and straightforward solution for implementing a retry mechanism in PowerShell. With some minor adjustments to the waiting time between retries, this script could become even more efficient and useful. Keep up the great work, and I look forward to reading more of your insightful blog posts in the future.

Anduin's Tech Blog