问题描述

创建一个PowerShell脚本的Azure Function，触发方式为 Storage Queue。但执行函数结果一直失败 (Failed).

错误消息为：

Executed \’Functions.QueueTrigger1\’ (Failed, Id=…, Duration=30ms) The input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or an illegal character among the padding characters.

Funciton 代码：

# Input bindings are passed in via param block.param([string] $QueueItem, $TriggerMetadata)# Write out the queue message and metadata to the information log.Write-Host \"PowerShell queue trigger function processed work item: $QueueItem\"Write-Host \"Queue item expiration time: $($TriggerMetadata.ExpirationTime)\"Write-Host \"Queue item insertion time: $($TriggerMetadata.InsertionTime)\"Write-Host \"Queue item next visible time: $($TriggerMetadata.NextVisibleTime)\"Write-Host \"ID: $($TriggerMetadata.Id)\"Write-Host \"Pop receipt: $($TriggerMetadata.PopReceipt)\"Write-Host \"Dequeue count: $($TriggerMetadata.DequeueCount)\"

通过向Storage Queue中添加消息时候触发：

az storage message put --content \"This is a function test message\"

问题分析

根据错误消息，Function (Storage Queue）触发的消息需要 Base64编码，如发送\”This is a function test message\” 这段消息，需要在发送消息时候转换为base64编码。

在CMD中调用PowerShell进行类型转换：

powershell \"[convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes(\\\"This is a function test message\\\"))\"

在Powershell中直接转换：

[convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes(\"This is a function test message\"))

所以，修改后的向Storage Queue中添加消息的命令为：

$queuemsg = [convert]::ToBase64String([Text.Encoding]::UTF8.GetBytes(\"This is a function test message\"))az storage message put --content $queuemsg

参考资料

适用于 Azure Functions 的 Azure 队列存储触发器：https://docs.azure.cn/zh-cn/azure-functions/functions-bindings-storage-queue-trigger?tabs=powershell#encoding