The old Windows-only add-on referenced in original question has been pulled down. Take a look at the new cross-platform Splunk Add-on for Microsoft Azure which pulls data from Azure Storage API using Azure Storage Python SDK.
Among others, the Add-on leverages TableService and BlockBlobService which use core.windows.net endpoint for Azure cloud. You'll need to set endpoint_suffix to core.chinacloudapi.cn endpoint to access Azure China cloud instead.
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