Azure Storage for Downlink

The Downlink.AzureStorage library (bundled with Downlink) adds support for Azure Storage as a remote storage backend.

Activating the Azure Storage backend

Check the configuration guide for full details

You can quickly enable the Azure Storage backend by setting the Storage configuration key to "AzureStorage".

This will invoke the AddAzureStorage() method and add Azure Storage to your application.

Configuration

The Azure Storage backend requires two things be added to your app configuration (i.e. downlink.json or downlink.yml): the connection string used for your Azure Storage account, and the name of the container to retrieve from.

Connection String

{
  "ConnectionStrings": {
    "AzureStorage": "DefaultEndpointsProtocol=https;AccountName=storagesample;AccountKey=<account-key>+"
  },
}

ConnectionStrings :
  AzureStorage: 'DefaultEndpointsProtocol=https;AccountName=storagesample;AccountKey=<account-key>+'

Follow the instructions in the official documentation to get your connection string.

Container Name

{
    "AzureStorage": {
        "Container": "container-name-here"
    }
}

AzureStorage:
  Container: 'container-name-here'

How it works

Much like the S3 backend, the Azure Storage backend relies on hierarchical storage of app artifacts, and defaults to using the container-name/version/platform/architecture form. For example:

# Path inside container
/v1.2/windows/x64/myapp.msi

Will be resolved for the /v1.2/windows/x64 path. Note that this mode requires each "directory" to contain only one file (Downlink will just return the first file in the matching directory).

Alternate modes

You can also provide the MatchStrategy option under AzureStorage configuration to control the matching behaviour.

Using FlatVersion results in a request for /v1.2/windows/x64 being mapped to the /v1.2 directory in the container, and the first file with windows and x64 in the name will be returned. Likewise, FlatPlatform will use the same method for the first file in the /windows directory.

Finally the Flat strategy just matches all files in the top level of the container against all three properties, and is not recommended if at all possible.

The default behaviour can be specified using the Hierarchical strategy config

Force Name Matching

Set the AzureStorage/ForceNameMatching option to true to also force any matches to include the requested version in the file name. This is useful if you have more than one file in the target folder (such as metadata etc).