How can I get multiple blobs out of an Azure Function?

Question

I'm coding a C# function which is triggered by the upload of a blob. I would like to read another file in the container. How would the input binding bring the second blob?

public static async Task Run([BlobTrigger("csv/{name}.csv", Connection = "StorageConnectionAppSetting")]Stream myBlob, string name, ILogger log)

In addition to this question, how can I reference values from the local.settings.json in my code? I'm able to reference the "StorageConnectionAppSetting" on the input binding but I'm not sure how to do the same for portions of my code where I'm creating clients using APIKEYs.

Thanks!

Answer 1

1. A blob-trigger can be a single blob, but you can add an input binding to your function. In this case you can add an input binding to CloudBlobContainer by adding a reference to the storage SDK, and then read any blobs in that container. https://docs.microsoft.com/en-us/azure/azure-functions/functions-bindings-storage-blob-input?tabs=csharp#usage .

Another option would be not to use input binding and read the container and its contents the way you would normally do using storage SDK. You will need to add reference to Microsoft.Azure.Storage.Blob in both the cases.

2. For app settings you can use System.Environment.GetEnvironmentVariable("APIKEY"); , assuming APIKEY is your customer setting. Remember, local.settings.json will only be local and you will need to set these values in Azure either via Azure Portal or your CI/CD pipeline via and ARM template.

You can also use Azure functions dependency injection and inject configuration. Check the section Working with options and settings at https://docs.microsoft.com/en-us/azure/azure-functions/functions-dotnet-dependency-injection#working-with-options-and-settings