F# Blob Bindings with Azure Functions

function.json

{
  "bindings": [
    {
      "name": "inputBlob",
      "type": "blobTrigger",
      "direction": "in",
      "path": "samples-workitems/input/{name}",
      "connection": "AzureWebJobsDashboard"
    },
    {
      "type": "blob",
      "name": "output1",
      "path": "samples-workitems/output1/{name}",
      "connection": "AzureWebJobsDashboard",
      "direction": "out"
    },
    {
      "type": "blob",
      "name": "output2",
      "path": "samples-workitems/output2/{name}",
      "connection": "AzureWebJobsDashboard",
      "direction": "out"
    },
    {
      "type": "blob",
      "name": "output3",
      "path": "samples-workitems/output3/{name}",
      "connection": "AzureWebJobsDashboard",
      "direction": "out"
    },
    {
      "type": "blob",
      "name": "output4",
      "path": "samples-workitems/output4/{name}",
      "connection": "AzureWebJobsDashboard",
      "direction": "inout"
    },
    {
      "type": "blob",
      "name": "$return",
      "path": "samples-workitems/output5/{name}",
      "connection": "AzureWebJobsDashboard",
      "direction": "out"
    }
  ],
  "disabled": false
}

run.fsx

#r "Microsoft.WindowsAzure.Storage"

open System
open System.Configuration
open System.Text
open Microsoft.WindowsAzure.Storage
open Microsoft.WindowsAzure.Storage.Blob

// Note: Can't bind Blobs to pocos (in or out) at the moment Trigger to type 'Run+Person
// https://github.com/Azure/azure-webjobs-sdk/issues/901

[<CLIMutable>]
type Person = { First:string; Last:string }

let GetBlob (storageAcc:string) containerName blobName =
    let connString = ConfigurationManager.AppSettings.[storageAcc]
    let storageAccount = CloudStorageAccount.Parse(connString)
    let blobClient = storageAccount.CreateCloudBlobClient()
    let container = blobClient.GetContainerReference(containerName)
    container.GetBlockBlobReference(blobName)

let Run(inputBlob: Stream, 
        name: string, 
        log: TraceWriter, 
        output1: byref<string>, 
        output2: TextWriter,
        output3: Stream,
        output4: ICloudBlob) =

    let message = sprintf "Got blob \n FileName: %s \n Length: %d " name inputBlob.Length
    log.Verbose(message)
    
    // output1: string
    output1 <- message
    
    // output2: TextWriter 
    output2.WriteLine("Hello")
    output2.WriteLine("World")
    
    // output3: Stream
    let bytes = Encoding.UTF8.GetBytes("Using CloudBlockBlob directly")
    output3.Write(bytes, 0, bytes.Length)
    
    // output4: binding to ICloudBlob (could also be CloudBlockBlob)
    // have to edit function.json and set direction to "inout" for it to work 
    output4.Metadata.["From"] <- "Mark Heath"
    output4.SetMetadata();
    let bytes = Encoding.UTF8.GetBytes("inout binding to ICloudBlob")
    output4.UploadFromByteArrayAsync(bytes, 0, bytes.Length).Wait()
    
    // write directly with blob storage without using an output binding
    let cloudBlockBlob = GetBlob "AzureWebJobsDashboard" "samples-workitems" "outputdirect/test.txt" 
    let bytes2 = Encoding.UTF8.GetBytes("Using CloudBlockBlob directly")
    log.Verbose("uploading text...")
    cloudBlockBlob.UploadFromByteArrayAsync(bytes2, 0, bytes2.Length).Wait()
    log.Verbose("text uploaded")
    cloudBlockBlob.Metadata.["From"] <- "Mark Heath"
    cloudBlockBlob.SetMetadata();
    log.Verbose("metadata set")
    
    // output5 is $return, so let's return a string
    "Returning via $return"