Azure EventGrid (Blob Created) Function output stream

Question

If I create an azure function Blob Trigger, I can define the both an input stream of the blob, and an output stream to which I would like to write some data, the signature being similar to below.

public async Task RunAsync(
            [BlobTrigger(BlobPath, Connection = "FileStorage")]
            Stream inputStream,
            [Blob(OutputBlobPath, FileAccess.Write, Connection = "FileStorage")]
            Stream outputStream,
            /* other fields removed for brevity */
            ) 
{ 
    /* ... */
}

Is it possible to define something similar when using an EventGrid trigger that fires for blob being created? ie

  public async Task RunAsync(
            [EventGridTrigger] EventGridEvent eventGridEvent, 
            [Blob("{data.url}", FileAccess.Read, Connection = "FileStorage")] Stream input,
/* is something like this possible -> */ [Blob(?, FileAccess.Write, Connection = "FileStorage")] Stream output)
        {
            /* ... */
        }

Answer 1

It's possible to bind to a CloudBlobContainer rather than a Stream for a blob, which provides the full storage API for blobs. It would look something like this:

public static async Task Run(
    [EventGridTrigger] EventGridEvent eventGridEvent,
    [Blob(/* container params */)] CloudBlobContainer blobContainer,
    ILogger log)
{
   // Use blobContainer to read/write blobs in container
}

From the Azure docs :

You can bind to the following types to write blobs:

TextWriter
out string
out Byte[]
CloudBlobStream
Stream
CloudBlobContainer
CloudBlobDirectory
ICloudBlob
CloudBlockBlob
CloudPageBlob
CloudAppendBlob

Answer 2

of course you can use output stream in EvenGrid Trigger Function. I test it locally. Firstly, I upload a blob named "input.txt" with the content "input". After run my function, I upload another blob (or delete another blob) to fire the trigger, then the content "input" is added to the blob named "test.txt".

Here is my code.

 [FunctionName("Function1")]
        public static async System.Threading.Tasks.Task RunAsync([EventGridTrigger] EventGridEvent eventGridEvent,
           [Blob("sample-items/input.txt", FileAccess.Read, Connection = "AzureWebJobsStorage")] Stream input,
           [Blob("sample-items/test.txt", FileAccess.Write, Connection = "AzureWebJobsStorage")] Stream output)
        {
            await input.CopyToAsync(output);
                    ......
         }